[FFmpeg-devel] [PATCH v2] avcodec/h264_sei: fix H.274 film grain parsing

[James Almer]

On 8/2/2021 9:06 AM, Niklas Haas wrote:
> From: Niklas Haas <git at haasn.dev>
> 
> The current code reads the wrong number of bits for `fg_model_id`, which
> causes all of the values downstream of this to contain corrupt values.
> 
> Fixes: corrupt SEI values
> Fixes: 4ff73add5dbe6c319d693355be44df2e17a0b8bf
> 
> Signed-off-by: Niklas Haas <git at haasn.dev>
> ---
>   libavcodec/h264_sei.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
> index 7797f24650..329c2ea4f2 100644
> --- a/libavcodec/h264_sei.c
> +++ b/libavcodec/h264_sei.c
> @@ -424,7 +424,7 @@ static int decode_film_grain_characteristics(H264SEIFilmGrainCharacteristics *h,
>   
>       if (h->present) {
>           memset(h, 0, sizeof(*h));
> -        h->model_id = get_bits(gb, 8);
> +        h->model_id = get_bits(gb, 2);
>           h->separate_colour_description_present_flag = get_bits1(gb);
>           if (h->separate_colour_description_present_flag) {
>               h->bit_depth_luma = get_bits(gb, 3) + 8;

LGTM.