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Hi,

I have a very strange experience. When i try to play the video file in Pro Tools 5.0.1 MIXPlus on G4 with ATTO DualChannel SCSI, it works better if I play it from internal ATA drive. if i try do play it from Seagate Barracuda 18 GB Ultra160 SCSI drive connected to the second ATTO bus, the movie is played with droped (lost) frames and get drops. It looks crazy! Anybody knows what's going on? Should I format by ATTo Express Pro Tools my SCSI drives for only HFS (I just have the HFS+ format on the SCSI drives)?

Comments

Greg Malcangi Sat, 12/02/2000 - 08:32

Hi Petrus,

Although I'm not an expert, I would guess the reason it works better off the internal ATA drive is because you are removing the load of the video going through the SCSI bus. PTools is using the SCSI bus for all the audio so piling the video through this bus as well could be putting a strain on the SCSI bus and causing you to drop frames.

Check on the Digi website about formating your drive. I seem to remember that you should use the Atto drivers on a G4 but with HFS, not the HFS+. Not sure about this though so check it out.

Greg

anonymous Tue, 01/09/2001 - 09:47

I second Greg's opinion: the SCSI bus is working VERY hard to poop out 24 bit audio & V, and unless you have LVD drives, putting the video on an ATA drive will smooth out PB of both media streams. Also, using 1 drive solely for video is the ONLY way if you do use SCSI for V PB. I've done tests with SCSI raid arrays VS. IDE raid arrays, and IDE are just as fast, much quieter, and very cheap. LVD is really the only SCSI way to fly w/ 24bits & video.

anonymous Tue, 01/09/2001 - 12:20

I think that the speed of a Seagate Barracuda drive 7200 rpm versus a newer generation drive like a Seagate Cheetah (10000rpm) might be the reason you have a hard time playing your files. The difference isn't much the bandwith, but more so the access time. There is even a newer generation Seagate drive at 15000 RPM (3.9ms).
Access time is crutial in sequencial data like audio or video, as fragemented data has to be accessed quickly. In the case of audio + video, the demand is even greater.