[FFmpeg-devel] [PATCH] cinepakenc: When rd_frame() doesn't use MC, mark pkt as keyframe and reset curframe

[Tomas Härdin]

tor 2019-08-15 klockan 12:54 -0300 skrev James Almer:
> On 8/15/2019 11:34 AM, Tomas Härdin wrote:
> > Hi
> > 
> > Attached patch detects when the cinepak encoder has generated a
> > keyframe on its own, and pushes the generation of forced keyframes into
> > the future. This is similar to what msvideo1enc.c does.
> > 
> > Example:
> > 
> > $ ./ffmpeg -i fate-suite/zmbv/zmbv_32bit.avi -keyint_min 20 -vcodec
> > cinepak out-before.avi
> > $ make
> > $ ./ffmpeg -i fate-suite/zmbv/zmbv_32bit.avi -keyint_min 20 -vcodec
> > cinepak out-after.avi
> > 
> > out-before.avi: 667338
> >  out-after.avi: 660928
> > 
> > Aside: what is -keyint_min for exactly? It seems to be used as a max in
> > msvideo1enc.c, but libx264.c and libxavs.c uses it and gop_size as
> > minimum and maximum respectively.. Feels like the relevant encoders
> > need to be brought into line (assuming it doesn't break user scripts)
> 
> Afaik, keyint_min is minimum interval/distance between keyframes. So
> yes, if it's being used as max distance then it's wrong, as that's what
> gop_size is for.

Make sense. But why is gop_size < keyint_min by default then? 12 vs 25.
I think the x264 people have complained multiple times about the
default gop_size setting even

/Tomas