Is Opus better than MP3?
On listening tests it ranked above the other standard formats at a given bit rate, Wikipedia reports, until the point of transparency is reached. Opus reaches 510 kbit/s and was built for speech as much as for music.
Opus to text
Transcribe an Opus file to text
Transcribe an Opus file to text: the open codec of calls and streams becomes a line per segment with timecodes and speaker labels. Free $0, 3 files a day.
3 files a day up to 30 minutes, free99+ languagesSpeaker separation and timestamps
In short
Upload the Opus and get the text: one line per segment with a timecode, speakers named on request. Opus is an open codec, and it travels inside Ogg, WebM or MP4. The free plan is $0 with 3 files a day, one file is up to 30 minutes.
How to transcribe an Opus file
- 1
Send the file with its wrapper
Opus usually travels inside an Ogg container, but Matroska, WebM and MP4 carry it too. Whatever the wrapper, the widget takes the file as it is.
- 2
Mark the language and the voices
Rthe recording language is detected automatically. Turn the split on when the recording holds more than one voice, and the lines stay attributable.
- 3
Save it and export
The transcript keeps a line per segment with both times. TXT, Markdown, SRT, VTT and CSV on every plan, DOCX on Pro.
What you get
- TXT
Plain text for an email, a note or a chat
- SRT
Subtitles for video editors and platforms
- VTT
Subtitles for a browser and a website
- CSV
A table: time, speaker, text
- DOCX
A Word document with speakers and times
- Markdown
Text with headings for notes
What Opus is, and what the transcript holds
| What | Value |
|---|---|
| The codec | free and open source, developed by the Xiph.Org Foundation and standardized by the IETF as RFC 6716; all its patents are royalty-free |
| The bit rate | from 6 to 510 kbit/s, with frame sizes from 2.5 to 60 ms and a delay of about 26.5 ms |
| The wrapper | Opus is carried in Ogg, Matroska, WebM, MPEG-TS and MP4; the .opus extension is recommended for Ogg files |
| Where it is used | voice over IP, messengers and streaming; Opus replaces Vorbis and Speex in new applications |
The case
Why the codec of a live call can be transcribed
Opus is the codec behind calls and streams: Xiph.Org developed it, the IETF standardized it as RFC 6716, and every patent over it is royalty-free. It runs from 6 to 510 kbit/s and adds about 26.5 milliseconds of delay, which is why it turns up in messengers, in WebRTC and in the sound track of a WebM.
Tips
An .opus file from a call goes up as it is.
Opus is at its best on speech, not on music.
Check the names in the opening minute.
Export CSV when the times belong in a sheet.
Questions this page answers
Do I have to convert an Opus file first?
No. Opus streams are carried in Ogg, Matroska, WebM, MPEG-TS and MP4, and the audio is read out of the container it sits in.
What is Opus good for in a transcript?
For short clips and for voice: the codec works at a low bit rate with a delay of about 26.5 milliseconds, and the reference implementation libopus is open source.
How long may the recording be?
One file is up to 30 minutes, on every plan. The free plan gives 3 files a day of up to 30 minutes each, and Pro carries no minute limit of audio a month.
Sources
- EWikipedia — Opus (audio format)en.wikipedia.org · checked 22 October 2026
- TTranscribsi — the pricing pagetranscrib.si · checked 22 October 2026
Reading: 5 minutesUpdated 
Transcribsi editorial team
Drop a recording — the text arrives in a minute
Speakers by name, a time on every line, export to TXT, SRT, VTT, CSV and Markdown.
3 files a day up to 30 minutes, free99+ languagesSpeaker separation and timestamps