I was recording screencasts on Ubuntu 16.04 for youtube with my plantronics headset C520-M which worked just nice. I was using ffmpeg successfully.
Now I wanted to add some "live" video explaining things at a whiteboard, to make the video more attractive.
I was planning to record the live view with Logitech HD Pro Webcam C920, which also has builtin microphones that work not that bad. I can not use the headset for sound, since the whiteboard is too far away from the computer... (plus it might look weird).
I was using this command:
ffmpeg -f v4l2 -framerate 25 -video_size 1280x720 -i /dev/video1 \ -f alsa -ac 2 -thread_queue_size 1024 -i default \ output.mkv
That always resulted in
[alsa @ 0x69d540] Thread message queue blocking; consider raising the thread_queue_size option (current value: 1024)
The sound then stops at this point for the rest of the recording.
Thus I have a couple of questions:
- Why does it happen that the audio queue blocks?
- How far should I raise the thread_queue_size?
- How can I avoid that the audio queue blocks?
- Which audio input should I use - actually I tried all of them an the sound stops at some point.
Thanks for any hints.