[FFmpeg-devel] libschroedinger FFmpeg bug

Anuradha Suraparaju anuradha
Fri May 16 08:16:34 CEST 2008


On Fri, 2008-05-16 at 00:58 +0200, Diego Biurrun wrote:
> Hello Anuradha,
> maybe you can have a look at the following bug:
> http://roundup.mplayerhq.hu/roundup/ffmpeg/issue453
> Somebody is having trouble encoding with libschroedinger.

I looked into this and there are two problems:

1. There is no fourcc code for CODEC_ID_DIRAC in riff.c. So even if we a
successfully wrap libschroedinger in AVI, we won't be able to play it

2. The second problem is to do with presentation time stamps. For frame
data, libschroedinger uses the frame number is display order as the pts
(it assumes a fixed frame rate input). However, libschroedinger also
returns some  non-frame data - e.g Sequence headers, padding data,
auxiliary data as separate packets. These data do not have a pts
associated with them hence the 'non monotone timestamps' error.

I looked at the code for MPEG4 encoding and it appears that, correct me
if I am wrong,  the GOP header (the sequence header in Dirac is similar
to this) in prepended to the encoder picture data and not as a separate
packet. Is this the way to solve the pts problem? i.e. prepend all
non-picture data to an encoded picture.

> Diego


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