#10158: bsf 264_metadata removes stuffing bytes from NAL units - destroys
original
bitrate
-------------------------------------+-------------------------------------
Reporter: emcodem | Owner: (none)
Type: enhancement | Status: new
Priority: normal | Component: avcodec
Version: git-master | Resolution:
Keywords: bsf | Blocked By:
264_metadata H264 filtering |
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Comment (by emcodem):
Just for info, i had a talk to mkver about this. He proposed to just
append zeros to the pkt instead of remembering the trailing bytes on a per
NALu basis. I played with this about 2 weeks but it was really too hard
for me to find a way add the trailing bytes per nalu. I was not able to
store any size modification of the nalu or the packet in
h264_metadata_update_fragment method (h264_metadata_bsf.c). I guess mostly
because of my missing understanding about how the ref stuff works.
Storing and restoring the trailing bytes on a per nalu base would probably
be what everyone expects from the bsf (not actually modify anything else
than it's instructed to modify) but for my usecase, it should be fine when
i just append zeros to the packet which hopefully leads to the last IDR
SLice NALu containing all the trailing bytes that have been removed by cbs
and it's unit de and re-composition.
What i do for testing (if it works of course in production :D) is a simple
hack in cbs.c ff_cbs_write_packet method; remember the original pkt size
before updating it and right before return 0:
if (original_size > pkt->size)
av_grow_packet(pkt,original_size - pkt->size);
--
Ticket URL: <https://trac.ffmpeg.org/ticket/10158#comment:2>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
_______________________________________________
FFmpeg-trac mailing list
[email protected]
https://ffmpeg.org/mailman/listinfo/ffmpeg-trac
To unsubscribe, visit link above, or email
[email protected] with subject "unsubscribe".
