What Is an .opus File (WhatsApp Audio) and How to Open, Play or Transcribe It

By Unai Goikoetxea · Published August 17, 2026

An .opus file is an audio file, most often a WhatsApp voice note. To play it, open it in VLC, in Chrome, Firefox or Edge, or in the app that created it. To get the words as text, upload the file to a transcription tool that accepts OPUS directly, so you do not have to convert anything first.

OPUS is a modern audio format. It sounds good at small file sizes, which is why messaging apps use it. The trade-off is that some older desktop players and some phone galleries still do not recognise the extension.

Below: what OPUS is, why your computer sometimes refuses to open it, three ways to play it, and how to turn a voice note into searchable text with timestamps.

What an .opus file actually is

OPUS is an open, royalty-free audio codec designed for speech and music over the internet. It was made for real-time use: voice calls, streaming, and short recordings. Because it compresses speech efficiently, a five-minute voice note can be a very small file.

The file you receive usually has the extension .opus, but the same codec also travels inside .ogg or .oga containers, and sometimes inside .webm. That is why the same audio can arrive with different names depending on the app that exported it.

WhatsApp voice notes are the most common source. When you export a chat or save a voice message on Android, you often get a file like PTT-20240115-WA0003.opus. Telegram voice messages, some browser recorders and several VoIP tools also produce OPUS.

Typical extensions: .opus, .ogg, .oga, sometimes .webm
Typical sources: WhatsApp and Telegram voice notes, browser recordings, VoIP apps
Typical size: much smaller than MP3 or WAV for the same length of speech

Why some players will not open it

Nothing is wrong with the file. The problem is support. Windows Media Player in older versions, some versions of QuickTime, a few car stereos and some phone gallery apps were built before OPUS became common, so they do not have a decoder for it.

You may also see a generic file icon with no preview, or a message saying the format is not supported. Some email clients and chat apps refuse to preview OPUS inline for the same reason, even though they will let you download it.

A second, smaller problem is the container. If a tool expects .ogg and the file is named .opus, it may refuse the file on the extension alone. Renaming can occasionally help, but it is not a reliable fix and it does not change the audio inside.

Old media players lack an OPUS decoder
Some phone galleries hide audio files they cannot preview
Some tools check the extension, not the actual content

Three reliable ways to play an .opus file

Start with the easiest option and stop as soon as the audio plays. You rarely need to install anything beyond a browser or VLC.

Option 1: your browser. Chrome, Firefox and Edge all decode OPUS. Open a new tab and drag the file into it, or use Ctrl+O (Cmd+O on Mac) and pick the file. It plays with a simple audio bar. This works offline and does not upload anything.

Option 2: VLC media player. VLC is free, available for Windows, macOS, Linux, Android and iOS, and it plays OPUS out of the box. After installing it, right-click the file, choose Open with, and select VLC. You can also set VLC as the default app for .opus so double-clicking works from then on.

Option 3: the app that made the file. If the voice note came from WhatsApp or Telegram, the simplest route is to play it inside the chat on your phone. No export, no format questions. On Android you can also open the WhatsApp Voice Notes folder with a file manager and play it with most modern Android audio players.

Browser: drag and drop into Chrome, Firefox or Edge
VLC: works on desktop and mobile, plays OPUS natively
Original app: play the voice note directly in the chat

Do you need to convert it to MP3?

Usually not. Converting adds a step, loses a little quality, and makes the file bigger. Convert only when the device or software you must use genuinely cannot read OPUS.

Good reasons to convert: an old car stereo, a video editor that rejects the format, a legacy voice-notes system, or a colleague whose computer you cannot change. In those cases MP3 or WAV are the safe destinations, and VLC itself can convert (Media, then Convert / Save).

Bad reason to convert: you only want the words. Transcription tools that support OPUS read the file as it is. Converting first will not improve the transcript, and re-encoding audio never adds detail that was not there.

Getting the text out of a voice note

Long voice notes are hard to search and hard to quote. Turning them into text makes them scannable, quotable and easy to translate. There are a few honest routes.

Native dictation on your phone can work in a pinch: play the voice note out loud and let the keyboard's speech-to-text listen. It is free, but the quality drops with background noise, it has no timestamps, and holding two devices next to each other is awkward.

Some platforms now offer their own transcript features for audio and video they host. Those are convenient when they exist, but they usually only cover content inside that platform, not a loose .opus file sitting in your downloads folder.

