On 11 March 2018 at 22:41, Mark Thompson <s...@jkqxz.net> wrote: > --- > doc/indevs.texi | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/doc/indevs.texi b/doc/indevs.texi > index 6951940a93..02d1cb3d86 100644 > --- a/doc/indevs.texi > +++ b/doc/indevs.texi > @@ -462,6 +462,14 @@ Capture from CRTC ID 42 at 60fps, map the result to > VAAPI, convert to NV12 and e > ffmpeg -crtc_id 42 -framerate 60 -f kmsgrab -i - -vf > 'hwmap=derive_device=vaapi,scale_vaapi=w=1920:h=1080:format=nv12' -c:v > h264_vaapi output.mp4 > @end example > > +@item > +To capture only part of a plane the output can be cropped - this can be > used to capture > +a single window, as long as it has a known absolute position. For > example, to capture > +and encode the middle quarter of a 1920x1080 plane: > +@example > +ffmpeg -f kmsgrab -i - -vf 'hwmap=derive_device=vaapi, > crop=960:540:480:270,scale_vaapi=format=nv12' -c:v h264_vaapi output.mp4 > +@end example > + > @end itemize > > @section libndi_newtek > -- > 2.16.1 > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >
On a related note, deriving a vaapi device from kms has never worked for me: libva: va_getDriverName() failed with operation failed,driver_name=i965 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel