AMR to M4A - Convert audio online
Conversion Results:
| # | Output File | Source File | Action |
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How to convert AMR to M4A:
1. Click the "Choose Files" button to select multiple files on your computer or click the "URL" button to choose an 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.
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 the "Convert Now!" button to start batch conversion. It will automatically retry conversion on another server if one fails, 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 cloud storage services such as Google Drive or Dropbox.
AMR vs M4A:
| Name | AMR | M4A |
| Full name | Adaptive Multi-Rate | Audio-only MPEG-4 |
| File extension | .amr, .3ga | .m4a |
| MIME | audio/amr | video/mp4 |
| Developed by | 3GPP | International Organization for Standardization |
| Type of format | Audio compression format | Media container |
| 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. | MPEG-4 Part 14 or MP4 is a digital multimedia container format most commonly used to store video and audio, but can also be used to store other data such as subtitles and still images. M4A stands for MPEG 4 Audio and is a filename extension used to represent audio files. |
| 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. | Audio-only MPEG-4 files generally have a .m4a extension. This is especially true of non-protected content. M4A is often compressed using AAC encoding (lossy), but can also be in Apple Lossless format. |
| Associated programs | Audacity, FFmpeg, MPlayer, QuickTime, VLC media player | Windows Media Player, RealPlayer, MPlayer, Media Player Classic, VLC Media Player, K-Multimedia Player |
| Sample file | sample.amr | sample.m4a |
| Wikipedia | AMR on Wikipedia | M4A on Wikipedia |