From 30b563a2fc73d011d48b64664ea8a16d2c95e037 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Tue, 1 Nov 2022 00:08:43 -0500
Subject: [PATCH] Tune ALSA parameters to avoid underruns

Fixes frequent underruns on Vero 4K
---
 src/audio/alsa.c  | 6 +++---
 src/audio/audio.h | 2 --
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/audio/alsa.c b/src/audio/alsa.c
index cec1156..c63538c 100644
--- a/src/audio/alsa.c
+++ b/src/audio/alsa.c
@@ -57,8 +57,8 @@ static int alsa_renderer_init(int audioConfiguration, POPUS_MULTISTREAM_CONFIGUR
 
   snd_pcm_hw_params_t *hw_params;
   snd_pcm_sw_params_t *sw_params;
-  snd_pcm_uframes_t period_size = samplesPerFrame * FRAME_BUFFER;
-  snd_pcm_uframes_t buffer_size = 2 * period_size;
+  snd_pcm_uframes_t period_size = (opusConfig->sampleRate * 20) / 1000; // 20 ms period
+  snd_pcm_uframes_t buffer_size = 3 * period_size; // 60 ms buffer
   unsigned int sampleRate = opusConfig->sampleRate;
 
   char* audio_device = (char*) context;
@@ -84,7 +84,7 @@ static int alsa_renderer_init(int audioConfiguration, POPUS_MULTISTREAM_CONFIGUR
   CHECK_RETURN(snd_pcm_sw_params_malloc(&sw_params));
   CHECK_RETURN(snd_pcm_sw_params_current(handle, sw_params));
   CHECK_RETURN(snd_pcm_sw_params_set_avail_min(handle, sw_params, period_size));
-  CHECK_RETURN(snd_pcm_sw_params_set_start_threshold(handle, sw_params, 1));
+  CHECK_RETURN(snd_pcm_sw_params_set_start_threshold(handle, sw_params, period_size));
   CHECK_RETURN(snd_pcm_sw_params(handle, sw_params));
   snd_pcm_sw_params_free(sw_params);
 
diff --git a/src/audio/audio.h b/src/audio/audio.h
index fe1fbfa..260e78d 100644
--- a/src/audio/audio.h
+++ b/src/audio/audio.h
@@ -21,8 +21,6 @@
 
 #include <Limelight.h>
 
-#define FRAME_BUFFER 12
-
 #ifdef HAVE_ALSA
 extern AUDIO_RENDERER_CALLBACKS audio_callbacks_alsa;
 #endif