For a file, a web transcription tool is the direct path. JustTranscribe accepts OPUS and OGG uploads, including WhatsApp voice notes, along with MP3, M4A, WAV, MP4 and MOV up to 500 MB. You do not convert first: you upload the .opus file as it is. The first transcript is free and needs no account, and that free transcript covers files up to 40 minutes; with an account the limit is 150 minutes.

You get a transcript with word-level timestamps, with the language detected automatically, and you can click a segment to jump to that point in the audio. From there you can generate a summary, ask the recording questions and get answers with timestamps, add speaker labels when several people are talking, translate the text into any of 111 languages, and export as TXT, SRT, VTT, CSV, Markdown, PDF or DOCX. Processing takes minutes.

Practical tips before you upload or share

A few small habits save time when you deal with voice notes regularly.

Rename the file to something meaningful before you archive it. PTT-20240115-WA0003.opus tells you nothing in six months; client-call-jan-15.opus does.

If the recording contains sensitive personal or business information, decide consciously where it goes. Playing it locally in VLC keeps it on your machine. Uploading it anywhere means it leaves your machine, which is fine for most work material but worth a thought for private matters.

If the audio is very quiet or full of crosstalk, no tool will read minds. When you can, re-record in a quieter place and closer to the microphone; the transcript quality follows the audio quality.

Rename files so you can find them later
Keep private recordings local if you have any doubt
Better audio in means better text out

Step by step

1
Locate the .opus file
On Android, open your file manager and go to WhatsApp, then Media, then WhatsApp Voice Notes. On a computer, look in your Downloads folder or in the folder where you saved the chat export. On iPhone, tap and hold the voice message, choose Share, and save it to Files.
2
Try playing it in your browser
Open Chrome, Firefox or Edge, press Ctrl+O (Cmd+O on Mac), and select the .opus file. A small audio player appears and the file plays. If this works, you do not need to install anything.
3
Install VLC if you want a proper player
Download VLC for your system and install it. Then right-click the .opus file, choose Open with, and pick VLC. To make it permanent, choose the option to always use VLC for this file type.
4
Open justtranscribe.ai to get the text
Go to justtranscribe.ai in any browser. You do not need to create an account for the first transcript. The page shows an upload area and a field for pasting a public link.
5
Upload the .opus file as it is
Drag the .opus or .ogg file into the upload area, or click to browse for it. No conversion to MP3 is needed. Start the job and wait; processing takes minutes, not hours.
6
Read, search and correct the transcript
The transcript appears with word-level timestamps and the detected language. Click any segment to jump to that moment in the audio and check a word you are unsure about. Turn on speaker labels if more than one person is talking.
7
Summarise, translate or export
Use the AI analysis for a summary, the main idea and key moments, or ask the recording a question and get an answer with a timestamp. Translate the transcript if you need another language. Then export as TXT, DOCX, PDF, SRT, VTT, CSV or Markdown, or send a share link.

Frequently asked questions

What is an .opus file?

It is an audio file encoded with the Opus codec, an open format built for speech and streaming. It gives good sound quality at small file sizes, which is why WhatsApp and Telegram use it for voice notes. The same codec also appears inside .ogg and .webm files.

Why can't Windows open my .opus file?

Older versions of Windows Media Player have no Opus decoder, so they report the format as unsupported. The file itself is fine. Play it in Chrome, Firefox or Edge, or install VLC and set it as the default app for .opus.

Can I play an .opus file on iPhone?

Yes, but usually not by tapping it in Files. Install VLC for iOS from the App Store and open the file with it, or simply play the voice note inside the chat where you received it.

Do I have to convert .opus to MP3 before transcribing?

No, if your transcription tool accepts OPUS. JustTranscribe takes OPUS and OGG uploads directly, including WhatsApp voice notes. Converting first only costs time and a little quality; it does not make the transcript better.

How do I transcribe a WhatsApp voice note for free?

Export or save the voice note as a file, then upload it to justtranscribe.ai. The first transcript is free and needs no account, for files up to 40 minutes. You get text with word-level timestamps that you can search, translate and export.

Is .opus better than MP3?

For speech at low file sizes, Opus generally sounds cleaner than MP3, and it was designed for internet transmission. MP3 wins on compatibility, because almost every device made in the last twenty years can play it. Choose Opus for messaging and storage, MP3 when you need an old device to cooperate.

Try it now

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