difference between Hi-SP from PC and Hi-SP optical in?

[dtaA]

Hi..

Is there a difference between recordings made from CD player -> Hi-SP optical in and those from PC -> Hi-SP ?

I've never used a PC to record before, so I dont understand the process.. is it

1) Sonic encodes the data from the CD, and then the MD encodes THAT data.

or

2) Sonic encodes the data from the CD in Hi-SP format, then the MD saves that data without further encoding

?

In case 1), the extra step would obviously cause a difference in the data saved to MD.

In case 2), my question is, is the Hi-SP encoding made by Sonic exactly the same as would be made on an MZ-NH1 ?

Further, if a recording is transferred to the MD player via the USB, is some data lost by the nature of the connection (as opposed to a lossless optical connection)?

I realise I probably couldnt even hear the difference between Hi-SP and Hi-LP, but psychologically I want to know I am hearing the best quality recording. I will do everything from a CD player in real time if I have to...

Thanks

[dex Otaku]

SonicStage [and MD Simple Burner] do it this way [your #2]:

Regardless of the data source, whether it be a wav file, mp3, unprotected windows media, or data from a ripped CD - it all gets transcoded on the PC into the format you've selected.

In the case of anything that's not already PCM - like ripped CDs and wave files generally are - the data gets decoded to PCM from whatever format it's in and then encoded to [for example] atrac3+.

There are bound to be differences, for several reasons, between encoding done in SS and that done by analogue or digital [optical] means on the recorder itself.

The recorder has a codec in it. That codec is frozen upon manufacture; it cannot be updated, upgraded, or improved in any way.

The fact that it is in hardware makes little difference at this point in history except to note that it can't be updated. [Or at least - Sony has never been willing to update anything, to my knowledge, even if it was technically possible.]

The codec in SS on the other hand is software. This means that it can be changed/updated over time quite easily.

Codecs in general are not perfectly consistent from one platform to another [whether that be computers or hardware players or what have you]. The general principle is that you must maintain the decoder according to the original standard, while you can change the encoder to reflect improved algorithms, faster hardware, etc.

As long as the stream itself always follows the same standards, the decoder will always play it. This is how the newest atrac versions [except for 3+ of course] in SP mode work for playback on 12 year-old MD equipment [and sound better than recording made on that equipment]. Same standard - better encoder.

Of course, on a computer the aim might not be the same as on the recorder. On the recorder you can expect things to be done pretty much exclusively in realtime, so whatever kind of processing capabilities you have with its DSP only have to cope with things in a realtime world; hence quality becomes the probable determining factor in its codec.

On the other hand, on the PC what most people want is fast rips and transcodes of their CDs and mp3s. So rather than quality being the focus, it's speed; the programmers take the standard for whatever codec and write algorithms that are tuned for speed, not quality.

I would expect that SS is currently not as good at encoding any of the formats as the hardware encoders are. On the other hand, I would expect the differences to be very slight, and probably not noticeable to the vast majority of users.

Perhaps at some point they'll come out with a quality-setting version of the codec; i.e. one where you can choose between highest quality or highest speed encoding. This being Sony, I doubt it would happen, but you never know.

At the very least, it's worth noting that since the SS codec is software, it has the potential for significant improvement over time.

Oh, and regarding the USB transfers: no data should be lost if everything is working correctly, same as via optical. If anything, the connection via USB should theoretically be more stable and more reliable than the optical one, simply because of the nature of USB vs. spdif.

[Ppk3000]

Further, if a recording is transferred to the MD player via the USB, is some data lost by the nature of the connection (as opposed to a lossless optical connection)?

That probably wouldn't happen. Sony wrapped my MZNH1's USB cables with 2 big magnetic shielding to prevent electro-magnetic interference (EMI), which may cause digital corruption.

Recently, I did some testing on data integrity with computer files. I first transferred 16 512KB files and 16 2048KB (2MB) files, all in randomly-generated text files (.txt). I then copied the files to my second machine and used MD5 file integrity signature to check all files. Not a single byte of data was changed/corrupted in the copying from PC->MD->PC.

It's the same with the encoded music as they are simply digital data, plus they are also encrypted by OpenMG. Smallest change to an encryption might cause the whole track to be unplayable... so it's pretty safe to assume no data is lossed through the transfer through the USB cable.

[Rumz]

So that's what those filters are for... good to know

[DrZhivago]

Very good point Dex. That's the reason I find that Hi-SP optical recordings sound better than those made through the SS. I wondered the same,during the NetMD era, but could not verify it, while SS 1.5 wouldn't have allowed for 1:1 SP rips(USB transfer used LP2 transcoded to SP).

Cheers

[dtaA]

Dex - very helpful reply, thanks very much!

[dex Otaku]

You're quite welcome. Something I worry that I'm just blathering.