[FFmpeg-devel] [PATCH 3/3] lavc/libxvid: workaround for bug in libxvidcore

[Lukasz Marek]

On 24.11.2014 01:17, Lukasz Marek wrote:
> libxvidcore calculate number of threads basing on video height.
> If height is small enough it allocates 0 bytes long memory and
> writes to it.
> Setting thread_count to 0 uses 1 thread and skips bugged code.
>
> Signed-off-by: Lukasz Marek <lukasz.m.luki2 at gmail.com>
> ---
>   libavcodec/libxvid.c | 11 +++++++++++
>   1 file changed, 11 insertions(+)
>
> diff --git a/libavcodec/libxvid.c b/libavcodec/libxvid.c
> index 70d52b9..efe7b8a 100644
> --- a/libavcodec/libxvid.c
> +++ b/libavcodec/libxvid.c
> @@ -471,6 +471,17 @@ static av_cold int xvid_encode_init(AVCodecContext *avctx)
>       xvid_enc_create.num_zones = 0;
>
>       xvid_enc_create.num_threads = avctx->thread_count;
> +    /* workaround for a bug in libxvidcore */
> +    if (avctx->height < 18) {
> +        if (avctx->thread_count < 2) {
> +            xvid_enc_create.num_threads = 0;
> +        } else {
> +            av_log(avctx, AV_LOG_ERROR,
> +                   "Too small height for threads > 1.");
> +            ret = AVERROR(EINVAL);
> +            goto fail;
> +        }
> +    }
>
>       xvid_enc_create.plugins     = plugins;
>       xvid_enc_create.num_plugins = 0;
>

Please comment this patch. xvid accepted fix for it.
Personally I don't care, but when configured "correctly" ffmpeg is using 
not allocated memory via external library.
I just don't know if keep it or just forget about it.