AMR — Narrowband Speech
The clip resampled to 8 kHz mono and encoded as AMR narrowband — the telephony/voice-note codec. For testing AMR decoding and speech-codec conversion.
Rendered preview of the amr file (4.7 KB). Download above for the original.
Specifications
- Source
- 3 s A-major triad, 44.1 kHz stereo
- Codec
- AMR-NB
- Sample Rate
- 8 kHz mono
- Lossless
- false
What is a .amr file?
AMR (Adaptive Multi-Rate) is a lossy speech codec optimized for narrowband human voice at very low bitrates, widely used in GSM and UMTS mobile telephony. It is efficient for spoken audio but poor for music. It commonly appears in voice recordings and MMS messages.
How to use this file
Use an example AMR to test speech-codec decoding, voice-recording import, and transcoding of low-bitrate mobile audio to more portable formats.
How to use this file for testing
“AMR — Narrowband Speech” is a deterministic Novus Examples fixture for Conversion testing, Audio analysis. The same content exported across many formats and linked as a group, so you can convert one and diff against the expected twin.
Documented properties for this file: AMR · 4,838 bytes. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Media fixtures are short and synthetic by design. Prefer waveform or transcript ground truth in the same group when measuring ASR, trim, upscale, or sync tools; do not assume broadcast-quality masters.
Related files
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- wav1 kHz Tone @ 96000 Hz Sample Rate (WAV)A 1 kHz sine tone sampled at 96000 Hz — part of a sample-rate ladder (8/16/44.1/48/96 kHz) of the identical tone, for testing resampling, sample-rate detection, and aliasing.
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Generated by generation/audio_codecs.py. Free for any use, no attribution required — license.