
MP - Header
===========

Folgende 32 Bit (durchbuchstabiert vom a-m) definieren den Header,
dessen Gueltigkeit nachgewiesen werden soll:

Bedeutung: AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM
Normal.?.: 11111111 11111011 01010100 00000000 = &FF, &FB, &54, (&00)

?  Nr. Bits  Position  Beschreibung

A        11   (31-21)  Frame sync: Alle bits MUESSEN gesetzt sein

B         2   (20,19)  MPEG Audio version ID
                       00 - MPEG Version 2.5
                       01 - reserviert
                       10 - MPEG Version 2 (ISO/IEC 13818-3)
                     * 11 - MPEG Version 1 (ISO/IEC 11172-3)

Der Player kann ansich alle Formate, aber wenn hier das Muster fuer
"reserviert" steht, ist es kein gueltiger Header!


C         2   (18,17)  Layer Beschreibung
                       00 - reserviert
                     * 01 - Layer III
                       10 - Layer II
                       11 - Layer I

Der Player kann Layer 2 und 3. Bei allen anderen und "reserviert" gilt:
"kein gueltiger Header"


D         1      (16)  Protection bit
                       0 - Protected by CRC (16bit crc follows header)
                     * 1 - Not protected

Das ist fuer den Player uninterressant...


E         4   (15-12)  Bitrate index

---------------------******--------------------
bits V1, L1  V1, L2  V1, L3  V2,L1  V2, L2 & L3
0000  free    free    free    free   free
0001   32      32      32      32      8
0010   64      48      40      48     16
0011   96      56      48      56     24
0100  128      64      56      64     32
0101  160      80      64      80     40  *** 64!
0110  192      96      80      96     48
0111  224     112      96     112     56
1000  256     128     112     128     64
1001  288     160     128     144     80
1010  320     192     160     160     96
1011  352     224     192     176    112
1100  384     256     224     192    128
1101  416     320     256     224    144
1110  448     384     320     256    160
1111  bad     bad     bad     bad    bad
---------------------******-------------

Diese Tabelle gibt die Bitrate der MP3 wieder.
Fuer ein MPEG-Audio Version 1, Layer3 (MP3) gilt z.B. V1, L3
Was fuer eine "MP3" vorliegt erkennt man an den vorhergehenden Bits.
Bei BAD und FREE gilt "kein gueltiger header"!

(Schluessel zu den Tabellen-Ueberschriften):
* V1 - MPEG Version 1
  V2 - MPEG Version 2 and Version 2.5
  L1 - Layer I
  L2 - Layer II
* L3 - Layer III


F         2   (11,10)  Sampling rate : (Werte in Hertz)

bits  MPEG1  MPEG2  MPEG2.5
---------------------------
  00  44100  22050    11025
* 01  48000  24000    12000
  10  32000  16000     8000
  11   res.   res.      res.

Auch hier gilt wieder res. = ungueltiger Header.


G         1       (9)  Padding bit

                       0 - frame is not padded
                       1 - frame is padded with one extra slot

Sagt aus ob der MP3 Frame zur vollen Framelaenge aufgefuellt wurde.
Ist fuer den Player aber ohne Bedeutung


H         1       (8)  Private Bit: Ohne Bedeutung

I         2     (7,6)  Channel Mode
                       00 - Stereo
                       01 - Joint stereo (Stereo)
                       10 - Dual channel (Stereo)
                       11 - Single channel (Mono)
Ohne Bedeutung....


J         2     (5,4)  Mode extension (nur bei Joint stereo)
Ohne Bedeutung...


K         1       (3)  Copyright
                       0 - Audio is not copyrighted
                       1 - Audio is copyrighted
Absolut Bedeutungslos ;-)


L         1       (2)  Original
                       Auch Egal
                       0 - Copy of original media
                       1 - Original media


M         2     (1,0)  Emphasis
                       00 - none
                       01 - 50/15 ms
                       10 - reserved
                       11 - CCIT J.17
Hier wieder: Reserved = ungueltig....


