[FFmpeg-devel] h264: dealing with "broken links"
Mon Nov 19 20:54:23 CET 2007
On Mon, 19 Nov 2007, Michael Niedermayer wrote:
> 1. all unavailable reference frames must be allocated and guessed from
> available frames (just memcpy them from a random available frame would
> do for now)
Actually, is this still a problem for H264? Code at the bottom of
decode_ref_pic_list_reordering appears to be looking through the whole
reference list, filling empty spots with a copy of the current picture.
Obviously not the perfect solution, but it makes them non-NULL.
> 2. drop unimportant frames (B frames / theres a priority field in the NAL
> header which could maybe be used)
Yes. mpegvideo MPV_frame_start expects last_picture_ptr to be valid
prior to allocating for B pictures. H264 doesn't guard this and that's
why people keep seeing the endless loop to eventual picture buffer
exhaustion (would assert if so enabled).
I've not yet had a chance to do a clean fix.
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