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| author | Alexander Strange <astrange@ithinksw.com> | 2011-06-12 20:40:00 +0000 |
|---|---|---|
| committer | Anton Khirnov <anton@khirnov.net> | 2011-06-16 20:51:51 +0200 |
| commit | 3803af22d8e1092e658110e77db093922ce63e80 (patch) | |
| tree | b2e4647ce2477009a13ba649951fa238ed3149d3 | |
| parent | c98b928fa7dea6418c24a163e7bcd36b0eb922a3 (diff) | |
| download | ffmpeg-3803af22d8e1092e658110e77db093922ce63e80.tar.gz | |
h264: Complexify frame num gap shortening code
By observation it did not seem to handle prev_frame_num > frame_num.
This does not affect any files I have.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
| -rw-r--r-- | libavcodec/h264.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/libavcodec/h264.c b/libavcodec/h264.c index 0aac09754a..ad591269c6 100644 --- a/libavcodec/h264.c +++ b/libavcodec/h264.c @@ -2681,9 +2681,20 @@ static int decode_slice_header(H264Context *h, H264Context *h0){ h->mb_field_decoding_flag= s->picture_structure != PICT_FRAME; if(h0->current_slice == 0){ - if(h->frame_num != h->prev_frame_num && - (h->prev_frame_num+1)%(1<<h->sps.log2_max_frame_num) < (h->frame_num - h->sps.ref_frame_count)) - h->prev_frame_num = h->frame_num - h->sps.ref_frame_count - 1; + // Shorten frame num gaps so we don't have to allocate reference frames just to throw them away + if(h->frame_num != h->prev_frame_num) { + int unwrap_prev_frame_num = h->prev_frame_num, max_frame_num = 1<<h->sps.log2_max_frame_num; + + if (unwrap_prev_frame_num > h->frame_num) unwrap_prev_frame_num -= max_frame_num; + + if ((h->frame_num - unwrap_prev_frame_num) > h->sps.ref_frame_count) { + unwrap_prev_frame_num = (h->frame_num - h->sps.ref_frame_count) - 1; + if (unwrap_prev_frame_num < 0) + unwrap_prev_frame_num += max_frame_num; + + h->prev_frame_num = unwrap_prev_frame_num; + } + } while(h->frame_num != h->prev_frame_num && h->frame_num != (h->prev_frame_num+1)%(1<<h->sps.log2_max_frame_num)){ |