Transcribe a long Asterisk SLN file signed linear call recordings.
A long Asterisk SLN file is headerless 16-bit audio at 8 kHz, about 58 MB an hour, so 8 hours come to roughly 460 MB and transcribe in about 16 minutes once converted to MP3 or WAV. The first 20 minutes are free on a first visit, and 480 minutes fit the $6 pack of 500.
SLN, explained
Asterisk's own working format: plain samples, no header, no compression.
Where .sln files come from
Signed linear is the audio Asterisk handles internally, so a dialplan that records with Record or MixMonitor writes .sln whenever the file name asks for it. Conference recordings, recorded IVR sessions and long hold-line captures on an Asterisk-based phone system can all end up this way. Variants such as .sln16 and .sln48 carry the sample rate in the extension.
Megabytes per hour
Plain .sln is 8,000 samples a second at 16 bits, mono: 16,000 bytes a second, about 57.6 MB an hour. A 10-hour file is about 576 MB. The .sln16 variant doubles that to about 115 MB an hour. Both stay below 2 GB for 10 hours, but long ones pass the 500 MB the box on this page takes.
Convert, then upload
With no header, most software cannot tell what a .sln file is. If the upload refuses it, convert to MP3 or MP4 with ffmpeg or VLC. With ffmpeg: ffmpeg -f s16le -ar 8000 -ac 1 -i bridge.sln bridge.mp3; use -ar 16000 for .sln16. The MP3 is far smaller, and anything over 500 MB carries on through upload page.
Calls and conferences, sorted
A long recording returns a brief of what was discussed and agreed, chapters where calls or agenda points change, the numbers, dates and names said aloud, the questions it answers, and a chat over the text. Participants are identified and named in the summary, key quotes and chapters.
Why SLN recordings stay on the server
The phone system wrote them perfectly well. Nothing outside the phone system can read them.
✗ Files only Asterisk understands
A spool directory full of .sln files, and a manager asking what was said on Tuesday.
- Desktop players that will not open .sln
- Audio that plays as static when guessed wrong
- Hours of conference audio nobody reviews
- Tools capped at short clips
- Per-seat analytics for an occasional need
- No summary of a long bridge call
✓ The same files, as text
One conversion, one upload, one transcript per recording.
- Eight hours in about 16 minutes
- Decisions listed in the brief
- Speakers named in the summary
- Moments found by timestamp
- $6 for 500 minutes
- Five export formats
Sample
Part of a long conference bridge recording, as text.
Illustrative only: written for this page. The people, company and figures are invented.
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
- AI chat over the whole 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
- Summary, chapters and key quotes
- All export formats
- AI chat over the whole transcript
Bulk pack
$24/5,000 min
83 hours of audio — $0.29 an hour. Credits never expire.
- 5,000 minutes of audio
- Summary, chapters and key quotes
- API access for batch pipelines
- All export formats
FAQ
Long Asterisk SLN files, the common questions.
Will a .sln file upload as it is?
Usually not, because it has no header and no standard audio type. Convert it with ffmpeg or sox first, stating the sample rate, 16-bit signed little-endian and one channel, then upload the MP3 or WAV.
How do I tell .sln from .sln16?
Go by the extension first. If a converted file sounds slow and deep, the source was at a higher rate than you stated; if it sounds fast and squeaky, it was lower. Try 16000 or 8000 until voices sound natural.
Can Asterisk write a format that uploads directly?
In most setups the recording format follows the file extension given in the dialplan, so naming the file .wav instead of .sln writes a WAV that uploads as it is. Check your Asterisk version's documentation before changing a live dialplan.
What does a month of recordings cost?
Four weekly three-hour conference calls, 720 minutes, fit the $12 pack of 2,000. Forty recorded hours in a month, 2,400 minutes, fit the $24 pack of 5,000. The first 20 minutes on a first visit are free, and packs never expire.
How long does it take?
About 2 minutes per audio hour once uploaded: a 3-hour bridge call in roughly 6 minutes, a 10-hour file in about 20. A file over 10 hours goes in as two. Recording calls needs the consent the law where you are requires.
Which languages, and is the audio kept private?
99 languages are detected automatically. Recordings are transcribed on our own servers and are never used for training. Downloads come as TXT, DOCX, SRT, VTT and JSON.
Related
Other telephony and raw formats
Convert the SLN, upload it. The first 20 minutes are free.
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