Convert audio files online

(It must be a valid sample rate value that target format supports.)
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. Choose target audio format. 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 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.

Compare 3GP with AMR:
Name 3GP AMR
Full name Third Generation Partnership Project Adaptive Multi-Rate
File extension .3gp, .3g2 .amr, .3ga
MIME Video/3gpp audio/amr
Developed by 3GPP 3GPP
Type of format Media container Audio compression format
Introduction 3GP (3GPP file format) is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services. It is used on 3G mobile phones but can also be played on some 2G and 4G phones. 3G2 (3GPP2 file format) is a multimedia container format defined by the 3GPP2 for 3G CDMA2000 multimedia services. It is very similar to the 3GP file format but consumes less space & bandwidth also has some extensions and limitations in comparison to 3GP. 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 3GP and 3G2 are container formats similar to MPEG-4 Part 14 (MP4), which is also based on MPEG-4 Part 12. The 3GP and 3G2 file format were designed to decrease storage and bandwidth requirements to accommodate mobile phones. They are good for lower end smartphones for faster streaming & download. 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 Windows Media Player, Apple QuickTime, VLC media player, Media Player Classic, K-Multimedia Player, Totem, RealPlayer, MPlayer, and GOM Player Audacity, FFmpeg, MPlayer, QuickTime, VLC media player
Sample file sample.3gp sample.amr
Wiki 3GP on Wikipedia AMR on Wikipedia