🎵 MP4 转 MP3（视频提取音频）MP4 to MP3 Converter
从 MP4、MOV、WebM、MKV 等视频中提取声音并保存为 MP3：可选 128–320 kbps 码率、立体声或单声道，可截取开始和结束时间，还能写入标题和歌手标签；解码和编码都在浏览器本地完成。Extract the soundtrack from MP4, MOV, WebM, MKV and other videos and save it as MP3 — 128–320 kbps, stereo or mono, optional start/end trim and title/artist tags. Decoding and encoding both run locally in your browser.
使用说明与常见问题How-to & FAQ
「MP4 转 MP3（视频提取音频）」是什么？What is the MP4 to MP3 Converter tool?
从 MP4、MOV、WebM、MKV 等视频中提取声音并保存为 MP3：可选 128–320 kbps 码率、立体声或单声道，可截取开始和结束时间，还能写入标题和歌手标签；解码和编码都在浏览器本地完成。Extract the soundtrack from MP4, MOV, WebM, MKV and other videos and save it as MP3 — 128–320 kbps, stereo or mono, optional start/end trim and title/artist tags. Decoding and encoding both run locally in your browser.
如何使用「MP4 转 MP3（视频提取音频）」？How do I use the MP4 to MP3 Converter tool?
在「MP4 转 MP3（视频提取音频）」中，按需设置「码率」、「声道」、「开始（秒或 分:秒）」、「结束」、「标题」等选项，然后点击「转换为 MP3」按钮即可。支持拖放文件。In the MP4 to MP3 Converter: Set "Bitrate", "Channels", "Start (s or m:ss)", "End", "Title", then click "Convert to MP3". Drag-and-drop files is supported.
支持哪些文件？Which files are supported?
只要浏览器能解码其中的音轨就可以：MP4、M4A、MOV（AAC 音频）、WebM、MKV（Opus/Vorbis）、MP3、WAV、FLAC、OGG 等。少数编码（如 AC-3/杜比、DTS、WMA）浏览器不能解码，会给出提示。文件最大 1 GB。Anything whose audio track the browser can decode: MP4, M4A, MOV (AAC audio), WebM, MKV (Opus/Vorbis), MP3, WAV, FLAC, OGG and more. A few codecs (AC-3/Dolby, DTS, WMA) can't be decoded by browsers and you'll be told. Up to 1 GB.
码率选多少合适？Which bitrate should I choose?
192 kbps 对音乐和讲话都足够清晰；追求音质选 256 或 320 kbps；只是录音、讲座可以选 128 kbps 单声道，文件更小。注意：原视频中的音频已经过压缩，选更高码率不会让音质超过原始音频。单声道最高 160 kbps。192 kbps is clear for music and speech; pick 256 or 320 kbps for the best quality; 128 kbps mono is fine for recordings and lectures and gives smaller files. The video's audio is already compressed, so a higher bitrate can't make it better than the source. Mono is capped at 160 kbps.
MP3 编码器是什么？Which MP3 encoder is used?
使用 lamejs（LAME 编码器的 JavaScript 移植版，LGPL-3.0 许可），在后台线程中运行，转换时页面不会卡住。音频统一输出为 44.1 kHz。lamejs, a JavaScript port of the LAME encoder (LGPL-3.0), running in a background thread so the page stays responsive. Output is 44.1 kHz.
视频会上传到服务器吗？Is my video uploaded?
不会。所有处理都在你的浏览器里完成，文件不会离开你的设备，所以也不受上传大小和网速限制（但受电脑内存和性能限制）。No. Everything runs in your browser and the file never leaves your device, so there are no upload limits or waits — only your computer's memory and speed.
「MP4 转 MP3（视频提取音频）」免费吗？需要注册吗？Is the MP4 to MP3 Converter free? Do I need an account?
「MP4 转 MP3（视频提取音频）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The MP4 to MP3 Converter is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.