[ogg-dev] ffmpeg2theora tool

Frank Barchard fbarchard at google.com
Mon Jun 29 15:34:31 PDT 2009

I've been encoding with ffmpeg.exe.  Due to the muxing issue, I tried
ffmpeg2theora, but I ran into some issues

1. it fails on 1080p content.  1920x1080.  1920x800 is okay.

2. I have raw yuv.  in ffmpeg I use -s 1920x1080 to specify the source
size.  ffmpeg2theora doesnt seem to have a way to accept width/height
for the raw yuv (420).  So I need to do an additional step of muxing
it into a quicktime or something?

3. -V to set bitrate seems wildly off.  Whereas -b in ffmpeg works
pretty well.  Even -v for quality factor seems ignored in one of my
clips, and uses way lower (10x) bitrate than I want, and the quality
thereof?  Should something like -v 8 be high quality

4. ffmpeg reports errors while decoding
[theora @ 0x3ef4a0]vp3: first frame not a keyframe
Error while decoding stream #0.0

5. quality is visually very poor.. both in my player, and others like
mplayer.  Likely due to (3) and (4).  If I use ffmpeg to encode the
video, quality is fine.

By decoding with ffmpeg to a file, I run a psnr tool on it and it says
PSNR is 26.318160.

This is using J's latest http://v2v.cc/~j/ffmpeg2theora/download.html (thanks!)

Here's an overall script you can criticize

:: *************************:: ogg container test matrix::
oggenc2 -o sync2.ogg sync2.wav
:: *************************:: ogv container test matrix::
:: Compress with libtheoraffmpeg2theora --optimize -v 8 -o sync.ogv
:: Mux all ogg video container variationsoggzmerge sync2.ogg sync.ogv
-o sync2.ogv
:: Compute PSNRffmpeg -y -i sync2.ogv -vcodec rawvideo -pix_fmt
yuv420p sync_ogv.720x480_30Hz_P420.yuvpsnr -s 720 480
sync.720x480_30Hz_P420.yuv sync_ogv.720x480_30Hz_P420.yuv
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