So your new proposal is within the quality demand which to me is fine for -3 though it's on the cutting edge.
Isn't that exactly where -3 should be? And -2 being "transparent as far as could be determined"?The average bitrate for my regular sample set is 335 kbps which is only 10 kbps lower than that of current -3. Average bitrate however of the problem essence is 446 kbps, and that's 18 kbps less than that of current -3.
3% to 4% extra compression is something lossless codecs would have to work very hard for, so nothing to give away easily, except for a reason of course.
Thanks, for your testing and observations.
I take on board what you're saying, but I agree with Halb27 that we're aiming for transparency at -3 with increasing resilience at -2 and -1. The initial aim of the process was to "slightly" reduce bitrate - what we have currently with -3 is significant reduction using the interplay of -nts, -skew and -snr. Maybe -3 -snr 18 -nts 7.5 would produce adequate results, maybe not. However, while there's only really Halb27 doing the ABX'ing, I will unconditionally accept his opinion.
Anyway,
lossyWAV beta v0.5.5 attached: Superseded.
-allowable, -dither, -clipping and -overlap removed;
Reference_threshold values used to determine bits_to_remove from calculated minimum_value have been re-calculated. Very slight increase in bitrate (406.9 v0.5.4 vs 407.3 v0.5.5 for my 53 sample set).
Code tidied.
[!--sizeo:1--][span style=\"font-size:8pt;line-height:100%\"][!--/sizeo--]lossyWAV beta v0.5.5 : WAV file bit depth reduction method by 2Bdecided.
Delphi implementation by Nick.C from a Matlab script, www.hydrogenaudio.org
Usage : lossyWAV <input wav file> <options>
Example : lossyWAV musicfile.wav
Quality Options:
-1 extreme settings [4xFFT] (-cbs 512 -nts -2.0 -skew 36 -snr 21
-spf 22224-22225-11235-11246-12358 -fft 11011)
-2 default settings [3xFFT] (-cbs 512 -nts +1.5 -skew 36 -snr 21
-spf 22224-22235-22346-12347-12358 -fft 10101)
-3 compact settings [2xFFT] (-cbs 512 -nts +6.0 -skew 36 -snr 21
-spf 22235-22236-22347-22358-2246C -fft 10001)
Standard Options:
-o <folder> destination folder for the output file
-nts <n> set noise_threshold_shift to n dB (-48.0dB<=n<=+48.0dB)
(-ve values reduce bits to remove, +ve values increase)
-force forcibly over-write output file if it exists; default=off
Codec Specific Options:
-wmalsl optimise internal settings for WMA Lossless codec; default=off
Advanced / System Options:
-snr <n> set minimum average signal to added noise ratio to n dB;
(-215.0dB<=n<=48.0dB) Increasing value reduces bits to remove.
-skew <n> skew fft analysis results by n dB (0.0db<=n<=48.0db) in the
frequency range 20Hz to 3.45kHz
-spf <5x5hex> manually input the 5 spreading functions as 5 x 5 characters;
These correspond to FFTs of 64, 128, 256, 512 & 1024 samples;
e.g. 22235-22236-22347-22358-2246C (Characters must be one of
1 to 9 and A to F (zero excluded).
-fft <5xbin> select fft lengths to use in analysis, using binary switching,
from 64, 128, 256, 512 & 1024 samples, e.g. 01001 = 128,1024
-cbs <n> set codec block size to n samples (512<=n<=4608, n mod 32=0)
-quiet significantly reduce screen output
-nowarn suppress lossyWAV warnings
-detail enable detailled output mode
-below set process priority to below normal.
-low set process priority to low.
Special thanks:
David Robinson for the method itself and motivation to implement it in Delphi.
Dr. Jean Debord for the use of TPMAT036 uFFT & uTypes units for FFT analysis.
Halb27 @ www.hydrogenaudio.org for donation and maintenance of the wavIO unit.
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