Can DVDs be written in mode 1?

stf92 · 03-22-2014, 11:24 PM

Hi: CD-R can be written in mode 1. Does DVD-R/+R have mode 1, or is it a concept which does not apply to DVD?

Doc CPU · 03-23-2014, 08:50 AM

Hi there,

Quote:

Originally Posted by stf92

Hi: CD-R can be written in mode 1.

yes, for CD-R/RW, there are these two different modes. That's all about the structure and contents of each single sector on a CD.
A sector on a CD always consists of 2352 bytes (actually, it's 2448, but it would go too far to explain this in depth). It depends on the type of CD how much of these 2352 bytes is data and control or error correction information:

Audio CD (CDDA) is the oldest type. It uses all 2352 bytes for data, there's no error detection. That's why CDDAs are most critical in terms of errors. But during audio playback, it normally doesn't matter if there are a few "bad" bits in between. Even if an entire sector is bad (which is 1/75 of a second), there's a good chance you won't even hear it.
There is no "Mode 1" oder "Mode 2" for CDDA, it's just raw data.
Data CDs (Mode 1) use 2048 of each sector as payload, 4 bytes to identify each sector, and the remainder for error detection and recovery. That's why information stored on a regular data CD can often be recovered even if the CD is scratched badly.
Video CDs (VCD, SVCD) and other special-type CDs use a compromise between these two extremes. Like Mode 1 CDs, they use 4 bytes to identify each sector, but no error correction data; the entire remaining 2336 bytes are payload.

Quote:

Originally Posted by stf92

Does DVD-R/+R have mode 1, or is it a concept which does not apply to DVD?

Right, it doesn't. Unlike CDs, which were first invented only for digital audio, the DVD standard was set with many different applications in mind. Therefore it was specified that all DVDs should have the same basic structure. In other words: All DVDs are DVD-ROMs at first. What they really contain (audio, video or arbitrary data) is determined by their contents. That's why there is no such distinction.

[X] Doc CPU

stf92 · 03-23-2014, 09:14 AM

Beautiful post! Thanks for that.

stf92 · 03-23-2014, 09:58 AM

One question: Using cdrecord with -vv, 'cdrecord -vv -media-info', I can read the mode under 'data mode'. I have tested it with CDs recorded in mode 1 and in mode 2. However, I inserted a DVD-R, and it says 'data mode: 1':

Code:

semoi2@darkstar:/DATA/home/semoi/STORE1/soft/linux/grabacion$ cdrecord -vv -media-info dev=2,0,0
Cdrecord-ProDVD-ProBD-Clone 3.01a08 (i686-pc-linux-gnu) Copyright (C) 1995-2012 Joerg Schilling
TOC Type: 1 = CD-ROM
..........................
..........................

Track  Sess Type   Start Addr End Addr   Size
==============================================
rzone size:         40
rzone number:       1
border number:      1
ljrs:               0
track mode:         4 copy: 0
damage:             0
reserved track:     0 blank: 0 incremental: 1 fp: 0
data mode:          1
lra valid:          1
nwa valid:          0
rzone start:        0
next wr addr:       0
free blocks:        0
blocking factor:    16
rzone size:         1169664
last recorded addr: 1169663
read compat lba:    0
    1     1 Data   0          1169663    1169664         -1
rzone size:         40
rzone number:       2
border number:      2
ljrs:               0
track mode:         4 copy: 0
damage:             0
reserved track:     0 blank: 1 incremental: 1 fp: 0
data mode:          1
lra valid:          0
nwa valid:          1
rzone start:        1207568
next wr addr:       1207568
free blocks:        1090320
blocking factor:    16
rzone size:         1090320
last recorded addr: 0
read compat lba:    0
    2     2 Blank  1207568    2297887    1090320      37904

Last session start address:         0
Last session leadout start address: 1169664
Next writable address:              1207568
Remaining writable size:            1090320
semoi2@darkstar:/DATA/home/semoi/STORE1/soft/linux/grabacion$

What can possibly be the cause? There is the fact that the first line says 'TOC Type: 1 = CD-ROM', which maybe is anyhow related.

Doc CPU · 03-23-2014, 10:23 AM

Hi there,

Quote:

Originally Posted by stf92

One question: Using cdrecord with -vv, 'cdrecord -vv -media-info', I can read the mode under 'data mode'. I have tested it with CDs recorded in mode 1 and in mode 2. However, I inserted a DVD-R, and it says 'data mode: 1'

I don't know how cdrecord determines this information, but I suspect that since the program must have a variable for "Mode", it just assumes a default of 1 and prints this information even if it's irrelevant. After all, if anything, a Mode 1 CD is about the closest match to a DVD.

[X] Doc CPU

stf92 · 03-23-2014, 10:58 AM

Thanks again, Doc CPU.