FFmpegSource Documentation

Changes

• 1.3
  • Compiled against ffmpeg rev9620
  • Added FFAudioRefSource
  • Added FFAudioSource (has big issues)
  • Renamed FFmpegSource to FFVideoSource
  • Adjusted seeking in the forward direction to only be done if the requested frame is more than 10 frames away to reduce unnecessary seeking
  • Now outputs the last frame properly when there are decoding delays
• 1.2
  • Compiled against ffmpeg rev9451
  • Somewhat cleaner source code
  • Linear access in addition to a few other modes of seeking can now be forced
  • Can now save the index information to a file which makes subsequent file opening fast
  • No longer skips indexing for any format
• 1.1
  • Skip indexing for avi
  • Prefix all error messages with the plugin name
  • Can write v2 timecodes to a file
  • Fixed reported framerate

Usage

FFVideoSource(string source, int track = -1, int seekmode = 1, string timecodes, bool cache = true, string cachefile)
A video source that is frame accurate for most popular containers

FFAudioSource(string source, int track = -1)
Very unreliable attempt at sample accurate seeking in audio files

FFAudioRefSource(string source, int track = -1, string cachefile)
Decodes all audio to a temporary file which ensures that it will always be sample accurate

source: source file

track: track number as seen by the relevant demuxer, starts from 0, -1 means it will pick the first suitable track

seekmode: force how seeking is handled, has no effect on matroska files which always use the equivalent of seekmode=1
0: linear access, the definition of slow but should make some formats "usable"
1: safe normal, bases seeking decisions on the reported keyframe positions
2: unsafe normal, same as 1 but no error will be thrown if the exact destination has to be guessed
3: aggressive, seek in the forward direction even if no closer keyframe is known to exist, only useful for containers where avformat doesn't report keyframes properly and testing

timecodes: file to output timecodes to, if the file exists it will always be overwritten

cache: write indexing information to a file for later use

cachefile: if specified the file to store the index information or raw audio in, if nothing is specified (source).ffcache is used for video and (source).ffracache for audio

Compatibility - Video

• AVI, MKV, MP4, FLV: Frame accurate
• WMV: Frame accurate(?) but avformat seems to pick keyframes relatively far away
• OGM: Messed up first frame and seeking produces smearing with seekmode=3, incredibly slow seeking without, remux to mkv or avi
• VOB: No rff flags applied, frame accurate?
• MPG: Seeking seems to be off by one or two frames now and then
• TS: don't bother

Compatibility - Audio

• Not sample accurate ever?

Compiling

zlib from http://www.zlib.net/

FFmpeg svn from http://ffmpeg.mplayerhq.hu/

Required Configuration: ./configure --enable-shared --disable-static --enable-memalign-hack --enable-gpl --enable-swscaler

Suggested Additional Options: --disable-encoders --disable-muxers --enable-small