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How to Determine if HDTV or Source is Doing Video Processing


Production lineImagine an assembly line staffed with people who all have the same or similar tools and all of whom, to varying degrees, want to do that same task… Now start up the belt and send a product requiring some bolts and rivets down the line. As the product flows down the assembly line everyone has the potential of filling any number of holes with bolts or rivets. But if the first person in the line fills a hole - then the rest of them can no longer work on that particular area - they have to see if there's another place that needs work. That's the picture I want you to put into your head about video processing. Now let's go back to the original example.

Joe has his fleet of top notch components. All of them provide video processing and they provide it very well… but how many times can a signal be deinterlaced? Just once (ignore any exceptions to the rule for now.) How many times will an image need to be scaled to match the native resolution of the projector or display? Just once. Hmmm… so why pay all that money for the best video processing in every single component? Well there are reasons for buying top quality products, but it wouldn't be solely for their ability to do the same types of video processing. Let's break down a worst-case scenario:

Scenario 1: DVD > Receiver > Processor > Display = What a Waste!

  • Our high-end Upconverting DVD player w/HQV Realta processing is not only deinterlacing - it's performing noise reduction and scaling as well! And it's doing a fine job of it. Output: 720p.
  • The AV Processor/Receiver is a new unit that provides HDMI scaling and upconversion as well with premium video processing built in. Guess what - it's not doing a thing to the signal since the DVD player is feeding 720p signal to the receiver. Output: Passed-through 720p.
  • The Processor/Receiver is also top-of the line and has an on-board DVDO scaler. While it may be useful for feeding additional inputs into it and handling video processing for other sources, the 720p output from the receiver (which was the same signal sent from the DVD player) isn't being touched but merely sent on to the display. Output: The same passed-through 720p. Ouch.
  • The Display is a native 720p unit with an integrated Gennum VXP processor that is not doing anything other than displaying the input signal as received. All of the video processing built into this unit is completely bypassed.

So what's the result of Scenario 1:

  • DVD Player - Upconversion & Scaling to 720p
  • Receiver: Pass-through only
  • Video Processor: Pass-through only
  • Display: No processing or scaling

Scenario 1 has the DVD player doing virtually ALL the video processing and all other components merely passing the signal on through the chain to the display. If we take nothing else into account but DVD playback for this system, then there is no reason to have anything other than a DVD player, mid-level receiver and display. Video could be sent directly to the display or sent through an HDMI switcher on its way to the projector or display while audio is routed separately to the receiver. The presence of a video processor, while handy for cableTV and scaling other sources, is completely useless in this focused example. But let's look at another scenario:

Scenario 2: DVD > Receiver > Processor > Display = What a Picture!

  • Entry level 480i DVD player w/clean 480i output: This transport is economical and has good clean 480i output (and believe us that's not always easy to find). Output: 480i.
  • The receiver is a mid-level unit whose real purpose is to provide excellent audio quality, not provide fancy video conversions. Output: Passed-through 480i or bypassed altogether.
  • The Processor is a top-of the line model from Gennum, Silicon Optix, Anchor Bay Technologies or another company. It is doing what it does best - processing the incoming video signal, deinterlacing, and scaling the output for the projector. Output: Processed 720p.
  • The Display is a good quality 720p unit that has good black levels and excellent color accuracy. All of the video processing built into this unit is completely bypassed - on purpose.

So what's the result of Scenario 2:

  • DVD Player - Provides clean 480i source
  • