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PCDP compression

post #1 of 13
Thread Starter 
I have a question regarding the compression of music when anti skipping is turned on. Where exactly is the music compressed to? Meaning i understand there's a buffer, but what kind of buffer? Is it a memory chip, like 128k? Just curious to know, if not a chip, where does it get buffered to?

George
post #2 of 13
To my knowledge, compression is usually used, so that the CDP doesn't need to be fitted with so much memory (DRAM) to provide the anti-skip we need. Let's say, the Panasonic 570. It provides 10-second anti-skip without compression, and 40-seconds when compressed.

I vaguely remember reading Panasonic's IC catalog, and somewhere it said MPEG compression. Don't take my word on this though

I think MD players that provide 40-second in SP mode uses a 16MB DRAM, not sure about CD players, but isn't CD's data rate something like 1MB/sec?
post #3 of 13
Well if it's not a memory chip what else might it be, cassette tape?
post #4 of 13
Today's anti-skip PCDPs have a "cache" buffer memory of 1MB or 2MB; the ones with 2MB will give you 10 seconds of "linear" (uncompressed) anti-skip. And music CD's transfer rate is 1.2Mb/s (or 150KB/s).

(Note: MB=megabytes; Mb=megabits.)
post #5 of 13
Thread Starter 
Quote:
Originally posted by Joe Bloggs
Well if it's not a memory chip what else might it be, cassette tape?
Seems to sound like that, based on the horrid quality when anti skip is turned on!

George
post #6 of 13
Speaking of tapes...wonder what happened to DAT tape...
They were so big when they came out, a few albums came out and they just vanished without a trace...

spooky...
post #7 of 13
Quote:
wonder what happened to DAT tape...
It's still in wide use in the recording industry. Some bands still record their albums on DAT.
post #8 of 13
i know but what about to the public

i was soo looking forward to them
i always liked tapes
post #9 of 13
Thread Starter 
Seems like a lot of bands use DAT to record their live shows as well. I do wish DAT became a little more popular, just too damn expensive to own one!

George

ps. I wonder how well a DAT recorder drives headphones?
post #10 of 13
I see LOTS of bootleggers using DAT tape and stereo mics at concerts. They are the easiest way to record a high quality mixed stereo signal, but they don't have widespread appeal (I think) because A. since they are still a physical medium, it takes time to fast forward/rewind between tracks and B. since they are a physical medium, they will degrade over time. Plus, the tape is quite thin and delicate, and can break easily.

cajunchrist
post #11 of 13
If good care is taken, I'd say they last longer than cds with cds being "scratable" and all. My DAT tapes are still going strong
post #12 of 13
DAT tapes are cool. There are potential long term problems with them because they are tape and can shed oxide. The recorders use helical head technology (as found in VCR's) so there are wear and tear aspects to take into account there too. However, they allow 48Khz recording with no compression. I love mini disc because it almost gives me that in disc format but, even though I rate ATRAC as the finest compression system available, it is still a compressed format. DAT isn't.

I hope this helps.
post #13 of 13
About DAT's demise, I vaguely recall something with the RIAA wanting to kick ass, and then the first DAT units couldn't do dubbing from CD (didn't have the 44.1kHz option). Around 91 decks with SCMS came out but it was too late.

Many DAT owners love their equipments, and I remember considering a DAT walkman as my next portable during 2000 and the first half of this year. In the end it's just out of my reach. Cost would've been around $500-700 for the walkman plus $90 for a converting optical cable. I'd need new rechargeables, and after a couple years the unit may need a professional cleaning. And everyone says the models I would've liked has a horribly slow mechanism

And there's the horror stories with tape dropouts.

Ever wondered what if those digital micro cassettes (Sony's NT format) made it for music use? The frequency response isn't at CD level but then again it never received much development after launch.
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