How can I record AMR audio format on the iPhone?

Question

A voice recorder doesn\'t need uncompressed Linear PCM audio. Compressed AMR would do fine. The iPhone framework built for recording audio is simple enough, b

Answer 1

AMR codec is NOT supported for encoding/recording on the iPhone, albeit it is supported for playback: this is the reason the kAudioFormatAMR constant exists.

Official api says that supported encoding formats are:

• ALAC (Apple Lossless) ~> kAudioFormatAppleLossless
• iLBC (internet Low Bitrate Codec, for speech) ~> kAudioFormatiLBC
• IMA/ADPCM (IMA4) ~> kAudioFormatAppleIMA4
• linear PCM ~> kAudioFormatLinearPCM
• µ-law ~> kAudioFormatULaw
• a-law ~> kAudioFormatALaw

You may try one of these formats or use an open source AMR encoder as goldenmean suggests.

edit: Updated Official api link