Im Prinzip muss man also bei allen Feldern bei denen nicht "ist wurscht"
oder so geschrieben steht testen, ob sie gueltig sind.

Ist auch nur ein Feld auf reserviert oder undefiniert, ist das zu
untersuchende Objekt alles andere als ein MP3 Header.

          00 - none
                       01 - 50/15 ms
                       10 - reserved
                       11 - CCIT J.17
Hier wieder: Reserved = ungueltig....


Im Prinzip muss man also bei allen Feldern bei denen nicht "ist wurscht"
odees,  it supports the standard
for B-drives, the great Vortex-Format with 704 KB. But XDDOS supports two other
0,7 MB formats: Data and System. They are blown up standard formats.  Therefore
X-DDOS is very compatible to much games and demos.
Beside the X-DDOS - ROM the expansion-port interface contains the connection to
the hard-disc. This is managed through a cable.

Contents of the HD20 hard-disc box itself
-----------------------------------------
The metal-boxed HD20 contains a 3.5 inch 20 MB hard-disc and two cards.  The
type of the hard-disc is MFM. Hard-drives from different producers are used,
for example Kalok (Octagon drive), Segate and so on ...
The pair of cards consist of a XT controller card and an interface card. The
HD controller interface card has a slot for the XT hard-disc controller-card
and it has a 25 pin connector for a cable, which leads to the second card at
the CPC expansion port.

HD controller interface
-----------------------
The interface card is called HD-Controller Interface 1189 BS and contain the
following two ICs:
- M74HC14B1, 99022 R (from ST)
- 74LS245N, FHB4892, 9022VF (from S)

XT HD controller
----------------
The XT hard-disc controller is the ST-11M, here is some information:

- Controller name: Segate ST-11M

- Controller BIOS: Segate ST11M/11R BIOS
                   P/N 80134-
                   Copyright 1989 Segate Technology
                   V2.0 001

- Controller IC: 11769-502
                 CF61893FN
                 W45010
                 9013

Some other XT controllers were tested, but only the Segate ST-11M seem to work.
But it seems that you can use every 20 MB 3.5" MFM hard-disc.

Producer
--------
The HD20 hard disc was produced by: Dobbertin Industrie Electronik.
First it costs 2000 DM (1000 Euro), later it was sold for 1200 DM (600 Euro).
And a to-do-it-your-self kit was sold for 300 DM (150 Euro).

TFM/FutureSoft


===============
=XzentriX 2003= Well, I tried to translate this live meeting report ... tfm
===============
Half the SixPack (Cranium, Octoate and TFM) was on the road again! This time we
went to the XzentriX meeting at Seeshaupt, in the high, high (geographical ;-))
South. I wait for Tim (Octoate) the academical, Stau-caused delay. Then we were
on the road again to drive to Aschaffenburg to Cranium's headquarters.  But the
way to him was ... Stau agian :-( Shit! One should really reprogram the highway
in Z80 assembler, maybe we will be faster then?! And - like every year - at the
well knows point on the road we miss the right way to drive off. I hope that we
will find the departure to Mainaschaff! And now the driver becomes weired!
But - no doubt - there is one good thing too. BSC is not the first in this
meeting report *ggg*
It's voting time. Nice! Sorrowly we only see politicans here on the walls and
no sign of the right street ;-( tfm

octo: So, now Cranium is driving and I can hit something in the keys.  We have
still 300 km to drive to go and I have my first cerebral breakdown, because of
the Stau ... We drive a Opel Passat (a big car) and it is full with CPC stuff.
Now I have to join the discussion again - I'll write some stuff later...

Jep! Just drive throug Stuttgart and all driving action is fine ;-) tfm

octo: after a little pause we continue driving to Seeshaupt.
Hopefully we will gain a correct salution - when we will arrive in the deep
night (with red floor and that stuff) *g* But I think we will only have new
troubles with that c64 users, because I use t