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<h1 class="titlefont">FFmpeg Codecs Documentation</h1>
<hr>
<a name="SEC_Top"></a>
<a name="SEC_Contents"></a>
<h1>Table of Contents</h1>
<div class="contents">
<ul class="no-bullet">
<li><a name="toc-Description" href="#Description">1 Description</a></li>
<li><a name="toc-Codec-Options" href="#Codec-Options">2 Codec Options</a></li>
<li><a name="toc-Decoders" href="#Decoders">3 Decoders</a></li>
<li><a name="toc-Video-Decoders" href="#Video-Decoders">4 Video Decoders</a>
<ul class="no-bullet">
<li><a name="toc-rawvideo" href="#rawvideo">4.1 rawvideo</a>
<ul class="no-bullet">
<li><a name="toc-Options-4" href="#Options-4">4.1.1 Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Audio-Decoders" href="#Audio-Decoders">5 Audio Decoders</a>
<ul class="no-bullet">
<li><a name="toc-ffwavesynth" href="#ffwavesynth">5.1 ffwavesynth</a></li>
</ul></li>
<li><a name="toc-Subtitles-Decoders" href="#Subtitles-Decoders">6 Subtitles Decoders</a>
<ul class="no-bullet">
<li><a name="toc-dvdsub" href="#dvdsub">6.1 dvdsub</a>
<ul class="no-bullet">
<li><a name="toc-Options-2" href="#Options-2">6.1.1 Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Encoders" href="#Encoders">7 Encoders</a></li>
<li><a name="toc-Audio-Encoders" href="#Audio-Encoders">8 Audio Encoders</a>
<ul class="no-bullet">
<li><a name="toc-ac3-and-ac3_005ffixed" href="#ac3-and-ac3_005ffixed">8.1 ac3 and ac3_fixed</a>
<ul class="no-bullet">
<li><a name="toc-AC_002d3-Metadata" href="#AC_002d3-Metadata">8.1.1 AC-3 Metadata</a>
<ul class="no-bullet">
<li><a name="toc-Metadata-Control-Options" href="#Metadata-Control-Options">8.1.1.1 Metadata Control Options</a></li>
<li><a name="toc-Downmix-Levels" href="#Downmix-Levels">8.1.1.2 Downmix Levels</a></li>
<li><a name="toc-Audio-Production-Information" href="#Audio-Production-Information">8.1.1.3 Audio Production Information</a></li>
<li><a name="toc-Other-Metadata-Options" href="#Other-Metadata-Options">8.1.1.4 Other Metadata Options</a></li>
</ul></li>
<li><a name="toc-Extended-Bitstream-Information" href="#Extended-Bitstream-Information">8.1.2 Extended Bitstream Information</a>
<ul class="no-bullet">
<li><a name="toc-Extended-Bitstream-Information-_002d-Part-1" href="#Extended-Bitstream-Information-_002d-Part-1">8.1.2.1 Extended Bitstream Information - Part 1</a></li>
<li><a name="toc-Extended-Bitstream-Information-_002d-Part-2" href="#Extended-Bitstream-Information-_002d-Part-2">8.1.2.2 Extended Bitstream Information - Part 2</a></li>
</ul></li>
<li><a name="toc-Other-AC_002d3-Encoding-Options" href="#Other-AC_002d3-Encoding-Options">8.1.3 Other AC-3 Encoding Options</a></li>
<li><a name="toc-Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options" href="#Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options">8.1.4 Floating-Point-Only AC-3 Encoding Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-Video-Encoders" href="#Video-Encoders">9 Video Encoders</a>
<ul class="no-bullet">
<li><a name="toc-libtheora" href="#libtheora">9.1 libtheora</a>
<ul class="no-bullet">
<li><a name="toc-Options" href="#Options">9.1.1 Options</a></li>
</ul></li>
<li><a name="toc-libvpx" href="#libvpx">9.2 libvpx</a>
<ul class="no-bullet">
<li><a name="toc-Options-3" href="#Options-3">9.2.1 Options</a></li>
</ul></li>
<li><a name="toc-libx264" href="#libx264">9.3 libx264</a>
<ul class="no-bullet">
<li><a name="toc-Options-1" href="#Options-1">9.3.1 Options</a></li>
</ul>
</li>
</ul></li>
<li><a name="toc-See-Also" href="#See-Also">10 See Also</a></li>
<li><a name="toc-Authors" href="#Authors">11 Authors</a></li>
</ul>
</div>
<hr size="6">
<a name="Description"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Description">1 Description</a></h1>
<p>This document describes the codecs (decoders and encoders) provided by
the libavcodec library.
</p>
<a name="Codec-Options"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Codec-Options">2 Codec Options</a></h1>
<p>libavcodec provides some generic global options, which can be set on
all the encoders and decoders. In addition each codec may support
so-called private options, which are specific for a given codec.
</p>
<p>Sometimes, a global option may only affect a specific kind of codec,
and may be unsensical or ignored by another, so you need to be aware
of the meaning of the specified options. Also some options are
meant only for decoding or encoding.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools, or by setting the value explicitly in the
<code>AVCodecContext</code> options or using the ‘<tt>libavutil/opt.h</tt>’ API
for programmatic use.
</p>
<p>The list of supported options follow:
</p>
<dl compact="compact">
<dt>‘<samp>b <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd><p>Set bitrate in bits/s. Default value is 200K.
</p>
</dd>
<dt>‘<samp>ab <var>integer</var> (<em>encoding,audio</em>)</samp>’</dt>
<dd><p>Set audio bitrate (in bits/s). Default value is 128K.
</p>
</dd>
<dt>‘<samp>bt <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
tolerance specifies how far ratecontrol is willing to deviate from the
target average bitrate value. This is not related to min/max
bitrate. Lowering tolerance too much has an adverse effect on quality.
</p>
</dd>
<dt>‘<samp>flags <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>’</dt>
<dd><p>Set generic flags.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>mv4</samp>’</dt>
<dd><p>Use four motion vector by macroblock (mpeg4).
</p></dd>
<dt>‘<samp>qpel</samp>’</dt>
<dd><p>Use 1/4 pel motion compensation.
</p></dd>
<dt>‘<samp>loop</samp>’</dt>
<dd><p>Use loop filter.
</p></dd>
<dt>‘<samp>qscale</samp>’</dt>
<dd><p>Use fixed qscale.
</p></dd>
<dt>‘<samp>gmc</samp>’</dt>
<dd><p>Use gmc.
</p></dd>
<dt>‘<samp>mv0</samp>’</dt>
<dd><p>Always try a mb with mv=<0,0>.
</p></dd>
<dt>‘<samp>input_preserved</samp>’</dt>
<dt>‘<samp>pass1</samp>’</dt>
<dd><p>Use internal 2pass ratecontrol in first pass mode.
</p></dd>
<dt>‘<samp>pass2</samp>’</dt>
<dd><p>Use internal 2pass ratecontrol in second pass mode.
</p></dd>
<dt>‘<samp>gray</samp>’</dt>
<dd><p>Only decode/encode grayscale.
</p></dd>
<dt>‘<samp>emu_edge</samp>’</dt>
<dd><p>Do not draw edges.
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>Set error[?] variables during encoding.
</p></dd>
<dt>‘<samp>truncated</samp>’</dt>
<dt>‘<samp>naq</samp>’</dt>
<dd><p>Normalize adaptive quantization.
</p></dd>
<dt>‘<samp>ildct</samp>’</dt>
<dd><p>Use interlaced DCT.
</p></dd>
<dt>‘<samp>low_delay</samp>’</dt>
<dd><p>Force low delay.
</p></dd>
<dt>‘<samp>global_header</samp>’</dt>
<dd><p>Place global headers in extradata instead of every keyframe.
</p></dd>
<dt>‘<samp>bitexact</samp>’</dt>
<dd><p>Use only bitexact stuff (except (I)DCT).
</p></dd>
<dt>‘<samp>aic</samp>’</dt>
<dd><p>Apply H263 advanced intra coding / mpeg4 ac prediction.
</p></dd>
<dt>‘<samp>cbp</samp>’</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p></dd>
<dt>‘<samp>qprd</samp>’</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p></dd>
<dt>‘<samp>ilme</samp>’</dt>
<dd><p>Apply interlaced motion estimation.
</p></dd>
<dt>‘<samp>cgop</samp>’</dt>
<dd><p>Use closed gop.
</p></dd>
</dl>
</dd>
<dt>‘<samp>sub_id <var>integer</var></samp>’</dt>
<dd><p>Deprecated, currently unused.
