Service Documentation
Authors: Charles Yates <charles.yates@pandora.be>
Dan Dennedy <dan@dennedy.org>
Last Revision: $Date: 2008-11-05 21:35:26 -0800 (Wed, 05 Nov 2008) $
SERVICES
--------
Services marked as "(Proprietary)" are not distributed with the LGPL
version of mlt.
Producers
---------
avformat
Description
ffmpeg libavformat based producer for video and audio.
Constructor Argument
'file' - a filename specification or URL in the form:
[{protocol}|{format}]:{resource}[?{format-parameter}[&{format-parameter}...]]
For example, video4linux:/dev/video1?width:320&height:240
Note: on the bash command line, & must be escaped as '\&'.
Also, note the use of ':' instead of '=' for parameters.
Use 'ffmpeg -formats' to see a list of supported protocols
and formats.
Details
Format parameters only appear to be useful with 'video4linux' or
'audio_device' formats. For 'video4linux' the parameters are
width, height, frame_rate, frame_rate_base, and standard (ntsc|pal).
For 'audio_device' the parameters are channels and sample_rate.
Initialisation Properties
int video_index - index of video stream to use (-1 is off)
int audio_index - index of audio stream to use (-1 is off)
int in - in point
int out - out point
Read Only Properties
string resource - file location
double source_fps - the framerate of the resource
double aspect_ratio - sample aspect ratio of the resource
- this is determined on every frame read
Dependencies
ffmpeg
Known Bugs
Audio sync discrepancy with some content.
Not all libavformat supported formats are seekable.
Fails to play beyond first frame of video of sources with PTS not
starting at 0 (video4linux).
fezzik
Description
A friendly giant that likes to rhyme and throw rocks
Constructor Argument
'file' - a filename specification:
[{mlt-service}:]{resource} | {mlt-service}
- can also be the name of a producer service that can
accept the resource specified post construction.
Initialisation Properties
int in - in point
int out - out point
+ all producer initialising properties
Read Only Properties
string resource - file location
+ all producer read only properties
Details
This producer has two roles:
1. it handles the mappings of all file names to the other
producers;
2. it attaches normalising filters (rescale, resize and resample)
to the producers (when necessary).
This producer simplifies many aspects of use. Essentially, it
ensures that a consumer will receive images and audio precisely as
they request them.
Dependencies
all.
Known Bugs
None.
colour
Description
A simple colour generator.
Constructor Argument
colour - A colour value is a hexadecimal representation of RGB plus
alpha channel as 0xrrggbbaa.
- Also colours can be the words: white, black, red, green,
or blue.
- The default colour is black.
Initialisation Properties
none
Read Only Properties
none
Dependencies
none
Known Bugs
none
libdv
Description
libdv based decoder for video and audio.
Constructor Argument
'file' - produce a/v from file
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
string resource - file location
double fps - output frames per second
int length - duration of resource (in frames)
Mutable Properties
string quality - one of "best," "fast" or anything else chooses
medium.
Dependencies
libdv.
Known Bugs
DVCPRO is incorrectly identified as 16:9 aspect ratio. You must use
libdv from CVS or a post 0.101 release.
mcdv (Proprietary)
Description
MainConcept based dv decoder for video and audio.
Constructor Argument
'file' - produce a/v from file
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
string resource - file location
double fps - output frames per second
int length - duration of resource (in frames)
Dependencies
MainConcept DV or DVCPRO SDK, libdv.
"dv_sdk" installed parallel to mlt.
Known Bugs
None
mcmpeg (Proprietary)
Description
MainConcept based mpeg decoder for video and audio.
Constructor Argument
'file' - produce a/v from file
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
string resource - file location
double fps - output frames per second
double aspect_ratio - sample aspect ratio of video
int length - duration of resource (in frames)
Dependencies
MainConcept MPEG SDK.
"mpeg_sdk_release" installed parallel to mlt.
