5 min read
Audio bitrate for video: how much is enough, and where it stops mattering
Bitrate only matters relative to the stage of the pipeline. The mistake is using a delivery bitrate on a working master.
Audio bitrate is one number doing four different jobs depending on where you are in the pipeline. Choosing well means asking whether this file will be encoded again.
Masters and working files: no bitrate at all
PCM audio in WAV, AIFF or inside a MOV has no bitrate setting, only sample rate and bit depth. 48 kHz 24 bit is the standard for film and video work. Anything you will edit, mix or re-export again belongs here.
Web delivery: 192 to 320 kbit/s AAC
For a final MP4 going to a website or a platform, stereo AAC at 192 kbit/s is transparent for most content and 256 to 320 kbit/s covers music heavy programmes. Beyond that you are adding file size, not quality.
Review copies: 128 kbit/s is fine
Dailies and client review links do not need more. Just never let a review copy become the source for a later export, which is how films end up delivered from a compressed proxy.
The generation loss trap
Every lossy encode discards information permanently. Encoding at 320 kbit/s from a 128 kbit/s source does not restore anything, it just stores the damage at a higher bitrate. Always go back to the PCM master.
Bitrate cheat sheet
- Master and edit: PCM, 48 kHz, 24 bit, no compression.
- Platform upload: PCM if allowed, otherwise AAC 256 to 320 kbit/s.
- Website embed: AAC 192 kbit/s stereo.
- Review and dailies: AAC or MP3 128 kbit/s, clearly labelled as a proxy.
- Archive: PCM masters plus the original camera and recorder files.
If you are unsure what a file actually is, inspect it. Bitrate, sample rate and channel count are all in the header, and the filename is not evidence.