From 963c4f85fe547ef51fafb66d7eceb3f5637d3843 Mon Sep 17 00:00:00 2001 From: Mark Thompson Date: Sat, 23 Mar 2019 16:18:49 +0000 Subject: doc/indevs: Add example using cropping to capture part of a plane --- doc/indevs.texi | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'doc') diff --git a/doc/indevs.texi b/doc/indevs.texi index 1d5ed65773..89ba4fb406 100644 --- a/doc/indevs.texi +++ b/doc/indevs.texi @@ -910,6 +910,14 @@ 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 and size. 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=960:540:nv12' -c:v h264_vaapi output.mp4 +@end example + @end itemize @section lavfi -- cgit v1.2.3