src/video/processor.py

"""
Video processing utilities for combining video, audio, and subtitles.
"""
import os
import shutil
import subprocess
from pathlib import Path
import tempfile

from src.utils.logger import get_logger
from config import OUTPUT_DIR, SUBTITLE_FONT_SIZE

logger = get_logger(__name__)

def combine_video_audio_subtitles(video_path, audio_path, srt_path, output_path=None):
    try:
        video_path = Path(video_path)
        audio_path = Path(audio_path)
        srt_path = Path(srt_path)

        if output_path is None:
            lang_code = srt_path.stem.split('_')[-1]
            output_path = OUTPUT_DIR / f"{video_path.stem}_translated_{lang_code}.mp4"
        else:
            output_path = Path(output_path)
            
        logger.info(f"Combining video, audio, and subtitles")
        
        # FIXED FFMPEG COMMAND:
        cmd = [
            'ffmpeg',
            '-y',  # Overwrite output
            '-i', str(video_path),  # Original video
            '-i', str(audio_path),  # Translated audio
            
            # Video processing (re-encode instead of copy to allow subtitles)
            '-vf', f"subtitles={str(srt_path)}:force_style='FontSize={SUBTITLE_FONT_SIZE}'",
            '-c:v', 'libx264',  # Re-encode video
            '-preset', 'fast',  # Faster encoding
            '-crf', '23',  # Good quality
            
            # Audio processing
            '-c:a', 'aac',
            '-b:a', '192k',
            
            # Stream selection
            '-map', '0:v:0',  # Video from first input
            '-map', '1:a:0',  # Audio from second input
            
            # Metadata
            '-metadata:s:a:0', 'language=' + lang_code[:3],  # Set audio language
            
            str(output_path)
        ]
        
        logger.debug(f"Running command: {' '.join(cmd)}")
        process = subprocess.run(cmd, capture_output=True, text=True)
        
        if process.returncode != 0:
            error_msg = f"FFmpeg failed: {process.stderr}"
            if "Filtergraph" in error_msg and "streamcopy" in error_msg:
                error_msg += "\nFIX: Cannot use both video filters and stream copy. Must re-encode video."
            raise Exception(error_msg)
            
        return output_path
        
    except Exception as e:
        logger.error(f"Combining failed: {str(e)}")
        raise Exception(f"Failed to combine video/audio/subtitles: {str(e)}")


        
def combine_method_subtitles_filter(video_path, audio_path, srt_path, output_path):
    """
    Combine video, audio, and subtitles using ffmpeg with subtitle filter.
    
    Args:
        video_path (Path): Path to the video file
        audio_path (Path): Path to the translated audio file
        srt_path (Path): Path to the subtitle file
        output_path (Path): Path for the output video
        
    Returns:
        Path: Path to the output video
    """
    logger.info(f"Using subtitles filter method")


    cmd = [
        'ffmpeg',
        '-i', str(video_path),  # Video input
        '-i', str(audio_path),  # Audio input
        '-vf', f"subtitles={str(srt_path)}:force_style='FontSize={SUBTITLE_FONT_SIZE}'",  # Subtitle filter
        '-map', '0:v',  # Map video from first input
        '-map', '1:a',  # Map audio from second input
        '-c:v', 'libx264',  # Video codec
        '-c:a', 'aac',  # Audio codec
        '-strict', 'experimental',
        '-b:a', '192k',  # Audio bitrate
        '-y',  # Overwrite output
        str(output_path)
    ]
    
    logger.debug(f"Running command: {' '.join(cmd)}")
    process = subprocess.run(cmd, capture_output=True, text=True)
    
    if process.returncode != 0:
        error_message = f"FFmpeg subtitles filter method failed: {process.stderr}"
        logger.error(error_message)
        raise Exception(error_message)
    
    return output_path

def combine_method_with_temp(video_path, audio_path, srt_path, output_path):
    """
    Combine video, audio, and subtitles using temporary files.
    
    Args:
        video_path (Path): Path to the video file
        audio_path (Path): Path to the translated audio file
        srt_path (Path): Path to the subtitle file
        output_path (Path): Path for the output video
        
    Returns:
        Path: Path to the output video
    """
    logger.info(f"Using temporary file method")
    
    # Create temporary directory
    temp_dir = Path(tempfile.mkdtemp(prefix="video_combine_", dir=OUTPUT_DIR / "temp"))
    try:
        # Step 1: Combine video with audio
        temp_video_audio = temp_dir / "video_with_audio.mp4"
        cmd1 = [
            'ffmpeg',
            '-i', str(video_path),
            '-i', str(audio_path),
            '-c:v', 'copy',
            '-c:a', 'aac',
            '-strict', 'experimental',
            '-map', '0:v',
            '-map', '1:a',
            '-y',
            str(temp_video_audio)
        ]
        
        logger.debug(f"Running command (step 1): {' '.join(cmd1)}")
        process1 = subprocess.run(cmd1, capture_output=True, text=True)
        
        if process1.returncode != 0:
            error_message = f"Step 1 failed: {process1.stderr}"
            logger.error(error_message)
            raise Exception(error_message)
            
        # Step 2: Add subtitles to the combined video
        cmd2 = [
            'ffmpeg',
            '-i', str(temp_video_audio),
            '-vf', f"subtitles={str(srt_path)}:force_style='FontSize={SUBTITLE_FONT_SIZE}'",
            '-c:a', 'copy',
            '-y',
            str(output_path)
        ]
        
        logger.debug(f"Running command (step 2): {' '.join(cmd2)}")
        process2 = subprocess.run(cmd2, capture_output=True, text=True)
        
        if process2.returncode != 0:
            error_message = f"Step 2 failed: {process2.stderr}"
            logger.error(error_message)
            raise Exception(error_message)
            
        return output_path
    finally:
        # Clean up temporary directory
        try:
            shutil.rmtree(temp_dir)
            logger.debug(f"Cleaned up temporary directory: {temp_dir}")
        except Exception as e:
            logger.warning(f"Failed to clean up temp directory: {str(e)}")

def combine_method_no_subtitles(video_path, audio_path, srt_path, output_path):
    """
    Fallback method: Combine only video and audio without subtitles.
    
    Args:
        video_path (Path): Path to the video file
        audio_path (Path): Path to the translated audio file
        srt_path (Path): Path to the subtitle file (unused in this method)
        output_path (Path): Path for the output video
        
    Returns:
        Path: Path to the output video
    """
    logger.info(f"Using fallback method (no subtitles)")
    
    # Just combine video and audio as fallback
    cmd = [
        'ffmpeg',
        '-i', str(video_path),
        '-i', str(audio_path),
        '-c:v', 'copy',
        '-c:a', 'aac',
        '-strict', 'experimental',
        '-map', '0:v',
        '-map', '1:a',
        '-y',
        str(output_path)
    ]
    
    logger.debug(f"Running command: {' '.join(cmd)}")
    process = subprocess.run(cmd, capture_output=True, text=True)
    
    if process.returncode != 0:
        error_message = f"Fallback method failed: {process.stderr}"
        logger.error(error_message)
        raise Exception(error_message)
    
    logger.warning("Video was combined without subtitles")
    return output_path