Motorola 6412 vs Series 3 Quality

[cuyahoga]

I wanted to get a discussion started in one place about perceived quality differences in a Motorola 6412-style box and the new CableCARD-powered Series 3.

My background is that I've had a 6412 (phase 2) for about a year and a couple of Series 2 units as well. I just swapped out the Motorola box for a pair of CableCARDs and a new Series 3. Both of these were hooked into a Sony Bravia 40" LCD over component.

I really didn't expect a quality difference at all, but I seem to see one. Standard Definition stuff looks improved to me. Less pixelation, just nicer to my eyes. The HD content is different. I'd swear is, well, kind of grainier. Like film grain, almost. Its not that its bad, but different.

What does everyone think? Would/should the CableCARD,TiVo output create a difference that one could see?

[bschott]

I've had several DCT-6412s (as they all seem to overhead and lock the drive up) and I always thought they look pretty good. I've just got my S3, but I'm waiting for Comcast to install these cablecards (I guess my 15+ years as a network engineer doesnt qualify me for some reason).

Based on your comments would you go back to the DCT?

[cuyahoga]

Based on your comments would you go back to the DCT?

I don't think I'd go back, but I do kind of wish I had them both for a day or two so I could compare them.

Its a digital stream, so I guess the difference is in the scaling that the 6412 does vs. the Series3. For now, I've settled on 720p fixed on the Series 3. On the 6412, I was 480p/720p.

I'll keep playing with it.

[classicX]

It's a digital stream, and both units record digital video unaltered. There are some variables though:

Resolution: 720p versus 1080i
Transport Medium: Component cables can degrade or otherwise affect the video signal.
Source: Comparing Cable / Satellite to OTA is unreliable.

If you can eliminate these variables by fixing the output resolution, using an HDMI cable, and using the same source, then I think you'd be hard pressed to find a different.

You might just be looking at the S3 picture with "excited" eyes, thinking it looks better than your old box just because you're excited about having one.

[cuyahoga]

It's a digital stream, and both units record digital video unaltered. There are some variables though:

Resolution: 720p versus 1080i
Transport Medium: Component cables can degrade or otherwise affect the video signal.
Source: Comparing Cable / Satellite to OTA is unreliable.

If you can eliminate these variables by fixing the output resolution, using an HDMI cable, and using the same source, then I think you'd be hard pressed to find a different.

You might just be looking at the S3 picture with "excited" eyes, thinking it looks better than your old box just because you're excited about having one.

Yes, I have considered the 'newness factor' as a reason that I think stuff looks different, and I haven't dismissed it!

I ran an HDMI cable into my LCD TV and switched back and forth from the component input. They both looked virtually identical.

Before the cable cards were installed, the comcast tech checked my cable going into the Series 3. He thought that the connector was poorly attached. Something about the center of the cable not as important as the area surrounding it or some other RF engineering talk. I get excellent signal strength on my channels (97-100 level).

Anyway, at this very moment I prefer the Series 3 for standard def and I prefer the 6412 for HD. And that confuses me. And its not that the S3 looks bad for HD in my setup, its just different (and hard to quantify).

Still have to run down some of the other variables since adding the S3 changed a lot of things.

[SCSIRAID]

It's a digital stream, and both units record digital video unaltered. There are some variables though:

Resolution: 720p versus 1080i
Transport Medium: Component cables can degrade or otherwise affect the video signal.
Source: Comparing Cable / Satellite to OTA is unreliable.

If you can eliminate these variables by fixing the output resolution, using an HDMI cable, and using the same source, then I think you'd be hard pressed to find a different.

You might just be looking at the S3 picture with "excited" eyes, thinking it looks better than your old box just because you're excited about having one.

Another likely contributor would be the MPEG decoder.

[timdorr]

Another likely contributor would be the MPEG decoder.

Actually, that's very much the likely cause. Each box has different methods for decompressing the data. On top of that, you have different reconstructive techniques like deblocking and deringing that would affect quality in varying ways. Those techniques also aren't part of the standard, so the visual quality can vary great from one decoder to the next.

Check these out for comparison: http://www.videohelp.com/images/compare.jpg

[HDTiVo]

:up: Actually, that's very much the likely cause. Each box has different methods for decompressing the data. On top of that, you have different reconstructive techniques like deblocking and deringing that would affect quality in varying ways. Those techniques also aren't part of the standard, so the visual quality can vary great from one decoder to the next.

Check these out for comparison: http://www.videohelp.com/images/compare.jpg

[HDTiVo]

:up: Actually, that's very much the likely cause. Each box has different methods for decompressing the data. On top of that, you have different reconstructive techniques like deblocking and deringing that would affect quality in varying ways. Those techniques also aren't part of the standard, so the visual quality can vary great from one decoder to the next.

Check these out for comparison: http://www.videohelp.com/images/compare.jpg

No more HDMI is HDMI puh-lease. ;)

[cuyahoga]

Actually, that's very much the likely cause. Each box has different methods for decompressing the data. On top of that, you have different reconstructive techniques like deblocking and deringing that would affect quality in varying ways. Those techniques also aren't part of the standard, so the visual quality can vary great from one decoder to the next.

