HDCD to 24 Bit

[linnsondek]

I have been trying to rip HDCDs in 24 bit. I have used the HDCD DSP setting and the FLAC file does appear from the properties to be 24 bit, and when playing it on a Linn Klimax DS it is reported to be 24 bit but my concern is that the file size is approximately the same as a 16 bit version of the track I did some time ago. The 24 bit file reports it has been 80% compressed by the FLAC encoder. I know HDCD has only got 20bit data in it but surely the FLAC file should be 25% larger or so than the 16 bit version on the same level 5 of compression. My other 24 bit FLAC files that I have generated from recorded LPs are always around 50% bigger than 16 bit versions. The HDCD FLAC file also plays a bit quieter than the 16 bit version.

Your thoughts would be appreciated.

[Jeff Flowerday]

Re: HDCD to 24 Bit

I have been trying to rip HDCDs in 24 bit. I have used the HDCD DSP setting and the FLAC file does appear from the properties to be 24 bit, and when playing it on a Linn Klimax DS it is reported to be 24 bit but my concern is that the file size is approximately the same as a 16 bit version of the track I did some time ago. The 24 bit file reports it has been 80% compressed by the FLAC encoder. I know HDCD has only got 20bit data in it but surely the FLAC file should be 25% larger or so than the 16 bit version on the same level 5 of compression. My other 24 bit FLAC files that I have generated from recorded LPs are always around 50% bigger than 16 bit versions. The HDCD FLAC file also plays a bit quieter than the 16 bit version.

Your thoughts would be appreciated.

Why should the flac files surely be 25% larger? Size isn't related to bit depth alone. Remember the data for HDCD was in the 16 bit source already, and really compressed in there.

[linnsondek]

Re: HDCD to 24 Bit

You are of course quite correct that regarding the size of the FLAC file being determined by a number of parameters in addition to bit depth. I was relying on my experience downloading FLAC files of both 16 and 24 bit from the Linn Records site. The CD I was ripping was from Linn Records. The Wave file should be 50% bigger as that is uncompressed and it is. However after further analysis I realise that the 24 bit depth is being compensated in the compression process by the absolute amplitude of the signal which for the track in question is -6db for the HDCD extraction. I reversed the 2 FLAC files for 16 and 24 bit which were approximately the same size and the Wave files were indeed 50% different in size.

[Porcus]

Re: HDCD to 24 Bit

Well ... first, HDCD gives at most 20 bits. dBpoweramp stores them in a 24-bit file with the last four bits equal to zero, but those are trivially compressed away.

Second, what if the original is 16 bits? Or, as in many cases, effectively less?