ffmpeg.py

def run_ffmpeg_video_process(
    input_path: str,
    output_path: str,
    srt_path: str | None = None,
    trim_seconds: float = 3.0,
) -> bool:
    """Process video with FFmpeg: trim, overlay text, and burn subtitles.

    Args:
        input_path: Path to the input video file.
        output_path: Path where the output video should be saved.
        srt_path: Optional path to SRT subtitle file to burn in.
        trim_seconds: Seconds to trim from end (default: 3.0).

    Returns:
        True if processing succeeded, False otherwise.
    """
    if not shutil.which("ffmpeg"):
        print("Error: 'ffmpeg' command not found. Please install FFmpeg.")
        return False

    # 1. Get duration via ffprobe
    try:
        cmd_dur = [
            "ffprobe",
            "-v",
            "error",
            "-show_entries",
            "format=duration",
            "-of",
            "default=noprint_wrappers=1:nokey=1",
            input_path,
        ]
        duration_str = subprocess.check_output(cmd_dur).decode().strip()
        duration = float(duration_str)
    except Exception as e:
        print(f"Error probing video duration: {e}")
        return False

    target_duration = max(0, duration - trim_seconds)

    # 2. Build filter chain
    filters = []

    # Text overlay (bottom right, black box, white text)
    font_info = _find_chinese_font()
    font_opt = ""
    font_name = ""
    if font_info:
        font_path, font_name = font_info
        escaped_font = _escape_ffmpeg_path(font_path)
        font_opt = f":fontfile='{escaped_font}'"
    drawtext = (
        f"drawtext=text='{VIDEO_WATERMARK_TEXT}'{font_opt}"
        ":fontsize=24:fontcolor=white"
        ":box=1:boxcolor=black@0.8:boxborderw=5"
        ":x=w-tw-15:y=h-th-33"
    )
    filters.append(drawtext)

    if srt_path and os.path.exists(srt_path):
        escaped_srt = _escape_ffmpeg_path(srt_path)
        font_style = f"FontName={font_name}," if font_name else ""
        subtitles = (
            f"subtitles='{escaped_srt}'"
            f":force_style='{font_style}FontSize=16,MarginV=25,Outline=1,Shadow=0'"
        )
        filters.append(subtitles)

    filter_complex = ",".join(filters)

    # 3. Build FFmpeg command
    cmd = [
        "ffmpeg",
        "-y",
        "-ss",
        "0",
        "-t",
        str(target_duration),
        "-i",
        input_path,
    ]
    if filter_complex:
        cmd.extend(["-vf", filter_complex])
    cmd.extend(
        [
            "-c:v",
            "libx264",
            "-preset",
            "medium",
            "-crf",
            "23",
            "-c:a",
            "aac",
            "-b:a",
            "128k",
            output_path,
        ]
    )

    # 4. Run
    print(f"Processing video: {input_path}")
    print(f"Duration: {duration:.2f}s → {target_duration:.2f}s")
    try:
        subprocess.run(cmd, check=True)
        return True
    except subprocess.CalledProcessError as e:
        print(f"FFmpeg failed: {e}")
        return False