thaytan/gst-rpicamsrc

Changing bitrate while streaming

Triuman opened this issue · 5 comments

Triuman commented

Hi,

Is there any chance to implement dynamic bitrate as x264enc supports. After setting pipeline to PLAYING state, even I change the bitrate property of rpicamsrc element, it doesn't change it's output bitrate. I'm coding it in C.

Thank you.

thaytan commented

When I implemented dynamic property changes a while back, I tried the various properties to see which ones the encoder supports changing. Unfortunately, it rejects dynamic bitrate changes. gst-rpicamsrc can't do it without the Rpi firmware supporting it first.

See https://github.com/thaytan/gst-rpicamsrc/blob/master/src/RaspiCapture.c#L1911

6by9 commented

Correct that you can't change the port format whilst the port is enabled, but MMAL_PARAMETER_VIDEO_BIT_RATE also you to change the bitrate setting at any time.
That's how it is done with the V4L2 driver (https://github.com/raspberrypi/linux/blob/rpi-4.4.y/drivers/media/platform/bcm2835/controls.c#L1103)

status = mmal_port_parameter_set_uint32(encoder_output, MMAL_PARAMETER_VIDEO_BIT_RATE, config->bitrate);

should do it for you.

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Triuman commented

I added the given line and I can confirm that it's working. This is quite a life saving help. Thank you very much.

@thaytan could you please implement this?

thaytan commented

Oh cool!

thaytan commented

Please let me know if you have any trouble with it

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