[FFmpeg-devel] [PATCH] avcodec/h264_slice: clear old slice POC values on parsing failure

[Andreas Rheinhardt]

James Almer:
> If a slice header fails to parse, and the next one uses different Sequence and
> Picture parameter sets, certain values may not be read if they are not coded,
> resulting in the previous slice values being used.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavcodec/h264_slice.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
> index 41338fbcb6..a31e804620 100644
> --- a/libavcodec/h264_slice.c
> +++ b/libavcodec/h264_slice.c
> @@ -1897,6 +1897,8 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
>      if (nal->type == H264_NAL_IDR_SLICE)
>          get_ue_golomb_long(&sl->gb); /* idr_pic_id */
>  
> +    sl->poc_lsb = 0;
> +    sl->delta_poc_bottom = 0;
>      if (sps->poc_type == 0) {
>          sl->poc_lsb = get_bits(&sl->gb, sps->log2_max_poc_lsb);
>  
> @@ -1904,6 +1906,7 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
>              sl->delta_poc_bottom = get_se_golomb(&sl->gb);
>      }
>  
> +    sl->delta_poc[0] = sl->delta_poc[1] = 0;
>      if (sps->poc_type == 1 && !sps->delta_pic_order_always_zero_flag) {
>          sl->delta_poc[0] = get_se_golomb(&sl->gb);
>  
> 
Does this patch actually change anything when all SPS use
pic_ordering_cnt_type 0?

- Andreas