</p>
</dd>
<dt>‘<samp>me_method <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set motion estimation method.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>zero</samp>’</dt>
<dd><p>zero motion estimation (fastest)
</p></dd>
<dt>‘<samp>full</samp>’</dt>
<dd><p>full motion estimation (slowest)
</p></dd>
<dt>‘<samp>epzs</samp>’</dt>
<dd><p>EPZS motion estimation (default)
</p></dd>
<dt>‘<samp>esa</samp>’</dt>
<dd><p>esa motion estimation (alias for full)
</p></dd>
<dt>‘<samp>tesa</samp>’</dt>
<dd><p>tesa motion estimation
</p></dd>
<dt>‘<samp>dia</samp>’</dt>
<dd><p>dia motion estimation (alias for epzs)
</p></dd>
<dt>‘<samp>log</samp>’</dt>
<dd><p>log motion estimation
</p></dd>
<dt>‘<samp>phods</samp>’</dt>
<dd><p>phods motion estimation
</p></dd>
<dt>‘<samp>x1</samp>’</dt>
<dd><p>X1 motion estimation
</p></dd>
<dt>‘<samp>hex</samp>’</dt>
<dd><p>hex motion estimation
</p></dd>
<dt>‘<samp>umh</samp>’</dt>
<dd><p>umh motion estimation
</p></dd>
<dt>‘<samp>iter</samp>’</dt>
<dd><p>iter motion estimation
</p></dd>
</dl>
</dd>
<dt>‘<samp>extradata_size <var>integer</var></samp>’</dt>
<dd><p>Set extradata size.
</p>
</dd>
<dt>‘<samp>time_base <var>rational number</var></samp>’</dt>
<dd><p>Set codec time base.
</p>
<p>It is the fundamental unit of time (in seconds) in terms of which
frame timestamps are represented. For fixed-fps content, timebase
should be 1/framerate and timestamp increments should be identically
1.
</p>
</dd>
<dt>‘<samp>g <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set the group of picture size. Default value is 12.
</p>
</dd>
<dt>‘<samp>ar <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>’</dt>
<dd><p>Set audio sampling rate (in Hz).
</p>
</dd>
<dt>‘<samp>ac <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>’</dt>
<dd><p>Set number of audio channels.
</p>
</dd>
<dt>‘<samp>cutoff <var>integer</var> (<em>encoding,audio</em>)</samp>’</dt>
<dd><p>Set cutoff bandwidth.
</p>
</dd>
<dt>‘<samp>frame_size <var>integer</var> (<em>encoding,audio</em>)</samp>’</dt>
<dd><p>Set audio frame size.
</p>
<p>Each submitted frame except the last must contain exactly frame_size
samples per channel. May be 0 when the codec has
CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not
restricted. It is set by some decoders to indicate constant frame
size.
</p>
</dd>
<dt>‘<samp>frame_number <var>integer</var></samp>’</dt>
<dd><p>Set the frame number.
</p>
</dd>
<dt>‘<samp>delay <var>integer</var></samp>’</dt>
<dt>‘<samp>qcomp <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set video quantizer scale compression (VBR). It is used as a constant
in the ratecontrol equation. Recommended range for default rc_eq:
0.0-1.0.
</p>
</dd>
<dt>‘<samp>qblur <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set video quantizer scale blur (VBR).
</p>
</dd>
<dt>‘<samp>qmin <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set min video quantizer scale (VBR). Must be included between -1 and
69, default value is 2.
</p>
</dd>
<dt>‘<samp>qmax <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set max video quantizer scale (VBR). Must be included between -1 and
1024, default value is 31.
</p>
</dd>
<dt>‘<samp>qdiff <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set max difference between the quantizer scale (VBR).
</p>
</dd>
<dt>‘<samp>bf <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set max number of B frames.
</p>
</dd>
<dt>‘<samp>b_qfactor <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set qp factor between P and B frames.
</p>
</dd>
<dt>‘<samp>rc_strategy <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set ratecontrol method.
</p>
</dd>
<dt>‘<samp>b_strategy <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set strategy to choose between I/P/B-frames.
</p>
</dd>
<dt>‘<samp>ps <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set RTP payload size in bytes.
</p>
</dd>
<dt>‘<samp>mv_bits <var>integer</var></samp>’</dt>
<dt>‘<samp>header_bits <var>integer</var></samp>’</dt>
<dt>‘<samp>i_tex_bits <var>integer</var></samp>’</dt>
<dt>‘<samp>p_tex_bits <var>integer</var></samp>’</dt>
<dt>‘<samp>i_count <var>integer</var></samp>’</dt>
<dt>‘<samp>p_count <var>integer</var></samp>’</dt>
<dt>‘<samp>skip_count <var>integer</var></samp>’</dt>
<dt>‘<samp>misc_bits <var>integer</var></samp>’</dt>
<dt>‘<samp>frame_bits <var>integer</var></samp>’</dt>
<dt>‘<samp>codec_tag <var>integer</var></samp>’</dt>
<dt>‘<samp>bug <var>flags</var> (<em>decoding,video</em>)</samp>’</dt>
<dd><p>Workaround not auto detected encoder bugs.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>autodetect</samp>’</dt>
<dt>‘<samp>old_msmpeg4</samp>’</dt>
<dd><p>some old lavc generated msmpeg4v3 files (no autodetection)
</p></dd>
<dt>‘<samp>xvid_ilace</samp>’</dt>
<dd><p>Xvid interlacing bug (autodetected if fourcc==XVIX)
</p></dd>
<dt>‘<samp>ump4</samp>’</dt>
<dd><p>(autodetected if fourcc==UMP4)
</p></dd>
<dt>‘<samp>no_padding</samp>’</dt>
<dd><p>padding bug (autodetected)
</p></dd>
<dt>‘<samp>amv</samp>’</dt>
<dt>‘<samp>ac_vlc</samp>’</dt>
<dd><p>illegal vlc bug (autodetected per fourcc)
</p></dd>
<dt>‘<samp>qpel_chroma</samp>’</dt>
<dt>‘<samp>std_qpel</samp>’</dt>
<dd><p>old standard qpel (autodetected per fourcc/version)
</p></dd>
<dt>‘<samp>qpel_chroma2</samp>’</dt>
<dt>‘<samp>direct_blocksize</samp>’</dt>
<dd><p>direct-qpel-blocksize bug (autodetected per fourcc/version)
</p></dd>
<dt>‘<samp>edge</samp>’</dt>
<dd><p>edge padding bug (autodetected per fourcc/version)
</p></dd>
<dt>‘<samp>hpel_chroma</samp>’</dt>
<dt>‘<samp>dc_clip</samp>’</dt>
<dt>‘<samp>ms</samp>’</dt>
<dd><p>Workaround various bugs in microsoft broken decoders.
</p></dd>
<dt>‘<samp>trunc</samp>’</dt>
<dd><p>trancated frames
</p></dd>
</dl>
</dd>
<dt>‘<samp>lelim <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set single coefficient elimination threshold for luminance (negative
values also consider DC coefficient).
</p>
</dd>
<dt>‘<samp>celim <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set single coefficient elimination threshold for chrominance (negative
values also consider dc coefficient)
</p>
</dd>
<dt>‘<samp>strict <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp>’</dt>
<dd><p>Specify how strictly to follow the standards.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>very</samp>’</dt>
<dd><p>strictly conform to a older more strict version of the spec or reference software
</p></dd>
<dt>‘<samp>strict</samp>’</dt>
<dd><p>strictly conform to all the things in the spec no matter what consequences
</p></dd>
<dt>‘<samp>normal</samp>’</dt>
<dt>‘<samp>unofficial</samp>’</dt>
<dd><p>allow unofficial extensions
</p></dd>
<dt>‘<samp>experimental</samp>’</dt>
<dd><p>allow non standardized experimental things
</p></dd>
</dl>
</dd>
<dt>‘<samp>b_qoffset <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set QP offset between P and B frames.
</p>
</dd>
<dt>‘<samp>err_detect <var>flags</var> (<em>decoding,audio,video</em>)</samp>’</dt>
<dd><p>Set error detection flags.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>crccheck</samp>’</dt>
<dd><p>verify embedded CRCs
</p></dd>
<dt>‘<samp>bitstream</samp>’</dt>
<dd><p>detect bitstream specification deviations
</p></dd>
<dt>‘<samp>buffer</samp>’</dt>
<dd><p>detect improper bitstream length
</p></dd>
<dt>‘<samp>explode</samp>’</dt>
<dd><p>abort decoding on minor error detection
</p></dd>
<dt>‘<samp>careful</samp>’</dt>
<dd><p>consider things that violate the spec and have not been seen in the wild as errors
</p></dd>
<dt>‘<samp>compliant</samp>’</dt>
<dd><p>consider all spec non compliancies as errors
</p></dd>
<dt>‘<samp>aggressive</samp>’</dt>
<dd><p>consider things that a sane encoder should not do as an error
</p></dd>
</dl>
</dd>
<dt>‘<samp>has_b_frames <var>integer</var></samp>’</dt>
<dt>‘<samp>block_align <var>integer</var></samp>’</dt>
<dt>‘<samp>mpeg_quant <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Use MPEG quantizers instead of H.263.
</p>
</dd>
<dt>‘<samp>qsquish <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>How to keep quantizer between qmin and qmax (0 = clip, 1 = use
differentiable function).
</p>
</dd>
<dt>‘<samp>rc_qmod_amp <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set experimental quantizer modulation.
</p>
</dd>
<dt>‘<samp>rc_qmod_freq <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set experimental quantizer modulation.
</p>
</dd>
<dt>‘<samp>rc_override_count <var>integer</var></samp>’</dt>
<dt>‘<samp>rc_eq <var>string</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set rate control equation. When computing the expression, besides the
standard functions defined in the section ’Expression Evaluation’, the
following functions are available: bits2qp(bits), qp2bits(qp). Also
the following constants are available: iTex pTex tex mv fCode iCount
mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex
avgTex.