Known Bugs
None.
noise
Description
White noise producer
Constructor Argument
none
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
string resource - file location
double fps - output frames per second
double aspect_ratio - sample aspect ratio of video
int length - duration of resource (in frames)
Dependencies
none
Known Bugs
none
pango
Description
A title generator that uses the Pango international text layout
and Freetype2 font renderer.
Constructor Argument
string file - a text file containing Pango markup, see:
http://developer.gnome.org/doc/API/2.0/pango/PangoMarkupFormat.html
- requires xml-like encoding special chars from:
<, >, & -to- <, >, &
Details
Supplying a filename with extension ".txt" causes the Fezzik
producer to load with pango. If the filename begins with "+" the
pango producer interprets the filename as pango text. This is a
shortcut to embed titles in inigo commands. For westley, it is
recommended that you embed the title text in the property value.
Pango has builtin scaling. It will rescale the originally rendered
title to whatever the consumer requests. Therefore, it will lose
its aspect ratio if so requested, and it is up to the consumer to
request a proper width and height that maintains the image aspect.
Initialisation Properties
int in - in point
int out - out point
Mutable Properties
string markup - a string containing Pango markup see:
http://developer.gnome.org/doc/API/2.0/pango/PangoMarkupFormat.html
- requires xml-like encoding special chars from:
<, >, & -to- <, >, &
string fgcolour - an RGBA colour specification of the text
(i.e. 0xrrggbbaa)
string bgcolour - an RGBA colour of the background rectangle
string align - paragraph alignment: left, centre, right
- also, numbers 0, 1 and 2 can be used respectively.
int pad - the number of pixels to pad the background rectangle
beyond edges of text. default 0.
string markup - see constructor argument
string text - non-markup string in UTF-8 encoding (can contain
markup chars un-encoded)
string font - the default typeface to use when not using markup.
default "Sans 48". FreeType2 renders at 72 dpi.
string encoding - the text encoding type of the input if not UTF-8.
- see 'iconv --list' for a list of possible inputs.
int weight - the weight of the font (default is 400)
Read Only Properties
string resource - the text/markup file or "pango" if no file.
int real_width - the original, unscaled width of the rendered title.
int real_height - the original, unscaled height of the title.
int width - the last requested scaled image width.
int height - the last requested scaled image height.
Dependencies
libpango-1.0, libpangoft2-1.0, libfreetype, libgdk_pixbuf-2.0,
libglib-2.0, libgobject-2.0, libgmodule-2.0, libfontconfig.
Known Bugs
The foreground and background Pango markup span attributes are not
supported.
Word wrapping is not supported.
pixbuf
Description
A still graphics to video generator using gdk-pixbuf
Constructor Argument
'file' - The name of a graphics file loadable by
a gdk-pixbuf loader. see /usr/lib/gdk-pixbuf/loaders
definitely png, jpeg, tiff, pnm, and xpm
- If "%" in filename, the filename is used with sprintf
generate a filename from a counter for multi-file/flipbook
animation. The file sequence ends when numeric
discontinuity >100.
- If filename contains "/.all.", suffix with an extension to
load all pictures with matching extension from a directory.
- If filename contains the string "<svg", then pixbuf tries
to load the filename as inline SVG XML, which is convenient
for inigo commands.
Details
Pixbuf has builtin scaling. It will rescale the originally rendered
title to whatever the consumer requests. Therefore, it will lose
its aspect ratio if so requested, and it is up to the consumer to
request a proper width and height that maintains the image aspect.
Initialisation Properties
int in - in point
int out - out point
int begin - when using an image sequence, this sets the starting
number.
Mutable Properties
int ttl - how long (in frames) to repeat each picture in file
sequences. default is 25.
Read Only Properties
string resource - file location. See Constructor Argument above.
int real_width - the original, unscaled width of the rendered title.
int real_height - the original, unscaled height of the title.
int width - the last requested scaled image width.
int height - the last requested scaled image height.
Dependencies
libgdk_pixbuf-2.0, libglib-2.0, libgobject-2.0, libgmodule-2.0
Known Bugs
XXX: in/out settings are incorrectly handled.
ppm
Description
Reads a stream of contiguous PPM images.
