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

[Randy Li]

On 08/29/2016 01:49 PM, Andrzej Hajda wrote:
> Hi,
>
> On 08/27/2016 11:55 AM, Randy Li wrote:
> > 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?
>
> There is control called rc_enable (rate control enable), it must be set
> to one if you want to control bitrate.
> This control confuses many users, I guess it cannot be removed as it
> is already part of UAPI, but enabling it internally by the driver
> if user sets bitrate, profille, etc, would make it more saner.
I see, thank you so much.
A guy told me that the "frame_level_rate_control_enable=1" in _ 
extra-controls="encode,h264_level=10,h264_profile=4,frame_level_rate_control_enable=1,video_bitrate=2097152"
would also make it works.
But I really know there is a switch need to turn on.

> Regards
> Andrzej

--
Randy Li
The third produce department