About this tool

What a .ts file is

A .ts file is an MPEG transport stream: the container broadcasters and tuners write because it is built to survive a lossy signal. Instead of an index at the head of the file, as MP4 has, it is a continuous run of small fixed-size packets, which lets a receiver tune in mid-stream and start playing. That design is why a recording plays fine in VLC and awkwardly — or not at all — in QuickTime, in most phones, and in editors that expect a seekable file. Nothing is wrong with the video inside; the wrapper is the whole problem, and moving it into MP4 is what this tool does.

You will usually meet one of three things, and they are the same conversion here: a capture from a network tuner such as an HDHomeRun, a recording pulled off a cable box or DVR, or an over-the-air capture. Files named .mts or .m2ts are the same family under different initials — AVCHD camcorders and Blu-ray use those extensions, and this tool takes all three.

Stream copy or re-encode?

Auto is the right answer almost every time: it copies the video and audio across untouched where they are already playable in an MP4, and re-encodes only the parts that are not. A copy is lossless and limited by your disk rather than your processor, so a two-hour recording finishes in seconds.

Stream copy — force it when you know the recording is already H.264 or HEVC video with AAC audio and you want the fastest, pixel-identical result. If the video cannot legally sit in an MP4 it will fail outright rather than quietly re-encode behind your back, which is the point of choosing it.
Re-encode — H.264 video and AAC audio, playable anywhere, but slow: roughly real time or worse on a laptop, and it discards the original quality in favour of compatibility. Reach for it when Auto produced a file that still will not play, or when you want the safest possible copy of an odd recording.

The 50 MB floor, and DVR .star files

Any .ts under 50 MB is skipped when you add it. Small files are almost always stubs, ad-break fragments or index scraps rather than real recordings, and converting them is noise. If a genuine clip is under the floor, the contact page explains what to send.
A .star file sitting next to a recording — hdz_0000.ts.star and the like — is a DVR sidecar naming the programme. Drop it in with the video and it is never converted itself; it just flags the matching row and rides along into the output name.
A same-named .jpg becomes that row’s thumbnail, since DVRs usually ship one beside each recording.

If something goes wrong

The MP4 plays but has no sound. The audio was probably AC-3, which MP4 players commonly refuse. Re-run that file with Re-encode.
The picture shows comb-like lines on movement. The source is interlaced. Re-encode de-interlaces; a stream copy cannot.
“Stream copy failed.” Expected — the video inside the stream is not MP4-legal. Auto or Re-encode handles it.
A very large file stops part-way. The whole input and output sit in the page’s memory, so a single recording over roughly 2 GB may run out of room. Split it first, or convert on a machine with more free memory.
Dropping a file does nothing. Check the extension is .ts, .mts or .m2ts, and that the file is over 50 MB.

Still stuck? The contact page lists exactly what to include so it can be worked out without sending the file.

Privacy, in one line

The conversion runs in this tab with FFmpeg compiled to WebAssembly, so the recording never leaves your machine — there is no upload step, and nothing is kept after you close the tab. The privacy page is the long version.