Constructor Argument
command - a shell command to run something that produces ppm
streams on stdout.
Initialisation Properties
none
Read Only Properties
string resource - the command
Dependencies
none
Known Bugs
Since it uses pipes, it is not compatible with bluefish.
westley
Description
Construct a service network from an XML description.
See docs/westley.txt.
Constructor Argument
URL - an XML text file containing westley XML (schema/DTD pending)
- Since westley files can be parameterised, the URL syntax is:
{file-name}[?{param-name}{'='|':'}{param-value}[&{param-name}{'='|':'}{param-value}...]]
A colon is allowed instead of an equal sign to pacify inigo,
who tokenises anything with an equal sign as a property
setting. Also, when running inigo from the shell, beware of
the '?' and shell filename expansion. You can surround the URL
with single quotations to prevent expansion. Finally, fezzik
will fail to match the filename when you use parameters, so
preface the url with 'westley:' to force fezzik to load with
the westley service.
Read Only Properties
string resource - file location
Dependencies
libxml2
Known Bugs
Non-referenced producers and playlists are not destroyed until the
network is destroyed.
A referenced producer or playlist must appear before the reference.
A filter that occurs before a producer has been defined causes a
segfault.
vorbis
Description
OGG Vorbis file reader.
Constructor Argument
'file' - file to use (only .ogg supported at the moment)
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
double fps - this is fixed at 25 for PAL currently
Dependencies
libvorbisfile
Known Bugs
Fixed frame size (PAL audio chunks).
Doesn't cover ogg files with multiple, differing sections.
Filters
-------
brightness
Description
Shift the luma component using a constant value.
Constructor Argument
start - the constant floating point numeric value to apply.
- the default is 0.
Initialisation Properties
int in - in point
int out - out point
double start - see Constructor Argument above.
double end - the ending adjustment value. the filter interpolates
between the start and end adjustments over the
duration of the effect.
Read Only Properties
none
Dependencies
none
Known Bugs
Does not go completely to black or white.
channelcopy
Description
Copy audio from one channel to another channel.
Constructor Argument
to - the 0-indexed channel to copy into, default is 1.
Mutable Properties
int to - see above
int from - the channel from which to copy, default is 0.
Dependencies
none
Known Bugs
none
deinterlace
Description
Deinterlace a frame consisting of two fields using bob, weave,
greedy, one-field, and linear blend methods. This code is
appropriated from the Xine XV video output plugin.
Constructor Argument
method - a string containing the deinterlace method: bob, weave,
greedy, onefield, or linearblend. The default is
linearblend.
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
none
Mutable Properties
string method
Details
If the frame properties "progressive" or "consumer_progressive"
are non-zero, then the filter is not applied. Also, if applied,
this sets the frame property "progressive" to 1.
Dependencies
none
Known Bugs
Not a bug, but it only provides fair quality.
gamma
Description
Adjust image luma using a non-linear power-law curve
Constructor Argument
gamma - a floating point value. The default is 1.0, or none.
Initialisation Properties
int in - in point
int out - out point
Mutable Properties
double gamma - the exponential factor of the power-law curve
Dependencies
none
Known Bugs
none
greyscale
Description
Convert colour image to greyscale
Constructor Argument
none
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
none
Dependencies
none
Known Bugs
none
gtkrescale
Description
Scale the producer video frame size to match the consumer.
This filter is designed for use as a Fezzik normaliser.
Constructor Argument
interpolation - the rescaling method, one of:
nearest (lowest quality, fastest),
tiles,
bilinear (default; good quality, moderate speed),
hyper (best quality, slowest).
Initialisation Properties
int in - in point
int out - out point
Mutable Properties
string interpolation - see constructor argument above
If a property "consumer_aspect_ratio" exists on the frame, then
rescaler normalises the producer's aspect ratio and maximises the
size of the frame, but may not produce the consumer's requested
dimension. Therefore, this option works best in conjunction with the
resize filter. This behavior can be disabled by another service by
either removing the property, setting it to zero, or setting
frame property "distort" to 1.
