Quick Load System

[Antonio Villena Godoy]

Hello
My name is Antonio, the Bacteria's developer. In last days I have
design a new system for load tapes in speccy 48KB using a diferent
comunication protocol (PSK "manchester" instead of FSK). Also I have
created a new compression algoritm specialized in fast decompressing
(and high rate of compression), and combinig this with the PSK you can
load a tape with the SoundBlaster or a Discman in 18 seconds. Here is
an example (in mono for Speculator):

www.speccy.org/bacteria/lfm.zip

And here in stereo, add this track in a CD-DA (for a real spectrum).

www.speccy.org/bacteria/lfs.zip

Bye
Antonio Villena

[Gerard Sweeney]

Post by Antonio Villena Godoy
load a tape with the SoundBlaster or a Discman in 18 seconds

Merciful crivvens! That's a rather impressive state of affairs.
I take my hat off to you, sirrah!

I'm afraid I couldn't test it, as I don't have either of the required
things to hand (fnar? Ed), but I think this sounds like a VERY
interesting project, particularly for those who want to use a real
Speccy - 18 seconds? Marvellous!

Not knowing much about this kind of thing, I'll risk looking stupid
here (as opposed to?! Ed) by asking if you plan to do some type of
TZX/TAP conversion utility?

Keep up your (what sounds like) splendid work!

Toodle-pip!
Gerard

[INDIVIDUAL]

Post by Gerard Sweeney

Post by Antonio Villena Godoy
load a tape with the SoundBlaster or a Discman in 18 seconds

Merciful crivvens! That's a rather impressive state of affairs.
I take my hat off to you, sirrah!
I'm afraid I couldn't test it, as I don't have either of the required
things to hand (fnar? Ed), but I think this sounds like a VERY
interesting project, particularly for those who want to use a real
Speccy - 18 seconds? Marvellous!
Not knowing much about this kind of thing, I'll risk looking stupid
here (as opposed to?! Ed) by asking if you plan to do some type of
TZX/TAP conversion utility?
Keep up your (what sounds like) splendid work!
Toodle-pip!
Gerard

For making compression avaiable is need an unprotected game (like a .TAP
file). But also I must know the START and END directions of this block. I
plan the developing of a new format (ZBL) and is need to translate TAP files
to this new format for making the compression possible.

Now I am developing a faster system of load, that speed up at 17640bps
(the lfm.wav loads at 11025bps). It's a FSK variant, the zeroes have pulses
of length 2 samples, and the ones 3 samples (at 44100 samples/second).
Because the TV is far of my bedroom I am not tested with a real spectrum,
but in Spectaculator works fine.

The time for loading is less than 30 secs, but major because the block
ocuppies the entire RAM (48K) and it is uncompressed. Here is the utility
that converts snapshots in WAV files.

www.speccy.org/bacteria/sna2wav.zip

And here the sourcecode:

www.speccy.org/bacteria/sna2wav_source.zip

But the main proyect is to convert games in ZBL format and use the
compression.

Regards
Antonio Villena

[Biggo]

Post by Antonio Villena Godoy
load a tape with the SoundBlaster or a Discman in 18 seconds

O_o! Blimey! *18* seconds!

I'll have to dig out my rubber friend (f'nar!) to check this. It's
incredible.
Where were you in 1984?! .-D

Do you expect to release this as free software, i.e. give out the source
code? I'm curious. Not that I could understand it, it's probably full of
numbers .D

[INDIVIDUAL]

Post by Biggo

Post by Antonio Villena Godoy
load a tape with the SoundBlaster or a Discman in 18 seconds

O_o! Blimey! *18* seconds!
I'll have to dig out my rubber friend (f'nar!) to check this. It's
incredible.
Where were you in 1984?! .-D
Do you expect to release this as free software, i.e. give out the source
code? I'm curious. Not that I could understand it, it's probably full of
numbers .D

Yes. It will be free and including sourcecode.
In 1984 I was 4 years old. Now I am 24. Do you understand?

[Stef Robb]

Yadda, yadda, yadda, Antonio Villena Godoy, blah, blah, blah, 29 Jan 2005,

Post by Antonio Villena Godoy
www.speccy.org/bacteria/lfm.zip

That's just scary. Why didn't anyone think of this at the time?

-Stef

[Chris Johnson]

Post by Stef Robb
That's just scary. Why didn't anyone think of this at the time?

The Spectrum was a little too early. Although Huffman compression had
been around since 1951, adaptive Huffman didn't appear until the late
70's and the near-ubiquitous LZW approach was developed in the early
80's. Popular awareness of the possibilities of data compression
probably came with Phil Katz's PKArc in 1986.

