Hello,
I am trying to play video with Gstreamer on a fullHD monitor. The board I’m using is Apalis iMX6.
Playing video works great with v4l2h264dec:
gst-launch-1.0 filesrc location=1080.mkv ! matroskademux ! h264parse \
! v4l2h264dec capture-io-mode=dmabuf \
! kmssink
However, it fails to scale video to 720p with v4l2convert:
gst-launch-1.0 filesrc location=1080.mkv ! matroskademux ! h264parse \
! v4l2h264dec capture-io-mode=dmabuf \
! v4l2convert output-io-mode=dmabuf-import \
! video/x-raw,width=1280,height=720 \
! kmssink
Added some debugs and I found that it failed at 'drivers/media/common/videobuf2/videobuf2-v4l2.c:__verify_length()'.
length = (b->memory == VB2_MEMORY_USERPTR)
? b->length : vb->planes[0].length;
if (b->bytesused > length)
return -EINVAL;
The “b->byteused” is 4177920 (= 2 x 1920 x 1088), while plane length is just 4147200 (= 2 x 1920 x 1080).
The actual frame size of H264 video is 1920x1088, so I added a bypass for this case and video can be scaled,
but that may not a correct way to fix this problem.
Is this a bug or I need to do extra steps before scale video?
Packages version in my environment are:
* Kernel: 5.10.19
* Gstreamer: 1.18.4
Thank you,
Trung
