James Almer:
> poc.delta_poc_bottom and poc.delta_poc[1] are only coded in the bitstream if
> pps->pic_order_present is true, so ensure they are not used otherwise, to
> prevent the potential use of stale values.
>
> Signed-off-by: James Almer <jamr...@gmail.com>
> ---
> This complements ce4a31cd1ff0348d279af74d49556d0315171e94, and is a more
> thorough fix for the issue described in it, affecting all users of
> ff_h264_init_poc(), like the parser, and not just the decoder.
>
> libavcodec/h264_parse.c | 7 ++++---
> libavcodec/h264_parse.h | 2 +-
> libavcodec/h264_parser.c | 2 +-
> libavcodec/h264_slice.c | 2 +-
> 4 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/libavcodec/h264_parse.c b/libavcodec/h264_parse.c
> index 1c1d1c04b0..5d642c7201 100644
> --- a/libavcodec/h264_parse.c
> +++ b/libavcodec/h264_parse.c
> @@ -275,9 +275,10 @@ fail:
> }
>
> int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
> - const SPS *sps, H264POCContext *pc,
> + const PPS *pps, H264POCContext *pc,
> int picture_structure, int nal_ref_idc)
> {
> + const SPS *sps = pps->sps;
> const int max_frame_num = 1 << sps->log2_max_frame_num;
> int64_t field_poc[2];
>
> @@ -300,7 +301,7 @@ int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
> pc->poc_msb = pc->prev_poc_msb;
> field_poc[0] =
> field_poc[1] = pc->poc_msb + pc->poc_lsb;
> - if (picture_structure == PICT_FRAME)
> + if (pps->pic_order_present && picture_structure == PICT_FRAME)
> field_poc[1] += pc->delta_poc_bottom;
> } else if (sps->poc_type == 1) {
> int abs_frame_num;
> @@ -336,7 +337,7 @@ int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
> field_poc[0] = expectedpoc + pc->delta_poc[0];
> field_poc[1] = field_poc[0] + sps->offset_for_top_to_bottom_field;
>
> - if (picture_structure == PICT_FRAME)
> + if (pps->pic_order_present && picture_structure == PICT_FRAME)
> field_poc[1] += pc->delta_poc[1];
delta_pic_order_cnt_bottom and both delta_pic_order_cnt elements are
supposed to be inferred to zero when they are not present. If this were
done, the above additions wouldn't make a difference. I thought that
ce4a31cd1ff0348d279af74d49556d0315171e94 actually did exactly that,
which makes me not understand the current patch.
> } else {
> int poc = 2 * (pc->frame_num_offset + pc->frame_num);
> diff --git a/libavcodec/h264_parse.h b/libavcodec/h264_parse.h
> index 4d01620125..35c4810f34 100644
> --- a/libavcodec/h264_parse.h
> +++ b/libavcodec/h264_parse.h
> @@ -78,7 +78,7 @@ int ff_h264_parse_ref_count(int *plist_count, int
> ref_count[2],
> int slice_type_nos, int picture_structure, void
> *logctx);
>
> int ff_h264_init_poc(int pic_field_poc[2], int *pic_poc,
> - const SPS *sps, H264POCContext *poc,
> + const PPS *pps, H264POCContext *poc,
> int picture_structure, int nal_ref_idc);
>
> int ff_h264_decode_extradata(const uint8_t *data, int size, H264ParamSets
> *ps,
> diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
> index d3c56cc188..6e2e7cde67 100644
> --- a/libavcodec/h264_parser.c
> +++ b/libavcodec/h264_parser.c
> @@ -440,7 +440,7 @@ static inline int parse_nal_units(AVCodecParserContext *s,
> /* Decode POC of this picture.
> * The prev_ values needed for decoding POC of the next picture
> are not set here. */
> field_poc[0] = field_poc[1] = INT_MAX;
> - ret = ff_h264_init_poc(field_poc, &s->output_picture_number, sps,
> + ret = ff_h264_init_poc(field_poc, &s->output_picture_number,
> p->ps.pps,
> &p->poc, p->picture_structure, nal.ref_idc);
> if (ret < 0)
> goto fail;
> diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
> index 0d7107d455..223cf21267 100644
> --- a/libavcodec/h264_slice.c
> +++ b/libavcodec/h264_slice.c
> @@ -1742,7 +1742,7 @@ static int h264_field_start(H264Context *h, const
> H264SliceContext *sl,
> }
>
> ret = ff_h264_init_poc(h->cur_pic_ptr->field_poc, &h->cur_pic_ptr->poc,
> - h->ps.sps, &h->poc, h->picture_structure, nal->ref_idc);
> + h->ps.pps, &h->poc, h->picture_structure,
> nal->ref_idc);
> if (ret < 0)
> return ret;
>
>
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
