MP3Packer—MP3码率压缩调整工具

On 2011年01月5日, in soft, by netoearth

VBR(Variable Bitrate)动态比特率。也就是没有固定的比特率,压缩软件在压缩时根据音频数据即时确定使用什么比特率。这是Xing发展的算法,他们将一首歌的复 杂部分用高Bitrate编码,简单部分用低Bitrate编码。主意虽然不错,可惜Xing编码器的VBR算法很差,音质与CBR相去甚远。幸运的 是,Lame完美地优化了VBR算法,使之成为MP3的最佳编码模式。这是以质量为前提兼顾文件大小的方式,推荐编码模式。

ABR(Average Bitrate)平均比特率,是VBR的一种插值参数。Lame针对CBR不佳的文件体积比和VBR生成文件大小不定的特点独创了这种编码模式。ABR也 被称为“Safe VBR”,它是在指定的平均Bitrate内,以每50帧(30帧约1秒)为一段,低频和不敏感频率使用相对低的流量,高频和大动态表现时使用高流量。举 例来说,当指定用192kbps ABR对一段wav文件进行编码时,Lame会将该文件的85%用192kbps固定编码,然后对剩余15%进行动态优化:复杂部分用高于192kbps 来编码、简单部分用低于192kbps来编码。与192kbps CBR相比,192kbps ABR在文件大小上相差不多,音质却提高不少。ABR编码在速度上是VBR编码的2到3倍,在128-256kbps范围内质量要好于CBR。可以做为 VBR和CBR的一种折衷选择。

CBR(Constant Bitrate),常数比特率,指文件从头到尾都是一种位速率。相对于VBR和ABR来讲,它压缩出来的文件体积很大,但音质却不会有明显的提高。

MP3 Packer is a free software for Windows and Linux that rearranges data in mp3 files to generate the smallest possible mp3 file but also for other purposes such as turning VBR files into CBR files which can be handy if players are used that do not support VBR.

The application is offered as a command line version and a version with a graphical user interface on Windows. Winmp3packer, that’s the name of the gui version, has already been configured to reduce the size of mp3 files loaded into the application.

winmp3packer gui

All it takes to use it is to select a folder or folders with mp3 files before clicking the process button. The application scans all mp3s located in the folders and will process them if they meet certain criteria.

winmp3packer

A log is displayed in the end giving information about the processed files and the decrease in size.

mp3 packer

We have run the application on three albums and it managed to decrease the size by about 5 Megabytes or 1.4%.

That may not look like much but it could add up if thousands of songs are stored on a device. The mp3 files need to be encoded with CBR for this to have any effect.

You may have noticed that the program offers additional options in its interface. Users can switch the output type from VBR to CBR, configure a fixed minimum bitrate, strip non-mp3 data from files and set a different output folder to avoid that files are overwritten by the application.

MP3Packer can be a handy program to run once on a mp3 collection to save space on the storage device. The application is available for download at the official website. (via)

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