</p>
</dd>
<dt>‘<samp>maxrate <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd><p>Set max bitrate tolerance (in bits/s). Requires bufsize to be set.
</p>
</dd>
<dt>‘<samp>minrate <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd><p>Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR
encode. It is of little use elsewise.
</p>
</dd>
<dt>‘<samp>bufsize <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd><p>Set ratecontrol buffer size (in bits).
</p>
</dd>
<dt>‘<samp>rc_buf_aggressivity <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Currently useless.
</p>
</dd>
<dt>‘<samp>i_qfactor <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set QP factor between P and I frames.
</p>
</dd>
<dt>‘<samp>i_qoffset <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set QP offset between P and I frames.
</p>
</dd>
<dt>‘<samp>rc_init_cplx <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set initial complexity for 1-pass encoding.
</p>
</dd>
<dt>‘<samp>dct <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set DCT algorithm.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>auto</samp>’</dt>
<dd><p>autoselect a good one (default)
</p></dd>
<dt>‘<samp>fastint</samp>’</dt>
<dd><p>fast integer
</p></dd>
<dt>‘<samp>int</samp>’</dt>
<dd><p>accurate integer
</p></dd>
<dt>‘<samp>mmx</samp>’</dt>
<dt>‘<samp>altivec</samp>’</dt>
<dt>‘<samp>faan</samp>’</dt>
<dd><p>floating point AAN DCT
</p></dd>
</dl>
</dd>
<dt>‘<samp>lumi_mask <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Compress bright areas stronger than medium ones.
</p>
</dd>
<dt>‘<samp>tcplx_mask <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set temporal complexity masking.
</p>
</dd>
<dt>‘<samp>scplx_mask <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set spatial complexity masking.
</p>
</dd>
<dt>‘<samp>p_mask <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set inter masking.
</p>
</dd>
<dt>‘<samp>dark_mask <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Compress dark areas stronger than medium ones.
</p>
</dd>
<dt>‘<samp>idct <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dd><p>Select IDCT implementation.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>auto</samp>’</dt>
<dt>‘<samp>int</samp>’</dt>
<dt>‘<samp>simple</samp>’</dt>
<dt>‘<samp>simplemmx</samp>’</dt>
<dt>‘<samp>libmpeg2mmx</samp>’</dt>
<dt>‘<samp>mmi</samp>’</dt>
<dt>‘<samp>arm</samp>’</dt>
<dt>‘<samp>altivec</samp>’</dt>
<dt>‘<samp>sh4</samp>’</dt>
<dt>‘<samp>simplearm</samp>’</dt>
<dt>‘<samp>simplearmv5te</samp>’</dt>
<dt>‘<samp>simplearmv6</samp>’</dt>
<dt>‘<samp>simpleneon</samp>’</dt>
<dt>‘<samp>simplealpha</samp>’</dt>
<dt>‘<samp>h264</samp>’</dt>
<dt>‘<samp>vp3</samp>’</dt>
<dt>‘<samp>ipp</samp>’</dt>
<dt>‘<samp>xvidmmx</samp>’</dt>
<dt>‘<samp>faani</samp>’</dt>
<dd><p>floating point AAN IDCT
</p></dd>
</dl>
</dd>
<dt>‘<samp>slice_count <var>integer</var></samp>’</dt>
<dt>‘<samp>ec <var>flags</var> (<em>decoding,video</em>)</samp>’</dt>
<dd><p>Set error concealment strategy.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>guess_mvs</samp>’</dt>
<dd><p>iterative motion vector (MV) search (slow)
</p></dd>
<dt>‘<samp>deblock</samp>’</dt>
<dd><p>use strong deblock filter for damaged MBs
</p></dd>
</dl>
</dd>
<dt>‘<samp>bits_per_coded_sample <var>integer</var></samp>’</dt>
<dt>‘<samp>pred <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set prediction method.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>left</samp>’</dt>
<dt>‘<samp>plane</samp>’</dt>
<dt>‘<samp>median</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>aspect <var>rational number</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set sample aspect ratio.
</p>
</dd>
<dt>‘<samp>debug <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>’</dt>
<dd><p>Print specific debug info.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>pict</samp>’</dt>
<dd><p>picture info
</p></dd>
<dt>‘<samp>rc</samp>’</dt>
<dd><p>rate control
</p></dd>
<dt>‘<samp>bitstream</samp>’</dt>
<dt>‘<samp>mb_type</samp>’</dt>
<dd><p>macroblock (MB) type
</p></dd>
<dt>‘<samp>qp</samp>’</dt>
<dd><p>per-block quantization parameter (QP)
</p></dd>
<dt>‘<samp>mv</samp>’</dt>
<dd><p>motion vector
</p></dd>
<dt>‘<samp>dct_coeff</samp>’</dt>
<dt>‘<samp>skip</samp>’</dt>
<dt>‘<samp>startcode</samp>’</dt>
<dt>‘<samp>pts</samp>’</dt>
<dt>‘<samp>er</samp>’</dt>
<dd><p>error recognition
</p></dd>
<dt>‘<samp>mmco</samp>’</dt>
<dd><p>memory management control operations (H.264)
</p></dd>
<dt>‘<samp>bugs</samp>’</dt>
<dt>‘<samp>vis_qp</samp>’</dt>
<dd><p>visualize quantization parameter (QP), lower QP are tinted greener
</p></dd>
<dt>‘<samp>vis_mb_type</samp>’</dt>
<dd><p>visualize block types
</p></dd>
<dt>‘<samp>buffers</samp>’</dt>
<dd><p>picture buffer allocations
</p></dd>
<dt>‘<samp>thread_ops</samp>’</dt>
<dd><p>threading operations
</p></dd>
</dl>
</dd>
<dt>‘<samp>vismv <var>integer</var> (<em>decoding,video</em>)</samp>’</dt>
<dd><p>Visualize motion vectors (MVs).
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>pf</samp>’</dt>
<dd><p>forward predicted MVs of P-frames
</p></dd>
<dt>‘<samp>bf</samp>’</dt>
<dd><p>forward predicted MVs of B-frames
</p></dd>
<dt>‘<samp>bb</samp>’</dt>
<dd><p>backward predicted MVs of B-frames
</p></dd>
</dl>
</dd>
<dt>‘<samp>cmp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set full pel me compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>sad</samp>’</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt>‘<samp>sse</samp>’</dt>
<dd><p>sum of squared errors
</p></dd>
<dt>‘<samp>satd</samp>’</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt>‘<samp>dct</samp>’</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt>‘<samp>bit</samp>’</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt>‘<samp>zero</samp>’</dt>
<dd><p>0
</p></dd>
<dt>‘<samp>vsad</samp>’</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt>‘<samp>vsse</samp>’</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt>‘<samp>nsse</samp>’</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt>‘<samp>w53</samp>’</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt>‘<samp>w97</samp>’</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt>‘<samp>dctmax</samp>’</dt>
<dt>‘<samp>chroma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>subcmp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set sub pel me compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>sad</samp>’</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt>‘<samp>sse</samp>’</dt>
<dd><p>sum of squared errors
</p></dd>
<dt>‘<samp>satd</samp>’</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt>‘<samp>dct</samp>’</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt>‘<samp>bit</samp>’</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt>‘<samp>zero</samp>’</dt>
<dd><p>0
</p></dd>
<dt>‘<samp>vsad</samp>’</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt>‘<samp>vsse</samp>’</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt>‘<samp>nsse</samp>’</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt>‘<samp>w53</samp>’</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt>‘<samp>w97</samp>’</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt>‘<samp>dctmax</samp>’</dt>
<dt>‘<samp>chroma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>mbcmp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set macroblock compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>sad</samp>’</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt>‘<samp>sse</samp>’</dt>
<dd><p>sum of squared errors
</p></dd>
<dt>‘<samp>satd</samp>’</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt>‘<samp>dct</samp>’</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt>‘<samp>bit</samp>’</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt>‘<samp>zero</samp>’</dt>
<dd><p>0
</p></dd>
<dt>‘<samp>vsad</samp>’</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt>‘<samp>vsse</samp>’</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt>‘<samp>nsse</samp>’</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt>‘<samp>w53</samp>’</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt>‘<samp>w97</samp>’</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt>‘<samp>dctmax</samp>’</dt>
<dt>‘<samp>chroma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>ildctcmp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set interlaced dct compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>sad</samp>’</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt>‘<samp>sse</samp>’</dt>
<dd><p>sum of squared errors
</p></dd>
<dt>‘<samp>satd</samp>’</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt>‘<samp>dct</samp>’</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt>‘<samp>bit</samp>’</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt>‘<samp>zero</samp>’</dt>
<dd><p>0
</p></dd>
<dt>‘<samp>vsad</samp>’</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt>‘<samp>vsse</samp>’</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt>‘<samp>nsse</samp>’</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt>‘<samp>w53</samp>’</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt>‘<samp>w97</samp>’</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt>‘<samp>dctmax</samp>’</dt>
<dt>‘<samp>chroma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>dia_size <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set diamond type & size for motion estimation.
</p>
</dd>
<dt>‘<samp>last_pred <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set amount of motion predictors from the previous frame.
