Can the Z68 chipset fix the Sandy Bridge 23.976 Hz video output issue?

[Fjodor2001]

Hi,

I just wonder if there is any chance the Z68 chipset coming in Q2 can fix the 23.976 Hz video output issue present in the H67 chipset, as mentioned in the Anandtech review of the Sandy Bridge CPU?

As I understand it, the Z68 cipset will be the same as the P67 chipset but with added support for Flexible Display Interface (FDI). Since the 23.976 Hz issue is a result of a faulty video handling in the H67 chipset, doesn't this mean that Intel will get a new chance to fixing this issue when they design the Z68 chipset (since they can take the P67 and add FDI in the correct way, i.e. without any 23.976 Hz bug)?

 

[SlitheryDee]

It seems doubtful since the flaw is built into the processor itself. I get the impression that intel knew that it had slipped through for a while before they actually launched SB. It was too late to make any changes in the CPU, but they had time to implement a chipset or driver solution before release if one was possible. That is of course assuming that they can make changes to chipsets more readily than to processors.

 

[PreferLinux]

Seems from the review that it's the chipset.

 

[SlitheryDee]

Seems from the review that it's the chipset.

Yeah, on a second read I see you're right. I misunderstood it in the first read through because they refer to clarkdale as being the source of the problem. Anand does say that intel had enough time to fix the problem but didn't, so if such a fix was possible then I don't see why they wouldn't implement it in the next chipset. I suppose it's likely that Z68 will have the correction.

 

[IntelUser2000]

OP: With problems like these you need to expect the worst and hope for the best. There is a chance that Intel released everything but the CPU too early to keep the Tick Tock schedule, and Z68 might have been the refined chipset.

Sandy Bridge launch wasn't the smoothest for Intel. They still have got OpenGL and Linux portion of the drivers to fix. The March or April which is the supposed launch timeframe of Z68 might as well be the date to remedy all these issues. The key point here is "might".

 

[Hulk]

I don't understand the practical ramifications of this not being able to display 23.976 frame rate issue? Anand never really said what the visual impact while watching video at that frame rate would be? Stuttering?

 

[XLNC]

The March or April which is the supposed launch timeframe of Z68 might as well be the date to remedy all these issues.

Do we have any confirmation that Z68 is due in Q1 2011? I got the 2500K sitting but I'm in no hurry to invest in a MB/chipset yet. Can wait till April if it's due that soon.

 

[Sp12]

Do we have any confirmation that Z68 is due in Q1 2011? I got the 2500K sitting but I'm in no hurry to invest in a MB/chipset yet. Can wait till April if it's due that soon.

I'm willing to bet it'll launch with a new silicon revision of SB for better overclocks.

 

[RocksteadyDotNet]

I don't understand the practical ramifications of this not being able to display 23.976 frame rate issue? Anand never really said what the visual impact while watching video at that frame rate would be? Stuttering?

From the article.

"What happens when you try to play 23.976 fps content on a display that refreshes itself 24.000 times per second? You get a repeated frame approximately every 40 seconds to synchronize the source frame rate with the display frame rate. That repeated frame appears to your eyes as judder in motion, particularly evident in scenes involving a panning camera."

 

[MrTransistorm]

I don't understand the practical ramifications of this not being able to display 23.976 frame rate issue? Anand never really said what the visual impact while watching video at that frame rate would be? Stuttering?

IIRC the exact ratio is 1000/1001. That means when playing back a 23.976 source at 24.000, one frame is doubled (displayed twice) every 1000 frames to keep it in sync with the audio (somebody please check my math). Since film already runs at a slow fps, a stutter like that is quite noticeable (especially on slow pans).

We have NTSC to blame for this 58-year-old absurdity. Backwards compatibility is the biggest impedance to technological progress. If it were up to me, I would gladly kill off fractional frame rates, interlaced video, Windows XP, etc.

 

[Hulk]

Do the relatively current nVidia and AMD video cards have this same limitation?

Also how much content out there is at this frame rate? Film based movies are 24 progressive right? Or are they converted to this frame rate for some reason?

 

[MrTransistorm]

Also how much content out there is at this frame rate? Film based movies are 24 progressive right? Or are they converted to this frame rate for some reason?

I'm pretty sure that most BD movies are 23.976. Native 24.000 is slowly catching on. I'm sure there were a lot of reasons for the slow transition, but the biggest one is probably the shortage (until recently) of consumer equipment that could handle true 24p.

Another reason is that DVD video is firmly stuck at 59.94 fields per second. Doing a simultaneous release on DVD and BD is probably an editing and mastering nightmare if you are dealing with two slightly different clocks.

Let's kill off DVD too while we're at it! :twisted:

 

[IntelUser2000]

Do we have any confirmation that Z68 is due in Q1 2011? I got the 2500K sitting but I'm in no hurry to invest in a MB/chipset yet. Can wait till April if it's due that soon.

No there's no confirmation and its supposedly Q2. Perhaps it'll be more toward April/May.

 

[IntelUser2000]

A little more about 24p.

When most HTPC enthusiasts refer to the refresh rate as "24p", they mean 23.976Hz. The reason for the weird frequency dates long time ago, when we used CRT tube televisions. Since North America uses 60Hz frequency as their 110/120V AC power, tuning the TV to be exactly 60Hz caused the televisions to create what's called a "hum line". To eliminate the problem, the strange frequencies were born, and that must have been 59.94.

Movie theatres are played at multiples of 24Hz. I think most movie theatres play them at 48Hz. To move that to TV sets, 24Hz was changed to the ratio-equivalent of TV's playing frequency, which is 23.976Hz.

-TV sets displayed odd line fields first then even. So, TV is really 30Hz, cause there's 2 fields per frame
-To move from 24Hz to 30Hz, they use what's called a 3:2 pulldown(or 2:3 pulldown). They display each alternating fields frames in 3:2 ratio. So, it goes like AAA BB CCC DD(10). Normally it would be AA BB CC DD(8). That moves the 24Hz up to 30Hz.

 

[Fjodor2001]

By the way, apparently the mobile Sandy Bridge CPUs use a different chipset called Intel HM65. Does anybody know if the 23.976 Hz video output issue is present on that chipset as well?