AMR stands for adaptive multi-rate audio codec. AMR is used in telephony applications to encode speech at low bit-rate.
- Store audio recordings in handsets (Example: Android Voice Recorder)
- Low bandwidth voice applications
AMR media comes inside a 3GPP 3gp container, or sometimes an simple .amr container. Inside .3gp files, AMR audio can go with a video track.
Repairability
AMR media is repaired without major problem. Treasured can detect it since 2013 release.
How to repair a corrupt AMR audio file
The easiest way is certainly to ask our Movie Repair Service to do it for you.
But for those who can program, here you have a few tips:
Techniques used are:
- Reindexing
- Patching of the file with a sample description from a good file
Audio track has a 'amr ' or 'samr' codec fourcc.
Example: immediately after mdat marker, we have a 32 bytes frames starting with 3c:
00000ea: 3cf8 c97a 4b45 7e02 5867 2c23 cf50 b62a <..zKE~.Xg,#.P.* 00000fa: 5824 0f5e 0116 3f0c 7bbd da4a 58ac c5d0 X$.^..?.{..JX... 000010a: 3c32 702c 3609 400c 7e01 4467 a5ae 1e1a <2p,6.@.~.Dg....