CD Pre-emphasis: How to detect? What software to rip? Tagging?

[audiofool]

Cool!  How does HQPlayer determine it needs pre-emphasis?  Is there a way to set a tag in a FLAC file to force it?   Does HQPlayer do anything with HDCD?  I am currently using ffmpeg to deal with HDCD.

 

[audiofool]

39 minutes ago, Miska said:

 

It is from the CDDA data.

 

No, once the data ends up in FLAC it should be already corrected without need for such measures.

 

So even CD's I've ripped years ago should be handled correctly by HQPlayer for pre-emphasis since it is embedded in the CDDA data and not depending on the TOC?  Is this a newer feature of HQPlayer?

 

41 minutes ago, Miska said:

But you won't find CDs that would have HDCD and pre-emphasis.

 

Good to know, I didn't know they were mutually exclusive.

 

43 minutes ago, Miska said:

 

No.... Only standard CDDA (RedBook), not any non-standard additions like HDCD or MQA.

 

I have a number of CD's that are HDCD.  I am using music forums to find them since I don't believe there is any way to know for sure from the CDDA data stream?

 

[audiofool]

1 hour ago, Miska said:

 

No, you need to use the actual physical media. Already made rips are lost case.

 

 

For the lost cases, what about a tag in the flac file that HQPlayer could recognize? ie. preemp=yes

 

1 hour ago, Miska said:

I think Microsoft owns HDCD these days. But there are so few discs with it that it is not worth trying to talk to Microsoft and potentially increase license price with decoding support.

 

I have at least 16 discs and am using ffmpeg to decode, interesting that an HDCD decoder can detect from the data stream.  I'm curious how ffmpeg is avoiding the license fee.

[audiofool]

2 hours ago, Miska said:

 

Technically possible, but just not implemented right now.

 

 

CD players with HDCD support do it the same way. The watch the least significant bit (LSB) for the encoded pattern. Normally this bit would be used for dither, but on HDCD it is used for control data.

 

 

Cutting some corners in this explanation... ffmpeg has a lot of such stuff. It is free and open source, nobody is doing it commercially, so it doesn't make any money someone could sue for "damages".

 

Thanks Miska,

For those interested here is a link to using ffmpeg to detect and convert HDCD, though the site claims the patent is expired it doesn't mention Microsoft's involvement so I suspect licensing is still involved.

https://opensource.com/article/20/7/hdcd

 

Also a link to another opensource library for HDCD

https://github.com/bp0/libhdcd