[theora-codecs] Call for bugs and suggestions

[Peter Mulholland]

Hello Mauricio,

Friday, February 7, 2003, 4:13:43 PM, you wrote:

MP> I would like to know what are the main issues people have today with the VP3
MP> codecs for QT and AVI.

I'm having a problem with the vfw codec and encoding video - it appears that in some circumstances, the vp3
codec loses sync between keyframes and the video just stops. It only resumes playback upon the next keyframe
(which with auto keyframe can be some considerable time).

It appears to be affected further by what audio codec/bitrate is used - example, on a test video, if the audio
is in PCM, it plays fine, if I encode it as IMA ADPCM, it causes the problem. The only thing I can think is
that the extra overhead of decoding the audio is upsetting it.

It is not specific to the AVI format either - for my development team we have an internal format similar to
AVI which can contain video and multiple audio soundtracks... it appears to be to do with how fast the data is
presented to the decoder. As of yet, I'm unsure as to whether it's an encoding or decoding (in real time)
problem - an affected AVI appears to have no problems decoding as long as it's not in real time (eg skipping
through the frames in VirtualDub).

It is probable that our format will be dropped in favour of Theora & Vorbis in an Ogg wrapper anyway - we
already use Vorbis audio in the custom format.


-- 
Best regards,
 Peter                            mailto:darkmatter at blueyonder.co.uk

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