Add a Whisper example for the Rust API (#3661)

.github/scripts/test-rust.sh

@@ -67,6 +67,7 @@ rm -rf sherpa-onnx-online-punct-*
 rm -rf sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile
 
 ./run-spoken-language-identification.sh
+./run-whisper.sh
 rm -rf sherpa-onnx-whisper-tiny spoken-language-identification-test-wavs
 
 ./run-offline-punctuation.sh

rust-api-examples/README.md

@@ -90,6 +90,7 @@ in your own Cargo project, see
 | 45 | [zipformer_transducer_simulate_streaming_microphone](#example-45-simulated-streaming-asr-with-zipformer-transducer-and-vad-from-microphone) | Simulated streaming ASR with Zipformer transducer and VAD from microphone |
 | 46 | [zipformer_transducer_simulate_streaming_microphone](#example-46-simulated-streaming-asr-with-zipformer-transducer-japanese-and-vad-from-microphone) | Simulated streaming ASR with Zipformer transducer (Japanese) and VAD from microphone |
 | 47 | [qwen3_asr_simulate_streaming_microphone](#example-47-simulated-streaming-asr-with-qwen3-asr-and-vad-from-microphone) | Simulated streaming ASR with Qwen3 ASR and VAD from microphone |
+| 48 | [whisper](#example-48-asr-with-non-streaming-whisper) | Non-streaming ASR with Whisper (multilingual) |
 
 ## Run it
 
@@ -415,3 +416,9 @@ Qwen3 ASR recognizer on each detected segment.
 ```bash
 ./run-qwen3-asr-simulate-streaming-microphone.sh
 ```
+
+### Example 48: ASR with non-streaming Whisper
+
+```bash
+./run-whisper.sh
+```

rust-api-examples/examples/whisper.rs

@@ -0,0 +1,119 @@
+// Copyright (c) 2026 Yujie Wu
+//
+// This file demonstrates how to use Whisper with sherpa-onnx's Rust API
+// for offline speech recognition.
+//
+// See ../README.md for how to run it.
+
+use clap::Parser;
+use sherpa_onnx::{OfflineRecognizer, OfflineRecognizerConfig, OfflineWhisperModelConfig, Wave};
+use std::time::Instant;
+
+/// Whisper offline ASR example
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+    /// Path to encoder ONNX model
+    #[arg(long)]
+    encoder: String,
+
+    /// Path to decoder ONNX model
+    #[arg(long)]
+    decoder: String,
+
+    /// Path to tokens file
+    #[arg(long)]
+    tokens: String,
+
+    /// Path to input WAV file
+    #[arg(long)]
+    wav: String,
+
+    /// Recognition language, e.g. "en", "zh". Leave empty for auto-detection
+    #[arg(long, default_value = "")]
+    language: String,
+
+    /// Task type: "transcribe" or "translate" (translate to English)
+    #[arg(long, default_value = "transcribe")]
+    task: String,
+
+    /// Provider (default: cpu)
+    #[arg(long, default_value = "cpu")]
+    provider: String,
+
+    /// Enable debug logs
+    #[arg(long, default_value_t = false)]
+    debug: bool,
+
+    /// Number of threads
+    #[arg(long, default_value_t = 2)]
+    num_threads: i32,
+}
+
+fn main() {
+    let args = Args::parse();
+
+    let wave = Wave::read(&args.wav).expect("Failed to read WAV file");
+    let audio_duration = wave.samples().len() as f64 / wave.sample_rate() as f64;
+
+    // Create default recognizer config
+    let mut recognizer_config = OfflineRecognizerConfig::default();
+
+    // Set the Whisper model
+    recognizer_config.model_config.whisper = OfflineWhisperModelConfig {
+        encoder: Some(args.encoder.clone()),
+        decoder: Some(args.decoder.clone()),
+        language: Some(args.language.clone()),
+        task: Some(args.task.clone()),
+        tail_paddings: 0,
+        enable_token_timestamps: false,
+        enable_segment_timestamps: false,
+    };
+
+    recognizer_config.model_config.tokens = Some(args.tokens.clone());
+    recognizer_config.model_config.provider = Some(args.provider.clone());
+    recognizer_config.model_config.debug = args.debug;
+    recognizer_config.model_config.num_threads = args.num_threads;
+
+    // Measure recognizer creation time
+    println!("Creating recognizer ...");
+    let start_creation = Instant::now();
+    let recognizer =
+        OfflineRecognizer::create(&recognizer_config).expect("Failed to create OfflineRecognizer");
+    let creation_elapsed = start_creation.elapsed().as_secs_f64();
+    println!("Recognizer created in {:.3} seconds.", creation_elapsed);
+
+    let stream = recognizer.create_stream();
+
+    // Measure recognition time
+    let start_recognition = Instant::now();
+    stream.accept_waveform(wave.sample_rate(), wave.samples());
+    recognizer.decode(&stream);
+    let recognition_elapsed = start_recognition.elapsed().as_secs_f64();
+
+    // Get recognition result
+    if let Some(result) = stream.get_result() {
+        println!("Decoded text: {}", result.text);
+
+        let total_elapsed = creation_elapsed + recognition_elapsed;
+        let rtf = recognition_elapsed / audio_duration;
+        println!("\n=== Performance Summary ===");
+        println!("Audio duration          : {:.3} seconds", audio_duration);
+        println!("Recognizer creation time: {:.3} seconds", creation_elapsed);
+        println!(
+            "Recognition time        : {:.3} seconds",
+            recognition_elapsed
+        );
+        println!("Total elapsed time      : {:.3} seconds", total_elapsed);
+        println!(
+            "Real-Time Factor (RTF)  : {:.3} (recognition_elapsed / audio_duration = {:.3} / {:.3})",
+            rtf, recognition_elapsed, audio_duration
+        );
+        println!(
+            "Number of threads       : {}",
+            recognizer_config.model_config.num_threads
+        );
+    } else {
+        eprintln!("Failed to get recognition result");
+    }
+}

rust-api-examples/run-whisper.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -ex
+
+# see
+# https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+if [ ! -f ./sherpa-onnx-whisper-tiny/tiny-encoder.onnx ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-whisper-tiny.tar.bz2
+  tar xvf sherpa-onnx-whisper-tiny.tar.bz2
+  rm sherpa-onnx-whisper-tiny.tar.bz2
+fi
+
+cargo run --example whisper -- \
+    --wav ./sherpa-onnx-whisper-tiny/test_wavs/0.wav \
+    --encoder ./sherpa-onnx-whisper-tiny/tiny-encoder.onnx \
+    --decoder ./sherpa-onnx-whisper-tiny/tiny-decoder.onnx \
+    --tokens ./sherpa-onnx-whisper-tiny/tiny-tokens.txt \
+    --language en \
+    --num-threads 2