</p>
</dd>
<dt>‘<samp>preme <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set pre motion estimation.
</p>
</dd>
<dt>‘<samp>precmp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set pre motion estimation compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>sad</samp>’</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt>‘<samp>sse</samp>’</dt>
<dd><p>sum of squared errors
</p></dd>
<dt>‘<samp>satd</samp>’</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt>‘<samp>dct</samp>’</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt>‘<samp>bit</samp>’</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt>‘<samp>zero</samp>’</dt>
<dd><p>0
</p></dd>
<dt>‘<samp>vsad</samp>’</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt>‘<samp>vsse</samp>’</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt>‘<samp>nsse</samp>’</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt>‘<samp>w53</samp>’</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt>‘<samp>w97</samp>’</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt>‘<samp>dctmax</samp>’</dt>
<dt>‘<samp>chroma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>pre_dia_size <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set diamond type & size for motion estimation pre-pass.
</p>
</dd>
<dt>‘<samp>subq <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set sub pel motion estimation quality.
</p>
</dd>
<dt>‘<samp>dtg_active_format <var>integer</var></samp>’</dt>
<dt>‘<samp>me_range <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set limit motion vectors range (1023 for DivX player).
</p>
</dd>
<dt>‘<samp>ibias <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set intra quant bias.
</p>
</dd>
<dt>‘<samp>pbias <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set inter quant bias.
</p>
</dd>
<dt>‘<samp>color_table_id <var>integer</var></samp>’</dt>
<dt>‘<samp>global_quality <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dt>‘<samp>coder <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>vlc</samp>’</dt>
<dd><p>variable length coder / huffman coder
</p></dd>
<dt>‘<samp>ac</samp>’</dt>
<dd><p>arithmetic coder
</p></dd>
<dt>‘<samp>raw</samp>’</dt>
<dd><p>raw (no encoding)
</p></dd>
<dt>‘<samp>rle</samp>’</dt>
<dd><p>run-length coder
</p></dd>
<dt>‘<samp>deflate</samp>’</dt>
<dd><p>deflate-based coder
</p></dd>
</dl>
</dd>
<dt>‘<samp>context <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set context model.
</p>
</dd>
<dt>‘<samp>slice_flags <var>integer</var></samp>’</dt>
<dt>‘<samp>xvmc_acceleration <var>integer</var></samp>’</dt>
<dt>‘<samp>mbd <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set macroblock decision algorithm (high quality mode).
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>simple</samp>’</dt>
<dd><p>use mbcmp (default)
</p></dd>
<dt>‘<samp>bits</samp>’</dt>
<dd><p>use fewest bits
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>use best rate distortion
</p></dd>
</dl>
</dd>
<dt>‘<samp>stream_codec_tag <var>integer</var></samp>’</dt>
<dt>‘<samp>sc_threshold <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set scene change threshold.
</p>
</dd>
<dt>‘<samp>lmin <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set min lagrange factor (VBR).
</p>
</dd>
<dt>‘<samp>lmax <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set max lagrange factor (VBR).
</p>
</dd>
<dt>‘<samp>nr <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set noise reduction.
</p>
</dd>
<dt>‘<samp>rc_init_occupancy <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set number of bits which should be loaded into the rc buffer before
decoding starts.
</p>
</dd>
<dt>‘<samp>inter_threshold <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dt>‘<samp>flags2 <var>flags</var> (<em>decoding/encoding,audio,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>fast</samp>’</dt>
<dd><p>allow non spec compliant speedup tricks
</p></dd>
<dt>‘<samp>sgop</samp>’</dt>
<dd><p>Deprecated, use mpegvideo private options instead
</p></dd>
<dt>‘<samp>noout</samp>’</dt>
<dd><p>skip bitstream encoding
</p></dd>
<dt>‘<samp>local_header</samp>’</dt>
<dd><p>place global headers at every keyframe instead of in extradata
</p></dd>
<dt>‘<samp>chunks</samp>’</dt>
<dd><p>Frame data might be split into multiple chunks
</p></dd>
<dt>‘<samp>showall</samp>’</dt>
<dd><p>Show all frames before the first keyframe
</p></dd>
<dt>‘<samp>skiprd</samp>’</dt>
<dd><p>Deprecated, use mpegvideo private options instead
</p></dd>
</dl>
</dd>
<dt>‘<samp>error <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dt>‘<samp>qns <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Deprecated, use mpegvideo private options instead.
</p>
</dd>
<dt>‘<samp>threads <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>auto</samp>’</dt>
<dd><p>detect a good number of threads
</p></dd>
</dl>
</dd>
<dt>‘<samp>me_threshold <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set motion estimation threshold.
</p>
</dd>
<dt>‘<samp>mb_threshold <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set macroblock threshold.
</p>
</dd>
<dt>‘<samp>dc <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set intra_dc_precision.
</p>
</dd>
<dt>‘<samp>nssew <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set nsse weight.
</p>
</dd>
<dt>‘<samp>skip_top <var>integer</var> (<em>decoding,video</em>)</samp>’</dt>
<dd><p>Set number of macroblock rows at the top which are skipped.
</p>
</dd>
<dt>‘<samp>skip_bottom <var>integer</var> (<em>decoding,video</em>)</samp>’</dt>
<dd><p>Set number of macroblock rows at the bottom which are skipped.
</p>
</dd>
<dt>‘<samp>profile <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>unknown</samp>’</dt>
<dt>‘<samp>aac_main</samp>’</dt>
<dt>‘<samp>aac_low</samp>’</dt>
<dt>‘<samp>aac_ssr</samp>’</dt>
<dt>‘<samp>aac_ltp</samp>’</dt>
<dt>‘<samp>aac_he</samp>’</dt>
<dt>‘<samp>aac_he_v2</samp>’</dt>
<dt>‘<samp>aac_ld</samp>’</dt>
<dt>‘<samp>aac_eld</samp>’</dt>
<dt>‘<samp>dts</samp>’</dt>
<dt>‘<samp>dts_es</samp>’</dt>
<dt>‘<samp>dts_96_24</samp>’</dt>
<dt>‘<samp>dts_hd_hra</samp>’</dt>
<dt>‘<samp>dts_hd_ma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>level <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>unknown</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>lowres <var>integer</var> (<em>decoding,audio,video</em>)</samp>’</dt>
<dd><p>Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.
</p>
</dd>
<dt>‘<samp>skip_threshold <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set frame skip threshold.
</p>
</dd>
<dt>‘<samp>skip_factor <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set frame skip factor.
</p>
</dd>
<dt>‘<samp>skip_exp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set frame skip exponent.
</p>
</dd>
<dt>‘<samp>skipcmp <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set frame skip compare function.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>sad</samp>’</dt>
<dd><p>sum of absolute differences, fast (default)
</p></dd>
<dt>‘<samp>sse</samp>’</dt>
<dd><p>sum of squared errors
</p></dd>
<dt>‘<samp>satd</samp>’</dt>
<dd><p>sum of absolute Hadamard transformed differences
</p></dd>
<dt>‘<samp>dct</samp>’</dt>
<dd><p>sum of absolute DCT transformed differences
</p></dd>
<dt>‘<samp>psnr</samp>’</dt>
<dd><p>sum of squared quantization errors (avoid, low quality)
</p></dd>
<dt>‘<samp>bit</samp>’</dt>
<dd><p>number of bits needed for the block
</p></dd>
<dt>‘<samp>rd</samp>’</dt>
<dd><p>rate distortion optimal, slow
</p></dd>
<dt>‘<samp>zero</samp>’</dt>
<dd><p>0
</p></dd>
<dt>‘<samp>vsad</samp>’</dt>
<dd><p>sum of absolute vertical differences
</p></dd>
<dt>‘<samp>vsse</samp>’</dt>
<dd><p>sum of squared vertical differences
</p></dd>
<dt>‘<samp>nsse</samp>’</dt>
<dd><p>noise preserving sum of squared differences
</p></dd>
<dt>‘<samp>w53</samp>’</dt>
<dd><p>5/3 wavelet, only used in snow
</p></dd>
<dt>‘<samp>w97</samp>’</dt>
<dd><p>9/7 wavelet, only used in snow
</p></dd>
<dt>‘<samp>dctmax</samp>’</dt>
<dt>‘<samp>chroma</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>border_mask <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Increase the quantizer for macroblocks close to borders.
</p>
</dd>
<dt>‘<samp>mblmin <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set min macroblock lagrange factor (VBR).
</p>
</dd>
<dt>‘<samp>mblmax <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set max macroblock lagrange factor (VBR).
</p>
</dd>
<dt>‘<samp>mepc <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set motion estimation bitrate penalty compensation (1.0 = 256).
