Convert MOV to FLAC

Most video formats arrive with lossy audio, which is why the honest opening line on a page about converting them to FLAC is that lossless cannot restore anything. That line is not automatically true here. Canon, Sony, Panasonic and Blackmagic bodies commonly write linear PCM into the QuickTime container, at 48 kHz and 16 or 24 bits, because a camera is recording rather than delivering.

When the source is PCM, this conversion is lossless in the strict sense: every sample that goes in comes back out of the FLAC identically. That is worth knowing because it changes the recommendation. On a phone recording, which writes AAC, the FLAC preserves the decoded AAC faithfully and cannot undo the AAC — still useful as an archive format, but a different claim.

This is the fact that decides the page. The WAV written by this site is 16-bit PCM, always, because that is the sample format the muxer is configured for. The FLAC encoder is not fixed that way: it writes 16 bits when the decoded audio is 16-bit and 24 bits when it is deeper.

So a camera set to 24-bit — which most are, for headroom against a level set in a hurry — keeps all of it through FLAC and loses a third of the depth through WAV. Everyone reaching for an archival format reaches for WAV first, and on this particular pair that instinct produces the less faithful file at roughly twice the size. It is worth saying plainly because nothing on the interface tells you.

Uncompressed stereo at 48 kHz and 16 bits is 11.5 MB a minute — 691 MB an hour — and the same audio as FLAC is typically forty to sixty per cent less. Speech, which is mostly quiet with a lot of predictable structure, compresses best; dense music and applause compress least.

The saving is real and it is not the point. FLAC’s value in an archive is that it stores a checksum with the audio, so a file that has quietly corrupted on a drive announces itself when it is decoded instead of playing back with a click nobody notices for six years. A WAV cannot tell you that. For material you cannot record again, that is worth more than the megabytes.

Other audio conversions here offer three bands, because a lossy encoder has to be told how many bits a second to spend. FLAC has nothing to trade: it encodes the samples it is handed and reproduces them exactly, so a setting would either do nothing or would be lying about what it did.

What does vary is the time. FLAC has to analyse the signal to find the redundancy, which is more work than copying samples into a WAV header, so the conversion takes noticeably longer than the uncompressed route. On a few minutes of audio the difference is seconds; it is the only cost the format has.

A FLAC file holds exactly one audio track. A camera MOV can hold more than one, and on a real recording it often does — an on-board microphone, a radio mic, a feed from the desk. Everything after the first is discarded, silently.

For an archive that is a decision worth making consciously. Convert one file, listen to what came out, and only then process the rest. If the track you want is not first, this page cannot select it; export the track from an editor, or archive the separate recorder’s files, which is what they exist for.

Only what the MOV already held crosses over. Title, description, artist and creation date are read out of the QuickTime metadata and written into the FLAC as Vorbis comments; a camera fills in the date and almost never the rest, so what you usually get is a file with a timestamp and no performer, no description and no note about where the recording was made. The picture, the timecode track and any subtitles are gone as well.

Fill in the rest immediately rather than eventually. FLAC supports Vorbis comments and every tagging tool writes them, so a title, a performer and a two-line description take a minute per file. A disciplined filename does most of the same work and survives being copied between systems that disagree about tags.

Every current browser decodes FLAC, as do VLC, foobar2000, Audacity, Android and recent versions of Apple’s software. That is a much wider set than the format’s reputation suggests, and it means an archive kept this way is also listenable without conversion.

The gaps are old hardware and car systems, which frequently understand MP3 and nothing else. That is not an argument against archiving as FLAC; it is an argument for making an MP3 from the FLAC when you actually want to listen in the car. Keep the lossless copy and generate the convenient ones from it, never the other way round.

The limit is on the source file, and camera footage reaches it fast — roughly 170 MB a minute for 4K at 30 frames a second, more for professional codecs. That means this page suits individual takes rather than a whole concert.

For a long recording, exporting audio from the editing software is both faster and better: it can select the track, keep the timecode and process a folder at once. This page is the right tool when one irreplaceable file is on the machine in front of you and you want a proper copy of its sound before anything else happens to it.

Reading the MOV, decoding the audio and encoding the FLAC all happen inside this browser tab, on your own processor. Nothing carrying the recording is transmitted, which the network tab will confirm while a file is converting.

For this audience that is close to the whole argument. The material is a relative talking, a service, a concert, a piece of field work — things that exist once. Uploading them to a converter chosen from a search result to obtain an archival copy is a strange way to look after something, and there is no reason to.