lossyWAV 1.3.0 released, Added noise WAV bitdepth reduction method. Options

[Nick.C]

lossyWAV 1.3.0 is released.

lossyWAV is a near lossless audio processor which dynamically reduces the bitdepth of the signal on a block-by-block basis. Bitdepth reduction adds noise to the processed output. The added noise is adaptively shaped by default and can alternatively be fixed noise shaped or white noise depending on command line parameters. When lossyWAV processed output is compressed with certain lossless codecs (FLAC, Wavpack, Tak, LPAC, MPEG-4 ALS and WMA-Lossless) the bitrate of the output file is significantly* reduced compared to the lossless original.

Changes from 1.2.0b:

• Adaptive noise shaping method kindly provided by SebastianG introduced and enabled by default;
• Fixed noise shaping reworked to allow effective shaping of samplerates other than 44.1kHz / 48kHz.
• Revised quality presets;
• Enhanced information output options;
• Major code cleanup.

Download

• Executable lossyWAV_1.3.0.zip
• Source lossyWAV_Source_20110806_1.3.0.zip

* on average, depending on content.

This post has been edited by Nick.C: Aug 10 2011, 21:12

[Northpack]

thank you Northpack. This increases speed to 9x, but still isn't close to the 33x I had with 1.1.0c

I guess that's still due to the new (fixed) noise shaping algorithms. Maybe Nic can comment on that. If you want it fast, I suppose you should stay with 1.1.0c

I always thought that there is unsuitable real-world wave input for lossyWAV (i.e. an input which won't result in significantly higher compression when prepocessed with lossyWAV). I just came across an example which seems to defy that rule.

No surprise here. It's known that there are some kind of signals which FLAC itself compresses very efficiently (i.e. solo piano music). Those signals can actually have a worse compression ratio when preprocessed with lossyWAV, because it forces FLAC to use a very small block size of 512 samples, thus decreasing it's efficiency (while lossyWAV can't always make up for the loss in those cases, see the small correction file).

This post has been edited by Northpack: Sep 19 2011, 18:39

[DonP]

No surprise here. It's known that there are some kind of signals which FLAC itself compresses very efficiently (i.e. solo piano music). Those signals can actually have a worse compression ratio when preprocessed with lossyWAV, because it forces FLAC to use a very small block size of 512 samples, thus decreasing it's efficiency (while lossyWAV can't always make up for the loss in those cases, see the small correction file).

I found this from a search after a piano track got bigger with lossywav (standard level for lossywav, and 5 for flac). Maybe there's some place to mention this caveat in the wiki article?

A similar piece on harpsichord (I guess due to more harmonics and less initial compression by flac) did shrink from 824 to 538 kb/s

[Nick.C]

Maybe there's some place to mention this caveat in the wiki article?

Sounds like a plan - it did come up in one of the development threads, but it bears repeating in the significantly more concise wiki article.