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

[chrizoo]

another issue I came across:

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. I am not sure why. Maybe user error?

The source file is the mp3 audio track of a documentary (so it's mostly human voice with occasional background music and f/x), converted to wav (16 bit stereo 44.1 KHz PCM).
I used --portable for lossyWAV and highest compression (8) for FLAC.

source.wav: 925 178 232 bytes
source.flac: 362 984 714 bytes (554 kbit/s)
source.1.1.0c.lossy.flac: 362 182 771 bytes (552 kbit/s) (-0,2%)
source.1.1.0c.lwcdf.flac: 10 507 100 bytes

The compressibility of the correction file suggests that the source wave file was not changed much. I inspected the correction file to confirm that. There are really very little changes and even those are hard to spot (it looked like a flatline and even when pointed to the peak values by Wavelab. Only after maximizing the vertical scale AND increasing gain by 400% I could barely see some not-zero-values).

The point is, preprocessing with lossyWAV saved only 0,2% in filesize (YES, I used 512 blocksize for flac),
while wiki gives these indicative expected results:

lossless flac: 854 kbit/s
--portable lossywav flac: 376 kbit/s (-56%)

This is quite different from my results. Both in terms of absolute kbit/s and relative savings (-56% vs -0,2%).


So, after updating to 1.3.0 I repeated this test:

source.wav: 925 178 232 bytes
source.flac: 362 984 714 bytes (554 kbit/s)
source.1.3.0.lossy.flac: 322 170 992 bytes (491 kbit/s) (-11%)

The -11% are of course a step forward from the next-to-nothing -0,2%,
but still it does not match the expectations for --portable settings, as indicated in wiki (-56%).

Sure, the wiki numbers are rough reference points only,
but these results are still way off.

Your thoughts?

(It was a documentary about paranormal phenomenons, maybe that's why )