What a .ts file actually is
A .ts file is an MPEG transport stream — the container built for broadcast and streaming rather than editing or local playback. It is what digital-TV tuners and DVB receivers write to disk, what PVRs and set-top boxes record, what many capture cards dump, what Blu-ray discs use internally, and what HLS slices a live stream into. The data is broken into fixed 188-byte packets that interleave video, audio, and program tables so a receiver can tune in mid-stream and recover from dropped packets. Great for over-the-air TV — and exactly why a raw .ts is awkward as a finished file.
Why a raw .ts won't play or seek cleanly
A transport stream has no clean global index, so seeking jumps around or fails, and its timestamps were written for a continuous broadcast clock rather than a tidy file — so duration is often reported wrong. On top of that, the inner video is frequently H.264 but the audio is usually AC3 or MP2, broadcast codecs that MP4-oriented players and editors do not reliably support. Many apps simply refuse to open a raw .ts at all. Re-wrapping it as a proper MP4 is the fix.
Why we re-encode instead of remux
Because the inner video is often already H.264, a remux — copying the stream straight into an MP4 wrapper — looks tempting, but it is fragile. Transport-stream timestamps are frequently discontinuous (a broadcast clock wraps, a recording starts mid-stream, segments were concatenated), and a straight copy produces MP4s that stutter, mis-report duration, or refuse to seek. The broadcast audio also has to change. So we do a clean re-encode: video to H.264 at CRF 23, audio to AAC at 160 kbps, pixel format forced to yuv420p, written with +faststart so it streams immediately. Slightly slower than a copy, far more reliable across players and editors.
Sister tools
For other camcorder and broadcast containers: MTS to MP4 converter handles AVCHD footage from camcorders, and MPG to MP4 converter handles older MPEG-1/2 program streams. For Matroska and QuickTime sources, MKV to MP4 converter and MOV to MP4 converter. Shrinking a finished MP4 further? Video compressor.
Skipping the conversion entirely
Transport streams exist because broadcast and capture hardware created them. If you are recording new content yourself, you can skip the format wrangling completely. Clipy records your screen straight to a shareable link — no local file, no transport stream, no format conversion, no watermark, no install.