From e1612a0151ef28c4e02c0f1843dd725a92d4c268 Mon Sep 17 00:00:00 2001
From: cai <cai@nbcai.cc>
Date: Wed, 08 Jul 2026 12:35:21 +0800
Subject: [PATCH] feat: default combrabo voice bot audio to 16k
---
src/main.rs | 128 ++++++++++++++++++++++++++++++++++--------
1 files changed, 102 insertions(+), 26 deletions(-)
diff --git a/src/main.rs b/src/main.rs
index 64eedd4..cf7cb4f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -34,8 +34,12 @@
use tokio::{sync::mpsc::UnboundedReceiver, task::JoinHandle};
use tracing::{info, warn};
-const TARGET_SAMPLE_RATE_HZ: u32 = 48_000;
-const TARGET_NUM_CHANNELS: u16 = 1;
+const USER_AUDIO_SAMPLE_RATE_HZ: u32 = 48_000;
+const USER_AUDIO_NUM_CHANNELS: u16 = 1;
+const DEFAULT_BOT_AUDIO_PROFILE: &str = "pcm-16k";
+const LIVEKIT_48K_SAMPLE_RATE_HZ: u32 = 48_000;
+const PCM_16K_SAMPLE_RATE_HZ: u32 = 16_000;
+const BOT_NUM_CHANNELS: u16 = 1;
const TRACK_NAME: &str = "bot-main-audio";
#[tokio::main(flavor = "multi_thread")]
@@ -58,8 +62,8 @@
&http,
config.greeting_audio_file.as_deref(),
config.greeting_audio_url.as_deref(),
- TARGET_SAMPLE_RATE_HZ,
- TARGET_NUM_CHANNELS,
+ config.bot_audio_profile.sample_rate_hz,
+ config.bot_audio_profile.num_channels,
config.audio_debug_dump_dir.as_deref(),
&config.call_id,
"greeting",
@@ -81,6 +85,9 @@
room_alias = %redact(&config.room_id),
participant_alias = %redact(&config.bot_participant_identity),
greeting_source = %config.greeting_source,
+ bot_audio_profile = %config.bot_audio_profile.profile,
+ bot_sample_rate_hz = config.bot_audio_profile.sample_rate_hz,
+ bot_num_channels = config.bot_audio_profile.num_channels,
"combrabo voice runtime helper connected"
);
emit_activity(
@@ -129,8 +136,9 @@
&config.call_id,
&config.trace_id,
TRACK_NAME,
- TARGET_SAMPLE_RATE_HZ,
- u32::from(TARGET_NUM_CHANNELS),
+ config.bot_audio_profile.profile.clone(),
+ config.bot_audio_profile.sample_rate_hz,
+ u32::from(config.bot_audio_profile.num_channels),
config.user_participant_identity.clone(),
)
.await?;
@@ -269,6 +277,54 @@
simple_vad_gate_until_greeting_done: bool,
simple_vad_post_greeting_delay_ms: u64,
simple_vad_config: SimpleVadConfig,
+ bot_audio_profile: BotAudioProfile,
+}
+
+#[derive(Clone)]
+struct BotAudioProfile {
+ profile: String,
+ sample_rate_hz: u32,
+ num_channels: u16,
+}
+
+impl BotAudioProfile {
+ fn from_env() -> Result<Self> {
+ let profile = env::var("CV_BOT_AUDIO_PROFILE")
+ .unwrap_or_else(|_| DEFAULT_BOT_AUDIO_PROFILE.to_string())
+ .trim()
+ .to_ascii_lowercase();
+ match profile.as_str() {
+ "livekit-48k" | "48k" => Ok(Self {
+ profile: "livekit-48k".to_string(),
+ sample_rate_hz: LIVEKIT_48K_SAMPLE_RATE_HZ,
+ num_channels: BOT_NUM_CHANNELS,
+ }),
+ "pcm-16k" | "16k" => Ok(Self {
+ profile: "pcm-16k".to_string(),
