Bitrate Planning Sheet
Bitrate is size over time. Take the audio out first - that is the step everyone skips.
BFCBrilliance · bfcbrilliance.com/tools/video-bitrate-calculator
The arithmetic
- TOTAL BITRATE (kbps)
- MB x 8000 ÷ seconds
- VIDEO BITRATE
- total − audio bitrate
- File size from a bitrate
- (video + audio) x seconds ÷ 8000
- 1 megabyte
- 8 megabits
- MB here is DECIMAL
- 1,000,000 bytes — what upload limits mean
- Windows shows MEBIbytes
- 1,048,576 — a 500 MB file reads as ~477
- ⚠ Audio comes out first
- or the file overshoots by the audio track
- ⚠ Container overhead
- ~1% — aim under a hard limit
- ⚠ Resolution is not here
- it changes how it LOOKS, not how big it is
Videos to encode
| Video | Target MB | Minutes | Audio kbps | VIDEO kbps | Actual size |
|---|---|---|---|---|---|
This video
- Project
- Date
- Target size
- Running time
- Audio bitrate
- TOTAL BITRATE
- VIDEO BITRATE
- In Mbps
- Audio share %
- Encoder mode
- Actual finished size
- Under the limit?
Before you encode
- Audio bitrate subtracted from the budget, not left in
- Target checked in DECIMAL MB, not what the file browser shows
- A few percent left spare for container overhead if the limit is hard
- Two-pass or target-size mode selected if the size must be hit
- A difficult section test-encoded and LOOKED AT, not just measured
- Running time confirmed after edits — trims change the budget
- Silent video? Audio set to 0 rather than left at the default
- Finished file measured against the real limit before uploading
The mistake this exists to prevent
Working out the total bitrate the file can afford and then typing that into the VIDEO bitrate box. The encoder adds the audio on top, so the file overshoots by exactly the size of the audio track — small on a generous target, and the difference between passing and failing an upload limit on a tight one.
Bitrate sets the size, not the quality
Resolution, frame rate and how much movement is in the shot decide how good a given bitrate looks. A static screen recording and a fast sport at the same bitrate are not comparable. Encode a hard thirty seconds at two candidate bitrates, look at them, then use the arithmetic to check the whole thing fits.