MKV to AMR - Convert audio online

Conversion Results:
# Output File Source File Action

Steps:

1. Click "Choose Files" button to select multiple files on your computer or 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. You can use file analyzer to get source audio's detailed information such as track name, genre, bitrate and sampling rate etc.

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.

MKV vs AMR:
Name MKV AMR
Full name Matroska Video Adaptive Multi-Rate
File extension .mkv, .mk3d, .mka, .mks .amr, .3ga
MIME video/x-matroska, audio/x-matroska audio/amr
Developed by www.matroska.org 3GPP
Type of format Container format Audio compression format
Introduction The Matroska Multimedia Container is an open standard free container format, a file format that can hold an unlimited number of video, audio, picture, or subtitle tracks in one file. It is intended to serve as a universal format for storing common multimedia content, like movies or TV shows. 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.
Technical details Matroska is similar in concept to other containers like AVI, MP4, or Advanced Systems Format (ASF), but is entirely open in specification, with implementations consisting mostly of open source software. 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.
Associated programs VLC Media Player Audacity, FFmpeg, MPlayer, QuickTime, VLC media player
Sample file sample.mkv sample.amr
Wikipedia MKV on Wikipedia AMR on Wikipedia