Pre quantize bits Is It a lossless or semi-lossless setting?

2025-03-09 07:59:02

I've been testing out 14-bit/44.1KHz with -hhx4 as some way to get even more compression. The only thing bugging me Is It safe to skip using dither since It just 2-bit's shaved off redbook audio?.

Re: Pre quantize bits Is It a lossless or semi-lossless setting?

Reply #1 – 2025-03-09 09:49:05

Re the post title: Pre-quantize is lossy. And if you want to use WavPack in a lossy way, I am not sure if pre-quantize is any better than WavPack's lossy mode. Of course the pre-quantization means you get something that unpacks well to PCM.

As for dither: Dither does, in practice, enhance the bit depth. So 14 bits undithered does in a way take more than 2 bits off a properly dithered 16 bits. No issue if you cannot hear the difference.

Re: Pre quantize bits Is It a lossless or semi-lossless setting?

Reply #2 – 2025-03-09 10:18:08

Replaygain album mode (with dither) during conversion may be a better way to get more compression.

Re: Pre quantize bits Is It a lossless or semi-lossless setting?

Reply #3 – 2025-03-10 02:22:45

I would not recommend truncating 16-bit audio to 14 bits to improve compression. As you mention, dither is certainly recommended whenever truncation occurs, and in this case you cannot rely on self-dither to always be enough. I imagine this would sometimes be audible, especially if quiet passages are played loudly.

This option was created by Justin Frankel (winamp, reaper) to truncate 24-bit audio down to 20 bits or so (because that’s all that most recording chains can deliver, at best). Of course, in theory, dither would be required there too, but there’s probably enough self-dither at that level that you can get away without it.

If you want improved compression with louder source material (where lossless sometimes comes up short) I would suggest adding -b8 to your command. That will give you about 50% compression (or better, source permitting) and will certainly be transparent always. Of course, it’s not lossless and if you ever want to convert to another codec (like FLAC) then you will lose the extra compression (unlike with truncation). But it’s a lot safer, in my opinion.

Re: Pre quantize bits Is It a lossless or semi-lossless setting?

Reply #4 – 2025-03-10 15:43:31

But then, the obligatory "storage is cheap":
You need a backup anyway. That could be a big spinning drive tucked away somewhere.

Use wavpack hybrid lossless ("-c"), and for your smaller drive: omit the .wvc?

Re: Pre quantize bits Is It a lossless or semi-lossless setting?

Reply #5 – 2025-03-13 06:49:01

I went back to Vorbis 192kbps VBR with some heavier music at 275kbps VBR. As I can't tell the differince,