Question / Help Typical issues with audio device and auto scaling

[zenobs]

Hi,

I am on OBS 0.11.4-70-gaf310fb on Ubuntu 14.04, but facing typical problems as follows:

1. OBS does not show the USB based audio devices like from Logitech C920 camera and Zoom H4n recorders which can easily be used in command line using ffmpeg. Tried with jackd server also, but does not seem to work except it asked for the number of audio channels under source properties.

2. OBS downsamples the framerate on it's own for Logitech C920 camera based on resolution. Though the camera has built-in x264 codec.

3. How can one use native built-in x264 capabilities of cameras like Logitech C920 to avoid re-encoding by ffmpeg?

4. Is there a possibility to execute obs in command line without running gui (like vokoscreen shows up in outputs)? Thanks!

/z

 

[Lain]

That's strange, my C920 works fine. Maybe I'll have to check that again.

For #2, downsamples the framerate? What are you referring to?

#3 I don't quite know or if that functionality of the camera is even supported on linux.

#4 Maybe in the future we'll make a CLI, completely doable, though honestly I couldn't guarantee that I personally could ever make time for it within the next few years.

 

[zenobs]

Thanks Jim!

1. I have tried with my desktop as well as my laptop with adequate resources (both with quad CPU and 32GB and 8GB of RAM respectively) and latest OpenGL, the C920 and Zoom H4n audio is not detected. Confirmed!

2. What I meant when I check 1080p, the framerate menu only provides 5fps as a choice, whereas when I get down to say 480p I get upto 30fps ranging from 5fps under drop down menu.

UPDATE: This part is solved. It happens when one selects YUV 4:2:2 as Video format. Selection of video format as YUV (emulated) sorted out the problem.

3. I used to capture video directly with built-in x264 from C920 without relying on ffmpeg's libx264 library. Isn't that something that can be done?

UPDATE: In guvcview, C920 allows to record in H264 native to the cameara (see screenshot) , but OBS-MP states not available. [info: v4l2-input: Pixelformat: H.264 (unavailable)]

4. Your efforts are highly appreciated!

5. A new question: How can one stream in different quality and record at a higher quality simultaneously with OBS-MP?

 

[Lain]

We wouldn't want to use h264 even if it's provided by the camera though. It would have to be decoded, and we'd additionally have to implement the decoders manually, so that won't be in any time soon. I wish it were more worth the time but it really isn't.

To stream/record at different qualities (I hope you have the CPU for it) you just use advanced output mode and select a custom encoder/settings for the recording.

 

[zenobs]

However, the audio usb devices (both from Logitech C920 and Zoom H4n recorder) are not detected by OBS (till version OBS 0.11.4-99-gec5059c).

ffmpeg can easily record from those inputs without a problem.

 

[bazukas]

However, the audio usb devices (both from Logitech C920 and Zoom H4n recorder) are not detected by OBS (till version OBS 0.11.4-99-gec5059c).

ffmpeg can easily record from those inputs without a problem.

Not sure about Zoom H4n, but for C920 setting profile to "Analog Stereo Input" in PulseAudio Volume Control should help.