Everyday

Convert video

Pick the video up, hold ⇧, let go toward the format.

The thing worth knowing: remuxing

A video file has two parts. The container is the box — MOV, MP4, MKV. The codec is how the picture is actually encoded inside it — H.264, HEVC, ProRes.

An iPhone MOV is almost always H.264 or HEVC. An MP4 holds H.264 or HEVC too. So converting one to the other often means relabelling the box without touching the video at all. That is a remux, and it is instant and completely lossless.

Arazio remuxes whenever the streams allow it. A MOV from your phone becomes an MP4 in about a second, bit for bit identical inside. When the codec genuinely cannot live in the destination container, it re-encodes using your Mac's hardware encoders.

You do not have to ask for this or know which one happened. The difference shows up as the job finishing immediately rather than taking a minute.

When a re-encode is unavoidable

• ProRes — common from cameras and editors, very large, not valid inside an MP4.
• HEVC where the destination wants H.264 — the container is fine, the recipient is not.
• Making it smaller. A remux does not change the size, because the video data is identical. Shrinking means re-encoding, by definition — use the Compress tool on ⌥.

Formats

MOV, MP4, MKV, WebM, M4V, AVI, MPEG, WMV, FLV and 3GP. Each has its own page with exactly what it converts to.

Converting an old AVI, WMV or FLV is nearly always a re-encode, because the codecs inside them are too old to put in a modern container.

Getting the audio out

Hold ⌥ rather than ⇧ and release toward Extract Audio. You get the soundtrack as its own file and the video is left alone. More.

Does it lose quality?

A remux: no, not a pixel.

A re-encode: yes, a little, always — video codecs are lossy and encoding an already-encoded video compounds it. Do it once from the best source you have.