[theora-dev] Choppy video with alpha7

William Volkman wkvtheora at netshark.com
Tue Dec 19 00:47:19 PST 2006


I use my system for time-shifting local TV and I usually re-encode the
capture card's MPEG2 into theora to create much smaller files.  However
since upgrading from alpha 5 to alpha 7 I can no longer do this.  The
problem seems that the bit rates are too high and the resulting files
are unplayable (tried mplayer, vlc, and theora_play).

I've built the alpha7 libtheora rpm (using the Fedora Core 6 SRPM)
and installed it on Fedora Core 4 (my current system).
(I use an older build of cinellera to edit the video and produce
a linux quicktime movie with DV/PCM).

If I use -v 5 theora_encode show bit rates in the 80-90kpbs range.
By specifying -V 1800 I see bit rates that in the 7-30kbps range.

lav2yuv in.mov | yuvdeinterlace | theora_encode -V 1800 in.wav - >

I also tried the statically built ffmpeg2theora and it exhibits the
same problem.

Executing ffmpeg2theora in.mov
results in a in.ogg file that shows the first couple of frames, then
freezes, it may update once or twice, then finishes.  The audio for
the most part is fine, occasionally there is a drop out.

If I use ffmpeg to create a 2K bit rate MPEG4 video and then
use ffmpeg2theora the result plays fine (with horrible video

I'm probably going to drop back to alpha 5 however I wanted to find
out if this is a known problem, and if not, what you would like
from me to be able to fix it.


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