📀 M2TS 转换助手M2TS Converter
生成把 .m2ts / .mts（及 .ts）转成 MP4 的 ffmpeg 命令：可选尝试 -c copy 无损封装，或重编码为 H.264+AAC。浏览器内不解码大视频；命令在你电脑上运行。Build an ffmpeg command to turn .m2ts / .mts (and .ts) into MP4: try -c copy remux, or re-encode to H.264+AAC. The browser does not decode large videos - run the command on your computer.
使用说明与常见问题How-to & FAQ
「M2TS 转换助手」是什么？What is the M2TS Converter tool?
生成把 .m2ts / .mts（及 .ts）转成 MP4 的 ffmpeg 命令：可选尝试 -c copy 无损封装，或重编码为 H.264+AAC。浏览器内不解码大视频；命令在你电脑上运行。Build an ffmpeg command to turn .m2ts / .mts (and .ts) into MP4: try -c copy remux, or re-encode to H.264+AAC. The browser does not decode large videos - run the command on your computer.
如何使用「M2TS 转换助手」？How do I use the M2TS Converter tool?
填写输入文件名和输出文件名，在「模式」中选择直接转封装（-c copy）或重新编码为 H.264 + AAC，点「生成命令」得到 ffmpeg 命令，再点「复制」并在自己的电脑上运行。浏览器不会处理视频本身。Enter the input and output file names, choose remux (-c copy) or re-encode to H.264 + AAC under Mode, click "Build command" to get the ffmpeg command, then Copy it and run it on your computer. The browser doesn't process the video itself.
为何只给 ffmpeg 命令？Why only an ffmpeg command?
M2TS/MTS 往往是摄像机 AVCHD 流，体积大、封装特殊；在浏览器里完整转码既慢又不稳定。本页生成可复制的命令，在你本机用 ffmpeg 封装或重编码。M2TS/MTS is often AVCHD from camcorders - large and awkward. Full in-browser re-encode is slow and fragile. This page builds a copyable ffmpeg command for remux or re-encode on your machine.
「无损封装」什么时候会失败？When does stream copy fail?
若音视频编码本就可以放进 MP4（常见 H.264 + AAC），-c copy 通常可行；若是 MPEG-2、PCM 或罕见音频，请改用「重编码 H.264+AAC」。AAC 比特流有时需要 -bsf:a aac_adtstoasc（命令里已带）。If the codecs already fit MP4 (often H.264 + AAC), -c copy usually works; for MPEG-2, PCM, or odd audio, pick Re-encode H.264+AAC. AAC bitstreams sometimes need -bsf:a aac_adtstoasc (already in the command).
文件名校验Filename checks
输入/输出名不能为空；若输入扩展名不是 .m2ts/.mts/.ts 会给出提示但仍生成命令（便于你改名）。路径请按你的 shell 自行加引号--本页用 JSON.stringify 包一层。Input/output names cannot be empty; a non-.m2ts/.mts/.ts extension shows a tip but still builds the command. Quote paths for your shell - this page wraps names with JSON.stringify.
「M2TS 转换助手」免费吗？需要注册吗？Is the M2TS Converter free? Do I need an account?
「M2TS 转换助手」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 M2TS 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.