MFC: different h264 profile and level output the same size encoded result

From: Randy Li
Date: Sat Aug 27 2016 - 05:56:10 EST


Hi:

I have been reported that the setting the profile, level and bitrate through the v4l2 extra controls would not make the encoded result different. I tried it recently, it is true. Although the h264 parser would tell me the result have been applied as different h264 profile and level, but size is the same.

You may try this in Gstreamer.

gst-launch-1.0 -v \
videotestsrc num-buffers=500 ! video/x-raw, width=1920,height=1080 ! \
videoconvert ! \
v4l2video4h264enc extra-controls="controls,h264_profile=1,video_bitrate=100;" ! \
h264parse ! matroskamux ! filesink location=/tmp/1.mkv

Is there any way to reduce the size of MFC encoded data?