AMR to OPUS - 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 OPUS:
Name AMR OPUS
Full name Adaptive Multi-Rate Opus Audio Format
File extension .amr, .3ga .opus
MIME audio/amr audio/opus
Developed by 3GPP IETF codec working group
Type of format Audio compression format Audio file 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. Opus is a lossy audio coding format developed by Xiph and standardized by the IETF, designed to efficiently code speech and general audio in a single format, while remaining low-latency enough for real-time interactive communication and low-complexity enough for low end ARM3 processors.
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. Opus supports constant and variable bitrate encoding from 6 kbit/s to 510 kbit/s, frame sizes from 2.5 ms to 60 ms, and five sampling rates from 8 kHz (with 4 kHz bandwidth) to 48 kHz (with 20 kHz bandwidth, the human hearing range). An Opus stream can support up to 255 audio channels, and it allows channel coupling between channels in groups of two using mid-side coding.
Associated programs Audacity, FFmpeg, MPlayer, QuickTime, VLC media player FFmpeg, AIMP, Amarok, cmus, foobar2000, Mpxplay, MusicBee, SMplayer, VLC media player, Winamp
Sample file sample.amr sample.opus
Wikipedia AMR on Wikipedia OPUS on Wikipedia