From 91fb68acc46bdd837c4a7e9b11977fa655e0787d Mon Sep 17 00:00:00 2001
From: laurent <laurent.mazare@gmail.com>
Date: Thu, 19 Jun 2025 09:57:53 +0200
Subject: [PATCH] Add timestamps to the rust example.

---
 stt-rs/src/main.rs | 67 +++++++++++++++++++++++++++++-----------------
 1 file changed, 42 insertions(+), 25 deletions(-)

diff --git a/stt-rs/src/main.rs b/stt-rs/src/main.rs
index 2d2a447..31e02ab 100644
--- a/stt-rs/src/main.rs
+++ b/stt-rs/src/main.rs
@@ -18,6 +18,10 @@ struct Args {
     /// Run the model on cpu.
     #[arg(long)]
     cpu: bool,
+
+    /// Display word level timestamps.
+    #[arg(long)]
+    timestamps: bool,
 }
 
 fn device(cpu: bool) -> Result<Device> {
@@ -32,6 +36,11 @@ fn device(cpu: bool) -> Result<Device> {
     }
 }
 
+#[derive(Debug, serde::Deserialize)]
+struct SttConfig {
+    audio_delay_seconds: f64,
+}
+
 #[derive(Debug, serde::Deserialize)]
 struct Config {
     mimi_name: String,
@@ -45,6 +54,7 @@ struct Config {
     num_heads: usize,
     num_layers: usize,
     causal: bool,
+    stt_config: SttConfig,
 }
 
 impl Config {
@@ -89,11 +99,12 @@ impl Config {
 struct Model {
     state: moshi::asr::State,
     text_tokenizer: sentencepiece::SentencePieceProcessor,
+    timestamps: bool,
     dev: Device,
 }
 
 impl Model {
-    fn load_from_hf(hf_repo: &str, dev: &Device) -> Result<Self> {
+    fn load_from_hf(hf_repo: &str, timestamps: bool, dev: &Device) -> Result<Self> {
         let dtype = dev.bf16_default_to_f32();
 
         // Retrieve the model files from the Hugging Face Hub
@@ -113,10 +124,12 @@ impl Model {
             &config.model_config(),
             moshi::nn::MaybeQuantizedVarBuilder::Real(vb_lm),
         )?;
-        let state = moshi::asr::State::new(1, 0, 0., audio_tokenizer, lm)?;
+        let asr_delay_in_tokens = (config.stt_config.audio_delay_seconds * 12.5) as usize;
+        let state = moshi::asr::State::new(1, asr_delay_in_tokens, 0., audio_tokenizer, lm)?;
         Ok(Model {
             state,
             text_tokenizer,
+            timestamps,
             dev: dev.clone(),
         })
     }
@@ -124,39 +137,43 @@ impl Model {
     fn run(&mut self, pcm: &[f32]) -> Result<()> {
         use std::io::Write;
 
+        let mut last_word = None;
         for pcm in pcm.chunks(1920) {
             let pcm = Tensor::new(pcm, &self.dev)?.reshape((1, 1, ()))?;
             let asr_msgs = self.state.step_pcm(pcm, None, &().into(), |_, _, _| ())?;
-            let mut prev_text_token = 0;
             for asr_msg in asr_msgs.iter() {
                 match asr_msg {
-                    moshi::asr::AsrMsg::Step { .. } | moshi::asr::AsrMsg::EndWord { .. } => {}
-                    moshi::asr::AsrMsg::Word { tokens, .. } => {
-                        for &text_token in tokens.iter() {
-                            let s = {
-                                let prev_ids =
-                                    self.text_tokenizer.decode_piece_ids(&[prev_text_token]);
-                                let ids = self
-                                    .text_tokenizer
-                                    .decode_piece_ids(&[prev_text_token, text_token]);
-                                prev_text_token = text_token;
-                                prev_ids.and_then(|prev_ids| {
-                                    ids.map(|ids| {
-                                        if ids.len() > prev_ids.len() {
-                                            ids[prev_ids.len()..].to_string()
-                                        } else {
-                                            String::new()
-                                        }
-                                    })
-                                })?
-                            };
-                            print!("{s}");
+                    moshi::asr::AsrMsg::Step { .. } => {}
+                    moshi::asr::AsrMsg::EndWord { stop_time, .. } => {
+                        if self.timestamps {
+                            if let Some((word, start_time)) = last_word.take() {
+                                println!("[{start_time:5.2}-{stop_time:5.2}] {word}");
+                            }
+                        }
+                    }
+                    moshi::asr::AsrMsg::Word {
+                        tokens, start_time, ..
+                    } => {
+                        let word = self
+                            .text_tokenizer
+                            .decode_piece_ids(tokens)
+                            .unwrap_or_else(|_| String::new());
+                        if !self.timestamps {
+                            print!(" {word}");
                             std::io::stdout().flush()?
+                        } else {
+                            if let Some((word, prev_start_time)) = last_word.take() {
+                                println!("[{prev_start_time:5.2}-{start_time:5.2}] {word}");
+                            }
+                            last_word = Some((word, *start_time));
                         }
                     }
                 }
             }
         }
+        if let Some((word, start_time)) = last_word.take() {
+            println!("[{start_time:5.2}-     ] {word}");
+        }
         println!();
         Ok(())
     }
@@ -177,7 +194,7 @@ fn main() -> Result<()> {
     // Add some silence at the end to ensure all the audio is processed.
     pcm.resize(pcm.len() + 1920 * 32, 0.0);
     println!("Loading model from repository: {}", args.hf_repo);
-    let mut model = Model::load_from_hf(&args.hf_repo, &device)?;
+    let mut model = Model::load_from_hf(&args.hf_repo, args.timestamps, &device)?;
     println!("Running inference");
     model.run(&pcm)?;
     Ok(())