Like VPutz, I was disappointed (my only Freevo disappointment thus far!) in the ripping speed through Freevo. As such I still rip using my Windoze box because it rips at 3x to 25x depending on the quality settings I use.
So, perhaps I am being dense about something here, but how is it that MusicMatch Jukebox and plenty of other ripping tools rip cds at 3x and higher? You explanation seems to say that this behavior is not good and will lead to poor recordings. I have not found that to be the case. Like I said, perhaps I am just missing something, and if so, please enlighten me! Thanks, Davin ----- Original Message ----- From: "Gray, Tim" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, January 14, 2004 1:29 PM Subject: RE: [Freevo-users] Speed up ripping? > here's an even better explination.... also stolen from the cdparanoia > website. > > The audio CD is not a random access format. It can only be played from some > starting point in sequence until it is done, like a vinyl LP. Unlike a data > CD, there are no synchronization or positioning headers in the audio data (a > CD, audio or data, uses 2352 byte sectors. In a data CD, 304 bytes of each > sector is used for header, sync and error correction. An audio CD uses all > 2352 bytes for data). The audio CD *does* have a continuous fragmented > subchannel, but this is only good for seeking +/-1 second (or 75 sectors or > ~176kB) of the desired area, as per the SCSI spec. > > When the CD is being played as audio, it is not only moving at 1x, the drive > is keeping the media data rate (the spin speed) exactly locked to playback > speed. Pick up a portable CD player while it's playing and rotate it 90 > degrees. Chances are it will skip; you disturbed this delicate balance. In > addition, a player is never distracted from what it's doing... it has > nothing else taking up its time. Now add a non-realtime, (relatively) > high-latency, multitasking kernel into the mess; it's like picking up the > player and constantly shaking it. > > CDROM drives generally assume that any sort of DAE will be linear and throw > a readahead buffer at the task. However, the OS is reading the data as > broken up, seperated read requests. The drive is doing readahead buffering > and attempting to store additional data as it comes in off media while it > waits for the OS to get around to reading previous blocks. Seeing as how, at > 36x, data is coming in at 6.2MB/second, and each read is only 13 sectors or > ~30k (due to DMA restrictions), one has to get off 208 read requests a > second, minimum without any interruption, to avoid skipping. A single swap > to disc or flush of filesystem cache by the OS will generally result in loss > of streaming, assuming the drive is working flawlessly. Oh, and virtually no > PC on earth has that kind of I/O throughput; a Sun Enterprise server might, > but a PC does not. Most don't come within a factor of five, assuming perfect > realtime behavior. > > To keep piling on the difficulties, faster drives are often prone to > vibration and alignment problems; some are total fiascos. They lose > streaming *constantly* even without being interrupted. Philips determined 15 > years ago that the CD could only be spun up to 50-60x until the physical CD > (made of polycarbonate) would deform from centripetal force badly enough to > become unreadable. Today's players are pushing physics to the limit. Few do > so terribly reliably. > > Note that CD 'playback speed' is an excellent example of advertisers making > numbers lie for them. A 36x cdrom is generally not spinning at 36x a normal > drive's speed. As a 1x drive is adjusting velocity depending on the access's > distance from the hub, a 36x drive is probably using a constant angular > velocity across the whole surface such that it gets 36x max at the edge. > Thus it's actually spinning slower, assuming the '36x' isn't a complete lie, > as it is on some drives. > > Because audio discs have no headers in the data to assist in picking up > where things got lost, most drives will just guess. > > This doesn't even *begin* to get into stupid firmware bugs. Even Plextors > have occasionally had DAE bugs (although in every case, Plextor has fixed > the bug *and* replaced/repaired drives for free). Cheaper drives are often > complete basket cases. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Victor > Putz > Sent: Wednesday, January 14, 2004 1:06 PM > To: [EMAIL PROTECTED] > Subject: [Freevo-users] Speed up ripping? > > > In my effort to get much of my CD collection onto my Freevo, I've started > trying to rip CDs, only to discover that my 32x CD-Rom drive is ripping at > 1x speed. Obviously I'd like to speed this up. I've tried tweaking > hdparm to turn on DMA, as well as modifying the command line a bit to > cdparanoia, but none of it seems to be making much difference. Anything > obvious I'm missing? > > -->VPutz > > > > ------------------------------------------------------- > This SF.net email is sponsored by: Perforce Software. > Perforce is the Fast Software Configuration Management System offering > advanced branching capabilities and atomic changes on 50+ platforms. > Free Eval! http://www.perforce.com/perforce/loadprog.html > _______________________________________________ > Freevo-users mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/freevo-users > > > ------------------------------------------------------- > This SF.net email is sponsored by: Perforce Software. > Perforce is the Fast Software Configuration Management System offering > advanced branching capabilities and atomic changes on 50+ platforms. > Free Eval! http://www.perforce.com/perforce/loadprog.html > _______________________________________________ > Freevo-users mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/freevo-users > ------------------------------------------------------- This SF.net email is sponsored by: Perforce Software. Perforce is the Fast Software Configuration Management System offering advanced branching capabilities and atomic changes on 50+ platforms. Free Eval! http://www.perforce.com/perforce/loadprog.html _______________________________________________ Freevo-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freevo-users