Dependencies
libgdk_pixbuf-2.0, libglib-2.0, libgobject-2.0, libgmodule-2.0
Known Bugs
none
jackrack
Description
Creates Jack ports and runs a JackRack project to process audio
through a stack of LADSPA filters.
Constructor Argument
src - a JackRack file
Details
If you are using a consumer that uses ALSA, then you should start
jackd with the dummy driver: jackd -d dummy.
I also recommend using a period size of 2048: -p 2048.
jackd -ddummy -r48000 -p2048
Initialisation Properties
int in - in point
int out - out point
The following can be used without a rack file in order to connect
filter_jackrack to a running instance of JackRack:
string out_1 - Jack port to connect MLT's output port (JackRack's input)
string out_2 - Jack port to connect MLT's output port (JackRack's input)
string in_1 - Jack port to connect MLT's input port (JackRack's output)
string in_2 - Jack port to connect MLT's input port (JackRack's output)
Read Only Properties
none
Mutable Properties
none
Dependencies
Jack, LADSPA, glib-2.0, libxml2
Known Bugs
Currently, due to timing and synchronisation issues, the audio
is distorted with repeated samples and latency clicks.
no encapsulated resampling and jack runs at a fixed frequency
ladspa
Description
Runs a JackRack project to process audio through a stack of
LADSPA filters without using Jack.
Constructor Argument
src - a JackRack file
Details
Due to audio integrity issues with the jackrack filter, this
filter is better for runtime, while jackrack is more suitable
for prototyping a rack file using the Jack Rack GUI.
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
none
Mutable Properties
none
Dependencies
Jack, LADSPA, glib-2.0, libxml2
Jack is still required because this coexists with the jackrack
filter.
Known Bugs
no encapsulated resampling and jack runs at a fixed frequency
luma
Description
Applies a luma transition between the current and next frames.
Useful for transitions from a slideshow created using producer
pixbuf.
Constructor Argument
file - a luma wipe
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
none
Mutable Properties
int period - how long to wait between success iterations of the
transition. For best results set this to a multiple
of ttl used in pixbuf. The default is 24.
luma. - all properties beginning with "luma." are passed to the
encapsulated luma transition. For example, luma.out controls
the duration of the wipe.
Dependencies
transition_luma and its dependencies
Known Bugs
none
mcrescale
Description
Scale the producer video frame size to match the consumer.
This filter is designed for use as a Fezzik normaliser.
Constructor Argument
interpolation - the rescaling method, one of:
nearest (lowest quality, fastest),
bilinear (default; good quality, moderate speed),
hyper (best quality, slowest).
Initialisation Properties
int in - in point
int out - out point
Mutable Properties
string interpolation - see constructor argument above
If a property "consumer_aspect_ratio" exists on the frame, then
rescaler normalises the producer's aspect ratio and maximises the
size of the frame, but may not produce the consumer's requested
dimension. Therefore, this option works best in conjunction with the
resize filter. This behavior can be disabled by another service by
either removing the property, setting it to zero, or setting
frame property "distort" to 1.
Dependencies
the mainconcept rescaling sdk.
Known Bugs
none
mirror
Description
Provides various mirror and image reversing effects.
Constructor Argument
mirror - horizontal, vertical, diagonal, flip, flop
Initialisation Properties
int reverse - being 0 or 1
int in - in point
int out - out point
Read Only Properties
none
Mutable Properties
none
Dependencies
none
Known Bugs
none
mono
Description
Mix all channels of audio into a mono signal and output it as
N channels.
Constructor Argument
channels - the number of output channels (default 2)
Initialisation Properties
none
Read Only Properties
none
Mutable Properties
none
Dependencies
none
Known Bugs
none
obscure
Description
Obscuring filter.
Constructor Argument
none
Initialisation Properties
string start - in the format X,Y:WxH[:PWxPY]
- PWxPY is the size of the averaging region in pixels.
string end - in the format X,Y:WxH[:PWxPY]
int in - in point
int out - out point
Read Only Properties
none
Dependencies
none
Known Bugs
none
region
Description
Apply one or more filters to a region of the video image. The region
can be shaped as well using the alpha channel of another producer.
