High CPU usage for audio-only uncompressed transmission

[reduzent]

When using uv for an audio-only transmission with --audio-codec PCM, the uv process saturates a full CPU core. Given that no complex encoding is involved, I'd expect uv to consume much less cycles.

Client A (nl-11852.lan):

UltraGrid-1.7.6-x86_64.AppImage --tool uv -r jack -s jack --audio-codec PCM --audio-capture-format channels=2 -P30104:11064:5016:5014 frank.lan

Client B (frank.lan):

UltraGrid-1.7.6-x86_64.AppImage --tool uv -r jack -s jack --audio-codec PCM --audio-capture-format channels=2 -P30104:11064:5014:5016 nl-11852.lan

On both clients htop shows that uv is using ~100%.

Tested on:

• Ubuntu 20.04 (frank.lan)
• Ubuntu 22.04 (nl-11582.lan)

With:

• UltraGrid 1.7.6 (AppImage)

[mpiatka]

This was caused by busy-waiting for audio samples on the sender. It should now be fixed on today's continuous builds.

[reduzent]

I confirm this issue is fixed. Thank you very much!