Atsc Timeshift Jerky - Minimum Cpu Requirement?

[jbodin]

I am running DVBViewer Pro on a Socket A Sempron 2600+ system (1.833 Mhz, 333 Mhz FSB, 768 MB RAM, 128 MB AGP GeForce 6800 video card, Air2PC ATSC tuner card) and I have having HORRIBLE problems with the timeshift function. I can view live HDTV OTA ATSC broadcasts just fine -- no audio or video sync problems, no stuttering, no jitter -- but when I enable "timeshift" or hit "pause" then unpause to resume viewing, the playback is HORRIBLY jerky/jittery.

 

I'm currently using the Overlay Mixer, and I have the "MPEG 2 PS (.mpg)" format selected under the Recording Options. I am currently using the trial version of the NVidia PureVideo decoder as my MPEG Video Decoder. I am aware that the GeForce 6800 cards do not take full advantage of the PureVideo functions, but these timeshift problems also existed with my previous 128 MB AGP GeForce 6600GT card, as well as my 128 MB AGP Radeon 9700 Pro card.

 

Any ideas or suggestions that might help solve my timeshift/pause function? Recorded programs look fine, by the way -- I can schedule a recording then watch it AFTER the broadcast with NO problems, but I am really puzzled by this problem.

 

Edited May 3, 2007 by jbodin

[jbodin]

Wow -- the lack of responses is stunning.

 

This isn't an ATSC-only question, folks -- I'd be interested in ANY input regrding problems with jerky video/audio when using timeshift. I've used the "Search" function exhaustively and I haven't found ANYTHING that helps.

 

 

Surely I'm not the ONLY person who has experienced problems? Any responses from folks using satellite or other non-ATSC sources would be GREATLY appreciated.

Edited May 8, 2007 by jbodin

[Moses]

did you try to watch the timeshift file, just like a recording? (You need to check "keep timeshift file" in Options and then just pause, wait a little and hit stop, then you should find a recorded file and try to view it)... does it contain any errors?

[jbodin]

Thanks for the feedback, Moses -- I have indeed tried that and the timeshift file itself is just fine (plays back okay with no jerkiness, stuttering, or sync issues. Recordings also play back fine when they are played-back after a broadcast has ended.

 

One thing I just discovered: I have 3 hard drives in my system -- an 80 GB drive (C:) for the OS (Windows 2000 Professional) and apps and Windows pagefile, a 160 GB Maxtor drive (D:) for some apps, games, and video processing, and another 160 GB Seagate drive (E:) that I use almost solely for videos (edited mpg files) and ISO files. All are internal IDE drives, 7200 rpm, 120ms seek time, etc., and my two larger "working" drives (D: and E:) typically have 30% - 50% free space, and I defrag both regularly. I have DVBViewer Pro installed on the D: drive, which is also the drive I have been using for recordings and for timeshift files. I discovered that when I move my recording and timeshift files to the E: drive I can watch live TV while timeshifting with NO problems at all -- and when I switched back to using the D: drive as the timeshift file location, the stutters and jerkiness returned.

 

I initially thought this might have something to do with the fact that I was trying to run DBViewer from the same drive that I was using for recording and timeshift, so I uninstalled DVBViewer and re-installed it to the C: drive. In this configuration, timeshift while viewing live TV remained jerky whenever I had the D: drive assigned for timeshift files. Changing the timeshift files over to the E: drive once again resulted in smooth viewing of live TV with no jerkiness or stutter while using the timeshift feature.

 

A defrag of the D: drive shows that has an appropriate amount of free space and very little fragmented files; the defrag utility reports that no defrag is required, but I went ahead and conducted a defrag to make sure. The defrag did not help the performance, though.

 

So, at this point in time the work-around for me seems to be using the E: drive for timeshift. This is definitely a good and work-able solution, but I am now trying to determine WHY DVBViewer performs differently when using the D: drive. I will run further diagnostics on the drive, but the drive specs for my D: and E: drives are identical, so I can't understand why I'm experiencing this performance difference.

 

Could it have something to do with the fact that my D: drive operating as a "slave" drive, and my E: drive is a "master"?

 

EDITED TO ADD: Since discovering this work-around, I have tried switching from the trial version of the NVidia Purevideo decoder back to the Cyberlink decoder, and as long as I am using my E: drive for the timeshift file location, my CPU utilization stays around 24% - 30% while watching live TV with timeshift enabled (allowing me to pause, rewind, and skip ahead while viewing). This adds up to very satisfactory performance for me with no need to purchase the Purevideo decoder, but I would still like to find out why I am having performance issues when using my D: drive.