Constructor Argument
resource - A file whose alpha channel will "shape" the region.
- The string "circle" is a shortcut but it requires pixbuf with
the librsvg loader. The circle is automatically stretched
to the region to create an ellipse.
Initialisation Properties
int in - in point
int out - out point
plus and region transition properties
Read Only Properties
see the region transition
Dependencies
transition_region
Known Bugs
"circle" is unpredictable in the absence of the librsvg pixbuf loader.
resample
Description
Adjust an audio stream's sampling rate, and duplicate channels if
producer provides less than consumer requested.
This filter is automatically invoked by Fezzik for the sake of
normalisation over inputs and with the consumer.
Constructor Argument
frequency - a numeric value for the new sample rate
Initialisation Properties
int in - in point
int out - out point
Mutable Properties
int frequency - the target sample rate
Dependencies
libresample
Known Bugs
Assumes 2 channels during libsamplerate initialisation. Untested
with >2 channels.
rescale
Description
Scale the producer video frame size to match the consumer.
This filter is designed for use as a Fezzik normaliser.
Constructor Argument
None.
Initialisation Properties
int in - in point
int out - out point
Mutable Properties
If a property "consumer_aspect_ratio" exists on the frame, then
rescaler normalises the producer's aspect ratio and maximises the
size of the frame, but may not produce the consumer's requested
dimension. Therefore, this option works best in conjunction with the
resize filter. This behavior can be disabled by another service by
either removing the property, setting it to zero, or setting
frame property "distort" to 1.
Dependencies
none
Known Bugs
none but... it only implements a nearest neighbour scaling - it is
used as the base class for the gtkrescale and mcrescale filters.
resize
Description
Image scaling and padding and field order adjustment.
Details
Normally resize is used to pad the producer's
output to what the consumer has requested after an upstream rescale
filter first scales the image to maximise usage of the image area.
This filter also adjusts the field order to lower field first
if the frame property "top_field_first" has been set to 1.
Therefore, when done, it sets the top_field_first to 0.
This filter is automatically invoked by Fezzik as part of image
sample aspect ratio normalisation.
Constructor Argument
scale - "affine" to use affine transform scaling, otherwise
center and pad.
Initialisation Properties
int in - in point
int out - out point
Read Only Properties
none
Dependencies
none
Known Bugs
Assumes lower field first output.
volume
Description
Adjust an audio stream's volume level
- based on the 'normalize' utility
Constructor Argument
gain - a string containing one of:
- a floating point value of the gain adjustment
- a numeric value with the suffix "dB" to adjust in terms of decibels
- "normalise" to normalise the volume to the target amplitude -12dBFS
Initialisation Properties
int in - in point
int out - out point
int window - the number of video frames over which to smooth normalisation.
defaults to 75.
Mutable Properties
string gain - same as constructor argument above
string normalise - normalise the volume to the amplitude:
- a numeric value with the suffix "dB" to set amplitude in decibels
- a floating point value of the relative volume
- an unspecified value uses the default -12dBFS
string limiter - limit all samples above:
- a numeric value with the suffix "dB"
- a floating point value ( dB = 20 * log10(x) )
- an unspecified value uses the default -6dBFS
double max_gain - a floating point or decibel value of the maximum gain that
can be applied during normalisation.
- an unspecified value uses the default 20dB
string end - a gain value just like the gain property above.
This causes the gain to be interpolated from 'gain' to 'end'
over the duration.
int window - the size of the normalising smoothing buffer in video frame units.
- the smoothing buffer prevents erratic gain changes.
- the default value is 75 video frames.
gain can be applied as a factor to the normalise amplitude!
Dependencies
none
Known Bugs
none
watermark
Description
Add a watermark to the frames.
