[FFmpeg-devel] [PATCH] avcodec/omx: fix xFramerate calculation

[Aman Gupta]

On Thu, Aug 29, 2019 at 5:56 PM Limin Wang <lance.lmwang at gmail.com> wrote:

> On Thu, Aug 29, 2019 at 05:30:25PM -0700, Aman Gupta wrote:
> > From: Aman Gupta <aman at tmm1.net>
> >
> > Integer overflow in the Q16 framerate calculation was sending
> > invalid values to the OMX encoder.
> >
> > On the RPI4, this manifested as bitrate controls being ignored
> > on video streams with 60000/1001 framerates. Video streams with
> > 30000/1001 framerates were not affected.
> >
> > Signed-off-by: Aman Gupta <aman at tmm1.net>
> > ---
> >  libavcodec/omx.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/libavcodec/omx.c b/libavcodec/omx.c
> > index 837f5df666..c745860242 100644
> > --- a/libavcodec/omx.c
> > +++ b/libavcodec/omx.c
> > @@ -473,9 +473,9 @@ static av_cold int omx_component_init(AVCodecContext
> *avctx, const char *role)
> >      in_port_params.format.video.nFrameWidth  = avctx->width;
> >      in_port_params.format.video.nFrameHeight = avctx->height;
> >      if (avctx->framerate.den > 0 && avctx->framerate.num > 0)
> > -        in_port_params.format.video.xFramerate = (1 << 16) *
> avctx->framerate.num / avctx->framerate.den;
> > +        in_port_params.format.video.xFramerate = (int64_t)(1 << 16) *
> avctx->framerate.num / avctx->framerate.den;
>
> change 1 > 1LL is more simple to solve the overflow.
>

Great, thank you for the tip! Updated my local patch accordingly.



>
>
> >      else
> > -        in_port_params.format.video.xFramerate = (1 << 16) *
> avctx->time_base.den / avctx->time_base.num;
> > +        in_port_params.format.video.xFramerate = (int64_t)(1 << 16) *
> avctx->time_base.den / avctx->time_base.num;
> >
> >      err = OMX_SetParameter(s->handle, OMX_IndexParamPortDefinition,
> &in_port_params);
> >      CHECK(err);
> > --
> > 2.20.1
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".