Fix video playback: strict 2s duration, chain method (no overlap), audio duration cap, and ffmpeg browser compatibility (yuv420p)

modules/story_reels/services/story_creator.py

@@ -438,12 +438,14 @@ class StoryCreator:
                 if result.get("path"):
                     temp_files.append(Path(result["path"]))
                     
-                    # Find matching chunk for duration
+                    # Force 2.0 seconds per image as requested
                     scene_duration = 2.0
-                    for chunk in image_chunks:
-                        if chunk['chunk_id'] == result["id"]:
-                            scene_duration = chunk['duration']
-                            break
+                    
+                    # (Optional) We can still look up chunk for debug/metadata but duration is fixed
+                    # for chunk in image_chunks:
+                    #     if chunk['chunk_id'] == result["id"]:
+                    #         # scene_duration = chunk['duration'] # Ignored
+                    #         break
                     
                     generated_scenes.append({
                         "scene_id": result["id"],
@@ -597,28 +599,34 @@ class StoryCreator:
             # Set duration
             clip = clip.set_duration(duration)
             
-            # Simple Zoom Effect (Ken Burns)
-            # We apply a slight zoom (1.0 -> 1.05) to all clips for movement
-            if duration > 0:
-               clip = clip.resize(lambda t: 1 + 0.04 * t / duration) 
-               # Re-crop to ensure no borders appear during zoom
-               clip = clip.crop(x_center=clip.w/2, y_center=clip.h/2, width=TARGET_WIDTH, height=TARGET_HEIGHT)
+            # Removed dynamic zoom to fix black screen/rendering issues
+            # Images will be static but stable
+            
+            # Transitions
 
             # Transitions
             if i > 0:
-                clip = clip.crossfadein(CROSSFADE_DURATION)
+                clip = clip.crossfadein(0.5) # Simple fade-in for smooth join without overlap
             
             clips.append(clip)
+            # For strict chain method, total is sum of durations
             total_video_duration += duration
         
-        # Concatenate clips
-        # method="compose" is safer for crossfades
-        video = concatenate_videoclips(clips, method="compose", padding=-CROSSFADE_DURATION)
+        # Concatenate clips (Chain Method: one after another)
+        # padding=0 ensures no overlap, preserving exact duration calculation
+        if len(clips) > 1:
+            video = concatenate_videoclips(clips, method="compose")
+        else:
+            video = clips[0]
         
-        # Final safety: match video length to audio exactly
-        if abs(video.duration - audio_duration) > 0.1:
-            if video.duration > audio_duration:
-                video = video.subclip(0, audio_duration)
+        # Final safety: FORCE video duration to match audio exactly
+        # If video is longer, cut it. If shorter, it's fine (but our logic tries to match)
+        if video.duration > audio_duration:
+            logger.info(f"Trimming video from {video.duration}s to match audio {audio_duration}s")
+            video = video.subclip(0, audio_duration)
+        else:
+             # Ideally shouldn't happen with our chain logic, but if slightly short, set duration
+             video = video.set_duration(audio_duration)
         
         video = video.set_audio(audio)