Constructor Argument
resource - the producer to use (ie: a .png)
Initialisation Properties
string resource - the producer to use
string factory - producer required for the resource ('fezzik')
string geometry - composite geometry
string distort - control scaling
int in - in point
int out - out point
Mutable Properties
none
Dependencies
mlt core modules and optionally, fezzik
Known Bugs
none
Transitions
-----------
composite
Description
A key-framable alpha-channel compositor for two frames.
Details
Performs dissolves and luma wipes in addition to alpha compositing.
By default, the aspect ratio of the B frame is respected and the
size portion of the geometry specification simply defines a
bounding rectangle.
This performs field-based rendering unless the A frame property
"progressive" or "consumer_progressive" or the transition property
"progressive" is set to 1.
Constructor Argument
none[*]
Initialisation Properties
int in - in point
int out - out point
string factory - The name of a factory service used as a non-PGM
producer loader. The default is fezzik.
Read Only Properties
none
Mutable Properties
string geometry - key frame specification
- this is a ; delimited form of the deprecated start,
key[n], end properties
int progressive - set to 1 to disable field-based rendering.
string distort - when set, causes the B frame image to fill the WxH
completely with no regard to B's aspect ratio.
string halign - when not distorting, set the horizontal alignment
of B within the geometry rectangle.
- one of: left (0), centre (1), or right (2).
- the default is left.
string valign - when not distorting, set the vertical alignment of
B within the geometry rectangle.
- one of: top (0), middle (1), or bottom (2).
- the default is top.
string luma - the luma map file name. If not supplied, a dissolve.
double softness - only when using a luma map, how soft to make the
edges between A and B. 0.0 = no softness. 1.0 =
too soft.
Any property starting with "luma." is passed to the non-PGM luma
producer.
Deprecated Properties
string start - a geometry specification as X,Y:WxH[!][:mix]
- X, Y, W, H are assumed to pixel units unless they
have the suffix '%'
- '!' is a shortcut to specify distort, see below.
- mix is always a 2 digit percentage, defaults to 100.
- default is "85%,5%:10%x10%"
string end - the ending size and position.
string key[F] - X,Y:WxH[:mix] - set a key frame for geometry between
the in and out. F is a frame number and can be
negative to make it relative to the out point.
Dependencies
none
Known Bugs
Assumes lower field first during field rendering.
luma
Description
A generic dissolve and wipe transition processor.
Details
luma gets its name
from how it uses a grayscale "map" file. As the luma value varies
over time, a threshold filter is applied to the map to determine
what parts of frame A vs. frame B to show. It reads PGM files
up to 16 bits! Alternatively, it can use the first frame from any
producer that outputs yuv, but it will be limited to the luma
gamut of 220 values.
This performs field-based rendering unless the A frame property
"progressive" or "consumer_progressive" or the transition property
"progressive" is set to 1.
Constructor Argument
string resource - the luma map file name - either PGM or any other
producable video.
- If not supplied, a dissolve.
Initialisation Properties
int in - in point
int out - out point
string factory - The name of a factory service used as a non-PGM
producer loader. The default is Fezzik.
Mutable Properties
string resource - same as above
double softness - only when using a luma map, how soft to make the
edges between A and B. 0.0 = no softness. 1.0 =
too soft.
int reverse - reverse the direction of the transition.
Any property starting with "producer." is passed to the non-PGM luma
producer.
Read Only Properties
none
Dependencies
none
Known Bugs
Assumes lower field first output.
mix
Description
An two stream audio mixer.
Constructor Argument
start - see below
Initalisation Properties
int in - in point
int out - out point
Mutable Properties
double start - the mix level to apply to the second frame.
- any negative value causes an automatic crossfade from 0 to 1.
double end - the ending value of the mix level. mix level will be interpolated
from start to end over the in-out range.
int reverse - set to 1 to reverse the direction of the mix.
Read Only Properties
none
Dependencies
none
Known Bugs
Samples from the longer of the two frames are discarded.
region
Description
Apply zero or more filters to B frame as it is composited onto
a region of the A frame. The "shape" of the region can be defined
by the alpha channel of a third producer.
