Convert audio without processing picture frames
The local pipeline selects the primary audio track and discards the video track. It decodes audio and creates the chosen MP3 or WAV result without decoding the video pictures.
Local video-audio converter
Extract the main audio track from a video
Choose a video file from this device and select MP3 or WAV. This route always decodes the primary audio track and creates a new audio-only result while discarding video frames; it does not fetch remote URLs.
Your selected file stays on this device. No upload, account, or server-side media job.
Browser-local workspace
Choose a local source to begin.
Choose one local audio file—or a local video on the conversion route—then create a separate, verified MP3 or WAV result. The source is not sent to Aftermath, modified, or handed to a fallback service.
No upload, account, or server-side media job.
The local workspace loads after you choose a source.
Create an audio-only MP3 or WAV
Extraction always creates a new MP3 or WAV rather than copying the original encoded packets. This keeps the output choices predictable, but re-encoding can affect quality. The tool does not download from YouTube, social platforms, or other remote links.
Private browser handling
Your source remains under your control.
Aftermath reads, decodes, processes, encodes, and verifies the selected file in this browser. It preserves the source and offers a separate MP3 or WAV result; unsupported inputs are never sent to an upload fallback.
How to use this tool
Use this route when a local video’s primary audio must become a new MP3 or 16-bit PCM WAV. The worker accepts a selected video, discards its video frames, decodes the primary audio track, always re-encodes the chosen audio format, and reopens the audio-only result. It does not copy the source codec or fetch a URL. For MP3-only extraction that can retain an already compatible MP3 track, use the separate video route.
What to choose and what you get
What to choose
- one supported MP4, M4V, MOV, or WebM video with a readable primary audio track
Result
- a separately downloaded MP3 or 16-bit PCM WAV audio-only result
Supported use
- One readable local MP4, M4V, MOV, or WebM video with a decodable primary audio track.
- A newly encoded MP3 or 16-bit PCM WAV result without processing video pictures.
- Reopened audio-only validation before a local download is offered.
Before you start
- Remote URLs, social-platform downloads, cloud-drive fetching, or access-control bypass.
- Original-codec packet copying, arbitrary output codecs, manual track selection, or a video output.
Supported formats
- Accepted formats: MP3, WAV, M4A, AAC, Ogg, Opus, FLAC, MP4, M4V, MOV, WebM.
- Output formats: MP3, WAV.
Browser support and permissions
- Modern browser with JavaScript and a bundled decoder/encoder path for the selected audio or video source. Output operations keep one completed result in browser memory and are limited to 500 MB; read-only inspection can handle larger accepted sources up to 4 GB.
- No camera, microphone, or screen permission is needed.
Choose the right settings
- Use this route when a video source needs a predictable newly encoded MP3 or WAV result.
- Use /video/mp4-to-mp3 when MP3 alone is required and compatible MP3 packet retention is desirable.
- Use /convert-audio for an audio-only source, or /audio-tools when comparing broader audio outcomes.
- Keep the source video until the reopened audio-only result has been reviewed.
Worked example
A supported lecture video needs its primary spoken track as a WAV while all video frames are discarded.
Starting facts
- The video contains a readable primary audio track.
- Only that track is intended for the result.
Observed operation: Decode the primary track locally, write a separate 16-bit PCM WAV and reopen the completed audio.
Review the result: Listen through the entire output and verify duration, channel facts and the absence of unexpected truncation.
Boundary: Extraction does not retain video, captions, secondary audio or establish rights to reuse the resulting recording.
What you can do
Decode one local video’s primary audio track into a new MP3 or 16-bit PCM WAV while discarding video frames
Choose another tool when
- Fast retention of an already compatible MP3 track belongs to /video/mp4-to-mp3.
- Converting an existing audio-only source belongs to /convert-audio.
- This route does not fetch remote URLs, decode video pictures, copy the original audio codec, or select among multiple tracks.
If it does not work
- An audio-only source or video with no readable primary audio track is rejected for extraction.
- Unsupported source audio decoding or local MP3/WAV encoding stops the job without a remote fallback.
- A written result that cannot be reopened as readable audio-only output is not offered for download.
Things to know
- Codec support, performance, and memory use vary by browser, device, source, and operation.
Privacy boundary
The selected media stays in the current browser session and is not sent to an Aftermath processing service. How local processing is verified.
What this tool verifies
Checks the displayed limits and reports or creates a separately downloaded MP3 or 16-bit PCM WAV audio-only result from one supported MP4, M4V, MOV, or WebM video with a readable primary audio track.
Check before sharing
Fast retention of an already compatible MP3 track belongs to /video/mp4-to-mp3.