Regards
Chris

[Biggo]

Post by Chris Johnson
Popular awareness of the possibilities of data compression
probably came with Phil Katz's PKArc in 1986.

Yep. Or I'd have invented the solid-state Walkman in 1982. I had,
actually, but carrying around a 30MB cartridge (which didn't exist and
would have had a price tag in the thousands of £ and a weight of about 3
stones) to hold one single song was asking too much .-D

[INDIVIDUAL]

Post by Chris Johnson

Post by Stef Robb
That's just scary. Why didn't anyone think of this at the time?

The Spectrum was a little too early. Although Huffman compression had
been around since 1951, adaptive Huffman didn't appear until the late
70's and the near-ubiquitous LZW approach was developed in the early
80's. Popular awareness of the possibilities of data compression
probably came with Phil Katz's PKArc in 1986.
Regards
Chris

Sorry. I don't use any LZW aproach neither Huffman. I use a LZ77 variant
with heuristic tricks, but it's better than ZIP algoritm. (Zip uses an
aproach to Huffman called Shannon Fano). The paper was published by Lempel
and Ziv in 1977, 5 year before that the spectrum.

[Paolo Ferraris]

Post by INDIVIDUAL
Sorry. I don't use any LZW aproach neither Huffman. I use a LZ77 variant
with heuristic tricks, but it's better than ZIP algoritm. (Zip uses an
aproach to Huffman called Shannon Fano). The paper was published by Lempel
and Ziv in 1977, 5 year before that the spectrum.

That explains the decompression speed, but I am surprised that a LZ77
algorithm can compress more than, or about the same as, deflate. Which
heuristics are you using, if I can ask?

[Antonio José Villena Godoy]

Post by Paolo Ferraris
That explains the decompression speed, but I am surprised that a LZ77
algorithm can compress more than, or about the same as, deflate. Which
heuristics are you using, if I can ask?

For example zero literal is very frecuent, it's code with 7 bits instead
9. Ocurrences with 1 bytes lengt also coded with 7 bits. But primary when
a match has the same position that the last one, it's only need code his
lentgh. Flexible parsing is not aplicable here and some heuristic is need
to apply. Also 2-3 length ocurrences are coded with less bits. When I
publish the code you can view all these (if you know assembler). Also you
can debug in an emulator the decode algoritm, but decoding it isn't posibble
to see the heuristic.

[Captain Trips]

Has anyone got this working successfully in Spin (v0.504)? Both the mono
and stereo versions load the BASIC loader OK and then just sit there
with no apparent attempt to process the PSK block.

Trips!

[Dunny]

Post by Captain Trips
Has anyone got this working successfully in Spin (v0.504)? Both the mono
and stereo versions load the BASIC loader OK and then just sit there
with no apparent attempt to process the PSK block.

Yep - no probs. Turn off all acceleration options, and turn off tape
auto-start/stop.

D.

[Dunny]

Post by Dunny
Yep - no probs. Turn off all acceleration options, and turn off tape
auto-start/stop.

Oops - no, you just have to turn off tape autostart/stop. The acceleration
works fine.

D.

[AndyC]

Post by Dunny
Oops - no, you just have to turn off tape autostart/stop. The acceleration
works fine.

Yes. Although having the acceleration on sort of defeats seeing how fast it
can load...

AndyC

[Juan Pablo López]

Hi Antonio,
Hehe, I guess you meant Spectaculator.
Speculator sounds really, really scary ;-)))

Jokes apart, congrats for your work. Simply outstanding!

Cheers,
Juan

[Paolo Ferraris]

combinig this with the PSK you can load a tape with the
SoundBlaster or a Discman in 18 seconds.

Impressive! Congratulations!

I am assuming that you are using the full bandwidth of a CD.
In your opinion, to what extent it is possible to apply this technique
to the old tape technology? Maybe a 1 min loading from a tape would be
possible?

[Antonio José Villena Godoy]

Post by Paolo Ferraris

combinig this with the PSK you can load a tape with the
SoundBlaster or a Discman in 18 seconds.

Impressive! Congratulations!
I am assuming that you are using the full bandwidth of a CD.
In your opinion, to what extent it is possible to apply this technique
to the old tape technology? Maybe a 1 min loading from a tape would be
possible?

No. I am not using the full bandwidth of a CD. I only use the half
bandwith (22050), because there is a delta-sigma encoder that produce an
important distortion. You can try to store this in a tape (if the tape is
enought good) and it's posible that works. I doesn't try this, but the
maximal frecuency generated by the WAV is 11 KHz (Nyquist).