Lossless Linking & Buffer Underrun Protection for DVD+R/RW

vbimport

#1

Just curious…

Since lossless linking is part of the DVD+R/RW format’s basic specs, does this mean that buffer underrun protection (JustLink, etc.) is not used (or is not needed) when writing to DVD+R/RW blanks due to the fact that “it’s possible to suspend and continue the burning process without any linking loss” with DVD+R/RW?

Any insights will be very much appreciated. Thanks! :slight_smile:

~Henjie


#2

AFAIK losslinking and buffer underrun protection are 2 seperate features and are both used when burning a DVD+RW.

losslinking has to do with suspending and continuing the write process (when encoding variable bitrate video) and allows the disc to be written so that it is compatible with standalone players.
"In the DVD+RW Video format, video can be encoded with a variable bit-rate (VBR). Because the writing process takes place at a constant bit rate, the writing process needs to be suspended and continued frequently. Normally, this would result in a linking loss, making the disc incompatible with read-only devices like DVD Video players and DVD-ROM drives. With DVD+RW it is possible to perform lossless linking, i.e. to suspend and continue the writing process without linking loss. This feature makes the format very efficient and suitable for random write in data as well as video applications. "
http://www.licensing.philips.com/information/dvdrw/documents161.html

Buffer underun protection has to do with the transfer of data when recording the disc. It prevents your disc from becoming a coaster when the transfer of data from your harddrive is stopped and the recorders buffer is emptied:

“If the interruption is so long that even the buffer is emptied, that’s a buffer underrun, which is a major cause of coasters.”

“If data transfer is delayed, and buffer memory approaches a critical level, the drive automatically pauses recording and waits for the buffer level to return to a safe level. Once the buffer has regained sufficient memory, recording will restart seamlessly from the exact point where it was suspended”
http://www.yamaha.co.jp/english/product/computer/handbook/hb04.html


#3

Thanks for the reply.

I’m kinda under the impression that buffer underrun protection is an inherent part of the DVD+R/RW format though. Since lossless linking makes it possible to suspend and continue the write process without any “gaps” appearing, then it functions just like the usual buffer underrun protection scheme, or am I mistaken?

From the Yamaha SafeBurn page you posted:
"SafeBurnâ„¢ buffer underrun error technology truly prevents buffer underrun errors. If data transfer is delayed, and buffer memory approaches a critical level, the drive automatically pauses recording and waits for the buffer level to return to a safe level. Once the buffer has regained sufficient memory, recording will restart seamlessly from the exact point where it was suspended.

The following points illustrate the precision and accuracy of Yamaha’s buffer underrun error technology.

* Virtually Zero Gap Although it is impossible to actually measure.
  The data gap is theoretically less than 1 micron."

1 micron is actually the same threshold for DVD+R/RW lossless linking. Seems like there’s some sort of redundancy there.

Any additional thoughts? Just wanna be absolutely sure. Thanks.

~Henjie


#4

Yes but regardless of losslesslinking, if the drive buffer were to empty and the drive had no buffer underrun protection, the burn would fail.


#5

Originally posted by wesociety
Yes but regardless of losslesslinking, if the drive buffer were to empty and the drive had no buffer underrun protection, the burn would fail.

Well, if the drive buffer was to empty, then lossless linking will allow the drive to stop and “wait” for data before continuing the write process, wouldn’t it?

If you note the SafeBurn description (data transfer is delayed… drive automatically pauses… recording will restart seamlessly…), that’s exactly the same function that lossless linking does. Which leads me to wonder if lossless linking is some form of internal “always on” buffer underrun protection for DVD+R/RWs.

~Henjie


#6

I don’t think so man, the description of lossless linking says nothing about the drive buffer or buffer underruns.
It says that losslinking works during the recording process, if the recording process were to be halted, I’m sure it would fail if no buffer underrun protection was present.
Anywayz the point is moot because every burner is going to have buffer underrun protection nowadays…