app.py

import gradio as gr
from pydub import AudioSegment
from moviepy.editor import VideoFileClip
import tempfile
import mimetypes
import os
import subprocess
import json
import moviepy.video.fx.all as vfx


# FFmpegの音声速度変更用のatempoフィルター生成
def build_atempo_filters(speed):
    if not 0.5 <= speed <= 2.0:
        factors = []
        while speed > 2.0:
            factors.append(2.0)
            speed /= 2.0
        while speed < 0.5:
            factors.append(0.5)
            speed /= 0.5
        factors.append(speed)
        return ",".join(f"atempo={round(f, 5)}" for f in factors)
    else:
        return f"atempo={round(speed, 5)}"


# FFmpegで動画の速度変更
def change_video_speed_ffmpeg(video_file, speed, export_format):
    result = subprocess.run(
        [
            "ffprobe", "-v", "error",
            "-select_streams", "a", "-show_entries", "stream=index",
            "-of", "json", video_file
        ],
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        text=True,
        check=True
    )
    audio_info = json.loads(result.stdout)
    has_audio = bool(audio_info.get("streams"))

    format_ext = os.path.splitext(video_file)[-1].lstrip(".") if export_format == "元のまま" else export_format
    output_file = tempfile.NamedTemporaryFile(suffix=f".{format_ext}", delete=False).name

    setpts_filter = f"setpts={1/speed}*PTS"
    atempo_filter = build_atempo_filters(speed)

    if has_audio:
        filter_complex = f"[0:v]{setpts_filter}[v];[0:a]{atempo_filter}[a]"
        map_args = ["-map", "[v]", "-map", "[a]"]
        codec_args = ["-c:v", "libx264", "-c:a", "aac"]
    else:
        filter_complex = f"[0:v]{setpts_filter}[v]"
        map_args = ["-map", "[v]"]
        codec_args = ["-c:v", "libx264"]

    cmd = [
        "ffmpeg", "-y", "-i", video_file,
        "-filter_complex", filter_complex,
        *map_args, *codec_args, output_file
    ]

    subprocess.run(cmd, check=True)
    return output_file


# FFmpegで音声の速度変更
def change_audio_speed_ffmpeg(audio_file, speed, export_format):
    atempo_filter = build_atempo_filters(speed)
    format_ext = os.path.splitext(audio_file)[-1].lstrip(".") if export_format == "元のまま" else export_format
    output_file = tempfile.NamedTemporaryFile(suffix=f".{format_ext}", delete=False).name

    cmd = [
        "ffmpeg", "-y", "-i", audio_file,
        "-filter:a", atempo_filter,
        "-c:a", "aac" if format_ext in ["mp4", "mov"] else "libmp3lame",
        output_file
    ]

    subprocess.run(cmd, check=True)
    return output_file


# Pydubで音声の速度変更
def change_audio_speed_pydub(audio_file, speed, export_format):
    audio = AudioSegment.from_file(audio_file)
    new_frame_rate = int(audio.frame_rate * speed)
    faster_audio = audio._spawn(audio.raw_data, overrides={'frame_rate': new_frame_rate})
    faster_audio = faster_audio.set_frame_rate(audio.frame_rate)

    format_ext = os.path.splitext(audio_file)[-1].lstrip(".") if export_format == "元のまま" else export_format
    with tempfile.NamedTemporaryFile(suffix=f".{format_ext}", delete=False) as tmpfile:
        faster_audio.export(tmpfile.name, format=format_ext)
        return tmpfile.name


# moviepyで動画の速度変更
def change_video_speed_moviepy(video_file, speed, export_format):
    clip = VideoFileClip(video_file)
    new_clip = clip.fx(vfx.speedx, speed)

    format_ext = os.path.splitext(video_file)[-1].lstrip(".") if export_format == "元のまま" else export_format
    output_file = tempfile.NamedTemporaryFile(suffix=f".{format_ext}", delete=False).name

    new_clip.write_videofile(
        output_file,
        codec="libx264" if format_ext in ["mp4", "mov"] else None,
        audio_codec="aac",
        verbose=False,
        logger=None
    )
    return output_file


# 全体のラッパー関数（処理方法の分岐）
def change_speed(file_path, speed, export_format, method):
    mime, _ = mimetypes.guess_type(file_path)
    print(speed)
    if mime and mime.startswith("audio"):
        if method == "FFmpeg":
            return change_audio_speed_ffmpeg(file_path, speed, export_format)
        else:
            return change_audio_speed_pydub(file_path, speed, export_format)
    elif mime and mime.startswith("video"):
        if method == "FFmpeg":
            return change_video_speed_ffmpeg(file_path, speed, export_format)
        else:
            return change_video_speed_moviepy(file_path, speed, export_format)
    else:
        raise gr.Error("対応していないファイル形式です。音声または動画をアップロードしてください。")


# Gradio UI
with gr.Blocks() as demo:
    gr.Markdown("# 🎬 音声・動画の再生速度を細かく調整して変換")
    gr.Markdown("""
| 項目       | Gradio（入力）                        | Pydub／MoviePy                                 | FFmpeg（フィルター）                       |
| -------- | --------------------------------- | --------------------------------------------- | ----------------------------------- |
| 入力形式     | `Slider(step=0.0001)` → 小数点以下4桁以上 | Python `float` → `AudioSegment` / `speedx`    | `float` → `atempo` / `setpts`       |
| 表現精度（理論） | 小数点以下4桁程度                         | 倍精度浮動小数点 → 最大小数点以下15桁                         | 同左（内部処理は浮動小数点）                      |
| 実効分解能    | 0.0001単位                          | 音声: サンプリングレート依存（約20μs）、動画: フレーム単位             | 音声: `atempo` (0.5–2.0連結対応)、動画: µs単位 |
| 出力方式     | `float` → `ChangeSpeed(speed)`    | `AudioSegment.export()` / `write_videofile()` | `ffmpeg` CLI を直接呼び出し                |

    """)

    with gr.Row():
        with gr.Column():
            file_input = gr.File(label="音声または動画をアップロード", file_types=[".mp3", ".wav", ".mp4", ".mov"])
            speed_input = gr.Slider(
                minimum=0.1, maximum=4.0, value=1.0, step=0.0001,
                label="再生速度（例：0.75 = 25%遅く、1.25 = 25%速く）"
            )
            export_format_input = gr.Dropdown(
                choices=["元のまま", "wav", "mp3", "mp4", "mov"],
                value="元のまま",
                label="出力フォーマット"
            )
            method_input = gr.Dropdown(
                choices=["FFmpeg", "Pydub/MoviePy"],
                value="FFmpeg",
                label="処理方法"
            )
            btn = gr.Button("変換")

        with gr.Column():
            file_output = gr.File(label="変換後のファイルをダウンロード")

    btn.click(fn=change_speed, inputs=[file_input, speed_input, export_format_input, method_input], outputs=file_output)

if __name__ == "__main__":
    demo.launch()