""" Video Export API Handles merging multiple video clips into a single output video """ from fastapi import APIRouter, HTTPException, UploadFile, File, Form from fastapi.responses import FileResponse, StreamingResponse from typing import List, Optional, Tuple import os import tempfile import subprocess import json from pathlib import Path router = APIRouter() def get_video_dimensions(video_path: Path) -> Tuple[int, int]: """Get video width and height using ffprobe""" try: cmd = [ 'ffprobe', '-v', 'error', '-select_streams', 'v:0', '-show_entries', 'stream=width,height', '-of', 'json', str(video_path) ] result = subprocess.run(cmd, capture_output=True, text=True, timeout=10) if result.returncode == 0: data = json.loads(result.stdout) streams = data.get('streams', []) if streams: width = streams[0].get('width', 1080) height = streams[0].get('height', 1920) return (width, height) except Exception as e: print(f"⚠️ Could not detect video dimensions: {e}") # Default to 9:16 portrait if detection fails return (1080, 1920) @router.post("/export/merge") async def merge_videos( clips_data: str = Form(...), # JSON string with clip metadata files: List[UploadFile] = File(...) ): """ Merge multiple video clips into a single output video clips_data: JSON string containing array of clip objects with: - index: order in timeline - startTime: start time in clip (seconds) - endTime: end time in clip (seconds) - type: 'video' or 'image' - duration: duration for images (seconds) files: Video/image files in the same order as clips_data """ try: # Parse clips data clips = json.loads(clips_data) if len(clips) != len(files): raise HTTPException( status_code=400, detail=f"Mismatch: {len(clips)} clips but {len(files)} files" ) if len(clips) == 0: raise HTTPException(status_code=400, detail="No clips to merge") # Create temporary directory for processing with tempfile.TemporaryDirectory() as temp_dir: temp_path = Path(temp_dir) # Save all uploaded files file_paths = [] for i, file in enumerate(files): clip = clips[i] file_path = temp_path / f"input_{i}.{file.filename.split('.')[-1] if '.' in file.filename else 'mp4'}" with open(file_path, 'wb') as f: content = await file.read() f.write(content) file_paths.append(file_path) # Detect dimensions from first video to preserve aspect ratio target_width, target_height = get_video_dimensions(file_paths[0]) print(f"📐 Detected video dimensions: {target_width}x{target_height}") # Build FFmpeg command output_path = temp_path / "output.mp4" # Helper function to check if video has audio stream def has_audio_stream(video_path: Path) -> bool: """Check if video file has an audio stream""" try: cmd = [ 'ffprobe', '-v', 'error', '-select_streams', 'a', '-show_entries', 'stream=codec_type', '-of', 'json', str(video_path) ] result = subprocess.run(cmd, capture_output=True, text=True, timeout=10) if result.returncode == 0: import json as json_lib data = json_lib.loads(result.stdout) streams = data.get('streams', []) return len(streams) > 0 return False except Exception: return False # Build filter complex - process clips in order filter_parts = [] input_args = [] concat_inputs = [] # Process all clips in order input_index = 0 for clip_idx, clip in enumerate(clips): file_path = file_paths[clip_idx] if clip['type'] == 'video': clip_duration = clip['endTime'] - clip['startTime'] input_args.extend(['-i', str(file_path)]) # Check if video has audio has_audio = has_audio_stream(file_path) # Trim video and scale to match first video's dimensions # Using scale with force_original_aspect_ratio to handle any size differences filter_parts.append( f"[{input_index}:v]trim=start={clip['startTime']}:end={clip['endTime']}," f"setpts=PTS-STARTPTS," f"scale={target_width}:{target_height}:force_original_aspect_ratio=decrease," f"pad={target_width}:{target_height}:(ow-iw)/2:(oh-ih)/2," f"setsar=1[v{clip_idx}];" ) if has_audio: # Use existing audio stream filter_parts.append( f"[{input_index}:a]atrim=start={clip['startTime']}:end={clip['endTime']}," f"asetpts=PTS-STARTPTS[a{clip_idx}];" ) else: # Generate silent audio for videos without audio filter_parts.append( f"anullsrc=channel_layout=stereo:sample_rate=44100,atrim=0:{clip_duration}," f"asetpts=PTS-STARTPTS[a{clip_idx}];" ) input_index += 1 else: # Image clip clip_duration = clip.get('duration', 3.0) # Default 3 seconds for images input_args.extend(['-loop', '1', '-t', str(clip_duration), '-i', str(file_path)]) # Scale image to match video dimensions filter_parts.append( f"[{input_index}:v]scale={target_width}:{target_height}:force_original_aspect_ratio=decrease," f"pad={target_width}:{target_height}:(ow-iw)/2:(oh-ih)/2," f"setsar=1,format=yuv420p[v{clip_idx}];" ) # Generate silent audio filter_parts.append( f"anullsrc=channel_layout=stereo:sample_rate=44100,atrim=0:{clip_duration}," f"asetpts=PTS-STARTPTS[a{clip_idx}];" ) input_index += 1 # Add to concat inputs in order concat_inputs.append(f"[v{clip_idx}][a{clip_idx}]") # Build complete filter complex filter_complex = ''.join(filter_parts) filter_complex += f"{''.join(concat_inputs)}concat=n={len(clips)}:v=1:a=1[outv][outa]" # Build FFmpeg command ffmpeg_cmd = [ 'ffmpeg', *input_args, '-filter_complex', filter_complex, '-map', '[outv]', '-map', '[outa]', '-c:v', 'libx264', '-c:a', 'aac', '-movflags', '+faststart', '-y', # Overwrite output str(output_path) ] print(f"🎬 Running FFmpeg merge with dimensions: {target_width}x{target_height}") # Run FFmpeg result = subprocess.run( ffmpeg_cmd, capture_output=True, text=True, timeout=300 # 5 minute timeout ) if result.returncode != 0: print(f"❌ FFmpeg error: {result.stderr}") raise HTTPException( status_code=500, detail=f"FFmpeg failed: {result.stderr[:500]}" ) if not output_path.exists(): raise HTTPException(status_code=500, detail="Output file was not created") # Read the entire file into memory before temp directory is deleted print(f"📦 Reading merged video file ({output_path.stat().st_size / 1024 / 1024:.2f} MB)...") with open(output_path, 'rb') as f: video_content = f.read() print(f"✅ Video merged successfully: {target_width}x{target_height}") # Return the merged video file def generate(): # Yield in chunks to avoid loading entire file in memory at once chunk_size = 8192 for i in range(0, len(video_content), chunk_size): yield video_content[i:i + chunk_size] return StreamingResponse( generate(), media_type="video/mp4", headers={ "Content-Disposition": "attachment; filename=exported-video.mp4", "Content-Type": "video/mp4", "Content-Length": str(len(video_content)) } ) except json.JSONDecodeError as e: raise HTTPException(status_code=400, detail=f"Invalid JSON: {str(e)}") except subprocess.TimeoutExpired: raise HTTPException(status_code=504, detail="Video processing timed out") except Exception as e: print(f"❌ Export error: {str(e)}") raise HTTPException(status_code=500, detail=f"Export failed: {str(e)}")