+ sample_rate_hz: PCM_16K_SAMPLE_RATE_HZ,
+ num_channels: BOT_NUM_CHANNELS,
+ }),
+ "custom" => {
+ let sample_rate_hz = u32_env("CV_BOT_SAMPLE_RATE_HZ", LIVEKIT_48K_SAMPLE_RATE_HZ);
+ let num_channels = u16_env("CV_BOT_NUM_CHANNELS", BOT_NUM_CHANNELS);
+ if sample_rate_hz == 0 {
+ return Err(anyhow!("CV_BOT_SAMPLE_RATE_HZ must be positive"));
+ }
+ if num_channels == 0 {
+ return Err(anyhow!("CV_BOT_NUM_CHANNELS must be positive"));
+ }
+ Ok(Self {
+ profile,
+ sample_rate_hz,
+ num_channels,
+ })
+ }
+ _ => Err(anyhow!(
+ "unsupported CV_BOT_AUDIO_PROFILE {}; expected livekit-48k, pcm-16k or custom",
+ profile
+ )),
+ }
+ }
}
#[derive(Clone)]
@@ -346,6 +402,7 @@
simple_vad_gate_until_greeting_done: bool_env("CV_VAD_GATE_UNTIL_GREETING_DONE", true),
simple_vad_post_greeting_delay_ms: u64_env("CV_VAD_POST_GREETING_DELAY_MS", 800),
simple_vad_config: SimpleVadConfig::from_env(),
+ bot_audio_profile: BotAudioProfile::from_env()?,
})
}
}
@@ -489,6 +546,13 @@
env::var(key)
.ok()
.and_then(|value| value.trim().parse::<u32>().ok())
+ .unwrap_or(default_value)
+}
+
+fn u16_env(key: &str, default_value: u16) -> u16 {
+ env::var(key)
+ .ok()
+ .and_then(|value| value.trim().parse::<u16>().ok())
.unwrap_or(default_value)
}
@@ -930,8 +994,8 @@
audio::write_pcm_wav(
&output_path,
&turn.samples,
- TARGET_SAMPLE_RATE_HZ,
- TARGET_NUM_CHANNELS,
+ USER_AUDIO_SAMPLE_RATE_HZ,
+ USER_AUDIO_NUM_CHANNELS,
)?;
let byte_size = fs::metadata(&output_path)
.context("failed to stat turn artifact")?
@@ -959,8 +1023,8 @@
artifact_type: "local_file".to_string(),
path_ref: path_ref.to_string(),
format: "wav".to_string(),
- sample_rate: TARGET_SAMPLE_RATE_HZ,
- channels: u32::from(TARGET_NUM_CHANNELS),
+ sample_rate: USER_AUDIO_SAMPLE_RATE_HZ,
+ channels: u32::from(USER_AUDIO_NUM_CHANNELS),
duration_ms: turn.duration_ms,
byte_size,
},
@@ -1343,16 +1407,14 @@
.trim()
.to_ascii_lowercase();
let frames = if format == "pcm_s16le" {
- let sample_rate = audio_chunk.sample_rate.unwrap_or(TARGET_SAMPLE_RATE_HZ);
- let channels = audio_chunk
- .channels
- .unwrap_or(u32::from(TARGET_NUM_CHANNELS));
+ let sample_rate = audio_chunk.sample_rate.unwrap_or(sink.sample_rate_hz);
+ let channels = audio_chunk.channels.unwrap_or(u32::from(sink.num_channels));
if state.pcm_stream_decoder.is_none() {
state.pcm_stream_decoder = Some(audio::PcmS16leStreamDecoder::new(
sample_rate,
channels,
- TARGET_SAMPLE_RATE_HZ,
- TARGET_NUM_CHANNELS,
+ sink.sample_rate_hz,
+ sink.num_channels,
)?);
}
state.pcm_stream_network_chunk_count =
@@ -1396,8 +1458,8 @@
match audio::decode_audio_bytes_to_frames(
&state.encoded_audio_buffer,
"stream_chunk",
- TARGET_SAMPLE_RATE_HZ,
- TARGET_NUM_CHANNELS,
+ sink.sample_rate_hz,
+ sink.num_channels,
