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Topic review (newest first)

24

And don't forget the P-channel is shifted by 1 sector forward.

To be perfectly precise (for people who follow this discussion) :

P channel activation should start one sector after start of gap and should end one sector after gap end ?

23

Both 75 and 150 sectors parts belong to Index 00 of the next track.

I know it is a rule on "Annex 10 / ECMA-394".

But I have a hard time getting used to it smile

For example, on a transition "Audio to Mode 1", I am always surprised that
Mode 1 track Index 0 could be constituted by a mix of 75 digital silence sectors (audio sectors) and 150 empty Mode 1 sectors (data sectors).

I have always thought that a track was a set of indexes.
And that an index was a contiguous zone of sectors of the same mode ...

Anyway, you're right : I will update the lazy chart.

Thanks smile

22

MagnAyato wrote:

Do you agree ?

Both 75 and 150 sectors parts belong to Index 00 of the next track. And don't forget the P-channel is shifted by 1 sector forward.

21

Thanks for having take time to respond my questions smile

I resumed the different case in a very lazy chart :

https://ibb.co/WnzZtCL

Do you agree ?

Regards.

(Happy Holidays)

20

MagnAyato wrote:

“PreGapMode” = [0,1,2]
most likelly the data type mode of the track's pregap: Mode 1, 2 or 0 (all three valid values for a data track)

“PreGapSubC” = [0,1]
track subchannels, allow or disallow (enabled or disabled)

What does this add to the data files when PreGapSubC = 1 instead of ( PreGapSubC = 0 ) ?

Maybe to support the images with pregaps cut and replaced with the PREGAP command in the cue? And maybe it supports .img files with the pregaps cut and full .sub files as PreGapSubC = 1 and .img files with the pregaps cut and .sub files with the pregaps cut as PreGapSubC = 0? Just a thought, haven't tested.

19

MagnAyato wrote:

H
Post Gap :

I have difficulty defining what a post gap is.
Obviously this is a set of a minimum of 150 sectors.
It is at the end of a track.
Then I have conflicting definitions.
One says that the post gap is contained in a separate index.

[Track]
[index  01][index 02]
              
The other says that the post gap immediately follows the track data.

[Track]
[index  01 (post gap)]

I would like a clarification of what the Red book /Yellow Book standard says.

ECMA-130 wrote:

c)  Post-gap : A last part of a Digital Data Track, not containing user data, and structured in Sectors. It has the
length of at least 150 Sections (at least 2 s). The setting of the Control field of the q-channel and
the setting of the Sector Mode byte are identical with those of the part of the track where the user
data is recorded.

Means no additional indexes/indices. Indexes 02 to 99 are only used for easier navigation, like bookmarks inside the audio track (and aren't normally used for the data tracks at all). Though, on certain 3DO and Sega CD discs the postgap has an additional index, yes, but that's out of the standard (also NGCD uses additional data track indexes as a part of their protection scheme, but that's a different story).

MagnAyato wrote:

Lead Out Transition :

I did not find information on what kind of transition is between
the last track of a session and the lead out.

[last track (audio)] [?] [Lead out]
[last track (data)]   [?] [Lead out]

ECMA-130 wrote:

Lead-in Area
The Lead-in Track is either a Digital Data Track or an Audio Track. If it is a Digital Data Track, it shall be
structured in Sectors and end with a Post-gap. If it is an Audio Track, it shall be according to IEC 908.

ECMA-130 wrote:

Lead-out Area
The Lead-out Track is either a Digital Data Track or an Audio Track. If it is a Digital Data Track, it shall be
structured in Sectors, without Pre-gap. If the Lead-out Track is an Audio Track, it shall be according to IEC 908.

Means the lead-in sectors are of the same type as the first track and the lead-out sectors are of the same type as the last track, no transitions.

MagnAyato wrote:

Mode 1 or 2 track to Audio track transition :

I read in ECMA 394 (13-17) :
"No Pre-gap, start Track with 2 seconds digital silence"
Is that 2 seconds merge with index 01 of audio track or is it encapsulated in an Index 00 ?

It's a very weird table in ECMA-394. Normally, those 2 seconds of digital silence are marked as pregap sectors (index 00).

ECMA-130 wrote:

b)  Pre-gap : A first part of a Digital Data Track not containing user data and encoded as a Pause. It is divided
into two intervals:
- first interval: at least 75 Sections (at least 1 s) coded as the preceding track, i.e. the Control field
(see 22.3.1) of the q-channel (see 22.3) and, in case of a preceding Digital Data Track, the setting
of the Sector Mode byte are identical with those of the previous Information Track;
- second interval: at least 150 Sections (at least 2 s) in which the Control field of the q-channel and
the setting of the Sector Mode byte are identical with those of the part of the track where user
data is recorded. In this interval of the Pre-gap the data is structured in Sectors.

But for the Data to Audio transitions it's usually only the second interval.

18

Hi,

I am trying to better understand the structuring of sector blocks in a CDrom.
That leads me to ask questions.
I know that in this forum, there are eminent specialists who could "enlighten" me.
Thank you for your help.


Post Gap :

I have difficulty defining what a post gap is.
Obviously this is a set of a minimum of 150 sectors.
It is at the end of a track.
Then I have conflicting definitions.
One says that the post gap is contained in a separate index.

[Track]
[index  01][index 02]
              
The other says that the post gap immediately follows the track data.

[Track]
[index  01 (post gap)]

I would like a clarification of what the Red book /Yellow Book standard says.

Lead Out Transition :

I did not find information on what kind of transition is between
the last track of a session and the lead out.

