[FFmpeg-devel] [PATCH] lavc/gifdec: unify get_buffer() calls I/P frames

[James Almer]

On 7/11/2023 2:12 PM, Anton Khirnov wrote:
> Always call ff_reget_buffer(), which ensures that get_buffer2() is
> called with AV_GET_BUFFER_FLAG_REF.
> 
> Fixes #10460.
> ---
>   libavcodec/gifdec.c | 29 +++++++++++------------------
>   1 file changed, 11 insertions(+), 18 deletions(-)
> 
> diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c
> index f2ab783ef0..af65baabd5 100644
> --- a/libavcodec/gifdec.c
> +++ b/libavcodec/gifdec.c
> @@ -489,29 +489,22 @@ static int gif_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
>               return ret;
>   
>           av_frame_unref(s->frame);
> -        if ((ret = ff_get_buffer(avctx, s->frame, 0)) < 0)
> -            return ret;
> -
>           av_fast_malloc(&s->idx_line, &s->idx_line_size, s->screen_width);
>           if (!s->idx_line)
>               return AVERROR(ENOMEM);
> -
> -        s->frame->pict_type = AV_PICTURE_TYPE_I;
> -        s->frame->flags |= AV_FRAME_FLAG_KEY;
> -        s->keyframe_ok = 1;
> -    } else {
> -        if (!s->keyframe_ok) {
> -            av_log(avctx, AV_LOG_ERROR, "cannot decode frame without keyframe\n");
> -            return AVERROR_INVALIDDATA;
> -        }
> -
> -        if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
> -            return ret;
> -
> -        s->frame->pict_type = AV_PICTURE_TYPE_P;
> -        s->frame->flags &= ~AV_FRAME_FLAG_KEY;
> +    } else if (!s->keyframe_ok) {
> +        av_log(avctx, AV_LOG_ERROR, "cannot decode frame without keyframe\n");
> +        return AVERROR_INVALIDDATA;
>       }
>   
> +    ret = ff_reget_buffer(avctx, s->frame, 0);
> +    if (ret < 0)
> +        return ret;
> +
> +    s->frame->pict_type = s->keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
> +    s->frame->flags     = AV_FRAME_FLAG_KEY * s->keyframe;

There's code setting these two in rframe below the 
gif_parse_next_image() call, so maybe change it to this instead, and 
remove the duplication.

> +    s->keyframe_ok     |= !!s->keyframe;
> +
>       ret = gif_parse_next_image(s, s->frame);
>       if (ret < 0)
>           return ret;