We're encountering a PCM underrun issue in Interleaved Mode while playing a single-channel audio through Alsa-lib. The error message "(snd_pcm_recover) underrun occurred" is being displayed when writing data to the speaker.

Here's what we've attempted so far:

1. Successfully played the same audio using aplay.
2. Generated complete buffers from text-to-speech engine and played them without issues using alsa-lib.

The problem arises when we simultaneously generate audio buffers from a Text-to-Speech Conversion engine and feed the data to the speaker through alsa-lib. PCM underrun occurs intermittently in this scenario.

We are using a sampling rate of 22kHz. Are there any specific ALSA configurations or settings that can be adjusted to prevent PCM underrun in this context?

Hello, Ravichandra & welcome to LQ.

You're off the map here for standard uses of alsa. Your problem happens when you have
I can't imagine the speed of text to speech being constant, so there must be instances where you run out of speech and the buffer has to feed. I imagine that's creating the buffer under-run.

If it keeps going, fine. I imagine it pukes, and exits. Solutions

• Use bigger buffers, or fill them before starting to hear them.
• Patch or hack to allow silence. This would give you unwanted pauses, which are probably better than unwanted exits.