什么是 AMR 文件？
为语音优化的移动音频格式
AMR was adopted as the standard speech codec by the 3rd Generation Partnership Project Group (3GPP)and is now widely used in GSM and UMTS for 3G mobile phones and devices.
The Adaptive Multi-Rate (AMR) audio file format that is optimized for speech coding. Thus, most audio saved in the AMR file format is compressed and optimized for human speech frequency ranges. Thus, the 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 normal quality speech starting at 7.4 kbit/s. Since it is used mainly for mobile speech communication, it chooses between the 8 different bit rates based on link conditions.
AMR 文件的常见用途
- 移动设备上的语音录音
- 语音信箱留言
- GSM 电话通话
- Android 录音机
- 手机语音信箱
- 3G 电话录音
谁会使用 AMR 文件？
录制电话采访的记者、查阅通话证据的法律与合规团队,以及处理运营商语音文件的呼叫中心或电信人员,经常会遇到 AMR。当采访或信息由旧款移动手机录制时,实地研究人员和支持团队也会收到 AMR 附件。
AMR 与 MP3：应该选择哪一个？
AMR 是一种窄带语音编解码器,采样率为 8 kHz,编码码率为 4.75–12.2 kbps,生成的文件非常小,仅限于电话语音范围;而 MP3 是通用音频格式,支持更高的采样率和码率,适用于音乐和全频段声音。MP3 在各类设备和软件上的播放支持也广泛得多。当手机或语音信箱系统自动生成 AMR 且文件大小很重要时,选择它是合理的;而对于分享、存档或任何超出语音范畴的音频,MP3 是更好的选择。
将 MP3 转换为文字