Constructor Argument
resource - a shape producer
Initialisation Properties
string resource - nothing is rectangle, "circle" is a pixbuf-
generated SVG circle, anything else is loaded by the factory.
string factory - the service that creates the shape producer.
- the default is fezzik.
string filter[N] - one or more filters to apply. All filter
properties are passed using the same filter "key"
Any property starting with "composite." is passed to the
encapsulated composite transition.
Read Only Properties
none
Dependencies
transition_composite
Known Bugs
none
Consumers
---------
avformat
Description
Multiformat transcoding consumer.
Constructor Argument
string target - the filename to write to, e.g. test.mpeg.
Initialisation Properties
int buffer - the number of frames to buffer, minimum 1, default 25.
string rescale - a rescale method, see the Filters/rescale.
int progressive - indicates whether to use progressive or field-
based rendering, default 0 (off).
Read Only Properties
none
Dependencies
libavformat
Known Bugs
Plenty.
bluefish (Proprietary)
Description
BlueFish444 audio and video output module.
Constructor Argument
card - a numeric card id starting at 1, default is 1.
Initialisation Properties
string standard - "PAL" (default) or "NTSC"
- default is based upon MLT_NORMALISATION
environment variable, which defaults to PAL.
int frames - the number of DMA video frames. default is 8.
minimum is 2. maximum on my system is 11.
int buffer - the number of frames to buffer within MLT, minimum 1,
default 25.
string rescale - a rescale method, see the Filters/rescale.
Read Only Properties
none
Dependencies
BlueVelvet SDK installed parallel to mlt in "bluefish."
Known Bugs
Does not work with any service that uses pipes!
If mlt crashes, you might need to reload the BlueDriver kernel
module due to unreleased DMA buffers.
Only supports 2 channel audio at the moment.
libdv
Description
libdv dv producer.
Constructor Argument
string target - the filename to write to, e.g. /dev/dv1394.
Initialisation Properties
int buffer - the number of frames to buffer, minimum 1, default 25.
string rescale - a rescale method, see the Filters/rescale.
Mutable Properties
int progressive - indicates whether to use progressive or field-
based rendering, default 0 (off).
Read Only Properties
none
Dependencies
libdv
Known Bugs
none
mcmpeg
Description
Mainconcept MPEG encoder.
Constructor Argument
string target - the filename to write to.
Initialisation Properties
int buffer - the number of frames to buffer, minimum 1, default 25.
string rescale - a rescale method, see the Filters/rescale.
string format - vcd [default], svcd or dvd provide base settings
int motion_search_type - 0 to 16 - reduces quality/cpu usage
int gop - group of picture size (default: format dependent)
Mutable Properties
int progressive - indicates whether to use progressive or field-
based rendering, default 0 (off).
Read Only Properties
none
Dependencies
Mainconcept MPEG SDK
Known Bugs
none
sdl
Description
Simple DirectMedia Layer audio and video output module.
Constructor Argument
string video_standard - "PAL" (default), "NTSC", or "WxH"
Initialisation Properties
int buffer - the number of frames to buffer, minimum 1, default 25.
string rescale - a rescale method, see the Filters/rescale.
- Hint: "none" works very good with SDL output.
Mutable Properties
double volume - audio level factor
int video_off - if 1, disable video output
int audio_off - if 1, disable audio output
int resize - TODO
int progressive - indicates whether to use progressive or field-
based rendering, default 0 (off).
int audio_buffer - size of the sdl audio buffer (default: 1024)
Read Only Properties
none
Dependencies
libSDL-1.2, libasound, libaudio, libXt, libX11, libXext, libSM, libICE
Known Bugs
none
westley
Description
Serialise the service network to XML.
See docs/westley.txt for more information.
Constructor Argument
resource - the name of a file in which to store the XML.
- stdout is default.
Initialisation Properties
string resource - same as above.
Dependencies
libxml2
Known Bugs
Untested arbitrary nesting of multitracks and playlists.
Property "id" is generated as service type followed by number if
no property named "id" exists, but it fails to guarantee uniqueness.
