[FFmpeg-devel] [PATCH] cbs_h264: Fix types of abs_diff_pic_num_minus1 and

[Mark Thompson]

On 07/06/2019 02:17, Andreas Rheinhardt wrote:
> difference_of_pic_nums_minus1
> 
> They are unsigned values.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> Sorry for sending the first email prematurely.
>  libavcodec/cbs_h264.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/cbs_h264.h b/libavcodec/cbs_h264.h
> index a31be298ba..b9b9d2d1fd 100644
> --- a/libavcodec/cbs_h264.h
> +++ b/libavcodec/cbs_h264.h
> @@ -379,7 +379,7 @@ typedef struct H264RawSliceHeader {
>      uint8_t ref_pic_list_modification_flag_l1;
>      struct {
>          uint8_t modification_of_pic_nums_idc;
> -        int32_t abs_diff_pic_num_minus1;
> +        uint32_t abs_diff_pic_num_minus1;
>          uint8_t long_term_pic_num;
>      } rplm_l0[H264_MAX_RPLM_COUNT], rplm_l1[H264_MAX_RPLM_COUNT];
>  
> @@ -406,7 +406,7 @@ typedef struct H264RawSliceHeader {
>      uint8_t adaptive_ref_pic_marking_mode_flag;
>      struct {
>          uint8_t memory_management_control_operation;
> -        int32_t difference_of_pic_nums_minus1;
> +        uint32_t difference_of_pic_nums_minus1;
>          uint8_t long_term_pic_num;
>          uint8_t long_term_frame_idx;
>          uint8_t max_long_term_frame_idx_plus1;
> 

Not sure of this one - the ranges easily fit in int32_t, and they are likely be used in signed contexts (PicNum for a given reference picture can be negative).  Is there really any benefit to the field being unsigned?

- Mark