5 min read
MOV to MP3: when a compressed extract is the right call
MP3 is a terrible master and an excellent messenger. Here is where it belongs in a film workflow, and where it does not.
Every so often the job is not archival. A director wants to hear a take on the train, a composer needs a temp reference, an ADR supervisor is emailing a line to an actor. A 40 MB WAV is the wrong object for that. A 3 MB MP3 is the right one.
Bitrate choices that actually matter
- 128 kbps mono: dialogue review and phone playback, smallest useful file.
- 192 kbps stereo: general reference, safe for music temp.
- 320 kbps stereo: the highest MP3 rate, for anything someone might listen to critically.
Above 192 kbps the difference on spoken word is close to inaudible. Below 96 kbps sibilance turns watery and consonants smear, which is exactly the detail you were asking someone to judge.
What MP3 destroys
MP3 discards content the encoder judges masked. That is fine for listening and fatal for processing. Noise reduction, phase alignment and loudness measurement all behave differently on decoded MP3, and encoding a second time on top compounds the artefacts.
The rule for film work
Extract WAV once from the MOV, archive it, and generate MP3s from that WAV whenever someone needs a lightweight copy. Never let an MP3 become the only surviving version of a take.