AMR to AAC - Convert audio online

Conversion Results:
# Output File Source File Action

Steps:

1. Click "Choose Files" button to select multiple files on your computer. You can also click the dropdown button to choose online file from URL, Google Drive or Dropbox. The source file can also be video format. Video and audio file size can be up to 200M.

2. Set target audio format, bitrate and sample rate. The target audio format can be WAV, WMA, MP3, OGG, AAC, AU, FLAC, M4A, MKA, AIFF, OPUS or RA.

3. Click "Convert Now!" button to start batch conversion. It will automatically retry another server if one failed, please be patient while converting. The output files will be listed in the "Conversion Results" section. Click icon to show file QR code or save file to online storage services such as Google Drive or Dropbox.

AMR vs AAC:
Name AMR AAC
Full name Adaptive Multi-Rate Advanced Audio Coding
File extension .amr, .3ga .aac
MIME audio/amr audio/aac
Developed by 3GPP Bell Labs, Fraunhofer Institute etc.
Type of format Audio compression format Audio compression format
Introduction The Adaptive Multi-Rate (AMR or AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding. AMR was adopted as the standard speech codec by 3GPP in October 1999 and is now widely used in GSM and UMTS. Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates. AAC has been standardized by ISO and IEC, as part of the MPEG-2 and MPEG-4 specifications.
Technical details AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200-3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s. Sampling frequency 8 kHz/13-bit (160 samples for 20 ms frames), filtered to 200-3400 Hz. AAC supports inclusion of 48 full-bandwidth audio channels in one stream plus 16 low frequency effects channels, up to 16 "coupling" or dialog channels, and up to 16 data streams. The quality for stereo is satisfactory to modest requirements at 96 kbit/s in joint stereo mode; however, hi-fi transparency demands data rates of at least 128 kbit/s.
Associated programs Audacity, FFmpeg, MPlayer, QuickTime, VLC media player foobar2000, AIMP, DirectShow, QuickTime, VLC media player.
Sample file sample.amr sample.aac
Wikipedia AMR on Wikipedia AAC on Wikipedia