问题
I have this pipeline to record from two webcams simultaneously:
gst-launch-1.0 -v v4l2src device=/dev/video0 num-buffers=300\
! "video/x-raw,width=800,height=600,framerate=30/1" ! videorate\
! "video/x-raw,framerate=30/1" ! jpegenc ! queue ! mux. \
pulsesrc device="alsa_input.pci-0000_00_1b.0.analog-stereo" \
! 'audio/x-raw,rate=88200,channels=1,depth=24' ! audioconvert ! \
avenc_aac compliance=experimental ! queue ! mux. matroskamux name="mux"\
! filesink location=/home/sina/T1.avi v4l2src device=/dev/video1 \
! 'image/jpeg,framerate=30/1,width=800,height=600' ! videorate ! \
! queue ! mux2. pulsesrc \
device="alsa_input.usb-046d_0990_94D7DC5E-02-Q9000.analog-mono" \
! 'audio/x-raw,rate=88200,channels=1,depth=24' ! audioconvert \
! avenc_aac compliance=experimental ! queue ! mux2. \
matroskamux name="mux2" ! filesink location=/home/sina/T2.mts
I'd like to rotate the video of the second Camera (/dev/video1) by 180 since it's mounted up side down, How can I do the rotation?
回答1:
The videoflip element can do this for your. You probably want use method=rotate-180 as option for this element. However this requires re-encoding of the image (e.g. jpeg-decode and jpeg-encode).
You may want to investigate the GstVideoOrientation interface. The v4l2src element implements this interface and allows control over some flipping options. You will need to write our own GStreamer application to get access to this interface though. Also since the flipping is then done in the hardware device itself it may or may not work for your device.
来源：https://stackoverflow.com/questions/32659930/rotate-a-video-in-gstreamer