Non-smooth DVD/LCD playback

[Unregistered]

I am using a (cheap) JVC DVD player (XV-N40 or something) and a Sharp 30" LCD flat panel (first generation) connected via component video. I occassionally notice very non-smooth playback in which the movement from frame to frame is really noticeable and seems slightly jerky. Switching between 720i and 720p on the player hence switching between the de-interlacer in the dvd player and the display does not really help at all. Neither does changing the deinterlacer settings on the display (normal to 'fast'). A friend speculated that perhaps the DVD player processor is just not quite keeping up. In this case a better DVD player, perhaps one with a name-brand de-interlacer, might be the solution. Another possibility is slowness of the LCD display. Yet a third is the nature of the beast : i.e. the larger sharper display simply shows off the frame differences more, try stepping frame by frame through any video (dvd or vhs) and there are significant differences between frames in any moving scene.

Anyone know what I am talking about and know the solution?

Thanks!

 

[djoxygen]

A friend of mine and I have discussed what I believe is the same issue. We came to the conclusion (strictly based on anecdotal evidence) that more people of our generation, having grown up in front of 75Hz+ progressive-scan computer displays playing Doom off video cards that can crank out 60 fps motion, just aren't happy with 24p source material.

Perhaps our brains are less able to smooth out the difference between 2 frames, or we're processing the images faster than our grandparents could. I really don't know as I'm an audio guy not an expert in psycho-perceptual matters. I do know that even watching movies at the best theaters (DLP, Imax) fast motion on the screen looks to me like a series of still frames rather than a continuous movement. Video-sourced material is slightly preferable at 29.97i, but still occasionally bothers. Also, the bigger the screen's apparent size, the worse the problem bothers me.

I hold out hope that someday true 60p source material on equivalently capable display technologies will satisfy.

 

[Unregistered]

Update and confustion about 3:2 pulldown:

I dug in deeper and found one source of the problem and a solution :

My JVC DVD player is a progressive scan/3:2 pulldown type machine. I had the 3:2 detection set to auto which should 'automatically' detect film vs video sources and do the appropriate conversion when required. On the DVD I was watching, The Prisoner (60s BBC show), the frames were put out as follows : 1 2 3 4 4 5 6 7 8 8 9 ... This is the source of the stuttering/jerkiness that I was seeing on this disc and others in the past I suspect. Changing the 3:2 detection on the display did absolutely nothing and changing from interlaced to progressive on either the player of display made no difference.

However, changing the player to film mode seemed to perform the 3:2 pulldown correctly giving the sequence 1 2 3 3/4 4 5 6 7 7/8 8 9 . In this case the display did a just slightly better job with the interlaced signal (using its deinterlacer I guess) than with the progressive signal from the player. I was unable to get the display to recognize the source as film and do 3:2 pulldown by itself. Does DVD just always put out 30fps so that the display never sees the need to do 3:2 itself??

I then looked at a couple of films on the shelf, and neither showed any of this. Were these films converted to 30fps by the DVD maker hence requiring no 3:2 pulldown?

 

[djoxygen]

Some DVDs don't have the proper flags set to identify whether or not they should be reverse 3:2-ed. I'd guess (and this is really only a guess) that by setting that DVD player to film mode you're forcing it to always treat the source as if it were film (24p), which is probably correct for The Prisoner and certainly for most movies. It is possible that if you watched true video-sourced (29.97fps) DVD material, you'd see the kind of interlacing motion artifacts shown at the bottom of this page...

http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html

... because your DVD player and TV are always going to treat the source as film.

My TV (Hitachi 43" CRT RP) only has pulldown detection on it's "movie" mode. I'm too lazy and don't care enough about broadcast material and getting the utmost quality out of The Daily Show to change the mode most of the time. So when I'm watching DirecTV channels I see, but ignore, that incorrect deinterlacing.