How to convert a short local media file with browser-supported codecs
Choose a short local media file and check the operations this browser can perform with its primary tracks. Export PCM WAV, transcode to WebM VP8/Opus or MP4 H.264/AAC when supported, or remux compatible encoded tracks. Processing runs in one cancellable Worker, with no processing API or server fallback.
How do you do it?
- Choose a local media file, or load the two-second sample tone. Wait for the file and codec capability check.
- Select an enabled output operation and a video height cap for transcoding. Run Convert locally; Cancel terminates the Worker.
- Preview and download the result, then check it in your target player. Changing the file or settings clears the previous result.
Export a two-second local sample as WAV
The sample is generated in this tab without a microphone. WAV uses built-in PCM processing. For compressed inputs, the original codec must also be decodable; video conversion depends on available encoders.
Input:
Sample tone: 2 seconds, 440 Hz, mono PCM, 48 kHz.
Operation: WAV audio extraction.
Output:
A downloadable WAV file with a 48 kHz, 16-bit mono PCM audio track, about 188 KiB.When is this workflow useful?
Use WAV extraction for an uncompressed audio copy, transcode when the target codec or dimensions must change, and remux to change compatible containers without re-encoding. A remux does not fix an unsupported playback codec and does not shrink video dimensions. Check the output in the application that will receive it.
What should you check before relying on the result?
Inputs: local MP4/MOV/M4A, WebM/Matroska, WAV, MP3, Ogg, FLAC or AAC when their tracks are supported. Maximum 30 seconds; desktop 25 MiB, touch devices 10 MiB. Input video: 1920 × 1080 or rotated equivalent (touch 1280 × 720), 900 frames. Transcoded video: at most 1280 × 720, 30 fps (touch 854 × 480), never upscaled. Audio: 1–2 channels, 8–96 kHz; re-encoded audio is 48 kHz. Output budget is 25 MiB/10 MiB; inspection stops after 20 seconds and conversion after 90 seconds. Only primary video/audio tracks are used; subtitles and descriptive metadata are omitted. Remuxing preserves original codecs and dimensions; MP4 remuxing is limited to H.264/AAC. A browser preview may be unavailable even for a valid output. No MP3 encoder, HLS/URL import, DRM, 4K, arbitrary codec guarantee or server fallback. Physical-phone performance has not been validated; use small files on mobile.
What can go wrong?
| Problem | What to try |
|---|---|
| MP4 or another operation is unavailable. | The file codec cannot be decoded or the requested encoder is unavailable. Container support alone does not guarantee encoding support. Choose an enabled operation. Firefox may lack AAC encoding even when H.264 is available. WAV extraction or compatible remuxing may still work; the tool rejects accidental track loss. |
| The file is rejected or processing stops. | The media is encrypted, damaged, unsupported, or exceeds duration, dimension, frame, file, output or time budgets. Use an unencrypted short mono/stereo file, shorten or resize it first, then recheck. No file is uploaded as a fallback. |
Frequently asked questions
Do I need to upload data or sign in?
No. Processing runs in the current browser. This site serves the page and required static engine assets.
Why does the result disappear after I edit the input?
The tool clears stale output so a previous result cannot be mistaken for the new one. Run again after changing input or settings.
References
First edition: steps checked against the current tool interface, with examples and known limits.