DVD playback jerky

[SaturnV]

This is a serious issue I have raised before, but never gets a response from DVDFab team. This is an intermittent issue, but nearly all DVD ISOs have jerky playback.

I have experimented with this a lot and sometimes a DVD ISO plays back OK, but at other times playback of the same DVD can be very jerky.
Somebody posted a while ago in this forum that playback is usually better if you manually select "2D" in the 3D options for DVD playback. I have no doubt that selecting "2D" usually improves playback. This is very odd, possibly indicating the 2D/3D default playback is wrong and the player might be incorrectly trying to de-multiplex a 2D video stream that it thinks is 3D? I have no 3D DVDs by the way.

How busy the DMS is with background jobs seems to make little or no difference. Sometimes the Movie Server can be very busy updating the library but the DVD plays back OK, but other times the playback is very jerky but the DMS does not seem to be doing any other background tasks. Another reason why I don't think this is a DMS resource issue (I/O, Processor, Memory etc) is because Blu-Rays play back perfectly (that is when the menus work OK). Both PAL and NTSC DVD play back is affected.

[nnuudd]

Have you tried the frame rate? Make sure it is set to auto or try to set it at 50 for dvd to see if it makes a difference. And look to see if you tv matches what is set on the dms

[SaturnV]

Thanks for the advice, but this makes no difference. I have the DMS display settings set to the normal mode of the screen 1080p 50Hz, but the same issue occurs even if I set the DMS display settings to 720p 50Hz to match the original DVD settings. The TV screen is of course HDMI, so TV settings are negotiated by the DMS. Also, the problem is exactly the same on the DMS analogue output on a different TV. In short, I don't believe this is anything to do with the interface to the screen.

Video playback is actually dropping video frames. This is particularly noticeable when there is supposed to be smooth movement in the video and very obvious when for example program titles are supposed to be smoothly scrolling up the screen, when the camera pans, or when a person walks or a car move. What is PERFECTLY smooth playing back for the ISO on PC - is often jerky on the DMS. Usually this playback can be improved if "3D Mode" is set to "2D" instead of "Auto" when you play the ISO.

If I convert a (jerky) ISO to an MPEG or MP4, that same video plays PERFECTLY smoothly. When you compare the ISO to MPEG playback the difference is VERY noticeable (you realise just how bad DVD ISO playback is when you compare an MPEG of the same video clip). I therefore think the problem lies in DVD ISO playback software. This problem NEVER occurs with Blu-Ray, MPEG, MP4, mkv etc.