</p>
</dd>
<dt>‘<samp>skip_loop_filter <var>integer</var> (<em>decoding,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>none</samp>’</dt>
<dt>‘<samp>default</samp>’</dt>
<dt>‘<samp>noref</samp>’</dt>
<dt>‘<samp>bidir</samp>’</dt>
<dt>‘<samp>nokey</samp>’</dt>
<dt>‘<samp>all</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>skip_idct <var>integer</var> (<em>decoding,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>none</samp>’</dt>
<dt>‘<samp>default</samp>’</dt>
<dt>‘<samp>noref</samp>’</dt>
<dt>‘<samp>bidir</samp>’</dt>
<dt>‘<samp>nokey</samp>’</dt>
<dt>‘<samp>all</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>skip_frame <var>integer</var> (<em>decoding,video</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>none</samp>’</dt>
<dt>‘<samp>default</samp>’</dt>
<dt>‘<samp>noref</samp>’</dt>
<dt>‘<samp>bidir</samp>’</dt>
<dt>‘<samp>nokey</samp>’</dt>
<dt>‘<samp>all</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>bidir_refine <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Refine the two motion vectors used in bidirectional macroblocks.
</p>
</dd>
<dt>‘<samp>brd_scale <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Downscale frames for dynamic B-frame decision.
</p>
</dd>
<dt>‘<samp>keyint_min <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set minimum interval between IDR-frames.
</p>
</dd>
<dt>‘<samp>refs <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set reference frames to consider for motion compensation.
</p>
</dd>
<dt>‘<samp>chromaoffset <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set chroma qp offset from luma.
</p>
</dd>
<dt>‘<samp>trellis <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dd><p>Set rate-distortion optimal quantization.
</p>
</dd>
<dt>‘<samp>sc_factor <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set value multiplied by qscale for each frame and added to
scene_change_score.
</p>
</dd>
<dt>‘<samp>mv0_threshold <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dt>‘<samp>b_sensitivity <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Adjust sensitivity of b_frame_strategy 1.
</p>
</dd>
<dt>‘<samp>compression_level <var>integer</var> (<em>encoding,audio,video</em>)</samp>’</dt>
<dt>‘<samp>min_prediction_order <var>integer</var> (<em>encoding,audio</em>)</samp>’</dt>
<dt>‘<samp>max_prediction_order <var>integer</var> (<em>encoding,audio</em>)</samp>’</dt>
<dt>‘<samp>timecode_frame_start <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Set GOP timecode frame start number, in non drop frame format.
</p>
</dd>
<dt>‘<samp>request_channels <var>integer</var> (<em>decoding,audio</em>)</samp>’</dt>
<dd><p>Set desired number of audio channels.
</p>
</dd>
<dt>‘<samp>bits_per_raw_sample <var>integer</var></samp>’</dt>
<dt>‘<samp>channel_layout <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p></dd>
<dt>‘<samp>request_channel_layout <var>integer</var> (<em>decoding,audio</em>)</samp>’</dt>
<dd>
<p>Possible values:
</p></dd>
<dt>‘<samp>rc_max_vbv_use <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dt>‘<samp>rc_min_vbv_use <var>float</var> (<em>encoding,video</em>)</samp>’</dt>
<dt>‘<samp>ticks_per_frame <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp>’</dt>
<dt>‘<samp>color_primaries <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dt>‘<samp>color_trc <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dt>‘<samp>colorspace <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dt>‘<samp>color_range <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dt>‘<samp>chroma_sample_location <var>integer</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dt>‘<samp>log_level_offset <var>integer</var></samp>’</dt>
<dd><p>Set the log level offset.
</p>
</dd>
<dt>‘<samp>slices <var>integer</var> (<em>encoding,video</em>)</samp>’</dt>
<dd><p>Number of slices, used in parallelized encoding.
</p>
</dd>
<dt>‘<samp>thread_type <var>flags</var> (<em>decoding/encoding,video</em>)</samp>’</dt>
<dd><p>Select multithreading type.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>slice</samp>’</dt>
<dt>‘<samp>frame</samp>’</dt>
</dl>
</dd>
<dt>‘<samp>audio_service_type <var>integer</var> (<em>encoding,audio</em>)</samp>’</dt>
<dd><p>Set audio service type.
</p>
<p>Possible values:
</p><dl compact="compact">
<dt>‘<samp>ma</samp>’</dt>
<dd><p>Main Audio Service
</p></dd>
<dt>‘<samp>ef</samp>’</dt>
<dd><p>Effects
</p></dd>
<dt>‘<samp>vi</samp>’</dt>
<dd><p>Visually Impaired
</p></dd>
<dt>‘<samp>hi</samp>’</dt>
<dd><p>Hearing Impaired
</p></dd>
<dt>‘<samp>di</samp>’</dt>
<dd><p>Dialogue
</p></dd>
<dt>‘<samp>co</samp>’</dt>
<dd><p>Commentary
</p></dd>
<dt>‘<samp>em</samp>’</dt>
<dd><p>Emergency
</p></dd>
<dt>‘<samp>vo</samp>’</dt>
<dd><p>Voice Over
</p></dd>
<dt>‘<samp>ka</samp>’</dt>
<dd><p>Karaoke
</p></dd>
</dl>
</dd>
<dt>‘<samp>request_sample_fmt <var>sample_fmt</var> (<em>decoding,audio</em>)</samp>’</dt>
<dd><p>Set sample format audio decoders should prefer. Default value is
<code>none</code>.
</p>
</dd>
<dt>‘<samp>pkt_timebase <var>rational number</var></samp>’</dt>
</dl>
<a name="Decoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Decoders">3 Decoders</a></h1>
<p>Decoders are configured elements in FFmpeg which allow the decoding of
multimedia streams.
</p>
<p>When you configure your FFmpeg build, all the supported native decoders
are enabled by default. Decoders requiring an external library must be enabled
manually via the corresponding <code>--enable-lib</code> option. You can list all
available decoders using the configure option <code>--list-decoders</code>.
</p>
<p>You can disable all the decoders with the configure option
<code>--disable-decoders</code> and selectively enable / disable single decoders
with the options <code>--enable-decoder=<var>DECODER</var></code> /
<code>--disable-decoder=<var>DECODER</var></code>.
</p>
<p>The option <code>-codecs</code> of the ff* tools will display the list of
enabled decoders.
</p>
<a name="Video-Decoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Video-Decoders">4 Video Decoders</a></h1>
<p>A description of some of the currently available video decoders
follows.
</p>
<a name="rawvideo"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-rawvideo">4.1 rawvideo</a></h2>
<p>Raw video decoder.
</p>
<p>This decoder decodes rawvideo streams.
</p>
<a name="Options-4"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-4">4.1.1 Options</a></h3>
<dl compact="compact">
<dt>‘<samp>top <var>top_field_first</var></samp>’</dt>
<dd><p>Specify the assumed field type of the input video.
</p><dl compact="compact">
<dt>‘<samp>-1</samp>’</dt>
<dd><p>the video is assumed to be progressive (default)
</p></dd>
<dt>‘<samp>0</samp>’</dt>
<dd><p>bottom-field-first is assumed
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dd><p>top-field-first is assumed
</p></dd>
</dl>
</dd>
</dl>
<a name="Audio-Decoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Audio-Decoders">5 Audio Decoders</a></h1>
<a name="ffwavesynth"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-ffwavesynth">5.1 ffwavesynth</a></h2>
<p>Internal wave synthetizer.
</p>
<p>This decoder generates wave patterns according to predefined sequences. Its
use is purely internal and the format of the data it accepts is not publicly
documented.
</p>
<a name="Subtitles-Decoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Subtitles-Decoders">6 Subtitles Decoders</a></h1>
<a name="dvdsub"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-dvdsub">6.1 dvdsub</a></h2>
<p>This codec decodes the bitmap subtitles used in DVDs; the same subtitles can
also be found in VobSub file pairs and in some Matroska files.
</p>
<a name="Options-2"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-2">6.1.1 Options</a></h3>
<dl compact="compact">
<dt>‘<samp>palette</samp>’</dt>
<dd><p>Specify the global palette used by the bitmaps. When stored in VobSub, the
palette is normally specified in the index file; in Matroska, the palette is
stored in the codec extra-data in the same format as in VobSub. In DVDs, the
palette is stored in the IFO file, and therefore not available when reading
from dumped VOB files.
</p>
<p>The format for this option is a string containing 16 24-bits hexadecimal
numbers (without 0x prefix) separated by comas, for example <code>0d00ee,
ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b</code>.
</p></dd>
</dl>
<a name="Encoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Encoders">7 Encoders</a></h1>
<p>Encoders are configured elements in FFmpeg which allow the encoding of
multimedia streams.
</p>
<p>When you configure your FFmpeg build, all the supported native encoders
are enabled by default. Encoders requiring an external library must be enabled
manually via the corresponding <code>--enable-lib</code> option. You can list all
available encoders using the configure option <code>--list-encoders</code>.
</p>
<p>You can disable all the encoders with the configure option
<code>--disable-encoders</code> and selectively enable / disable single encoders
with the options <code>--enable-encoder=<var>ENCODER</var></code> /
<code>--disable-encoder=<var>ENCODER</var></code>.
</p>
<p>The option <code>-codecs</code> of the ff* tools will display the list of
enabled encoders.
</p>
<a name="Audio-Encoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Audio-Encoders">8 Audio Encoders</a></h1>
<p>A description of some of the currently available audio encoders
follows.
</p>
<a name="ac3-and-ac3_005ffixed"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-ac3-and-ac3_005ffixed">8.1 ac3 and ac3_fixed</a></h2>
<p>AC-3 audio encoders.
</p>
<p>These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
the undocumented RealAudio 3 (a.k.a. dnet).
