Step 1: Transfer your AMR files using the button above or by slide and deposit.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Retrieve your converted MP4 files.
AMR to MP4 Conversion FAQ
How do I convert an AMR file to MP4?
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Upload your AMR file using the picker above and the converter detects the source type and runs the AMR → MP4 pipeline. The result downloads automatically when conversion completes; no account needed for one-off conversions. AMR is Adaptive Multi-Rate, the speech codec 3GPP standardised for GSM voice calls and mobile voice recorders. MP4 is ISO/IEC 14496-14, standardised in 2001 and derived from the same QuickTime box layout MOV uses.
What will the picture be if I put AMR audio into an MP4 file?
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You choose it, because audio alone has no picture. The default is a static waveform render, and you can supply a still image instead — cover art, a title card, a photo — which is held for the whole duration. That is what makes the file uploadable to video-only platforms that will not accept a bare audio track. MP4 is the safest possible delivery target — every phone, browser, console, editor and Smart TV built in the last decade plays it without extra software.
Is the AMR audio re-encoded when it goes into the MP4?
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Only if it has to be. Where the MP4 container accepts the source audio codec directly, the stream is copied in untouched and stays bit-identical. Where it does not, the audio is transcoded once to whatever MP4 does accept, at a bitrate matched to the source so the second pass costs as little as possible. AMR is a narrowband speech codec running between 4.75 and 12.2 kbps, modelling the human vocal tract rather than the full audio spectrum. Almost every MP4 in the wild is H.264 video with AAC audio; the container also legally holds HEVC, AV1 and VP9.
How large will the MP4 be compared with the AMR?
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Barely larger, if you use the default still image. A single held frame compresses to almost nothing across the whole duration because every frame is identical to the last, so the file is dominated by the audio track. Choosing an animated waveform instead adds real video data and can double or triple the result.
Will the MP4 open directly in a browser?
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Yes, and the AMR would not have. Browsers ship a decoder for MP4 and none for AMR, so an AMR link forces a download while an MP4 renders inline. That is usually the deciding factor when the file is going onto a web page rather than into an application.
Is the AMR to MP4 converter free?
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Yes — basic AMR → MP4 conversion is free with no registration required. Premium adds higher per-file size limits, more parallel batch workers, longer retention, and removes ads.
How big an AMR file can I convert to MP4?
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Free accounts: up to 100 MB per AMR file. Premium: typically 1 GB per file depending on the source type. Very large files are split into chunks server-side when the MP4 format allows.
Will conversion change the content of my AMR?
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Conversion preserves all information that both AMR and MP4 can represent. Format-specific features the MP4 cannot represent (e.g. vector data in raster output, formulas in plain-text output) are rasterized or stripped — the result page lists what changed.
Can I convert many AMR files to MP4 at once?
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Yes — drop multiple AMR files into the upload zone and they are queued in parallel. Premium runs more parallel workers; on a 50-file batch this is the difference between minutes and seconds.
Does the AMR to MP4 converter work on phones and tablets?
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Yes — the UI is responsive and the conversion pipeline runs server-side, so mobile devices upload-then-download just like desktops. iOS and Android browser file pickers (camera roll, Files app) work end-to-end.
Which browsers does the converter support?
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Chrome, Firefox, Safari (15+), Edge, and Opera. The converter uses standard `<input type="file">` upload — no WebAssembly or PWA dependency — so even older browsers work to upload an AMR and download the MP4.
Are my AMR files kept private?
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Yes — uploaded AMR files are processed in isolated workers and deleted within minutes. We never view, retain, or share content. The retention window is at /privacy/. AMR makes voice recordings absurdly small — an hour of speech fits in a few megabytes — and it is what many phones still record calls in.
AMR (Adaptive Multi-Rate) is an audio compression format optimized for speech coding. It is commonly used in mobile phones for voice recordings and audio playback.
