pits are no longer at rectangular shape at high speed

[jtan]

is it true that the pits your cd-writer make on cd-r is no longer rectangular in shape when you write them in high speed?

[CDRecorder]

Interesting... I don't know if this is true, but I didn't know that they were supposed to be rectangular in the first place.

[Halc]

jtan,

can you be more specific? What do you mean by 'rectangular'?

It is true that at a higher writing speed the offset from land to pit is spread to a longer area (i.e. the transition is not as fast). Do you mean this or some other effect?

regards,
Halcyon

[jtan]

isn't it that ideally, it should be of sharp edges...




see the picture, the above is when it's written in slow speed, below is when it's written in high speed. that's what i'm told... i don't know how true it is..

[ryus]

Its probably true that when writing at higher speeds the pits are not as sharp. But since optical drives read read digital data, in binary, as long as the drive can distinguish between a '1' or a '0', land or a pit, then the decoding of the data will be fine.

[jtan]

i wonder if the pits not being sharp is the reason why C1/C2 errors happen?

[rdgrimes]

It's the edge of the pit that's important, not the "shape". Sharp, clean edges are what makes it readable.

[jtan]

now i wonder... does the speed of the burn affects the sharpness of the pits?

[Halc]

jtan,

yes, speed of the burn affects the transition from land to pit (the steepness of the edge).

Yes, it is conceivable that really bad transition can cause bit-level errors. However before that, they contribute to the jitter on the signal being read.

regards,
Halc

[jtan]

that makes it confusing to me... burning slowly make the steepness of the pit better, but how come on some cases, burning faster do produce a lesser C1/C2 errors!

[Halc]

jtan,

can you show me an example of where burning faster produces less C1/C2 errors than burning slower?

I'm now assuming that you are only comparing real hardware supported burning speeds.

It is possible to make worse burns by burning at a lower speed that the hardware does not support natively, hence it gets simulated by the burning software.

regards,
halc

[CDRecorder]

Check out this thread.

[jtan]

jtan,

can you show me an example of where burning faster produces less C1/C2 errors than burning slower?

I'm now assuming that you are only comparing real hardware supported burning speeds.

It is possible to make worse burns by burning at a lower speed that the hardware does not support natively, hence it gets simulated by the burning software.

regards,
halc

how do we know whether it's natively supported or not?

i doubt it's indicated...

[Halc]

You can read the hardware specs or you can test with a Nero tool to find out the speeds supported. Some burnign programs indicate real hardware supported burning speeds from simulated ones.