Use proper lifetimes, add DTW usage example

examples/audio_transcription.rs

@@ -9,9 +9,37 @@ use whisper_rs::{FullParams, SamplingStrategy, WhisperContext, WhisperContextPar
 /// Loads a context and model, processes an audio file, and prints the resulting transcript to stdout.
 fn main() -> Result<(), &'static str> {
     // Load a context and model.
+    let mut context_param = WhisperContextParameters::default();
+
+    // Enable DTW token level timestamp for known model by using model preset
+    context_param.dtw_parameters.mode = whisper_rs::DtwMode::ModelPreset {
+        model_preset: whisper_rs::DtwModelPreset::BaseEn,
+    };
+
+    // Enable DTW token level timestamp for unknown model by providing custom aheads
+    // see details https://github.com/ggerganov/whisper.cpp/pull/1485#discussion_r1519681143
+    // values corresponds to ggml-base.en.bin, result will be the same as with DtwModelPreset::BaseEn
+    let custom_aheads = [
+        (3, 1),
+        (4, 2),
+        (4, 3),
+        (4, 7),
+        (5, 1),
+        (5, 2),
+        (5, 4),
+        (5, 6),
+    ]
+    .map(|(n_text_layer, n_head)| whisper_rs_sys::whisper_ahead {
+        n_text_layer,
+        n_head,
+    });
+    context_param.dtw_parameters.mode = whisper_rs::DtwMode::Custom {
+        aheads: &custom_aheads,
+    };
+
     let ctx = WhisperContext::new_with_params(
         "example/path/to/model/whisper.cpp/models/ggml-base.en.bin",
-        WhisperContextParameters::default(),
+        context_param,
     )
     .expect("failed to load model");
     // Create a state
@@ -33,6 +61,8 @@ fn main() -> Result<(), &'static str> {
     params.set_print_progress(false);
     params.set_print_realtime(false);
     params.set_print_timestamps(false);
+    // Enable token level timestamps
+    params.set_token_timestamps(true);
 
     // Open the audio file.
     let reader = hound::WavReader::open("audio.wav").expect("failed to open file");
@@ -87,8 +117,24 @@ fn main() -> Result<(), &'static str> {
             .full_get_segment_t1(i)
             .expect("failed to get end timestamp");
 
+        let first_token_dtw_ts = if let Ok(token_count) = state.full_n_tokens(i) {
+            if token_count > 0 {
+                if let Ok(token_data) = state.full_get_token_data(i, 0) {
+                    token_data.t_dtw
+                } else {
+                    -1i64
+                }
+            } else {
+                -1i64
+            }
+        } else {
+            -1i64
+        };
         // Print the segment to stdout.
-        println!("[{} - {}]: {}", start_timestamp, end_timestamp, segment);
+        println!(
+            "[{} - {} ({})]: {}",
+            start_timestamp, end_timestamp, first_token_dtw_ts, segment
+        );
 
         // Format the segment information as a string.
         let line = format!("[{} - {}]: {}\n", start_timestamp, end_timestamp, segment);

src/whisper_ctx.rs

@@ -469,7 +469,7 @@ impl Drop for WhisperInnerContext {
 unsafe impl Send for WhisperInnerContext {}
 unsafe impl Sync for WhisperInnerContext {}
 
-pub struct WhisperContextParameters {
+pub struct WhisperContextParameters<'a> {
     /// Use GPU if available.
     ///
     /// **Warning**: Does not have an effect if OpenCL is selected as GPU backend
@@ -482,11 +482,11 @@ pub struct WhisperContextParameters {
     /// GPU device id, default 0
     pub gpu_device: c_int,
     /// DTW token level timestamp parameters
-    pub dtw_parameters: DtwParameters,
+    pub dtw_parameters: DtwParameters<'a>,
 }
 
 #[allow(clippy::derivable_impls)] // this impl cannot be derived
-impl Default for WhisperContextParameters {
+impl<'a> Default for WhisperContextParameters<'a> {
     fn default() -> Self {
         Self {
             use_gpu: cfg!(feature = "_gpu"),
@@ -496,7 +496,7 @@ impl Default for WhisperContextParameters {
         }
     }
 }
-impl WhisperContextParameters {
+impl<'a> WhisperContextParameters<'a> {
     pub fn new() -> Self {
         Self::default()
     }
@@ -512,7 +512,7 @@ impl WhisperContextParameters {
         self.gpu_device = gpu_device;
         self
     }
-    pub fn dtw_parameters(&mut self, dtw_parameters: DtwParameters) -> &mut Self {
+    pub fn dtw_parameters(&mut self, dtw_parameters: DtwParameters<'a>) -> &mut Self {
         self.dtw_parameters = dtw_parameters;
         self
     }
@@ -606,12 +606,12 @@ impl WhisperContextParameters {
 
 /// [EXPERIMENTAL] Enable Token-level timestamps with DTW, default Disabled
 #[derive(Debug, Clone)]
-pub struct DtwParameters {
+pub struct DtwParameters<'a> {
-    pub mode: DtwMode,
+    pub mode: DtwMode<'a>,
     pub dtw_mem_size: usize,
 }
 
-impl Default for DtwParameters {
+impl Default for DtwParameters<'_> {
     fn default() -> Self {
         Self {
             mode: DtwMode::None,
@@ -621,7 +621,7 @@ impl Default for DtwParameters {
 }
 
 #[derive(Debug, Clone)]
-pub enum DtwMode {
+pub enum DtwMode<'a> {
     /// DTW token level timestamps disabled
     None,
     /// Use N Top Most layers from loaded model
@@ -633,7 +633,7 @@ pub enum DtwMode {
     /// 0 < n_text_layer < model n_text_layer, 0 < n_head < model n_text_head for each element
     /// See details https://github.com/ggerganov/whisper.cpp/pull/1485#discussion_r1519681143
     Custom {
-        aheads: &'static [whisper_rs_sys::whisper_ahead],
+        aheads: &'a [whisper_rs_sys::whisper_ahead],
     },
     /// Use predefined preset for standard models
     ModelPreset { model_preset: DtwModelPreset },