Invalid bitrate control for preset V4L2_ENC_HW_PRESET_MEDIUM

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Xavier
1

Dear Sir.

When I use the low level API to set the device working in V4L2_ENC_HW_PRESET_FAST mode, I find the bitrate control is not worked.

command as below：

./video_encode 1080p.nv12 3840 2160 H264 sdj.264 -br 3000000 -hpt 2

jetpack is 4.6

3

Hi,
For 4K resolution, bitrate=3Mbps is too small. We would suggest set reasonable bitrate and check again.

4

I see!

But in some condition, I will need the low bitrate 4K with poor quality.

Any suggestion?

And if I use the hw preset V4L2_ENC_HW_PRESET_MEDIUM, the bit rate is more in control. But the encoding performance is less than V4L2_ENC_HW_PRESET_FAST.

5

How is it going? Any suggestion?

6

Hi,
You may refer to this post and check if all frames are quantized with q=50:
Constant Bitrate help - #12 by DaneLLL

If yes this is the lowest bitrate the hardware encoder can achieve. We are not able to achieve lower bitrate. Bitrate and quality are tradeoff. The bitrate is too small for 4K. It is not easy to get better video quality.

8

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