lossyWAV Development
Thanks to unfortunateson for the 96khzsample FLAC file - when I tried to process the contained WAV file lossyWAV crashed. It turned out to be a divide by zero error in the preparation of the skewing factors. This led me to re-assess the skewing factor preparation and I quickly found a simple fix (which also improved the methodology) - however, the fix reduces the bitrate of all the quality presets by around 20kbps. I had already made an unrelated change to the spreading function which increased the bitrate for -3 to -7 by between 2kbps and 4kbps. However, the amendment to the skewing function preparation has reduced the difference in bitrate between the 3 existing spreading functions. So, I have amended the skewing function preparation and there is now only one spreading function (that for quality preset -1). lossyWAV beta v0.9.3 attached to post #1 in this thread. As this beta has changed some longstanding "constants" of the method, I will be extremely grateful if some of our more acutely eared members could ABX some of the more problematic samples and post feedback. I am fairly sure that quality *should* not have suffered, but my ears are not good enough to perform the critical evaluation required. Thanks, Nick. I have processed my 53 problem sample set using beta v0.9.3 and the change in spreading function has changed the variation in bitrate somewhat:|-------------|-----------|-----------|-----------|-----------|-----------|-----------|-----------| | Version |lossyWAV -1|lossyWAV -2|lossyWAV -3|lossyWAV -4|lossyWAV -5|lossyWAV -6|lossyWAV -7| |-------------|-----------|-----------|-----------|-----------|-----------|-----------|-----------| | v0.9.2 RC3 | 543kbps | 494kbps | 433kbps | 408kbps | 385kbps | 365kbps | 348kbps | |-------------|-----------|-----------|-----------|-----------|-----------|-----------|-----------| | beta v0.9.3 | 505kbps | 467kbps | 435kbps | 406kbps | 381kbps | 357kbps | 337kbps | |-------------|-----------|-----------|-----------|-----------|-----------|-----------|-----------| From this, I feel that maybe -1 should become (even) more conservative in its -snr and -nts settings (currently 24 and -3 respectively). However, the change in change in bitrate between quality presets is now significantly more linear than it has ever been. Also, as all quality presets now use the same spreading function I could (nearly) implement a fractional quality preset (like oggenc) between -1.000 and -7.000.