what file is amr

amr is a file format that stores AMR speech encoding files; many mobile phones allow users to store short-term AMR format recordings, and some open source and commercial software have programs to convert to other formats; but AMR is a speech format , not optimized for other sounds; the common file extension is ".amr".

#The operating environment of this article: Windows 7 system, Dell G3 computer.

AMR is also a file format that stores AMR speech encoding files. Many mobile phones allow users to store short-term AMR format recordings, and some open source (see external links) and commercial software have programs for converting to other formats. But AMR is a speech format and is not optimized for other sounds. The common file extension is .amr.

Because amr is an audio file format, there are many software that can open amr files. For example, commonly used audio and video playback software such as Baofeng Yingyin and Xunlei Kankan can all open amr files. In addition, Nokia mobile phones can also open amr files. It can open amr ringtone files.

Features

• ## Sampling rate 8 kHz/13-bit (160 sampling points every 20ms), only retains the 200-3400 Hz range after filtering signal within.

• The encoder uses 8 bit rates: 12.2, 10.2, 7.95, 7.40, 6.70, 5.90, 5.15 and 4.75 kbit/s.

• The generated frame length is 95, 103, 118, 134, 148, 159, 204 or 244bit, and the corresponding bit rates are 4.75, 5.15, 5.90, 6.70, 7.40, 7.95 respectively , 10.2 or 12.2 kbit/s.

• AMR uses Discontinuous Transmission (DTX), Voice Activity Detection (VAD) and Comfort Noise Generation (CNG) to reduce bandwidth during silent times.

• The algorithm delay is 20ms per frame. When the bit speed is 12.2, there is no lookahead delay. The lookahead delay for other rates is 5 ms. Note that there is a 5 ms pseudo-lookahead delay, allowing accurate frame width mode conversion for other rates.

• AMR is a mixed language encoder using Algebraic Code Excited Linear Prediction (ACELP).

• If the complexity of the algorithm is 5, then G.711 is 1 and G.729a is 15.

• PSQM tested lossy Mean Opinion Scores AMR (12.2 kbit/s) under ideal conditions is 4.14, compared to G.711 (u-law) which is 4.45.

• PSQM Mean Opinion Scores AMR (12.2 kbit/s) under network conditions is 3.79, compared to G.711 (u-law) which is 4.13.

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