[FFmpeg-devel] [PATCH] avcodec/nvenc: Fix segfault with intra-only

Dennis Mungai dmngaie at gmail.com
Mon Jul 1 21:05:22 EEST 2024


On Mon, 1 Jul 2024 at 21:01, Timo Rothenpieler <timo at rothenpieler.org>
wrote:

> On 01.07.2024 18:52, Josh Allmann wrote:
> > On Thu, 20 Jun 2024 at 17:39, Josh Allmann <joshua.allmann at gmail.com>
> wrote:
> >>
> >> In intra-only mode, frameIntervalP is 0, which means the frame
> >> data array is smaller than the number of surfaces. This causes a
> >> crash when closing the encoder.
> >>
> >> Fix this by making sure the frame data array is at least as big as
> >> the number of surfaces.
> >> ---
> >>   libavcodec/nvenc.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/libavcodec/nvenc.c b/libavcodec/nvenc.c
> >> index a9945355ba..93e87b21db 100644
> >> --- a/libavcodec/nvenc.c
> >> +++ b/libavcodec/nvenc.c
> >> @@ -1021,7 +1021,7 @@ static av_cold int
> nvenc_recalc_surfaces(AVCodecContext *avctx)
> >>
> >>       // Output in the worst case will only start when the surface
> buffer is completely full.
> >>       // Hence we need to keep at least the max amount of surfaces plus
> the max reorder delay around.
> >> -    ctx->frame_data_array_nb = ctx->nb_surfaces +
> ctx->encode_config.frameIntervalP - 1;
> >> +    ctx->frame_data_array_nb = FFMAX(ctx->nb_surfaces,
> ctx->nb_surfaces + ctx->encode_config.frameIntervalP - 1);
> >>
> >>       return 0;
> >>   }
> >> --
> >> 2.39.2
> >>
> >
> > Hello,
> >
> > Ping for review. This patch fixes an easily triggered crash with nvenc
> > in intra-only mode, eg
> >
> > ffmpeg -i <in> -c:v h264_nvenc -g 0 <out>
> >
> > Josh
>

Can this also be back-ported to FFmpeg 7.x upon merging?


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