ios 幾種格式錄音大小

Here are the results for few encoding supported by iPhone. Size of audio file in KB of duration 10 sec.

kAudioFormatMPEG4AAC : 164,

kAudioFormatAppleLossless : 430,

kAudioFormatAppleIMA4 : 475,

kAudioFormatULaw : 889,

kAudioFormatALaw : 889,

Among these kAudioFormatMPEG4AAC is having smallest size

iOs系統支持視頻音頻格式

iOs系統支持視頻格式及編碼要求：

The video technologies in iOS support the playback of movie files with the .mov, .mp4, .m4v, and .3gp filename extensions and using the following compression standards:
 H.264 video, up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second, Low-Complexity version of the H.264 Baseline Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats
 H.264 video, up to 768 Kbps, 320 by 240 pixels, 30 frames per second, Baseline Profile up to Level 1.3 with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats
 MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats

iOs系統支持音頻格式及編碼要求：
AAC (16 至 320 Kbps)、Protected AAC (來自 iTunes Store)、MP3 (16 至 320 Kbps)、MP3 VBR、Audible (formats 2、3、4)、Apple Lossless、AIFF 及 WAV
The audio technologies in iOS support the following audio formats:
• AAC
• Apple Lossless (ALAC)
• A-law
• IMA/ADPCM (IMA4)
• Linear PCM
• µ-law
• DVI/Intel IMA ADPCM
• Microsoft GSM 6.10
• AES3-2003