[vlc-devel] [PATCH 3/3] x264: the frame rate of the output block is one of the output format

[Alexandre Janniaux]

Hi,

Sorry misread the first snippet of code, then first and
the second snippet should probably be fixed to only use
fmt_out. ;)

Regards,
--
Alexandre Janniaux
Videolabs

On Fri, Jan 15, 2021 at 10:13:33AM +0100, Alexandre Janniaux wrote:
> Hi,
>
> This seems logical but are you sure this is correct as is?
>
> The code in the transcode seems to assign the framerate to
> the input video format and not the output video format:
>
>
>     transcode_video_framerate_apply( p_src, p_enc_out );
>     p_enc_in->i_frame_rate = p_enc_out->i_frame_rate;
>     p_enc_in->i_frame_rate_base = p_enc_out->i_frame_rate_base;
>     msg_Dbg( p_obj, "source fps %u/%u, destination %u/%u",
>              p_dec_out->i_frame_rate, p_dec_out->i_frame_rate_base,
>              p_enc_in->i_frame_rate, p_enc_in->i_frame_rate_base );
>
> And in x264, it's used there from fmt_in:
>
>     if( p_enc->fmt_in.video.i_frame_rate_base > 0 )
>     {
>         p_sys->param.i_fps_num = p_enc->fmt_in.video.i_frame_rate;
>         p_sys->param.i_fps_den = p_enc->fmt_in.video.i_frame_rate_base;
>         p_sys->param.b_vfr_input = 0;
>     }
>
> There's not much rationale in the commit message that would
> help understand why this should be in the output format and
> why it was wrong before.
>
> Regards,
> --
> Alexandre Janniaux
> Videolabs
>
> On Tue, Jan 12, 2021 at 05:41:26PM +0100, Steve Lhomme wrote:
> > ---
> >  modules/codec/x264.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/modules/codec/x264.c b/modules/codec/x264.c
> > index dbb8ea2ddc7..70049f50b8b 100644
> > --- a/modules/codec/x264.c
> > +++ b/modules/codec/x264.c
> > @@ -1546,8 +1546,8 @@ static block_t *Encode( encoder_t *p_enc, picture_t *p_pict )
> >      {
> >          /* This isn't really valid for streams with B-frames */
> >          p_block->i_length = vlc_tick_from_samples(
> > -                    p_enc->fmt_in.video.i_frame_rate_base,
> > -                    p_enc->fmt_in.video.i_frame_rate );
> > +                    p_enc->fmt_out.video.i_frame_rate_base,
> > +                    p_enc->fmt_out.video.i_frame_rate );
> >      }
> >
> >      /* scale pts-values back*/
> > --
> > 2.29.2
> >
> > _______________________________________________
> > vlc-devel mailing list
> > To unsubscribe or modify your subscription options:
> > https://mailman.videolan.org/listinfo/vlc-devel
> _______________________________________________
> vlc-devel mailing list
> To unsubscribe or modify your subscription options:
> https://mailman.videolan.org/listinfo/vlc-devel