bridge_config.audio_debug_dump_dir.as_deref(),
call_id,
&format!("stream-reply-{}", turn.turn_id),
@@ -1526,8 +1588,11 @@
"debugSourcePath": debug_source_path,
"debugPcmWavPath": debug_pcm_wav_path,
"debugPcmWavSizeBytes": debug_pcm_wav_size_bytes,
- "sampleRate": audio_chunk.sample_rate,
- "channels": audio_chunk.channels,
+ "sourceSampleRate": audio_chunk.sample_rate,
+ "sourceChannels": audio_chunk.channels,
+ "targetAudioProfile": sink.profile.as_str(),
+ "targetSampleRate": sink.sample_rate_hz,
+ "targetChannels": sink.num_channels,
"replyTotalAfterVadEndMs": turn_pipeline_started_at.elapsed().as_millis() as u64,
}),
);
@@ -1566,8 +1631,8 @@
artifact_type: "local_file".to_string(),
path_ref: path_ref.to_string(),
format: "wav".to_string(),
- sample_rate: TARGET_SAMPLE_RATE_HZ,
- channels: u32::from(TARGET_NUM_CHANNELS),
+ sample_rate: USER_AUDIO_SAMPLE_RATE_HZ,
+ channels: u32::from(USER_AUDIO_NUM_CHANNELS),
duration_ms: turn.duration_ms,
byte_size,
},
@@ -1730,8 +1795,8 @@
http,
Some(&audio_path_string),
None,
- TARGET_SAMPLE_RATE_HZ,
- TARGET_NUM_CHANNELS,
+ sink.sample_rate_hz,
+ sink.num_channels,
bridge_config.audio_debug_dump_dir.as_deref(),
call_id,
&reply_debug_label,
@@ -2075,8 +2140,8 @@
tokio::spawn(async move {
let mut stream = NativeAudioStream::new(
track.rtc_track(),
- TARGET_SAMPLE_RATE_HZ as i32,
- i32::from(TARGET_NUM_CHANNELS),
+ USER_AUDIO_SAMPLE_RATE_HZ as i32,
+ i32::from(USER_AUDIO_NUM_CHANNELS),
);
let started_at = Instant::now();
let mut frame_count: u64 = 0;
@@ -2563,6 +2628,9 @@
rtc_source: NativeAudioSource,
track: LocalAudioTrack,
device_output_destination_identity: Option<String>,
+ profile: String,
+ sample_rate_hz: u32,
+ num_channels: u16,
}
impl BotAudioOutputSink {
@@ -2573,6 +2641,7 @@
call_id: &str,
trace_id: &str,
track_name: &str,
+ profile: String,
sample_rate: u32,
num_channels: u32,
device_output_destination_identity: Option<String>,
@@ -2601,11 +2670,14 @@
"failed to publish bot audio track in room {room_alias} for participant {participant_alias}: {error}"
)
})?;
+ let num_channels_u16 = u16::try_from(num_channels)
+ .map_err(|_| anyhow!("unsupported bot audio channel count {num_channels}"))?;
info!(
room_alias = %room_alias,
participant_alias = %participant_alias,
track_name = %track_name,
+ bot_audio_profile = %profile,
sample_rate,
num_channels,
"runtime helper published bot audio track"
@@ -2620,6 +2692,7 @@
None,
json!({
"trackName": track_name,
+ "audioProfile": profile,
"sampleRate": sample_rate,
"numChannels": num_channels,
}),
@@ -2630,6 +2703,9 @@
rtc_source,
track,
device_output_destination_identity,
+ profile,
+ sample_rate_hz: sample_rate,
+ num_channels: num_channels_u16,
})
}
--
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