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TAK 1.0.4 压缩设置指南(TAK音频格式推广贴)

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发表于 2008-5-19 21:04 | 显示全部楼层 |阅读模式
原贴地址:http://1.stdcb.com/blog/article.asp?id=24

“TAK (Tom's lossless Audio Kompressor) 汤姆的无损音频压缩器是一个无损音频编码器,该编码器承诺其压缩性能与 Monkey's Audio "High" 相仿,而解码速度与 FLAC 相仿。现在其基本格式已经完成,可以安全使用,其他诸如内部tag信息支持,更多的播放软件支持等功能正在开发中。”

官方网页(德):http://www.thbeck.de/Tak/Tak.html

由于TAK 1.0.4 多了很多压制选项,以下跟据程序的说明文件做一些翻译与推荐设置。

Options 选项设置
The Options dialog lets you choose encoder options like the preset, which determines compression efficiency, encoding and decoding speed. Furthermore you can modify stream properties and specify output options like for instance the destination directory.

该选项对话框可以让你设置编码选项,如选择 预设值(可以决定压缩效率,编码和解码速度)。你甚至可以修改 流选项 和指定 文件输出 的选项,如选择存放输出文件的目录。

Encoder options

Presets 预设值
The table contains 15 rows. Each is representing one encoder preset, which affects compression efficiency, encoding and decoding speed. You select a preset with a mouse click.

该表格有15行。每一行表示一个影响编码效率和编解码速度的预设值。单击所选的预设值即选择该预设值。

Each preset selects a set of internal encoder options. Some of them affect only the encoding speed, the others also the decoding speed.

选择一个预设值即选择一套内置的编码选项,其中一些选项只会影响编码速度,而另外一些选项则会影响解码速度。

Slower decoding usually means higher hardware requirements (memory size and/or cpu power) for a playback device. Some devices may be too weak to support the more demanding internal encoder options. But any option, which only affects the encoding speed and complexity, is always applicable.

更慢的解码速度意味着更高的回放设备硬件要求(内存大小或CPU速度)。一些设备也许支持不了更高要求的内置编码选项。但任何选项只是影响编码的速度和复杂度,总是可适用的。

Therefore each preset consists of two components:

因此任意一个预设值都由两部份组成:

The profile selects internal encoder options which affect both encoding and decoding speed. Profiles are declared as a number from 0 to 5 (fastest to strongest).
预设档(profile)用来选择影响编解码速度的内置编码选项。预设档(profile)被申明为0到5(最快到最强)六个等级。
The evaluation level selects only internal encoder options, which have no effect on the decoding speed. The evaluation levels are named Standard, Extra and Max and abbreviated as s, e and m (fastest to strongest).
评估值(evaluation level)用来选择不影响解码速度的内置编码选项。几个评估值被命名为 标准(Standard), 特强(Extra)和最强(Max),对应缩写s,e和m(最快到最强)。
Presets are beeing declared as a combination of the profile and the abbreviated evaluation level (if not specified Standard is beeing used): 0 is the fastest, 5m the strongest setting.

预设值(preset)被申明为预设档(profile)和评估值(evaluation level)的组合(如果评估值未被申明则默认使用标准(standard)):0对应最快预设值,5m则为最强预设值。

Put a -p in front of the preset and you get the corresponding command line parameter for TAKC, which is also used in the table as name for the preset.

在预设值前加入“-p”即为对应的TAKC命令行参量,也就是表格里使用的预设值名。

A hardware manufacturer supporting TAK has only to specify the strongest profile it's hardware can decode, because the evaluation level does not affect the hardware requirements.

TAK的硬件支持产家只会标明产品所能支持的最强预设档,这是因为评估值并不影响硬件要求。

Hint: If you want higher compression and fast encoding, and are able to accept some decrease in decoding speed, it is usually preferable to select a higher profile instead of increasing the evaluation level.

提示:如果你追求更高的压缩率和更快的压缩速度,而且能够接受牺牲解码速度的前提,通常选择一个更高的预设档(profile)会优于选择更高的评估值(evaluation level)。

Comparison 对照
The table contains results from my primary test file set to give you an idea of the effect of profiles and evaluation levels on compression efficiency, encoding and decoding speed. Depending on your files and system you may get quite different results!

该表格包括了个人原始测试文件的结果,这些结果可以帮助你理解预设档(profile)和评估值(evaluation level)对编码效率和编解码速率的影响。但由于系统和文件的不同你也有可能得到不一样的测试结果。

The data in columns 2 to 4 is always relative to the currently selected preset:

2至4列的数据与当前选择的预设值(preset)有关:

Compression difference tells you, how much better (positive values) or worse (negative values) the other presets performed. Example: if 2 is selected (Default), you can see, that 5 + MAX achieved 1.10 percent better compression on my file set. Percentage values always refer to the original, uncompressed file size.

