[FFmpeg-devel] [PATCH] avcodec/cbs_av1: fix parsing delta_frame_id_minus1

Mark Thompson sw at jkqxz.net
Thu Dec 20 22:45:59 EET 2018


On 20/12/2018 15:39, James Almer wrote:
> delta_frame_id_minus1 is not a single value in the bitstream, and can
> store values up to 17 bits wide.
> 
> Fixes parsing files with frame ids.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> See https://code.videolan.org/videolan/dav1d/uploads/a23d47dda3011a8e39ab1ac7c508b220/input.ivf
> 
>  libavcodec/cbs_av1.h                 | 2 +-
>  libavcodec/cbs_av1_syntax_template.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/cbs_av1.h b/libavcodec/cbs_av1.h
> index 84622ed189..71ceff9427 100644
> --- a/libavcodec/cbs_av1.h
> +++ b/libavcodec/cbs_av1.h
> @@ -170,7 +170,7 @@ typedef struct AV1RawFrameHeader {
>      uint8_t last_frame_idx;
>      uint8_t golden_frame_idx;
>      int8_t  ref_frame_idx[AV1_REFS_PER_FRAME];
> -    uint8_t delta_frame_id_minus1;
> +    uint32_t delta_frame_id_minus1[AV1_REFS_PER_FRAME];
>  
>      uint8_t allow_high_precision_mv;
>      uint8_t is_filter_switchable;
> diff --git a/libavcodec/cbs_av1_syntax_template.c b/libavcodec/cbs_av1_syntax_template.c
> index 0da79b615d..48f4fab514 100644
> --- a/libavcodec/cbs_av1_syntax_template.c
> +++ b/libavcodec/cbs_av1_syntax_template.c
> @@ -1323,8 +1323,8 @@ static int FUNC(uncompressed_header)(CodedBitstreamContext *ctx, RWContext *rw,
>              if (!current->frame_refs_short_signaling)
>                  fbs(3, ref_frame_idx[i], 1, i);
>              if (seq->frame_id_numbers_present_flag) {
> -                fb(seq->delta_frame_id_length_minus_2 + 2,
> -                   delta_frame_id_minus1);
> +                fbs(seq->delta_frame_id_length_minus_2 + 2,
> +                    delta_frame_id_minus1[i], 1, i);
>              }
>          }
>  
> 

Yep, LGTM.  (I hate the mutable single-syntax-element variables in that spec.)

Thanks,

- Mark


More information about the ffmpeg-devel mailing list