Check these out for comparison: http://www.videohelp.com/images/compare.jpg

Great link, and a great point. I'm also going to see if I can tolerate leaving the resolution set to native. Someone pointed out that setting my output to 720p fixed when my display is technically 768p results in the TiVo and the TV processing the image.

Could be contributing to the visual difference, but I did have the 6412 setting to 720p output as well.

[JakiChan]

Great link, and a great point. I'm also going to see if I can tolerate leaving the resolution set to native. Someone pointed out that setting my output to 720p fixed when my display is technically 768p results in the TiVo and the TV processing the image.

There is no such thing as "768p".

If your HDTV has a native resolution of > 720 line but < 1080 lines then "720p" is the native resolution. The other pixels are just overscan. So setting your box to 720p would result in no scaling.

For example, I have a Mac Mini hooked up to my 50" Hitachi LCD RPTV via DVI. If I were to set the resolution to 1366x768 (the native resolution of the LCD panel itself) then I wouldn't be able to see the top menu bar nor the dock on the bottom because the extra lines are lost.

[cuyahoga]

If your HDTV has a native resolution of > 720 line but < 1080 lines then "720p" is the native resolution. The other pixels are just overscan. So setting your box to 720p would result in no scaling.

For example, I have a Mac Mini hooked up to my 50" Hitachi LCD RPTV via DVI. If I were to set the resolution to 1366x768 (the native resolution of the LCD panel itself) then I wouldn't be able to see the top menu bar nor the dock on the bottom because the extra lines are lost.

I see what you mean. Wasn't even thinking of overscan.

I should have looked at the settings for the Mac Mini hooked up to my LCD. Just went with the old plug-and-play with that one. :)

Thanks!

[keenanSR]

There is no such thing as "768p".

If your HDTV has a native resolution of > 720 line but < 1080 lines then "720p" is the native resolution. The other pixels are just overscan. So setting your box to 720p would result in no scaling.

For example, I have a Mac Mini hooked up to my 50" Hitachi LCD RPTV via DVI. If I were to set the resolution to 1366x768 (the native resolution of the LCD panel itself) then I wouldn't be able to see the top menu bar nor the dock on the bottom because the extra lines are lost.
This is wrong.

The "768p" display will take the input, whether it's 1920x1080i or 1280x720p and deinterlace/scale it to the native resolution of the display. There's no overscan or underscan if the display does the job correctly.

I'd recommend trying both input resolutions and see which one looks better. Just because a 720p image is close to 768p doesn't mean it will look better on the 768p display than an input of 1080i. Typically, but not always, the 1080i input signal will result in a better image.

[cuyahoga]

This is wrong.

The "768p" display will take the input, whether it's 1920x1080i or 1280x720p and deinterlace/scale it to the native resolution of the display. There's no overscan or underscan if the display does the job correctly.

I'd recommend trying both input resolutions and see which one looks better. Just because a 720p image is close to 768p doesn't mean it will look better on the 768p display than an input of 1080i. Typically, but not always, the 1080i input signal will result in a better image.

I'll give this a try.

[JakiChan]

The "768p" display will take the input, whether it's 1920x1080i or 1280x720p and deinterlace/scale it to the native resolution of the display. There's no overscan or underscan if the display does the job correctly.

The vast majority of HD displays have overscan. Just ask someone who has attempted to connect an HTPC to an HD display that doesn't have a "computer" mode (or VGA input). Go the avsforum and read through the threads of folks trying to figure out the monitor timings for their HD set.

The exception to this rule is the new 1080p sets, at least the LCDs. It seems they're doing things "right".

I'd recommend trying both input resolutions and see which one looks better. Just because a 720p image is close to 768p doesn't mean it will look better on the 768p display than an input of 1080i. Typically, but not always, the 1080i input signal will result in a better image.

It depends on your TV for sure. Some deinterlacers are better than others. But given that the S3 is THX certified I'm guessing that it's scalers and interlacers are probably better than the ones in most sets out there, and probably better than the ones in my 2 year old set.

BTW, "768p" isn't a real term. The HDTV resolutions are 480i, 480p, 720p, 1080i, and 1080p. Your set is usally classified by the highest HDTV resolution it can do, so though my set has a 768-line LCD it's a 720p set. Until I replace it with a 1080p that is. :)

[JakiChan]

I should have looked at the settings for the Mac Mini hooked up to my LCD. Just went with the old plug-and-play with that one. :)

With some TVs it's not a problem. The TV's PNP setup tells the computer the right thing. However, on my 50v500 they don't want you plugging a computer in. In fact it specifically says it's not for a computer, don't try this at home, yada yada yada. The guys on avsforum hooked me up with the right numbers, a bit of SwitchResX magic, and voila a 50" Mac Mini display. Essential for any good HT setup. :)

[cuyahoga]

The vast majority of HD displays have overscan. It depends on your TV for sure. Some deinterlacers are better than others. But given that the S3 is THX certified I'm guessing that it's scalers and interlacers are probably better than the ones in most sets out there, and probably better than the ones in my 2 year old set.