</p>
<p>The <var>ac3</var> encoder uses floating-point math, while the <var>ac3_fixed</var>
encoder only uses fixed-point integer math. This does not mean that one is
always faster, just that one or the other may be better suited to a
particular system. The floating-point encoder will generally produce better
quality audio for a given bitrate. The <var>ac3_fixed</var> encoder is not the
default codec for any of the output formats, so it must be specified explicitly
using the option <code>-acodec ac3_fixed</code> in order to use it.
</p>
<a name="AC_002d3-Metadata"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-AC_002d3-Metadata">8.1.1 AC-3 Metadata</a></h3>
<p>The AC-3 metadata options are used to set parameters that describe the audio,
but in most cases do not affect the audio encoding itself. Some of the options
do directly affect or influence the decoding and playback of the resulting
bitstream, while others are just for informational purposes. A few of the
options will add bits to the output stream that could otherwise be used for
audio data, and will thus affect the quality of the output. Those will be
indicated accordingly with a note in the option list below.
</p>
<p>These parameters are described in detail in several publicly-available
documents.
</p><ul>
<li> <a href="http://www.atsc.org/cms/standards/a_52-2010.pdf">A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard</a>
</li><li> <a href="http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf">A/54 - Guide to the Use of the ATSC Digital Television Standard</a>
</li><li> <a href="http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf">Dolby Metadata Guide</a>
</li><li> <a href="http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf">Dolby Digital Professional Encoding Guidelines</a>
</li></ul>
<a name="Metadata-Control-Options"></a>
<h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Metadata-Control-Options">8.1.1.1 Metadata Control Options</a></h4>
<dl compact="compact">
<dt>‘<samp>-per_frame_metadata <var>boolean</var></samp>’</dt>
<dd><p>Allow Per-Frame Metadata. Specifies if the encoder should check for changing
metadata for each frame.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dd><p>The metadata values set at initialization will be used for every frame in the
stream. (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dd><p>Metadata values can be changed before encoding each frame.
</p></dd>
</dl>
</dd>
</dl>
<a name="Downmix-Levels"></a>
<h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Downmix-Levels">8.1.1.2 Downmix Levels</a></h4>
<dl compact="compact">
<dt>‘<samp>-center_mixlev <var>level</var></samp>’</dt>
<dd><p>Center Mix Level. The amount of gain the decoder should apply to the center
channel when downmixing to stereo. This field will only be written to the
bitstream if a center channel is present. The value is specified as a scale
factor. There are 3 valid values:
</p><dl compact="compact">
<dt>‘<samp>0.707</samp>’</dt>
<dd><p>Apply -3dB gain
</p></dd>
<dt>‘<samp>0.595</samp>’</dt>
<dd><p>Apply -4.5dB gain (default)
</p></dd>
<dt>‘<samp>0.500</samp>’</dt>
<dd><p>Apply -6dB gain
</p></dd>
</dl>
</dd>
<dt>‘<samp>-surround_mixlev <var>level</var></samp>’</dt>
<dd><p>Surround Mix Level. The amount of gain the decoder should apply to the surround
channel(s) when downmixing to stereo. This field will only be written to the
bitstream if one or more surround channels are present. The value is specified
as a scale factor. There are 3 valid values:
</p><dl compact="compact">
<dt>‘<samp>0.707</samp>’</dt>
<dd><p>Apply -3dB gain
</p></dd>
<dt>‘<samp>0.500</samp>’</dt>
<dd><p>Apply -6dB gain (default)
</p></dd>
<dt>‘<samp>0.000</samp>’</dt>
<dd><p>Silence Surround Channel(s)
</p></dd>
</dl>
</dd>
</dl>
<a name="Audio-Production-Information"></a>
<h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Audio-Production-Information">8.1.1.3 Audio Production Information</a></h4>
<p>Audio Production Information is optional information describing the mixing
environment. Either none or both of the fields are written to the bitstream.
</p>
<dl compact="compact">
<dt>‘<samp>-mixing_level <var>number</var></samp>’</dt>
<dd><p>Mixing Level. Specifies peak sound pressure level (SPL) in the production
environment when the mix was mastered. Valid values are 80 to 111, or -1 for
unknown or not indicated. The default value is -1, but that value cannot be
used if the Audio Production Information is written to the bitstream. Therefore,
if the <code>room_type</code> option is not the default value, the <code>mixing_level</code>
option must not be -1.
</p>
</dd>
<dt>‘<samp>-room_type <var>type</var></samp>’</dt>
<dd><p>Room Type. Describes the equalization used during the final mixing session at
the studio or on the dubbing stage. A large room is a dubbing stage with the
industry standard X-curve equalization; a small room has flat equalization.
This field will not be written to the bitstream if both the <code>mixing_level</code>
option and the <code>room_type</code> option have the default values.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>notindicated</samp>’</dt>
<dd><p>Not Indicated (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>large</samp>’</dt>
<dd><p>Large Room
</p></dd>
<dt>‘<samp>2</samp>’</dt>
<dt>‘<samp>small</samp>’</dt>
<dd><p>Small Room
</p></dd>
</dl>
</dd>
</dl>
<a name="Other-Metadata-Options"></a>
<h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Other-Metadata-Options">8.1.1.4 Other Metadata Options</a></h4>
<dl compact="compact">
<dt>‘<samp>-copyright <var>boolean</var></samp>’</dt>
<dd><p>Copyright Indicator. Specifies whether a copyright exists for this audio.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>off</samp>’</dt>
<dd><p>No Copyright Exists (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>on</samp>’</dt>
<dd><p>Copyright Exists
</p></dd>
</dl>
</dd>
<dt>‘<samp>-dialnorm <var>value</var></samp>’</dt>
<dd><p>Dialogue Normalization. Indicates how far the average dialogue level of the
program is below digital 100% full scale (0 dBFS). This parameter determines a
level shift during audio reproduction that sets the average volume of the
dialogue to a preset level. The goal is to match volume level between program
sources. A value of -31dB will result in no volume level change, relative to
the source volume, during audio reproduction. Valid values are whole numbers in
the range -31 to -1, with -31 being the default.
</p>
</dd>
<dt>‘<samp>-dsur_mode <var>mode</var></samp>’</dt>
<dd><p>Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
(Pro Logic). This field will only be written to the bitstream if the audio
stream is stereo. Using this option does <b>NOT</b> mean the encoder will actually
apply Dolby Surround processing.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>notindicated</samp>’</dt>
<dd><p>Not Indicated (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>off</samp>’</dt>
<dd><p>Not Dolby Surround Encoded
</p></dd>
<dt>‘<samp>2</samp>’</dt>
<dt>‘<samp>on</samp>’</dt>
<dd><p>Dolby Surround Encoded
</p></dd>
</dl>
</dd>
<dt>‘<samp>-original <var>boolean</var></samp>’</dt>
<dd><p>Original Bit Stream Indicator. Specifies whether this audio is from the
original source and not a copy.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>off</samp>’</dt>
<dd><p>Not Original Source
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>on</samp>’</dt>
<dd><p>Original Source (default)
</p></dd>
</dl>
</dd>
</dl>
<a name="Extended-Bitstream-Information"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Extended-Bitstream-Information">8.1.2 Extended Bitstream Information</a></h3>
<p>The extended bitstream options are part of the Alternate Bit Stream Syntax as
specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
If any one parameter in a group is specified, all values in that group will be
written to the bitstream. Default values are used for those that are written
but have not been specified. If the mixing levels are written, the decoder
will use these values instead of the ones specified in the <code>center_mixlev</code>
and <code>surround_mixlev</code> options if it supports the Alternate Bit Stream
Syntax.
</p>
<a name="Extended-Bitstream-Information-_002d-Part-1"></a>
<h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Extended-Bitstream-Information-_002d-Part-1">8.1.2.1 Extended Bitstream Information - Part 1</a></h4>
<dl compact="compact">
<dt>‘<samp>-dmix_mode <var>mode</var></samp>’</dt>
<dd><p>Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
(Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>notindicated</samp>’</dt>
<dd><p>Not Indicated (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>ltrt</samp>’</dt>
<dd><p>Lt/Rt Downmix Preferred
</p></dd>
<dt>‘<samp>2</samp>’</dt>
<dt>‘<samp>loro</samp>’</dt>
<dd><p>Lo/Ro Downmix Preferred
</p></dd>
</dl>
</dd>
<dt>‘<samp>-ltrt_cmixlev <var>level</var></samp>’</dt>
<dd><p>Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
center channel when downmixing to stereo in Lt/Rt mode.
</p><dl compact="compact">
<dt>‘<samp>1.414</samp>’</dt>
<dd><p>Apply +3dB gain
</p></dd>
<dt>‘<samp>1.189</samp>’</dt>
<dd><p>Apply +1.5dB gain
</p></dd>
<dt>‘<samp>1.000</samp>’</dt>
<dd><p>Apply 0dB gain
</p></dd>
<dt>‘<samp>0.841</samp>’</dt>
<dd><p>Apply -1.5dB gain
</p></dd>
<dt>‘<samp>0.707</samp>’</dt>
<dd><p>Apply -3.0dB gain
</p></dd>
<dt>‘<samp>0.595</samp>’</dt>
<dd><p>Apply -4.5dB gain (default)
</p></dd>
<dt>‘<samp>0.500</samp>’</dt>
<dd><p>Apply -6.0dB gain
</p></dd>
<dt>‘<samp>0.000</samp>’</dt>
<dd><p>Silence Center Channel
</p></dd>
</dl>
</dd>
<dt>‘<samp>-ltrt_surmixlev <var>level</var></samp>’</dt>
<dd><p>Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
surround channel(s) when downmixing to stereo in Lt/Rt mode.
