DVD read speed

[Dominus Atheos]

I have a very large DVD collection and I am trying to digitize it by ripping the discs to ISO. The problem is my DVD drives aren't getting anywhere near their rated speed. One of them seems to be firmware limited to about 3x, and the other one hovers around 8x.

I want to know if there is anything I can do about this, or what drives would make good replacements. Newegg has an 18x DVD-ROM drive for $20, but even though it says that I don't know what the actual read speed would be.

[Darth Wong]

I think you should just be happy that they're reading cleanly, to be honest. The faster drives tend to get more read errors, and in fact, it's common for people who do a lot of DVD ripping to look for a utility that will slow down the drive, because so many dodgy discs will read perfectly at 1x but give endless read errors at 8x.

[charlemagne]

Yeah, it's just like with ripping music to MP3 - slower is "safer" and better, you're more or less guaranteed clean results while reading at drive top speed often leads to dropouts and "clicking" and stuff like that.

That's why speed drive numbers are just marketing babble. If you want good results you don't read at top speeds anyways, like DW said.

[phongn]

cdrlabs.com has good reviews of optical drives.

[Stark]

I've found this with many cheaper combo drives too; the quoted speed is generally CD speed and is pretty misleading for anything else.

Slower is better, but if your drive has issues more than one or two steps below it's highest speed it's probably broken. Most of the software I've used automatically drops the speed when it hits damaged areas, though, and surface damage seems much more common or important on DVDs compared to games disks.

[Starglider]

That's why speed drive numbers are just marketing babble.

Quoted speeds are for good quality media, i.e. data DVDs. Also many brands of optical disk can deteriorate over time, so DVDs made ten years ago may be out of spec for that reason alone.

If you want good results you don't read at top speeds anyways, like DW said.

In data mode, if any errors occur the region is re-read. Audio and video is designed to be streamed, so re-reads do not normally occur. A competently designed ripper (e.g. CDparanoia) will realise that it doesn't need to stream, read the media in RAW mode and implement track re-read. This should not produce any errors no matter what the speed setting, except when the medium is physically so damaged that the data is irrecoverable.

Of course there is a lot of incompetently designed ripping software and drivers out there.

Most of the software I've used automatically drops the speed when it hits damaged areas, though, and surface damage seems much more common or important on DVDs compared to games disks.

As well as the fact that data tracks use re-read by default and video/audio does not, data tracks also use an additional layer of error correction, trading storage capacity and read speed for more defect tolerance.

[Stark]

It seems strange to me that when ripping an ISO, the software would behave according to any streaming requirements. Error-checking should be paramount.

[Starglider]

It seems strange to me that when ripping an ISO, the software would behave according to any streaming requirements. Error-checking should be paramount.

The normal API for reading optical media treats data, video and audio tracks differently at the driver level - it pretty much has to because of the block structure and timing requirements. Crappy ripping software relies on the driver to handle all error correction, and cheap drives have horrible drivers. The CDparanoia FAQ has a good summary; see here and here. As of 2009 almost all manufacturers have finally sorted out the CD-Audio issues, but getting a bit-perfect copy of MPEG-2 video streams from DVDs has similar problems.