Hi, I am playing a bit with the coda encoder on i.MX6 and try to get the most quality out of it. So, I am trying to use the controls of the driver, in particular h264_i_frame_qp_value and h264_p_frame_qp_value. I can get something with the following pipeline : gst-launch-1.0 -evvv v4l2src num-buffers=2000 device=/dev/v4l/by-path/ipu1-capture io-mode=dmabuf ! "video/x-raw,width=1280,height=720,framerate=25/1,format=YUY2" ! v4l2convert device=/dev/v4l/by-path/ipu1-scaler capture-io-mode=dmabuf output-io-mode=dmabuf-import ! 'video/x-raw,width=640,height=360,format=NV12' ! v4l2video0h264enc output-io-mode=dmabuf-import extra-controls="controls,h264_i_frame_qp_value=24,h264_p_frame_qp_value=30,video_gop_size=32" ! queue ! progressreport name=p2 ! h264parse ! matroskamux ! filesink location=/data/test_encode_360p.mkv With those values, I get ~800kbps for a 360p converted frame. This is nice :). The same video as an input with only the "bitrate" parameter set is not visually similar. But, when trying to encode a 720p video with the same QP parameters, it is not working (the first keyframe is not ok, seems to be a P frame instead of I, as it is 2000 bits and should be ~40000). I am keeping the videoscaler in this second case, as it should be used as a color converter. Philipp, did you do some tests like this one ? Did you observe that the encoder can maybe be too long to get a frame encoded when desired quality is "high" ? Maybe do you have some ideas about this ? Thanks, JM -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
