Which has better quality, MKV or MP4?

Neither — the container does not touch quality. The same streams in MKV or MP4 are identical. MKV carries more (multi-track, chapters); MP4 is accepted everywhere.

When should I pick WebM?

Self-hosted web pages with a Chrome/Firefox-majority audience — VP9/AV1 is smaller at equal quality. For anything touching Apple devices or upload platforms, MP4 stays safer.

How do I turn a TS file into a normal video?

If the TS carries H.264, remux to MP4 — instant and lossless. If it carries MPEG-2, re-encode. An inspection tool tells you which case you are in.

Formats & playback 5 min read

Choosing Output Formats: MP4, WebM, MKV and TS by Purpose

There is no "best" container — only the right one for the destination. Social feeds, embedded players, multi-track archives and live streams each have their answer. The wrong container costs compatibility and features, never quality.

Where each container rules

MP4 is the universal distribution answer: every device, platform and player accepts H.264/H.265 plus AAC inside it. Sending to anyone, anywhere — MP4 cannot fail. It is the default, not a specialty.

WebM targets embedded web playback: VP9/AV1 efficiency, royalty-free, native in Chrome and Firefox — but Apple support is limited, so choose it for web projects, not public distribution. MKV is the multi-track vault: unlimited audio, subtitle and chapter tracks for archiving and local playback — social platforms will not take it. TS is the broadcast veteran: fault-tolerant streaming for live TV chains, poorly supported by general players.

The purpose decision table

Social platforms and chat: MP4, no second option. Self-hosted web embeds: MP4 for safety, WebM for size (with a Safari fallback). Local archives and multi-track collections: MKV. TV boxes and broadcast chains: TS. Feeding an editor: MP4 or MOV.

Know the conversion costs: remuxing between MP4/WebM/MKV/TS re-encodes nothing and finishes instantly; but if a TS carries MPEG-2 video, converting to MP4 usually implies re-encoding to H.264 — that is codec conversion, not container conversion. Judge them separately.

Symptoms of a wrong choice

The symptoms are direct: an MKV a friend "cannot open" (their player lacks multi-track support), a WebM gone black on iPhone (Apple support gaps), a TS that will not double-click (general players lack the demuxer). All are correctable by remux or transcode to MP4.

A practical default: when unsure, pick MP4. It is rarely the optimum and always the passing grade — get the file to a "plays everywhere" state first, then optimize for specific uses. Container mistakes are almost always losslessly fixable, so anxiety is unnecessary.