[FFmpeg-devel] [PATCH] avcodec/nuv: call ff_reget_buffer() only when the picture data is going to change

[James Almer]

On 8/27/2019 11:25 AM, James Almer wrote:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> This is an alternative approach to "avcodec/nuv: Avoid duplicating frames",
> similar to the one from "avcodec/qtrle: call ff_reget_buffer() only when the
> picture data is going to change", to workaround fuzzer reported timeouts but
> without changing the behavior of the decoder.
> 
>  libavcodec/nuv.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/nuv.c b/libavcodec/nuv.c
> index 75b14bce5b..4b171fde36 100644
> --- a/libavcodec/nuv.c
> +++ b/libavcodec/nuv.c
> @@ -268,7 +268,15 @@ retry:
>          init_frame = 1;
>      }
>  
> -    if ((result = ff_reget_buffer(avctx, c->pic)) < 0)
> +    if (comptype == NUV_COPY_LAST) {
> +        if (!c->pic->data[0])
> +            return AVERROR_INVALIDDATA;
> +        // ff_reget_buffer() isn't needed when frames don't change, so just update
> +        // frame props.
> +        ret = ff_decode_frame_props(avctx, c->pic);
> +        if (ret < 0)
> +            return ret;
> +    } else if ((result = ff_reget_buffer(avctx, c->pic)) < 0)
>          return result;
>      if (init_frame) {
>          memset(c->pic->data[0], 0,    avctx->height * c->pic->linesize[0]);

Pushed a simpler version now that ff_reget_buffer() has a flags field
for this purpose.