utils.py

from faster_whisper import WhisperModel
import subprocess
import os
import datetime

# Load model một lần khi khởi tạo
model = WhisperModel("guillaumekln/faster-whisper-small", compute_type="int8")

def format_timestamp(seconds: float) -> str:
    hours = int(seconds // 3600)
    minutes = int((seconds % 3600) // 60)
    secs = int(seconds % 60)
    millis = int((seconds - int(seconds)) * 1000)
    return f"{hours:02}:{minutes:02}:{secs:02},{millis:03}"

def extract_audio(video_path):
    audio_path = video_path.replace(".mp4", ".wav")
    command = [
        "ffmpeg", "-y",
        "-i", video_path,
        "-vn",                  # Không lấy hình
        "-acodec", "pcm_s16le", # WAV
        "-ar", "16000",         # 16kHz
        "-ac", "1",             # Mono
        audio_path
    ]

    subprocess.run(command, check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
    return audio_path
    
def generate_subtitles(video_path):
    # 🔊 Tách audio từ video
    audio_path = extract_audio(video_path)

    # 🧠 Dùng audio để sinh phụ đề
    segments, _ = model.transcribe(audio_path, language='zh', task='translate')
    
    srt_path = os.path.abspath(video_path.replace(".mp4", ".srt"))
    with open(srt_path, "w", encoding="utf-8") as f:
        for i, seg in enumerate(segments):
            f.write(f"{i+1}\n")
            f.write(f"{format_timestamp(seg.start)} --> {format_timestamp(seg.end)}\n")
            f.write(f"{seg.text.strip()}\n\n")
    
    print(f"✅ Subtitle saved at: {srt_path}")
    return srt_path

def burn_subtitles(video_path, srt_path):
    if not os.path.exists(srt_path):
        raise FileNotFoundError(f"❌ Không tìm thấy phụ đề: {srt_path}")

    video_path = os.path.abspath(video_path)
    srt_path = os.path.abspath(srt_path)
    output_path = video_path.replace(".mp4", "_subtitled.mp4")

    filter_arg = f"subtitles='{srt_path}'"

    command = [
        "ffmpeg", "-y",
        "-i", video_path,
        "-vf", filter_arg,
        "-c:v", "libx264",
        "-c:a", "copy",
        "-preset", "ultrafast", 
        "-threads", str(os.cpu_count()),
        "-c:a", "copy",  
        output_path
    ]

    print(f"🚀 Running FFmpeg command:\n{' '.join(command)}")

    result = subprocess.run(command, capture_output=True, text=True)
    if result.returncode != 0:
        print("❌ FFmpeg error output:")
        print(result.stderr)
        raise RuntimeError("⚠️ Lỗi khi chạy FFmpeg để chèn phụ đề!")

    print(f"✅ Video with subtitles saved at: {output_path}")
    return output_path
    
def process_video(video_path):
    srt_path = generate_subtitles(video_path)
    final_video = burn_subtitles(video_path, srt_path)
    return final_video