[last track (audio)] [?] [Lead out]
[last track (data)]   [?] [Lead out]


Mode 1 or 2 track to Audio track transition :

I read in ECMA 394 (13-17) :
"No Pre-gap, start Track with 2 seconds digital silence"
Is that 2 seconds merge with index 01 of audio track or is it encapsulated in an Index 00 ?

Regards.

17

“PreGapMode” = [0,1,2]
most likelly the data type mode of the track's pregap: Mode 1, 2 or 0 (all three valid values for a data track)

“PreGapSubC” = [0,1]
track subchannels, allow or disallow (enabled or disabled)

What does this add to the data files when PreGapSubC = 1 instead of ( PreGapSubC = 0 ) ?

16

MagnAyato wrote:

How CloneCd compute ALBA in those case (PLBA should have same issue) ?

Read errors or protection. 255/255/255 is FF FF FF, doesn't look like a real value. "160" is also impossible, since the minutes are BCD-coded and it can't be more than 2 digits (i.e. larger than 99).

15

Question about LBA computing in CLoneCd CCD file.

Hi,

Those days, I try to code a little thing to parse a .CCD file.
I am sure that people here are very comfortable with some definitions
I am about to tell : it is only to clarify the subject of my question.

I start from the fact that time in CCD file is indicated by 3 fields :
   
    - Minute
    - Second
    - Frame
   
These time information is present twice on a section called "Entry".

An example below :

[Entry 8]
Session=1
Point=0xc1
ADR=0x05
Control=0x00
TrackNo=0
AMin=4
ASec=152
AFrame=96
ALBA=29346

Zero=0
PMin=0
PSec=0
PFrame=0
PLBA=-150
   
AMin, ASec, AFrame to indicate Absolute time (I think).
PMin, PSec, PFrame to indicate Point time (I think).
   
In a theoretical point of view, there are means to translate a time to an address.
The address is called LBA (Logical Block Address) and there are ALBA to indicate Absolute address and PLBA
to indicate Point address.

As I want is to deal with the less fields and datas in my code, I take only Minute, Second, Frame values
and later use means to compute address value.

I know two means to compute it :

- a translation table between LBA and MSF found in a file called "SCSI-3 – Multimedia Commands" from "American National Standards Institute" page 115.

- a formula from ECMA-394 Chapter 13: Attachment 11 : LBN = (((MIN*60)+SEC)*75+FRAMES)-150


But quickly I face very confusing LBA values that do not match any known means result.

Let's concentrate about Absolute time and Absolute address.

I have selected three (from many) examples where I could not understand
how CloneCd figure it out.


Problem 1

[Entry 8]
Session=1
Point=0xc1
ADR=0x05
Control=0x00
TrackNo=0
AMin=4
ASec=152
AFrame=96
ALBA=29346

Zero=0
PMin=0
PSec=0
PFrame=0
PLBA=-150

AMin=4
ASec=152
AFrame=96
ALBA=29346

Using LBA to MSF transaltion table :
269898 <=> 60:00:48
Using ECMA formula :
(((4 * 60) + 152) * 75 + 96) - 150  = 29346


Problem 2

[Entry 10]
Session=2
Point=0xb0
ADR=0x05
Control=0x04
TrackNo=0
AMin=255
ASec=255
AFrame=255
ALBA=716730

Zero=1
PMin=79
PSec=59
PFrame=73
PLBA=359848


AMin=255
ASec=255
AFrame=255
ALBA=716730

Using LBA to MSF transaltion table :
impossible because 255 is out of range
Using ECMA formula :
(((255 * 60) + 255) * 75 + 255) - 150 = 1166730


Problem 3

[Entry 5]
Session=1
Point=0xc0
ADR=0x05
Control=0x04
TrackNo=0
AMin=160
ASec=0
AFrame=48
ALBA=269898

Zero=0
PMin=97
PSec=26
PFrame=66
PLBA=-11634

AMin=160
ASec=0
AFrame=48
ALBA=269898

Using LBA to MSF transaltion table :
269898 <=> 60:00:48
Using ECMA formula :
(((160 * 60) + 0) * 75 + 48) - 150  = 719898


How CloneCd compute ALBA in those case (PLBA should have same issue) ?

Thanks in advance for any help smile

14

Ok,  I consider DataTracksScrambled is always  set to 0.

13

MagnAyato wrote:

But I have read many CCD files and   DataTracksScrambled is always  set to 0.

Is that consistent ?

For the dumps - most likely yes, unless there's a custom dumping tool to dump into ccd as scrambled either on Plextors or via swapping. As I've said, I'm unsure this flag is actually supported, should be tested.

12

I read the Annex B (p31).

Scrambling seems to be a sort of obfuscation of data bits in a sector to prevent some bad schemes to appear.

The document ECMA 130 tells us that sectors data should be scrambled.

At page 16 : "Bytes 12 to 2 351 of each Sector shall be scrambled according to annex B".

But I have read many CCD files and   DataTracksScrambled is always  set to 0.

Is that consistent ?

11

https://www.ecma-international.org/publ … ma-130.pdf - you can read about the scrambling here.
IIRC, CloneCD theoretically supports data tracks in scrambled form, "1" should mean the data is scrambled, "0" surely means descrambled.

10

Question about CloneCD CCD file Disc section

[Disc]
TocEntries=18
Sessions=1
DataTracksScrambled=0
CDTextLength=810
CATALOG=5479154328763

What means DataTracksScrambled and what values could be set ?



Thanks for help.


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