In order to load FFmpegSource all included dlls except ffmpegsource.dll must be located in the path or in the current working directory.
It is also possible to autoload it if you put all dlls and the avsi file in avisynth's autoloading directory (usually C:\Program Files\AviSynth 2.5\plugins).
Note that the audio cache will always be created when opening files with audio and that it will be huge since it stores all audio as raw signed 16/24/32 bit pcm, unsigned 8 bit pcm or as float, using flac to compress it is also possible to reduce the size by half.
Specifies the file to store the index information or raw audio in, if nothing is specified (source).ffv(tracknumber)cache is used for video and (source).ffa(tracknumber)cache for audio.
See the table below for a full description, an empty string means no processing. It is recommended to avoid the autoq option since it's currently unknown what effect it will have on the processing.
<b>-1:</b> linear access without rewind, will throw an error if each successive requested frame number isn't bigger than the last one, only intended for opening images but might work on well with some obscure video format<br/>
<b>0:</b> linear access, the definition of slow but should make some formats "usable"<br/>
<b>1:</b> safe normal, bases seeking decisions on the reported keyframe positions<br/>
<b>2:</b> unsafe normal, same as 1 but no error will be thrown if the exact destination has to be guessed<br/>
<b>3:</b> aggressive, seek in the forward direction even if no closer keyframe is known to exist, only useful for testing and containers where avformat doesn't report keyframes properly
<li>Now always sorts the output timecodes so native avc in mkv won't have out of order values</li>
<li>Fixed the missing '# timecode format v2' line in saved timecode files</li>
<li>Now properly handles video files where the output resolution isn't known until a frame has been decoded (seems to fix flv4)</li>
<li>Now throws an error if the video decoder returns zero size video</li>
<li>Added an avsi file for easy autoloading</li>
<li>Updated libFLAC to 1.2.1<li>
<li>Updated FFmpeg to rev 10671 + camtasia swapped colors fix</li>
</ul></li>
<li>1.12<ul>
<li>Now caches the last fully decoded frame to increase the reliability of seekmode=-1 and possibly reduce seeking in other modes</li>
<li>Video that needs to be converted to a suitable output format should now always have correct colors (was reversed in 1.11 and inconsistent in earlier versions)</li>
<li>Added seekmode=-1 which is mostly useful for opening image files very carefully</li>
<li>Now throws an error if the container is unseekable and seekmode=-1 isn't set</li>
<li>Updated FFmpeg to rev 10492 + camtasia swapped colors fix</li>
</ul></li>
<li>1.11<ul>
<li>Now officially uses the MIT license</li>
<li>Much cleaner source</li>
<li>Can be compiled without support for compressing the audio cache with FLAC</li>
<li>Supports more audio formats in matroska</li>
<li>RGB24 output no longer has swapped colors if the video is converted to it for output (there still seems to be some bugs lurking when conversion is done with libswscale)</li>
<li>Fixed an access violation on close when no audio is opened (introduced in 1.10)</li>
<li>Updated FFmpeg to rev 10423</li>
</ul></li>
<li>1.10<ul>
<li>The audio cache compression level is now ignored if the source isn't 16bit and the raw format is used instead</li>
<li>FLAC is now actually initialized properly so the cache actually works for files that aren't stereo (16bit limit still applies)</li>
<li>Now uses proper callbacks for FLAC so it works with larger than 2GB files</li>
<li>Doesn't (over)write the video cache with an empty one in certain cases when avformat is used for the source</li>
</ul></li>
<li>1.9<ul>
<li>Added the possibility to compress the audio cache with FLAC (currently only works with 16bit audio)</li>
<li>Added another planar YUV 4:2:0 format to the supported output formats (fixes certain mov files)</li>
<li>Less memory is now allocated on the stack which makes av_find_stream_info() work for all files (fixes certain mov files)</li>
<li>Updated FFmpeg to rev 10186</li>
</ul></li>
<li>1.8<ul>
<li>Updated FFmpeg to rev 10141</li>
</ul></li>
<li>1.7<ul>
<li>Updated FFmpeg</li>
<li>Fixed error with mkv for codecs without codec private data and the first packet doesn't belong to them</li>
</ul></li>
<li>1.6<ul>
<li>Fixed ac3 and other formats stored in mkv</li>
<li>Skip unnecessary seeking when index information already exists (gif file opening only 3/4 broken now)</li>
<li>Throws an error when the selected audio/video track has no frames/samples</li>
</ul></li>
<li>1.5<ul>
<li>Fixed a bug that made avformat opened files only return audio if only the audio cache needed to be created</li>
<li>Rejects more corrupt cache files</li>
<li>Fixed crash when a 0 byte audio cache file is present</li>
<li>Improved framerate guessing for avformat which now takes takes the duration of the first frame into account</li>
<li>Fixed a bug introduced in 1.4 that would make the number of reported frames too high for files opened with avformat</li>
<li>Fixed mpeg2 and probably some other formats stored in mkv</li>
<li>Fixed issues with large mkv files and large audio cache files</li>
<li>FFmpeg is now compiled with liba52 and faad2</li>
</ul></li>
<li>1.4<ul>
<li>Uses the average framerate for mkv files</li>
<li>Naming scheme of cache files changed to prevent confusion with the default names in files with multiple tracks of the same type</li>
<li>Use mmx optimizations in swscaler when possible</li>
<li>Now uses normal windows linebreaks in all files</li>
<li>Removed FFAudioSource</li>
<li>Merged FFVideoSource and FFAudioRefSource into FFmpegSource</li>
<li>Added postprocessing with libpostproc in FFmpegSource and separately in FFPP</li>
</ul></li>
<li>1.3<ul>
<li>Compiled against ffmpeg rev9620</li>
<li>Added FFAudioRefSource</li>
<li>Added FFAudioSource (has big issues)</li>
<li>Renamed FFmpegSource to FFVideoSource</li>
<li>Adjusted seeking in the forward direction to only be done if the requested frame is more than 10 frames away to reduce unnecessary seeking</li>
<li>Now outputs the last frame properly when there are decoding delays</li>
</ul></li>
<li>1.2<ul>
<li>Compiled against ffmpeg rev9451</li>
<li>Somewhat cleaner source code</li>
<li>Linear access in addition to a few other modes of seeking can now be forced</li>
<li>Can now save the index information to a file which makes subsequent file opening fast</li>
<li>No longer skips indexing for any format</li>
</ul></li>
<li>1.1<ul>
<li>Skip indexing for avi</li>
<li>Prefix all error messages with the plugin name</li>