</p><dl compact="compact">
<dt>‘<samp>0.841</samp>’</dt>
<dd><p>Apply -1.5dB gain
</p></dd>
<dt>‘<samp>0.707</samp>’</dt>
<dd><p>Apply -3.0dB gain
</p></dd>
<dt>‘<samp>0.595</samp>’</dt>
<dd><p>Apply -4.5dB gain
</p></dd>
<dt>‘<samp>0.500</samp>’</dt>
<dd><p>Apply -6.0dB gain (default)
</p></dd>
<dt>‘<samp>0.000</samp>’</dt>
<dd><p>Silence Surround Channel(s)
</p></dd>
</dl>
</dd>
<dt>‘<samp>-loro_cmixlev <var>level</var></samp>’</dt>
<dd><p>Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
center channel when downmixing to stereo in Lo/Ro mode.
</p><dl compact="compact">
<dt>‘<samp>1.414</samp>’</dt>
<dd><p>Apply +3dB gain
</p></dd>
<dt>‘<samp>1.189</samp>’</dt>
<dd><p>Apply +1.5dB gain
</p></dd>
<dt>‘<samp>1.000</samp>’</dt>
<dd><p>Apply 0dB gain
</p></dd>
<dt>‘<samp>0.841</samp>’</dt>
<dd><p>Apply -1.5dB gain
</p></dd>
<dt>‘<samp>0.707</samp>’</dt>
<dd><p>Apply -3.0dB gain
</p></dd>
<dt>‘<samp>0.595</samp>’</dt>
<dd><p>Apply -4.5dB gain (default)
</p></dd>
<dt>‘<samp>0.500</samp>’</dt>
<dd><p>Apply -6.0dB gain
</p></dd>
<dt>‘<samp>0.000</samp>’</dt>
<dd><p>Silence Center Channel
</p></dd>
</dl>
</dd>
<dt>‘<samp>-loro_surmixlev <var>level</var></samp>’</dt>
<dd><p>Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
surround channel(s) when downmixing to stereo in Lo/Ro mode.
</p><dl compact="compact">
<dt>‘<samp>0.841</samp>’</dt>
<dd><p>Apply -1.5dB gain
</p></dd>
<dt>‘<samp>0.707</samp>’</dt>
<dd><p>Apply -3.0dB gain
</p></dd>
<dt>‘<samp>0.595</samp>’</dt>
<dd><p>Apply -4.5dB gain
</p></dd>
<dt>‘<samp>0.500</samp>’</dt>
<dd><p>Apply -6.0dB gain (default)
</p></dd>
<dt>‘<samp>0.000</samp>’</dt>
<dd><p>Silence Surround Channel(s)
</p></dd>
</dl>
</dd>
</dl>
<a name="Extended-Bitstream-Information-_002d-Part-2"></a>
<h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Extended-Bitstream-Information-_002d-Part-2">8.1.2.2 Extended Bitstream Information - Part 2</a></h4>
<dl compact="compact">
<dt>‘<samp>-dsurex_mode <var>mode</var></samp>’</dt>
<dd><p>Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
(7.1 matrixed to 5.1). Using this option does <b>NOT</b> mean the encoder will actually
apply Dolby Surround EX processing.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>notindicated</samp>’</dt>
<dd><p>Not Indicated (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>on</samp>’</dt>
<dd><p>Dolby Surround EX Off
</p></dd>
<dt>‘<samp>2</samp>’</dt>
<dt>‘<samp>off</samp>’</dt>
<dd><p>Dolby Surround EX On
</p></dd>
</dl>
</dd>
<dt>‘<samp>-dheadphone_mode <var>mode</var></samp>’</dt>
<dd><p>Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
option does <b>NOT</b> mean the encoder will actually apply Dolby Headphone
processing.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>notindicated</samp>’</dt>
<dd><p>Not Indicated (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>on</samp>’</dt>
<dd><p>Dolby Headphone Off
</p></dd>
<dt>‘<samp>2</samp>’</dt>
<dt>‘<samp>off</samp>’</dt>
<dd><p>Dolby Headphone On
</p></dd>
</dl>
</dd>
<dt>‘<samp>-ad_conv_type <var>type</var></samp>’</dt>
<dd><p>A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
conversion.
</p><dl compact="compact">
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>standard</samp>’</dt>
<dd><p>Standard A/D Converter (default)
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>hdcd</samp>’</dt>
<dd><p>HDCD A/D Converter
</p></dd>
</dl>
</dd>
</dl>
<a name="Other-AC_002d3-Encoding-Options"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Other-AC_002d3-Encoding-Options">8.1.3 Other AC-3 Encoding Options</a></h3>
<dl compact="compact">
<dt>‘<samp>-stereo_rematrixing <var>boolean</var></samp>’</dt>
<dd><p>Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
is an optional AC-3 feature that increases quality by selectively encoding
the left/right channels as mid/side. This option is enabled by default, and it
is highly recommended that it be left as enabled except for testing purposes.
</p>
</dd>
</dl>
<a name="Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options">8.1.4 Floating-Point-Only AC-3 Encoding Options</a></h3>
<p>These options are only valid for the floating-point encoder and do not exist
for the fixed-point encoder due to the corresponding features not being
implemented in fixed-point.
</p>
<dl compact="compact">
<dt>‘<samp>-channel_coupling <var>boolean</var></samp>’</dt>
<dd><p>Enables/Disables use of channel coupling, which is an optional AC-3 feature
that increases quality by combining high frequency information from multiple
channels into a single channel. The per-channel high frequency information is
sent with less accuracy in both the frequency and time domains. This allows
more bits to be used for lower frequencies while preserving enough information
to reconstruct the high frequencies. This option is enabled by default for the
floating-point encoder and should generally be left as enabled except for
testing purposes or to increase encoding speed.
</p><dl compact="compact">
<dt>‘<samp>-1</samp>’</dt>
<dt>‘<samp>auto</samp>’</dt>
<dd><p>Selected by Encoder (default)
</p></dd>
<dt>‘<samp>0</samp>’</dt>
<dt>‘<samp>off</samp>’</dt>
<dd><p>Disable Channel Coupling
</p></dd>
<dt>‘<samp>1</samp>’</dt>
<dt>‘<samp>on</samp>’</dt>
<dd><p>Enable Channel Coupling
</p></dd>
</dl>
</dd>
<dt>‘<samp>-cpl_start_band <var>number</var></samp>’</dt>
<dd><p>Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
value higher than the bandwidth is used, it will be reduced to 1 less than the
coupling end band. If <var>auto</var> is used, the start band will be determined by
the encoder based on the bit rate, sample rate, and channel layout. This option
has no effect if channel coupling is disabled.
</p><dl compact="compact">
<dt>‘<samp>-1</samp>’</dt>
<dt>‘<samp>auto</samp>’</dt>
<dd><p>Selected by Encoder (default)
</p></dd>
</dl>
</dd>
</dl>
<a name="Video-Encoders"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Video-Encoders">9 Video Encoders</a></h1>
<p>A description of some of the currently available video encoders
follows.
</p>
<a name="libtheora"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-libtheora">9.1 libtheora</a></h2>
<p>Theora format supported through libtheora.
</p>
<p>Requires the presence of the libtheora headers and library during
configuration. You need to explicitly configure the build with
<code>--enable-libtheora</code>.
</p>
<a name="Options"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options">9.1.1 Options</a></h3>
<p>The following global options are mapped to internal libtheora options
which affect the quality and the bitrate of the encoded stream.
</p>
<dl compact="compact">
<dt>‘<samp>b</samp>’</dt>
<dd><p>Set the video bitrate, only works if the <code>qscale</code> flag in
‘<samp>flags</samp>’ is not enabled.
</p>
</dd>
<dt>‘<samp>flags</samp>’</dt>
<dd><p>Used to enable constant quality mode encoding through the
‘<samp>qscale</samp>’ flag, and to enable the <code>pass1</code> and <code>pass2</code>
modes.
</p>
</dd>
<dt>‘<samp>g</samp>’</dt>
<dd><p>Set the GOP size.
</p>
</dd>
<dt>‘<samp>global_quality</samp>’</dt>
<dd><p>Set the global quality in lambda units, only works if the
<code>qscale</code> flag in ‘<samp>flags</samp>’ is enabled. The value is clipped
in the [0 - 10*<code>FF_QP2LAMBDA</code>] range, and then multiplied for 6.3
to get a value in the native libtheora range [0-63]. A higher value
corresponds to a higher quality.
</p>
<p>For example, to set maximum constant quality encoding with
<code>ffmpeg</code>:
</p><div class="example">
<pre class="example">ffmpeg -i INPUT -flags:v qscale -global_quality:v "10*QP2LAMBDA" -codec:v libtheora OUTPUT.ogg
</pre></div>
</dd>
</dl>
<a name="libvpx"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-libvpx">9.2 libvpx</a></h2>
<p>VP8 format supported through libvpx.