BTW, "768p" isn't a real term. The HDTV resolutions are 480i, 480p, 720p, 1080i, and 1080p. Your set is usally classified by the highest HDTV resolution it can do, so though my set has a 768-line LCD it's a 720p set. Until I replace it with a 1080p that is. :)

I'm learning a lot on this thread, which is exactly what I hoped for! Thanks for the education.

[cuyahoga]

With some TVs it's not a problem. The TV's PNP setup tells the computer the right thing.

That's what happened to me, it sounds like. Plugged into VGA for the MacMini, used component for everything else and HDMI for the up-converting DVD player .

[keenanSR]

The vast majority of HD displays have overscan. Just ask someone who has attempted to connect an HTPC to an HD display that doesn't have a "computer" mode (or VGA input). Go the avsforum and read through the threads of folks trying to figure out the monitor timings for their HD set.

The exception to this rule is the new 1080p sets, at least the LCDs. It seems they're doing things "right".
Yes, they do have overscan, but we're only talking a few percentage points in most cases, and it doesn't really have much to do with with resolution you're inputing to the display. Plus, any competently built display will adjustment capability in the service menu to adjust the overscan, or underscan if that's the condition


It depends on your TV for sure. Some deinterlacers are better than others. But given that the S3 is THX certified I'm guessing that it's scalers and interlacers are probably better than the ones in most sets out there, and probably better than the ones in my 2 year old set.

BTW, "768p" isn't a real term. The HDTV resolutions are 480i, 480p, 720p, 1080i, and 1080p. Your set is usally classified by the highest HDTV resolution it can do, so though my set has a 768-line LCD it's a 720p set. Until I replace it with a 1080p that is. :)
"768p" relates to the native resolution of the panel-1366x768p in this example. Since all broadcast, cable and satellite HD TV programming originates as either 1920x1080i or 1280x720p at the source the ideal is to have the display represent that signal as closely as possible. Functions of the content provider, the provider of the signal to you, and the equipment you have all have an effect on that signal.

When sending a 720p signal to a 768p display some of the image is being extrapolated by the deinterlacer/scaler in the display, IOW, it has to "make it up". When sending a 1080i signal to the 768p display, the signal is "shaved" or removed of some of it's resolution by the deinterlacing/scaling process to fit the native resolution of the panel. That's a very rough description of what happens.

It makes sense to start with more data than less when using a using a display resolution different than one of the standards. How well it looks in the end will depend on how well th equipment does the job of deinterlacing and scaling.

Over/underscan is an adjustment of the final processed image presented on the display and is not really anything to do with the resolution being input.

P.S. I spend a fair amount of time at AVS. ;)

[JakiChan]

That's what happened to me, it sounds like. Plugged into VGA for the MacMini, used component for everything else and HDMI for the up-converting DVD player .

My hitachi gave me crappy 640x480 until I hacked it.

If you are messing with display resolutions SwitchResX is the way to go. It's the Mac equivalent of Powerstrip for Windows folks.

[JakiChan]

Yes, they do have overscan, but we're only talking a few percentage points in most cases, and it doesn't really have much to do with with resolution you're inputing to the display. Plus, any competently built display will adjustment capability in the service menu to adjust the overscan, or underscan if that's the condition

Then why, when I set my Mac for native resolution of 1366x768 does it look fine except for the top and bottom chopped off? And no, it doesn't need to be tweaked for overscan/understand according to Avia.

"768p" relates to the native resolution of the panel-1366x768p in this example.

Yes, I know what you're using it to refer to, and I know that folks on AVS use the term, but be clear: there is no "768p" HDTV format.


It makes sense to start with more data than less when using a using a display resolution different than one of the standards. How well it looks in the end will depend on how well th equipment does the job of deinterlacing and scaling.

Perhaps, but keep in mind that 720p is .96million pixels per 1/60th sec, and 1080i is 1.04 milllion pixels per 1/60th of a second. By giving up those .08million pixels/60th second you avoid having to do a deinterlacing process. And I can tell you from how my Mac mini plays DVDs, deinterlacing doesn't always appear to be trivial. Yes, the de-interlacer in your digital display is probably pretty good (or everything would look like crap) but I'm thinking maybe the one in the S3, being THX and all, is better than the one on my TV. I'm sure it's better than the one in the Moto 6412 III I have..

[Tivortex]

My hitachi gave me crappy 640x480 until I hacked it.

If you are messing with display resolutions SwitchResX is the way to go. It's the Mac equivalent of Powerstrip for Windows folks.

I can second the opinion about SwitchResX. That's what I used to get a display from my Mac Mini to my 62" DLP, until OS X finally came with an "overscan" toggle option.

[JakiChan]

I can second the opinion about SwitchResX. That's what I used to get a display from my Mac Mini to my 62" DLP, until OS X finally came with an "overscan" toggle option.

Uh...check your PMs. :D

[keenanSR]

Yes, the de-interlacer in your digital display is probably pretty good (or everything would look like crap) but I'm thinking maybe the one in the S3, being THX and all, is better than the one on my TV. I'm sure it's better than the one in the Moto 6412 III I have..
That we can agree on, the S3 is much better than the Moto 6412.