什么是 M4A 文件？
Apple 的音频格式,以小体积实现出众音质
An M4A audio file is a lossless audio format (and encoding algorithm) created by Apple and utilized on a variety of Apple products (including iPod, iPhone, iPad, iTunes, and Quicktime products). The m4a codec has been open-sourced so it is quite popular. M4A files are usually encoded with Advanced Audio Coding (AAC) which was originally designed to be the successor to MP3.
Both MP3 and M4A files are used for audio-only files, and are both unprotected (free from DRM features). Protected files will have a *.m4p file extension. AAC or M4A files do have better audio quality when compared to MP3 files when encoded at the same bitrate due to some of the codec’s improvements such as compression based on perception and a smaller block size for changing audio sounds and signals.
M4A 文件的常见用途
- iTunes 音乐库
- Apple 播客
- 有声读物分发
- iPhone 上的语音备忘录
- Apple Music
- iTunes Store
- iPhone/iPad 录音
- 语音备忘录应用
谁会使用 M4A 文件？
用 iPhone 录制采访或讲座的记者、学生和研究人员经常使用 M4A 文件,因为 iOS 录音应用默认保存为该格式。播客编辑和定性研究团队在嘉宾或实地人员用 Apple 设备录制音频时,也会收到 M4A 文件。
M4A 与 MP3：应该选择哪一个？
M4A 通常将 AAC 音频存储在 MPEG-4 容器中,而 MP3 使用较旧的 MPEG-1 Layer III 编解码器。在相同码率下,AAC 通常能生成比 MP3 更清晰的音频,尤其是对于语音,但 MP3 在旧设备和软件上仍是受支持更广泛的格式。当每兆字节的音质很重要,或你在 Apple 生态中工作时,选择 M4A;当最大兼容性是首要考虑时,选择 MP3。
将 MP3 转换为文字