</p>
<p>Requires the presence of the libvpx headers and library during configuration.
You need to explicitly configure the build with <code>--enable-libvpx</code>.
</p>
<a name="Options-3"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-3">9.2.1 Options</a></h3>
<p>Mapping from FFmpeg to libvpx options with conversion notes in parentheses.
</p>
<dl compact="compact">
<dt>‘<samp>threads</samp>’</dt>
<dd><p>g_threads
</p>
</dd>
<dt>‘<samp>profile</samp>’</dt>
<dd><p>g_profile
</p>
</dd>
<dt>‘<samp>vb</samp>’</dt>
<dd><p>rc_target_bitrate
</p>
</dd>
<dt>‘<samp>g</samp>’</dt>
<dd><p>kf_max_dist
</p>
</dd>
<dt>‘<samp>keyint_min</samp>’</dt>
<dd><p>kf_min_dist
</p>
</dd>
<dt>‘<samp>qmin</samp>’</dt>
<dd><p>rc_min_quantizer
</p>
</dd>
<dt>‘<samp>qmax</samp>’</dt>
<dd><p>rc_max_quantizer
</p>
</dd>
<dt>‘<samp>bufsize, vb</samp>’</dt>
<dd><p>rc_buf_sz
<code>(bufsize * 1000 / vb)</code>
</p>
<p>rc_buf_optimal_sz
<code>(bufsize * 1000 / vb * 5 / 6)</code>
</p>
</dd>
<dt>‘<samp>rc_init_occupancy, vb</samp>’</dt>
<dd><p>rc_buf_initial_sz
<code>(rc_init_occupancy * 1000 / vb)</code>
</p>
</dd>
<dt>‘<samp>rc_buffer_aggressivity</samp>’</dt>
<dd><p>rc_undershoot_pct
</p>
</dd>
<dt>‘<samp>skip_threshold</samp>’</dt>
<dd><p>rc_dropframe_thresh
</p>
</dd>
<dt>‘<samp>qcomp</samp>’</dt>
<dd><p>rc_2pass_vbr_bias_pct
</p>
</dd>
<dt>‘<samp>maxrate, vb</samp>’</dt>
<dd><p>rc_2pass_vbr_maxsection_pct
<code>(maxrate * 100 / vb)</code>
</p>
</dd>
<dt>‘<samp>minrate, vb</samp>’</dt>
<dd><p>rc_2pass_vbr_minsection_pct
<code>(minrate * 100 / vb)</code>
</p>
</dd>
<dt>‘<samp>minrate, maxrate, vb</samp>’</dt>
<dd><p><code>VPX_CBR</code>
<code>(minrate == maxrate == vb)</code>
</p>
</dd>
<dt>‘<samp>crf</samp>’</dt>
<dd><p><code>VPX_CQ</code>, <code>VP8E_SET_CQ_LEVEL</code>
</p>
</dd>
<dt>‘<samp>quality</samp>’</dt>
<dd><dl compact="compact">
<dt>‘<samp><var>best</var></samp>’</dt>
<dd><p><code>VPX_DL_BEST_QUALITY</code>
</p></dd>
<dt>‘<samp><var>good</var></samp>’</dt>
<dd><p><code>VPX_DL_GOOD_QUALITY</code>
</p></dd>
<dt>‘<samp><var>realtime</var></samp>’</dt>
<dd><p><code>VPX_DL_REALTIME</code>
</p></dd>
</dl>
</dd>
<dt>‘<samp>speed</samp>’</dt>
<dd><p><code>VP8E_SET_CPUUSED</code>
</p>
</dd>
<dt>‘<samp>nr</samp>’</dt>
<dd><p><code>VP8E_SET_NOISE_SENSITIVITY</code>
</p>
</dd>
<dt>‘<samp>mb_threshold</samp>’</dt>
<dd><p><code>VP8E_SET_STATIC_THRESHOLD</code>
</p>
</dd>
<dt>‘<samp>slices</samp>’</dt>
<dd><p><code>VP8E_SET_TOKEN_PARTITIONS</code>
</p>
</dd>
<dt>‘<samp>max-intra-rate</samp>’</dt>
<dd><p><code>VP8E_SET_MAX_INTRA_BITRATE_PCT</code>
</p>
</dd>
<dt>‘<samp>force_key_frames</samp>’</dt>
<dd><p><code>VPX_EFLAG_FORCE_KF</code>
</p>
</dd>
<dt>‘<samp>Alternate reference frame related</samp>’</dt>
<dd><dl compact="compact">
<dt>‘<samp>vp8flags altref</samp>’</dt>
<dd><p><code>VP8E_SET_ENABLEAUTOALTREF</code>
</p></dd>
<dt>‘<samp><var>arnr_max_frames</var></samp>’</dt>
<dd><p><code>VP8E_SET_ARNR_MAXFRAMES</code>
</p></dd>
<dt>‘<samp><var>arnr_type</var></samp>’</dt>
<dd><p><code>VP8E_SET_ARNR_TYPE</code>
</p></dd>
<dt>‘<samp><var>arnr_strength</var></samp>’</dt>
<dd><p><code>VP8E_SET_ARNR_STRENGTH</code>
</p></dd>
<dt>‘<samp><var>rc_lookahead</var></samp>’</dt>
<dd><p>g_lag_in_frames
</p></dd>
</dl>
</dd>
<dt>‘<samp>vp8flags error_resilient</samp>’</dt>
<dd><p>g_error_resilient
</p>
</dd>
</dl>
<p>For more information about libvpx see:
<a href="http://www.webmproject.org/">http://www.webmproject.org/</a>
</p>
<a name="libx264"></a>
<h2 class="section"><a href="ffmpeg-codecs.html#toc-libx264">9.3 libx264</a></h2>
<p>H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 format supported through
libx264.
</p>
<p>Requires the presence of the libx264 headers and library during
configuration. You need to explicitly configure the build with
<code>--enable-libx264</code>.
</p>
<a name="Options-1"></a>
<h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-1">9.3.1 Options</a></h3>
<dl compact="compact">
<dt>‘<samp>preset <var>preset_name</var></samp>’</dt>
<dd><p>Set the encoding preset.
</p>
</dd>
<dt>‘<samp>tune <var>tune_name</var></samp>’</dt>
<dd><p>Tune the encoding params.
</p>
</dd>
<dt>‘<samp>fastfirstpass <var>bool</var></samp>’</dt>
<dd><p>Use fast settings when encoding first pass, default value is 1.
</p>
</dd>
<dt>‘<samp>profile <var>profile_name</var></samp>’</dt>
<dd><p>Set profile restrictions.
</p>
</dd>
<dt>‘<samp>level <var>level</var></samp>’</dt>
<dd><p>Specify level (as defined by Annex A).
Deprecated in favor of <var>x264opts</var>.
</p>
</dd>
<dt>‘<samp>passlogfile <var>filename</var></samp>’</dt>
<dd><p>Specify filename for 2 pass stats.
Deprecated in favor of <var>x264opts</var> (see <var>stats</var> libx264 option).
</p>
</dd>
<dt>‘<samp>wpredp <var>wpred_type</var></samp>’</dt>
<dd><p>Specify Weighted prediction for P-frames.
Deprecated in favor of <var>x264opts</var> (see <var>weightp</var> libx264 option).
</p>
</dd>
<dt>‘<samp>x264opts <var>options</var></samp>’</dt>
<dd><p>Allow to set any x264 option, see <code>x264 --fullhelp</code> for a list.
</p>
<p><var>options</var> is a list of <var>key</var>=<var>value</var> couples separated by
":". In <var>filter</var> and <var>psy-rd</var> options that use ":" as a separator
themselves, use "," instead. They accept it as well since long ago but this
is kept undocumented for some reason.
</p></dd>
</dl>
<p>For example to specify libx264 encoding options with <code>ffmpeg</code>:
</p><div class="example">
<pre class="example">ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
</pre></div>
<p>For more information about libx264 and the supported options see:
<a href="http://www.videolan.org/developers/x264.html">http://www.videolan.org/developers/x264.html</a>
</p>
<a name="See-Also"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-See-Also">10 See Also</a></h1>
<p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>, <a href="ffserver.html">ffserver</a>,
<a href="libavcodec.html">libavcodec</a>
</p>
<a name="Authors"></a>
<h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Authors">11 Authors</a></h1>
<p>The FFmpeg developers.
</p>
<p>For details about the authorship, see the Git history of the project
(git://source.ffmpeg.org/ffmpeg), e.g. by typing the command
<code>git log</code> in the FFmpeg source directory, or browsing the
online repository at <a href="http://source.ffmpeg.org">http://source.ffmpeg.org</a>.
</p>
<p>Maintainers for the specific components are listed in the file
‘<tt>MAINTAINERS</tt>’ in the source code tree.
</p>
<footer class="footer pagination-right">
<span class="label label-info">This document was generated on <i>June 12, 2013</i> using <a href="http://www.nongnu.org/texi2html/"><i>texi2html 5.0</i></a>.</span></footer></div>
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