Update rust_highlight/src/lib.rs

rust_highlight/src/lib.rs

@@ -161,7 +161,27 @@ fn generate_video_clip(id: usize, text: String, audio_path: String, duration: f6
 
     println!("Total animation frames to render: {}", frame_specs.len());
 
-    // Parallel rendering using rayon
+    // STEP 3: Start FFmpeg process first
+    let mut child = Command::new("ffmpeg")
+        .arg("-y")
+        .arg("-f").arg("rawvideo")
+        .arg("-pix_fmt").arg("bgr24")
+        .arg("-s").arg(format!("{}x{}", width, height))
+        .arg("-r").arg(fps.to_string())
+        .arg("-i").arg("-")
+        .arg("-an")
+        .arg("-c:v").arg("libx264")
+        .arg("-preset").arg(ffmpeg_preset)
+        .arg("-crf").arg(crf)
+        .arg("-pix_fmt").arg("yuv420p")
+        .arg(&animation_video_path)
+        .stdin(Stdio::piped())
+        .spawn()
+        .map_err(|e| pyo3::exceptions::PyRuntimeError::new_err(format!("Failed to spawn FFmpeg: {}", e)))?;
+
+    let mut stdin = child.stdin.take().unwrap();
+
+    // Parallel rendering using rayon and streaming to FFmpeg
     let animation_frames: Vec<Vec<u8>> = frame_specs
         .par_iter()
         .map(|(visible_sub, pen_x, pen_y, anim_step)| {
@@ -197,30 +217,10 @@ fn generate_video_clip(id: usize, text: String, audio_path: String, duration: f6
 
     println!("Animation frames rendered in {:.3}s", t0.elapsed().as_secs_f64());
 
-    // STEP 3: Write animation frames to FFmpeg
-    let mut child = Command::new("ffmpeg")
-        .arg("-y")
-        .arg("-f").arg("rawvideo")
-        .arg("-pix_fmt").arg("bgr24")
-        .arg("-s").arg(format!("{}x{}", width, height))
-        .arg("-r").arg(fps.to_string())
-        .arg("-i").arg("-")
-        .arg("-an")
-        .arg("-c:v").arg("libx264")
-        .arg("-preset").arg(ffmpeg_preset)
-        .arg("-crf").arg(crf)
-        .arg("-pix_fmt").arg("yuv420p")
-        .arg(&animation_video_path)
-        .stdin(Stdio::piped())
-        .spawn()
-        .map_err(|e| pyo3::exceptions::PyRuntimeError::new_err(format!("Failed to spawn FFmpeg: {}", e)))?;
-
-    let mut stdin = child.stdin.take().unwrap();
-
     // Write all animation frames in one large batch
     let mut buffer: Vec<u8> = Vec::with_capacity(animation_frames.len() * width as usize * height as usize * 3);
-    for frame_data in animation_frames {
-        buffer.extend_from_slice(&frame_data);
+    for frame_data in &animation_frames {
+        buffer.extend_from_slice(frame_data);
     }
     
     stdin.write_all(&buffer)