由压缩比的区别可知其他预设值(preset)在这方面表现得更好(正值)或更差(负值)。例如,如果选择预设值2(默认),你将看到5+MAX在压缩比方面比选择的2强1.10百分点。该百分比值与未压缩前的原始文件相关。

Encoding/Decoding speed: How much faster / slower are the other presets on encoding / decoding.

编码/解码速度:其它预设值比当前预设值 快/慢 多少。

既然选择了TAK肯定选择最强的-p5m啦

Details 详细设置
The Details dialog let's you modify some internal encoder options.

详细设置对话框可让你修改某些内置编码选项。



Frame Size Limit 帧大小限制
The Frame size is defined as samples per channel. The encoder first calculates the frame size for the preset's Frame Duration and then compares the resulting sample count with the Frame Size Limit value. If it's bigger, it will be limited. An Example:

帧大小(Frame Size)是指每个声道的采样数量。编码器首先由预设值的帧持续时间计算出帧大小,然后拿结果的采样数与帧大小限定的值作比较。如果结果的采样数比帧大小限定的值大,帧大小将会被限制。例如:

Profile 0 is using a Frame Duration of 94 ms. CD-Audio has a sample rate of 441000. 44100 * 0.094 = 4145 samples. This value is bigger than the profile's Frame Size Limit and will therefore be limited to 4096.

预设档0的帧持续时间为94ms。CD音频的采样率为44100Hz。44100 * 0.094 = 4145 采样数。这个值比预设档的帧大小限定值大所以被限制在4096。

Caution: if you increase the frame size limit, you are breaking the profile's specification! Some hardware players may not have enough memory to decode the bigger frames. Decreasing the frame size usually reduces the compression efficiency.

注意:如果你增加帧大小限制的值,你将破坏预设档的规格!一些硬件播放器可能没有足够的内存去解码比它大的帧。减小帧大小则会降低压缩效率。

There is only one situation where you are adviced to change the frame size limit: If you want to encode files generated by the high quality LossyWav- preprocessor, Tak's frame size has to match the preprocessors frame size (usually 512 samples). For more information about LossyWave please read those threads at Hydrogenaudio.org: Near-lossless / lossy FLAC, An idea & MATLAB implementation and lossyWAV Development, WAV bit reduction by 2BDecided.

只在一种情况下我们建议你修改帧大小:如果你想使用高质量的 LossyWav- 预处理程序 去编码生成文件。Tak 的帧大小必须与该预处理程序的帧大小相符(通常为512采样数)。更多关于 LossyWave 的信息请访问 Hydrogenaudio.org: Near-lossless / lossy FLAC, An idea & MATLAB implementation and lossyWAV Development, WAV bit reduction by 2BDecided。

Another warning: Frame Size Limit's of 512, 1024 and 2048 are not backwards compatible and can not be decoded by TAK applications and libraries prior to V1.0.2!

另一个警告:帧大小限制值为 512, 1024 和 2048 时不能向下兼容即无法被 V1.0.2 版本以前的 TAK 程序和库解码。

Prefilter 预滤器
The prefilter cleans the signal slightly, before it is sent to the linear predictor. It usually gives, on average, 0.15 to 0.20 percent better compression - up to 4 percent on (very) specific files (for instance files that come from lossy compressed sources).

预滤器可以在信号被送去线性预报器之前轻微地过滤信号。通常它可以提高平均 0.15% 到 0.20% 的压缩比,对于一些特别的文件(如一些由有损压缩解压出来的文件)甚至可以提高 4% 的压缩比。

This can significantly reduce the decoding speed (10-20 %).

但这将会大幅地降低解码速度(10-20%)。

The profile specification only permits the Prefilter usage for the profiles 3 to 5. If you enable the Prefilter for the profiles 0 to 2, TAK will regard your configuration as profile 3.

预设档规范只允许预设档等级 3 以上可以使用预滤器。如果你在预设档等级 0 到 2 使用预滤器的话,TAK 将把你的配置当预设档等级 3 看待。

Verify 数据校检
With Verify enabled, any compressed frame is subsequently decompressed and then compared to the original data. This reduces encoding speed, but is useful for the more paranoid among us!

