TAK 2.2.0 - Alpha release Options

[TBeck]

Alpha release 1 of TAK 2.2.0 ((T)om's lossless (A)udio (K)ompressor)

It consists of:

- TAK Applications 2.2.0 Alpha 1 b in "\Applications".
- TAK Winamp plugin 2.2.0 Alpha 1 in "\WinAmp".
- TAK Decoding library 2.2.0 Alpha 1 in "\Deco_Lib".

The final release will additionally contain the SDK.

Download:

Download link removed. TAK 2.2.0 Final has been released.

What's new

This release brings support for multi-channel audio and speed optimizations for encoder and decoder.

New features:

- Support for multi-channel audio. While the stream format supports up to 16 channels, the codec currently is restricted to a maximum of 6 channels.
- Support for the "Wave Format Extensible" file format.

Improvements:

- Encoding speed improvements of up to 10 percent for my primary file set. Most of it is achieved by a modification of the algorithm which selects the optimal predictor order for each subframe. It will now often use less predictors than before, what may on average result in about 0.01 percent worse compression. You will only notice an speed advantage, if your files benefit from high predictor orders.
- Decoding speed improvements of up to 18 percent for my primary file set. Some of it is attributed to the above-noted modification of the encoder's predictor order selection algorithm. Therefore it will only take effect when decoding files encoded with this version and only, if they benefit from high predictor orders. Additionally SSSE3-instructions can be used for predictor counts of 32 and more. This affects the presets p3, p4 and sometimes p2, but only, if a particular file benefits from high predictor orders.

Known issues:

- If you use pipe decoding and the application reading the pipe is beeing terminated before the whole file has been read, TAKC may get into an endless loop and has to be manually killed with the task manager. I don't think this is a big issue but i will try to fix it in one of the next versions. BTW: Big thanks to shnutils for testing the pipe decoding!
- There seem to be some compatibility issues with pipe decoding to some other applications ("crc1632.exe" has been reported). I will try to fix it in the next release.

Alpha testing

This alpha release has already gone through extensive testing performed by my automatic scripts. Nevertheless there may be bugs left. Especially because i had to write a lot of new code for the support of multi-channel audio. This also involved a lot of minor modifications of the existing code. Therefore i would like you to verify the proper function of the codec: Compress -> Decompress -> Compare resulting wave with the original file, either by a binary compare or by the use MD5-check sums.

Certainly i am very interested into efficiency comparisons of the new multi-channel audio codec and other compressors.

Some remarks:

The most time consuming part of the new codec is it's channel decorrelation mechanism. The strongest presets sometimes check any possible channel combination. Principially you have n * (n - 1) (n = channel count) possible combinations, if you count "A predicts B" and "B predicts A" as two combinations.

Some figures:

2 channels -> 2 combinations
4 channels -> 12 combinations
5 channels -> 20 combinations
6 channels -> 30 combinations
8 channels -> 56 combinations

This rapid increase is the reason, why the codec currently is restricted to a maximum of 6 channels. I have to find and evaluate more heuristics for a fast estimation of optimal pairings which doesn't require a full evaluation of all possibilities.

Some are alreaday working. Most of them rely on the presence of a speaker assignment mask in the source wave file. If present, some faster presets will only test those combinations, which were most useful in my evaluations. A low frequency channel will never be evaluated.

But this only works, if the speaker assignment is known. Therefore the encoding time of the same audio data may differ considerably dependent on the presence of a speaker mask in the original wave file.

Im my evaluations the new codec often did beat Mpeg4Als -7 compressionwise, if a particular file provided good opportunities for channel decorrelation. Unfortunately for some files there are zero opportunities. My test corpus is still too small to make any generalized statement regarding the new codecs efficiency.

Therefore i am very interested into compression results and comparisons with other codecs.

Thanks for testing and have fun

Thomas

This post has been edited by TBeck: Jul 10 2011, 23:53

[Destroid]

And here's some test results

Not sure exactly what settings to use with MP4ALS I ended up supplying using no arguments at all. Comparing that with -p0 TAK came up a little less compressed in every file. I re-ran with -p1 and TAK edged out every MP3ALS file, so I'm guessing the closet TAK setting to default MP4ALS for compression ratio is either -p0e or -p0m.

CODE

6ch 48KHz 16bit TAK 2.2.0alpha -p1 MP4alsRM23
WAV filesize ratio enc dec ratio enc dec
----- --------- ------ ------ ------ ------ ------ ------
D1-02 106.15 MB 44.95% 42.80x 81.36x 45.68% 13.00x 34.16x
D1-03 228.73 MB 41.33% 44.94x 87.38x 42.10% 13.15x 35.49x
D1-05 407.76 MB 33.35% 48.04x 97.76x 34.04% 13.66x 36.94x
D1-08 506.63 MB 42.42% 44.79x 86.55x 43.47% 13.00x 36.78x
D1-10 140.89 MB 45.28% 44.01x 87.80x 46.21% 13.12x 36.81x
D2-05 153.60 MB 43.40% 44.08x 81.35x 43.98% 12.95x 34.61x
D2-09 201.40 MB 36.35% 47.12x 90.26x 37.13% 13.45x 37.67x
D2-10 378.39 MB 42.43% 44.40x 87.83x 43.04% 12.88x 37.27x
D2-11 296.93 MB 45.78% 42.19x 84.29x 46.29% 12.79x 36.19x
D2-18 340.04 MB 45.58% 43.54x 85.02x 46.55% 12.84x 36.79x
D3-02 87.80 MB 49.94% 42.81x 76.37x 51.55% 12.87x 37.89x
D3-05 184.21 MB 48.95% 43.27x 81.93x 50.45% 12.91x 36.44x
D3-09 211.97 MB 45.15% 44.26x 86.97x 46.62% 12.86x 35.85x
D3-11 501.20 MB 44.19% 44.04x 84.76x 45.54% 12.90x 36.61x
D3-12 191.09 MB 46.88% 44.00x 83.70x 48.29% 12.91x 36.56x

I did try the settings from the TAK 2.2.0 development thread but MP4ALS encoder was so incredibly slow I abandoned the test early on, but here's what I got:

CODE

6ch 48KHz 16bit TAK 2.2.0alpha -p2m MP4alsRM23 -7 -o160 -t6
WAV filesize ratio enc dec ratio enc dec
----- --------- ------ ------ ------ ------ ------ ------
D1-02 106.15 MB 43.72% 4.184x 76.83x 43.12% 0.206x 7.12x
D1-03 228.73 MB 40.38% 4.231x 74.86x 39.58% 0.209x 7.55x
D1-05 407.76 MB 32.70% 4.357x 84.39x 32.40% 0.220x 8.41x
D1-08 506.63 MB 41.07% 4.087x 75.10x 40.66% 0.211x 9.07x
D1-10 140.89 MB 44.11% 4.134x 79.31x 43.30% 0.209x 7.09x