2017-02-03 16:59 GMT+02:00 Carl Eugen Hoyos <ceffm...@gmail.com>: > 2017-02-03 15:14 GMT+01:00 Ivo Andonov <ivo.ando...@gmail.com>: > > 2017-02-03 15:58 GMT+02:00 Carl Eugen Hoyos <ceffm...@gmail.com>: > > >> > I've got some old Pinetron DVRs that are supposed to produce a MPEG4 > >> > bitstream. Indeed they are but no non-Pinetron software can decode it. > >> > >> Please provide a sample! > >> > >> > I do now know what is the best approach for registering this as a new > >> > decoder > >> > >> It should be possible to identify the codec while reading the bitstream. > > The encoder sets no user data, so identification is not as simple as > hoped: How do subsequent frames start? Do you know what the > first bytes mean? > > Yes, no user data is set and as such automatic identification is not possible. The raw stream coming from the DVR is prefixed by a propriatory frame header (that I filter) which is not MPEG stream compliant and is meant for the viewer/recorder (timestamp, keyframe flag, frame data size etc).
So far I'm attempting to implement the decoding by explicitly specifing to ffmpeg the video codec to use (-vcodec xvid_alogics). xvid_alogics AVCodec is initialized the same way the mpeg4 one, just a different id. In the decode_init I change the avctx->codec_id to AV_CODEC_ID_MPEG4 and set a flag in workaround_bugs that I later use in the initially submitted block condition code. However it seems somewhere else in the code avctx->codec_id reverts back to avctx->codec->id and as a result I end up with a "Bad picture start code" due to ff_h263_decode_frame calling ff_h263_decode_picture_header instead of ff_mpeg4_decode_picture_header. I forgot to mention that my changes are against ffmpeg 2.6. (libavcodec 56.26.100) > > Not sure if attachments are fine here... Attempting one. > > I can confirm that your suggested change (above "pred = FASTDIV") > works as expected. > > Carl Eugen > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
