lossyWAV 1.3.0 Delphi to C++ Translation Thread, Added noise linear PCM bitdepth reduction method. Options

[Nick.C]

And he's off!

Tycho has kindly started the translation of lossyWAV from Delphi to C++.

I'll need to learn it to be able to contribute meaningfully....

Changelog:

lossyWAV beta 1.3.0m 25/03/2013

• experimental parameter --feedback introduced to modify bit removal process to include an added noise check. Seems to work well in conjunction with "--maxclips 0" or "--maxclips 1" at lower quality settings.

lossyWAV beta 1.3.0m 25/03/2013

• Removed experimental new parameter --noisebtr.
• --interp-curve reinstated.
• experimental parameter --altfilter introduced to modify adaptive noise shaping method.

lossyWAV beta 1.3.0k3 08/03/2013

• Introduction of experimental new parameter --noisebtr which applies a new method of detemining bits to remove. Well, I say new - SebastianG did point me in this direction *quite* some time ago. Basically, the creation of the noise shaping filter for each channel outputs a numerical value that I have finally used to determine the number of bits to remove from that codec-block channel. It even works on (non-clipping) tonal samples. It should be noted that this is a complete departure from the original method - no searching for the lowest signal in the FFT output bins. Limited tuning so far - however the presets should give approximately the same resultant FLAC output bitrate from --portable up to --insane. Below --portable, I have made the quality settings more aggressive and --extraportable results in a FLAC output bitrate of approximately 283kbit/s. This is quite a drop from the 308 to 311kbit/s previously. If anyone is prepared to spend the time on some testing, that would be very much appreciated. I think that --extraportable is a bit *too* aggressive at the moment, but that is more of a feeling than anything else.
• --interp-curve removed at this time.
• beta 1.3.0k2 issued due to omission of --noisebtr from text output parameter list (used in FACT chunk and log file).
• beta 1.3.0k3 issued due to last minute fix for bits-per-sample not equal to 16.

lossyWAV beta 1.3.0j 08/02/2013

• Further experimental modification to the adaptive noise shaping routine, backed off a little but now works well with >96kHz samplerate

lossyWAV beta 1.3.0i 30/01/2013

• Further experimental modification to the adaptive noise shaping routine. NB: Testing has shown that this does not work well with >96kHz samplerate!!.
• Bug-fix: now processes >16-bit properly - unexpected integer overflow discovered where floating point was thought to be used.

lossyWAV beta 1.3.0h 23/01/2013

• Further experimental modification to the adaptive noise shaping routine. FLAC encode (-5 -b 512) from "-q X -i" results in 302kbit/s (compared to 309 kbit/s for vanilla --extraportable).

lossyWAV beta 1.3.0g 18/01/2013

• Experimental modification to the adaptive noise shaping routine, new parameter -i, --interp-curve; adds optional cubic curve interpolation in lieu of linear interpolation when determining target spectral shape for each noise shaping filter. When encoded in FLAC (-5 -b 512) using the --extraportable preset, my 10 album test set results in 304kbit/s (compared to 309 kbit/s for vanilla --extraportable).

lossyWAV beta 1.3.0f 26/10/2012

• First attempt at FFMPEG compatibility;

lossyWAV beta 1.3.0e 24/09/2012

• More rounding issues found and amended;
• Output is hopefully bit identical with reference output (2nd attempt....);

lossyWAV beta 1.3.0d 18/09/2012

• Bit removal chain error identified: C++ inherently rounds 0.5 differently from Delphi, Delphi uses Banker's rounding (round to even);
• Banker's rounding implemented;
• Output is now bit identical with reference output (caveat: from testing so far). [edit] Found not to be at --portable. Bug hunting continues.... [/edit]

lossyWAV beta 1.3.0c 15/09/2012

• Piped I/O implemented - please report problems;
• Most bugs in bit-removal chain removed - output not yet bit identical;
• Internal FFT routines optimised.

This post has been edited by Nick.C: Mar 30 2013, 15:37

Attached File(s)

 lossyWAV_beta_1.3.0n.zip ( 337K ) Number of downloads: 62

 

[Jan7887]

Hello everybody,

I am very new at this forum but I'm very interested in lossywav.
I'd like to mention from a general scientific view that audio compression (lossy/lossless) is a very mind expanding subject. Just the fact that people with the right tools, insight and with help of math/calculus can accomplish such things.

I would like to thank the author Nick.c and all other people contributing in this thread for making this possible.
Certainly from my point of view it is a great accomplishment to be able to shrink to smaller audio files while trying to stay as close as possible to the original.
Thank you very much for creating such a piece of software and please, if you have time and resources, keep up the good work.
I understand that Tycho has been a great contributor or fellow author with the C / C++ version.

I'm still using the Delphi 1.3.0 version, but as I understand the C++ version will have some speed improvements ?

I do have another question about the block size of FLAC. Is the block size of 512 the most optimized size ? Is it possible to use a blocksize of 256 with the extraportable setting in Lossywav or would this be too restricting to let flac store the audio in a correct manner ?

Anyway, thanks again and I will follow the development and this thread of course.