Upsampling CD and burning to DVD-Audio DISC

[alvaius]

Hardest part of this question, is what forum to put it in........

I am looking to buy a DVD-Burner and software such that I can burn 192KHz, 24bit DVD-Audio discs.

One of my primary reasons for doing this is to upsample many of my existing CDs [using my own software and playing around with the algorithms], and then to burn them onto a DVD at 192KHz, 24 bit.

I have been doing "paper" designs on an upsampling CD player, and have somewhat come to the conclusion that it may be cheaper to take the music that I really like and simply upsample and burn to DVD-Audio and then do modifications on a DVD-Audio player.

Has anyone done this?

Does anyone know any software that will support DVD-Audio burning. I have done some searching and the only one that seems to definately do it is GEAR. Does anyone have any experience with this?

Alvaius

[matt_uk]

Hi,

I just came across this idea in your post under a Chip Amp thread and was about to copy/paste it into this forum as a new thread for disscussion.

The idea intrigues me, but since I only just saw it I haven't done any research into what is/isn't available and what has/hasn't been done.

With Playstation 1 games you used to be able to make a RAW Data CD Image on your hard-drive then apply a 'patch' to it that would change the CD data (crack the copy protection!) then it could be burned to a CD from the image.

I haven't looked to see if the DVD-Audio spec is readily available yet? or how it compares with that of CD-Audio. But my take on the idea would be to create a CD-Audio Image and patch it to a DVD-Audio image.

I have read in previous threads about a piece of Unix software that can read an Audio CD to a PC with maximum accuracy, but have no idea what kind of output is produced.

I'm going to go off and explore on Google to see what I can find.

Matt

[alvaius]

I am hoping not to apply any "patches" at all.

My intention is to pull a 16 bit wave file off the CD. I will then upsample this using either code written in C, or possibly just one of the system simulation packages that I have. Then I plan to use software such as GEAR, to burn this to DVD-Audio. I am hoping it all works ...............

Alvaius

[Cradle22]

Hi!

Theoretically it would be very easy (but not by simply patching it, no way).

It is always possible to (losslessly) "enhance" binary data (from 44.1 kHz, 16 bit to 196 kHz, 24 bit) to a larger scale (it is being done with image material all the time), but you would gain nothing from it.

You could also interpolate between the digital values, but that again would create additional musical information that was not there in the original recording (I doubt that it would be hearable).

Maybe I will post this idea in Doom9's forum, where the programmer of BeSweet hangs arounf (the de-facto standard tool which is being used to downscale musical signals from DVDs in order to use them in DVD rips), I think upscaling would not require a lot of changes to the code...

But again, I do not think that you would gain anything by doing this (except that special feeling that you would be really using the playback capabilities of the hardware you've bought).

Bye,

Arndt

[Won]

I can see why you would do this, but I'm guessing the non-integer sample rate conversion might be kind of annoying... Does DVD-A support 4x44.1kHz ~176kHz? You also have to create dither. Perhaps instead of a DVD-A player/burner, you can get a non-oversampling DAC, and play it directly from your computer.

Could you tell us about your approach? Tweaked FIR type thing?

-Won

[matt_uk]

Originally posted by Cradle22
Theoretically it would be very easy (but not by simply patching it, no way).

Having thought about it some more, I realised that I had completely overlooked the fact that the data for DVD-Audio is recorded differently, not just stored differently. So yes, a 'patch program' would not be suitable and something a bit more exotic would be required.

I guess the key to the original idea is the average Bit Error Rates of CD-Audio compared to the same CD-Audio recording in DVD-Audio format. The idea being simplicity and commercial software rather than coding a very good CD-Ripper, upsampler and DVD-Audio Image maker.

I'm in a situation of wanting to do a CD Player Project but can't decide what...

1) Upgrade a cheaper CD/DVD Player
2) Try a multi-speed buffered or ATA CD Transport from a CD-ROM drive
3) Something Else???

I will probably go with number 2, and if the quality isn't great at least I should still have a project to be proud of, as I would code the interface chip myself.

Matt

[peufeu]

Originally posted by matt_uk

I guess the key to the original idea is the average Bit Error Rates of CD-Audio compared to the same CD-Audio recording in DVD-Audio format.
Matt

Unless you sand-paper your CDs, there are no bit errors. I checked. The error correction codes are powerful enough. I have put a LED on my system which lights when there is an error. It never does unless there is a huge scratch. Ripping on a PC will also give you bit perfect copies. So that's not the issue.

Now if you want to experiment with signal processing, that's interesting !

[alvaius]

Okay, why am I doing this:

1 - DVD-Audio players, even the cheap ones, are inherently buffered. Hence, eliminating jitter will be much easier in my opinion. Eliminating jitter in a CD is not impossible, but if I can start with something that is better designed, then why not.

2 - There are errors in CD reading. I wonder if that LED used in the above post was actually reporting the correct errors. There are errors that can be corrected, errors that are covered up, and errors that are given up on for lack of a better term. Single bit errors can be fixed. Multi-bit errors on a CD are much more difficult to deal with. The DVD format is more robust w.r.t. errors.

3 - What does this give me? Well for one, a DAC running at 192KHz as opposed to one running at 44.1KHz. That makes for really nice low order analog filters.

Mathematically, the conversion is relatively simple. Since I am doing the conversion off-line on a PC, I do not have to be worried about the amount of time that it takes. Also having a 3GHz processor with MMX that will run rings around most DSPs does not hurt. I can do all the arithmetic in floating point with as many taps as I wish, or use double precision and IIR filters. Actually playing around with the conversion, filtering, etc. is something that I want to try?

So what it will give me is essentially a mathematically perfect 24 bit, 192Khz signal for my DAC. For all those NON-OS lovers, wouldn't you prefer a 192KHz DAC instead of a 44.1KHz DAC? I think most of the complaints with OS are more in the way the digital oversampling/filtering is applied as opposed to the concept.

I am going to start with the sigma-delta DACS already in the DVD player, but I will likely change them.

So that is what I will accomplish. Besides, I need a DVD Burner for backup on my computer.

Alvaius

[peufeu]

DVD-Audio players, even the cheap ones, are inherently buffered

All CD players are buffered too. It wouldn't be possible to do otherwise. Eliminating jitter has more to see with how the clock & noise issue are dealt wih than anything else.

Syncing a CDP to a master clock is really easy, too.

There are errors in CD reading

Not under normal conditions. Only if you have scratches. I took a CD from my collection, ripped it to HD with the PC, ripped it with the CD player through the SPDIF output, all the bits were the same. IMHO all this "digital error" babbling is nonsense. I don't dispute the fact that blue leds et al. do something, but it shouldn't be related to digital processing...

I think most of the complaints with OS are more in the way the digital oversampling/filtering is applied as opposed to the concept.

I agree with you here. Some filters are badly implemented. Some don't dither, etc. I think you're gonna have real fun playing with that. It's something I'd really want to experiment with.

You'll probably be able to do better than the available chip filters.

[alvaius]

CD --- PC (44.1KHz, 16bit) - Adobe Audition - (24 bit 192KHz) -- Gear DVD - DVD Audio DISC ... we have success.

Ok, I am not using my own upsampling software yet, but I have proven the process. For the record, on my old cheapy JVC DVD-Audio player, the upsampled version sounds much better than straight off the CD.

Alvaius