[Feat] Make prev_frame_length parameter configurable via config (#276)

* [Feat] Make prev_frame_length parameter configurable via config

* Add newline at end of file in wan_audio_runner.py

---------
Co-authored-by: Yang Yong(雍洋) <yongyang1030@163.com>

lightx2v/models/runners/wan/wan_audio_runner.py

@@ -237,7 +237,7 @@ class AudioProcessor:
         else:
             interval_num = max(int((expected_frames - max_num_frames) / (max_num_frames - prev_frame_length)) + 1, 1)
             res_frame_num = expected_frames - interval_num * (max_num_frames - prev_frame_length)
-            if res_frame_num > 5:
+            if res_frame_num > prev_frame_length:
                 interval_num += 1
 
         # Create segments
@@ -255,7 +255,7 @@ class AudioProcessor:
 
                 segments.append(AudioSegment(segment_audio, 0, max_num_frames, False, useful_length))
 
-            elif res_frame_num > 5 and idx == interval_num - 1:
+            elif res_frame_num > prev_frame_length and idx == interval_num - 1:
                 # Last segment (might be shorter)
                 start_frame = idx * max_num_frames - idx * prev_frame_length
                 audio_start, audio_end = self.get_audio_range(start_frame, expected_frames)
@@ -284,6 +284,7 @@ class WanAudioRunner(WanRunner):  # type:ignore
     def __init__(self, config):
         super().__init__(config)
         self.frame_preprocessor = FramePreprocessor()
+        self.prev_frame_length = self.config.get("prev_frame_length", 5)
 
     def init_scheduler(self):
         """Initialize consistency model scheduler"""
@@ -307,7 +308,7 @@ class WanAudioRunner(WanRunner):  # type:ignore
         expected_frames = min(max(1, int(video_duration * target_fps)), audio_len)
 
         # Segment audio
-        audio_segments = self._audio_processor.segment_audio(audio_array, expected_frames, self.config.get("target_video_length", 81))
+        audio_segments = self._audio_processor.segment_audio(audio_array, expected_frames, self.config.get("target_video_length", 81), self.prev_frame_length)
 
         return audio_segments, expected_frames
 
@@ -464,7 +465,7 @@ class WanAudioRunner(WanRunner):  # type:ignore
         audio_features = self.audio_adapter.forward_audio_proj(audio_features, self.model.scheduler.latents.shape[1])
 
         self.inputs["audio_encoder_output"] = audio_features
-        self.inputs["previmg_encoder_output"] = self.prepare_prev_latents(self.prev_video, prev_frame_length=5)
+        self.inputs["previmg_encoder_output"] = self.prepare_prev_latents(self.prev_video, prev_frame_length=self.prev_frame_length)
 
         # Reset scheduler for non-first segments
         if segment_idx > 0:
@@ -475,8 +476,8 @@ class WanAudioRunner(WanRunner):  # type:ignore
         self.gen_video = torch.clamp(self.gen_video, -1, 1).to(torch.float)
 
         # Extract relevant frames
-        start_frame = 0 if self.segment_idx == 0 else 5
-        start_audio_frame = 0 if self.segment_idx == 0 else int(6 * self._audio_processor.audio_sr / self.config.get("target_fps", 16))
+        start_frame = 0 if self.segment_idx == 0 else self.prev_frame_length
+        start_audio_frame = 0 if self.segment_idx == 0 else int((self.prev_frame_length + 1) * self._audio_processor.audio_sr / self.config.get("target_fps", 16))
 
         if self.segment.is_last and self.segment.useful_length:
             end_frame = self.segment.end_frame - self.segment.start_frame