selected 2.4x, written at 8x

[alexnoe]

I wanted to see what the error rate looks like when recording verbatim 4x dvd+r media at 2.4x (just to check it), and DVD Decryptor burnt at 8x :o

Seems like the speed selection is a bit b0rked :p

Selecting 4x works

[LIGHTNING UK!]

maybe 2.4x isnt supported on those discs?

It should say in the log if the speed you've selected isnt the one the drive thinks its going to write at.

What drive do you have? The plextor 708a I assume?

[alexnoe]

The drive *always* reports a b0rked speed setting.

Examples:

Disc: Maxell 2x
max speed / actual speed: 4x (!!)
Written: 2x

Mitsubishi 4x -R:
actual speed: always 4x
written: tried at 2x and 4x

Mitsubishi 4x +R:
actual speed: always 6x (i tried some GET PERFORMANCE on my own, and the drive reports 6x: 0x000000 - 0x05DFFF, 8x: 0x05E000 - <end> as current setting, while it reports 2.4x, 4x and 8x as available speed descriptors)
written: 4x and 8x work, but 2.4x is ignored. It is however not ignored when setting it in cdrecord-prodvd (however, this one currently fails to close discs like Nero, so it needs to be worked on...). Weird enough, cdrecord fails to set the drive to 8x...

In any case, if a drive does not support a selected speed, it should round, but never go to max.

Yes, it is a Plextor 708, Fw 1.03

The firmware of the drive is, according to the author of cdrecord, severely b0rked.
Example (error output in cdrecord):
Average write speed 4.0x.
>Min drive buffer fill was 81%
>Fixating...
>cdrecord-prodvd: I/O error. close track/session: scsi sendcmd: retryable error
>CDB: 5B 01 01 00 00 FF 00 00 00 00
>status: 0x2 (CHECK CONDITION)
>Sense Bytes: 70 00 05 00 00 00 00 0A 00 00 00 00 26 00
>Sense Key: 0x5 Illegal Request, Segment 0
>Sense Code: 0x26 Qual 0x00 (invalid field in parameter list) Fru 0x0
>Sense flags: Blk 0 (not valid)
>cmd finished after 0.001s timeout 1000s

The 5B command does not have a parameter list, so it should not report 'invalid field in parameter list'...And don't expect the drive to send a CHECK CONDITION if you set the EXACT Bit in SET STREAMING, but write utter nonsense into the write speed descriptor :(

EDIT
selected speed: 2x
actual speed: 6x
written: 2.4x
(-> which is OK, since dvd+r can't do slower than 2.4x)

[gooki]

I've got an even weirder one.

GSC001 DVD-R disc ment for 1x speed writing. Recordnow Max just burned it at 4x speed on my modded Liteon 401s?????

Quality seems better than my G04's though. Very smooth readback in Nero DVDSpeed.

[LIGHTNING UK!]

alexnoe, Im not sure why cdrecord-prodvd is closing using that CDB.
I dont think 'track' should be set to FF like it is. FF wouldnt exist and although I guess you could argue FF should just work anyway, ive never had a problem with it just set to 01 !
But yes, the error is somewhat weird! And ive also noticed that whatever you set the speed to in the plex, it always returns weird values for GET PERFORMANCE. Just one of those things I guess!

With the exact bit set, I can understand the setting to 2.4 not working, but as you've probably seen, I dont set that bit!
From my code, if 2.4 isnt supported it should do the next lowest (as you know) and therefore write at 4x.
I've ordered myself some of those dvd+r discs that burn at 8x now so I can do some testing - I normally stick with -R discs.

[alexnoe]

The drive should not return a 2.4x speed descriptor if 2.4x were not supported on those discs :rolleyes:

The MMC specs say that a drive should set the speed as close as possible to the demanded speed. That means, if someone sets 2.4x on a disc, but the drive can't do 2.4x, then the DRIVE is the one which should set the speed to 4x, but not you....

[thop]

that's a general problem of many DVD+R drives, they will completely ignore any speed settings you tell them and burn at max speed.

[alexnoe]

Then why does it:
-> burn 2.4x when setting 2x (logical)
-> burn 4x when setting 4x (logical)
-> burn 8x when setting 2.4x (illogical)

In the meantime, i've verified that behaviour with the same disc type! Those discs DO support 2.4x