数据校检选项被激活后,任何已被压缩的帧将会被重新解压并与原始数据进行比较。这将会降低编码速率,但对我们当中一些偏执的人来讲很有用。

这一段翻译完我自己也不太明白帧大小的原理,不过选好预设值(preset)后就已经自动配置好帧大小限制(Frame Size Limit)和预滤器(Prefilter)的值了,不需要修改,如果有心的话可以勾上数据校检(Verify)

Stream 流选项

Wave file meta data Wave文件元数据
When decompressing TAK always generates a bit identical copy of the audio data of the original wave file. Nevertheless, the resulting wave file may be different from the original!

在解码时 TAK 会生成与原始 WAVE 文件一致的音频数据。但生成的WAVE文件可能与原始文件不一样!

This is because a wave file contains not only raw audio data, but also some header structures describing the audio format, and sometimes additional data which is not needed for the playback - for instance meta information created by the application that created the original wave.

这是因为一个 WAVE 文件不仅包含源音频数据,还包含了一些用来申明音频格式的标题结构,还有其它一些不影响回放的附属信息——例如一些由生成WAVE文件的应用程序所创建的信息。

Even if there is no additional (dropped) information besides the wave header, the wave file created by the decoder can be different from the original. This is because there are several different ways to create a valid wave header describing the same audio format. TAK may use an alternative to the creator of the original wave.

即便除了标题结构外没有其它的附属信息,解码器生成的 WAVE 文件也会与原始文件不一致。这是因为不止一种方法可以有效地创建同一种音频格式的 WAVE 标题。TAK 可针对原始 WAVE 文件生成程序提供各种选择。

All this does not affect the validity of the audio data itself. It will always be bit identical to the original!

所有这些操作不会影响音频数据自身的正确性。音频数据将始终与原始文件一致!

By default TAK will store up to 1 MByte of non-audio data into the compressed file. This guarantees a bit identical reproduction of the whole wave file, including the non-audio data.

在默认下,TAK 将在压缩文件内预置 1MByte 的空间给非音频数据。这可以保障重新生成的WAVE文件与整个原始的WAVE文件完全一致,包括非音频数据在内。

Maximum size 最大值
Specify a maximum size for the meta data. If it is bigger, it will not be be copied into the TAK file.

制定一个元数据的最大值。如果元数据比该值大,将不会被拷贝进 TAK 文件。

是否保留元数据和保存多少看个人爱好了,如果重视与原始WAVE文件的一致性就按默认吧。但我一般压缩音频是以保存为目的的,所以选择关闭(off)。

Output 文件输出


Destination 存放于
Where should the compressed files be stored:

指定压缩完的文件存放的目录:

in the same directory as the source files, or
存放到与源文件相同的目录下,或
in a user-specified directory. After selecting this option you can select Browse to select the directory.
存放到用户指定的目录下。在选择这一选项后你可以单击浏览去选择所要存放的目录。
NB: The selection dialog is a bit different from the standard Windows dialogs. The treeview does not show plus symbols, which can usually be clicked to show directories located within the parent folder. Here you have to perform a double click on the directory name to open it.
注意:目录选择对话框与一般 Windows 里的不一样。树状浏览不会显示平时单击后显示子目录的+号。在这里你必须双击目录去浏览它的子目录。
!!! Overwrite existing TAK files !!!
!!!覆盖已存在的 TAK 文件!!!
Enable this option to overwrite already existing TAK files; otherwise they will be skipped. You will not be asked for a confirmation!
激活这一选项将会覆盖已存在的 TAK 文件;否则这些文件将会被跳过。在覆盖前将不会有任何确认信息!

Protocol 记录文件
TAK can save information about the compression process in the protocol file "Tak_Enco_Proto.txt", which will be created in the output directory.

TAK 可以储存压缩进程的信息到一个记录文件“Tak_Enco_Proto.txt”,这个文件存放在文件输出指定的目录下。

Level 等级
What should be stored into the protocol file:
指定被存储进记录文件的信息:

Off: Don't generate a protocol file.
关闭:不生成记录文件。
Result: Save a copy of the screen output.
压缩结果:储存压缩完成后屏幕显示的信息。
Result & Diagnostics: Save results and settings.
压缩结果与诊断信息:储存结果和设置。

Append 附加
Append new protocol data to an existing protocol file, instead of overwriting it.

如果记录文件已经存在的话存储为另外一个文件而不是覆盖掉已存在的记录文件。

Use MMX 使用MMX指令集
Uses MMX-assembler instead of pure Pascal on the most time consuming functions. Increases speed performance.

在运行大多数耗时的功能编译时使用 MMX 汇编指令替代纯 Pascal 语言,加强编译速度表现。

This option affects the Decoder too! It should really be in a new General Options dialog...

这个选项同样影响解码速度!所以出现在一个新的一般选项对话框中。
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