Transcribe a long RF64 file from a broadcast or field recorder.
An RF64 file, the broadcast WAV that carries on past 4 GB, takes about 1,037 MB per hour at 48 kHz 24-bit stereo, so it reaches the 5 GB per-file limit near 4.8 hours, and it transcribes at about 2 minutes per audio hour. If the upload refuses it, convert it to FLAC or MP3 first; a 6-hour broadcast is 360 minutes, which fits on the $6 pack of 500 minutes after the first 20 minutes free.
RF64, worked out
A recorder switches to RF64 when the take gets long. The 5 GB line is close behind.
What RF64 is
RF64 is the EBU's extension of Broadcast Wave for files over 4 GB, with a 64-bit size chunk in place of the 32-bit one. Broadcast systems and some field recorders write it when a long take passes 4 GB; others split the take into several files instead, so check your recorder's settings.
Size per hour, by the numbers
Mono at 48 kHz, 24-bit is 1,152,000 bits a second, about 518 MB an hour. Stereo doubles that to about 1,037 MB. So a stereo take passes 4 GB near 3.9 hours and 5 GB near 4.8; a 10-hour mono take is about 5.2 GB, just over the line.
FLAC or MP3 when it is too big
If the upload refuses the RF64, or the file is over 5 GB, convert it to MP3 first, or to FLAC if you want to stay lossless. ffmpeg -i take.rf64.wav -c:a flac take.flac usually halves the size; a mono MP3 at 64 kbps keeps 10 hours under 300 MB. A big file continues on the upload page.
From a long take to usable text
A long outdoor broadcast, an all-day event feed or a field recording returns with a brief, chapters with timestamps, the names, numbers and dates said, and the questions it answers. Each presenter and guest is identified and named in the summary, key quotes and chapters.
Why RF64 files stall
A format made for files past 4 GB is rarely welcome where 25 MB is the norm.
✗ Software made for short clips
An hour of stereo RF64 is about forty times the OpenAI Whisper API's documented 25 MB upload limit, before you reach the 64-bit header.
- Readers that only understand 32-bit WAV
- Multi-gigabyte uploads that fail late
- Cutting the take into numbered pieces
- Timestamps reset in every piece
- Hand-logging a long broadcast
- Nothing that sums up the full day
✓ The take as one transcript
An RF64 under 5 GB, or a FLAC or MP3 of it, comes back as one transcript on one clock.
- One take up to 5 GB or 10 hours
- Roughly 2 minutes for each hour of audio
- FLAC keeps it lossless and smaller
- Chapters across the full take
- Names and figures with their timestamps
- A 6-hour take on the $6 pack
Sample
A long outside broadcast, five hours in.
Illustrative: this sample was written for this page and is not from any real station or event. Times show the position in a long RF64 take.
Export
One transcript. Five clean formats.
Every pack exports all five — no format is held back for a higher tier.
Plain text
De-ummed paragraphs. Ready to paste.
SRT captions
Timed to the speech. Every video editor reads this.
WebVTT
HTML5 player + YouTube uploads.
Show notes
Formatted with chapters and pull-quotes.
Machine-readable
Timestamped text for your own tools.
Pricing
Honest pricing, no surprises.
A pack from $6 (500 minutes) opens the full transcript. After that, no subscription and no auto-renew — every tier is a one-time minute pack, and credits never expire. Buy once, use the minutes whenever you need them.
Casual pack
$6/500 min
8 hours of audio — $0.72 an hour. One-time — credits never expire.
- 500 minutes of audio
- All export formats
- Unlimited AI chat per transcript
- Executive summary & key quote
Best value
$12/2,000 min
33 hours of audio — $0.36 an hour. Credits never expire.
- 2,000 minutes of audio
- Priority queue
- All export formats
- Unlimited AI chat per transcript
Bulk pack
$24/5,000 min
83 hours of audio — $0.29 an hour. Credits never expire.
- 5,000 minutes of audio
- Priority queue
- API access for batch pipelines
- All export formats
FAQ
Long RF64 files, the usual questions.
How long does an RF64 take to transcribe?
About 2 minutes per hour of audio, so a 6-hour take is ready in roughly 12 minutes after upload. On most connections, a 5 GB upload takes longer than the transcription.
What does a long RF64 cost to transcribe?
A 6-hour take is 360 minutes on the $6 pack of 500. Three 8-hour event days total 1,440 minutes on the $12 pack of 2,000, and a week of five 8-hour days is 2,400 minutes on the $24 pack of 5,000. A first-time visitor's opening 20 minutes are free.
How large is an RF64 per hour?
About 518 MB per hour for mono at 48 kHz, 24-bit, and about 1,037 MB for stereo. Before the first pack, files up to 2 GB upload; after it, up to 5 GB.
The RF64 runs past 10 hours. What now?
Split it at a break into two files and upload each; each gets its own transcript with timestamps starting at zero. If it is under 10 hours but over 5 GB, convert it instead of splitting.
Which languages work?
It detects 99 languages on its own. Crowd noise, music and effects in a broadcast are not transcribed; the speech is.
What exports do I get, and is the file private?
All five exports are included: TXT, DOCX, SRT, VTT and JSON. RF64 recordings are transcribed on our own servers and are never used for training.
Related
Other long formats
Upload the RF64. Or a FLAC copy if it is over 5 GB.
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