Wavpack - 3 Questions
2005-02-19 23:11:01
I have three newbie questions concerning wavpack that I have not found with search or in the documentation. 1. Would high-bitrate wavpack hybrid be "safer" (lack of killer samples) at the very high bitrates than pure lossy encoders? From what I understand, when you throw more and more bits into a pure-lossy encoder, the effectiveness that the bits are used for becomes less and less, as the bottleneck becomes the psymodel itself rather than the lack of bits. Does wavpack hybrid mode suffer from this? Meaning, as more bits are thrown in, they actually attend to reproducing the original waveform rather than still abiding by the psymodel? From the documentation I read "Above 256 kbps the quality of WavPack's lossy mode increases rapidly, with added quantization noise (which is the only artifact) dropping by about 1 dB for every 15 kbps." If I understand that correctly, as bits go above a threshold, they break free of the psymodel and only quantization occurs? If this is so, then... 2. Would then this "quantization-only lossiness" necessarily increase the chances for transparency? As I have read, more faithfulness to waveform does not always correlate to more transparency. And finally, 3. I found this in the documentation:"For the best lossless compression WavPack can offer, use -hx." But then the table below, at "High quality" 384kbps, -h was not used. Bitrate High quality Faster Encode Faster Decode ------- ------------ ------------- ------------- 256 kbps -hb256x -hb256 -b256x 320 kbps -hb320x -hb320 -b320x 384 kbps -b384x -hb384 -fb384x Can anyone explain why high quality 384kbps does not warrant the -h switch? Is it because of feasibility (it's utterly unnecessary at that bitrate and only slows down encode immensely), or is it because of some mechanism with -h? (it only improves quality at lower bitrates, and actually reduces at higher ones?)