Stuttering HD playback

[Wagon]

I think I know the source of my problem, but just asking for any input. I have a Sage box I have been using for quite some time, finally put in a HD tuner. Sometimes when playing a HD show, playback is very jerky. It seems to happen mostly when multiple recordings are occurring. The same file will play back just fine at a later time.

Task manager reports that the CPU isn’t maxing out when the jerkiness occurs. I'm playing back on the same machine that I record on, so the network isn't a factor. I am thinking that the problem is my hard drives are simply too slow, since I can’t really think of what else might be a factor.

I am running XP, no virusscan, and 64k clusters. I never defragment and have seen conflicting statements weather it has any effect or not. I have 3 hard drives, all 250gb IDE drives. HDtune says they all average about 50 mb/s.

I have set comskip to run only when we're asleep, it helps but hasn't fixed the problem. Do I need to get a newer, faster drive? Even though all my drives are now IDE, the system does support SATA. Would there be any need to set up the drives in a RAID 0 configuration? At some point I want to switch out one of the standard def tuners to a high def tuner. Should this have any impact?

[Wagon]

Oh, when I say HD I am just talking about 720p, not 1080. My tuner cards are the HVR-1600 and PVR-500.

[bnh]

Can you describe the stuttering a little more? For me, it was during playback on either of my clients (not the HD200 though)... smooth for 10-15 seconds, then a hitch, smooth, then hitch, over and over. I off loaded comskip processing to clients when not viewing media by using Sage Job Queue. I seem to have finally licked the problem by increasing the java heap size to 512. Apparently, after upgrading to the later releases, that setting got reset to the default, and i hadn't realized it.

[Wagon]

Originally Posted by bnh

Can you describe the stuttering a little more?

The video won't play back at the full 60 frames a second. I couldn't say exactly what the framerate is, but it is very noticeable. It looks more like watching a slideshow of pictures than a video. I would guess that the framerate drops to as low as 1 frame per second.

Right now all 4 tuners are recording, but I'm not having the problem. Both the HD show and 1 standard def show are recording to the same hard drive, but the other 2 tuners are recording to different drives.

I seem to have finally licked the problem by increasing the java heap size to 512. Apparently, after upgrading to the later releases, that setting got reset to the default, and i hadn't realized it.

I know I had it set at 512 before, but I guess I've upgraded since then. Guess it can't hurt to change it back.