Choppy audio on Raspberry Pi

[ftab]

I've got nrsc5 compiled for Raspberry Pi and that is working fine (40% CPU usage on a single core of a 3B+, audio is smooth, signal comes in great). Playing through a USB sound card rather than the Pi audio out.

nrsc5-gui however seems to play very choppy, even on a Pi 4. This is not the case when I run it on an x86-64 PC. I've tried fiddling around with the queue size but it doesn't seem to have any effect.

The Pi does not seem to be sweating too hard at decoding the audio itself, when running just nrsc5, it's just when it's run through the gui.

Any ideas?

[ftab]

Added frames_per_buffer=8192 parameter to the audio.open call (the PyAudio default is 1024 according to http://people.csail.mit.edu/hubert/pyaudio/docs/#pyaudio.Stream.__init__ ), and it gets better, but there's still some dropouts. They seem to coincide with when it's receiving/decoding station or image data, not sure what that's about. Threading issue, perhaps? But, the audio is already in a different thread, I don't quite get it...

[chrismrutledge]

Thank you very much for tracking that down. That stuttering issue has been driving me crazy for a long time. My lack of Python knowledge was definitely the hold up though.. Like you, I am also still seeing (hearing) the pause.. And I definitely hear it more often on iHeart Media stations who send the Traffic and Weather map images regularly. So, you might be on the right track there with threading.

P.S. this is happening on a 4GB RAM Pi 4 as well..