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mpromonet / v4l2tools

V4L2 tools using V4L2 C++ wrapper
The Unlicense
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v4l2compress encodes as fast as possible instead of at device FPS #35

Open gabenell opened 3 years ago

gabenell commented 3 years ago

I noticed that v4l2compress uses 100% CPU when running, and that when I serve the output of v4l2compress using v4l2rtspserver, it sends hundreds of FPS. My video source is a v4l2loopback device.

The problem seems to be the while loop in v4l2compress.cpp, which encodes as fast as possible. I verified by adding a sleep that the CPU usage dropped and the FPS received by the RTSP client went down to a sane rate.

Is there any way to make v4l2compress run at the native framerate of the source device? Trying to achieve this by sleeping is not ideal.

flixman commented 3 years ago

@gabenell I find myself on this same situation. Did you manage to get it fixed? Where did you put the sleep, as a fallback option?

Edit: I just put it at the end of the loop, but when serving the stream through v4l2rtspserver now I get a static image :-/.

fplanque commented 5 months ago

Even when using a USB camera as source, how would one decide to compress a 15fps stream instead of the max 30fps stream?

There is no framerate option for v4l2compress nor v4l2compress_omx.

Also I don't see how I could modify the device framerate with v4l2-ctl ... ?

Thank you.

mpromonet commented 5 months ago

Hi @fplanque

This tools are not setting fps, you should set it using v4l2-ctl --set-parm.

Best Regards, Michel.