AMR and MP3 File Formats
AMR is also a file format for storing spoken audio using the AMR codec. Many modern mobile telephone handsets will allow you to store short recordings in the AMR format, both Open Source (see the external links) and commercial programs exist to convert between this and other formats such as MP3, although it should be remembered that AMR is a speech format and is unlikely to give ideal results for other audio. The common filename extension is .amr.
The AMR codec uses eight source codecs with bit-rates of 12.2, 10.2, 7.95, 7.40, 6.70, 5.90, 5.15 and 4.75 kbit/s.
Adaptive Multi Rate – WideBand (AMR-WB) is a speech coding standard developed after the AMR using same technology like ACELP. The codec provides excellent speech quality due to wider speech bandwidth of 50–7000 Hz compared to narrowband speech codecs which in general are optimized for POTS wireline quality of 300–3400 Hz. AMR-WB is codified as G.722.2, an ITU-T standard speech codec. A common file extension for AMR-WB is .awb.
An MP3 file that is created using the mid-range bitrate setting of 128 kbit/s will result in a file that is typically about 1/10th the size of the CD file created from the original audio source. An MP3 file can also be constructed at higher or lower bitrates, with higher or lower resulting quality. The compression works by reducing accuracy of certain parts of sound that are deemed beyond the auditory resolution ability of most people.
Converting AMR to MP3 with NoteBurner Converter
NoteBurner AMR to MP3 Converter has the excellent capability of converting AMR to MP3, WMA and WAV. This versatile AMR to MP3 Converter can also convert AAC, M4P, WMA, AA, WAV, AIFF and many other audio files to MP3, WMA and WAV.
NoteBurner AMR to MP3 Converter installs a virtual CD-RW, it helps you burn any unprotected or DRM protected audio files , such as AMR, M4P, M4A, WMA music files onto the virtual CD, rips tracks on the virtual CD, encodes tracks onto MP3, WAV or WMA music files. It can repeat this audio converting procedure until your whole music collection is done.
NoteBurner AMR to MP3 Converter has been used and praised by numerous users around the world as an ideal solution for converting various audio or music files format to MP3,WMA or WAV format.
As AMR-WB operates at internal sampling rate 12.8 kHz, AMR-WB+ also supports various internal sampling frequencies ranges from 12.8 kHz to 38.4 kHz. 3GPP originally developed the AMR-WB+ audio codec for streaming and messaging services in Global System for Mobile communications (GSM) and Third Generation (3G) cellular systems. Its primary target applications are Packet-Switched Streaming service (PSS), Multimedia Messaging Service (MMS) and Multimedia Broadcast and Multicast Service (MBMS).
The AMR-WB+ codec has a wide bit-rate range, from 5.2–48 kbit/s. Mono rates are scalable from 5.2–36 kbit/s, and stereo rates are scalable from 6.2–48 kbit/s, reproducing bandwidth up to 20 kHz (approaching CD quality). Moreover, it provides backward compatibility with AMR wideband.