Edited May 8, 2007 by jbodin

[jbodin]

Problem solved -- and this will probably be important for ANYBODY experiencing jerky jittery behavior with regards to recording and playback. I spent a couple of weeks chasing decoder issues and I ultimately thought I would have to go with some "high-end" decoder option like the NVidia Purevideo decoder, but this solved my problem and now with the Cyberlink decoder DVBViewer only uses between 15% - 30% CPU utilization while timeshifting or recording.

 

My discovery that the jitter/stutter only occurred when using my D: drive as the Timeshift/Record drive proved that this issue had nothing to do with the decoder performance -- the real problem had to do with the Transfer Mode settings for my IDE/ATA/ATAPI CONTROLLER under Windows Device Manager. Basically, my D: drive had reverted to using PIO mode despite being set to use "DMA if Available." Here's where I found the info that ultimately led to the solution (this write-up is for WinXP but the registry tweaks discussed also worked fine on my Windows 2000 Professional system):

 

Source: http://sniptools.com/tipstricks/getting-ba...e-in-windows-xp

 

===================================================

 

CD-ROM and DVD-ROM drives can revert to using PIO mode, despite being set to use "DMA if Available." Here's how to make Windows XP redetect the DMA capabilities of the drives.

 

This behaviour occurs with the following conditions:

 

* Windows XP is the operating system

* A CD-ROM or DVD-ROM drive, which is known to support DMA mode now works only in PIO mode.

* The drive controller is set to use "DMA if available" but reports to be only in PIO mode.

 

Following is the mechanism that has worked for me, please try it at your own risk, it involves hacking the registry:

 

1. Open RegEdit

2. Find the following KEY:

 

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}00x

 

3. The last four digits will be 0000, 0001, 0002, 0003, and so on.

4. Under each key, delete all occurences of the following values:

MasterIdDataChecksum

SlaveIdDataChecksum

5. Reboot the computer. Windows will now redetect DMA settings.

 

 

==================================================

 

 

To enable DMA mode using the Device Manager

 

1. Open Device Manager.

 

2. Double-click IDE ATA/ATAPI Controllers to display the list of controllers and channels.

 

3. Right-click the icon for the channel to which the device is connected, select Properties, and then click the Advanced Settings tab.

 

4. In the Current Transfer Mode drop-down box, select DMA if Available if the current setting is “PIO Only.â€

If the drop-down box already shows "DMA if Available" but the current transfer mode is PIO, then the user must toggle the settings. That is:

 

* Change the selection from "DMA if available" to PIO only, and click OK.

 

* Then repeat the steps above to change the selection to "DMA if Available."

 

==================================================

 

[NOTE that the Device Manager method alone did not solve the problem for me -- I also had to use the registry edits referenced above on my Windows 2000 Professional system; also, I had to do a reboot after doing the registry tweaks, but after rebooting my drive came up in UltraDMA Mode and my jitter/stutter problems with timeshift and recording to my D: drive were gone]

Edited May 11, 2007 by jbodin

[Gioxy]

...a very good job!

 

And I found, in the page you mention, another useful trick:

Sometimes can help the following procedure:

 

Set the following registry key

HKLM\HARDWARE\DEVICEMAP\Scsi\Scsi Port N\DMAEnabled

 

to

1 - enable master DMA

2 - enable slave DMA

3 - enable master/slave DMA

 

To choose the proper “Scsi Port N” (N can be 0,1,2, …) take look inside

 

HKLM\HARDWARE\DEVICEMAP\Scsi\Scsi Port N\Target Id 0\Logical Unit Id 0\Identifier

 

If Identifer contains the name of your CD then you found the correct N.

 

[jbodin]

...a very good job!

 

 

 

Thanks! This problem was driving me crazy, so it's a HUGE relief to find an actual solution (and to finally figure out what the problem REALLY was)!

 

Here are more details from Microsoft -- more explanation of the problem, along with details on hotfixes for WinXP and Win2K (and also Windows Server 2003) that others might find useful:

 

http://support.microsoft.com/?kbid=817472

 

Here's another write-up pertaining to this issue, along with a layman's explanation of why PIO is inferior to DMA mode, and some details pertaining to DMA mode for CD and DVD drives:

 

http://blogs.msdn.com/matt_pietrek/archive.../18/244154.aspx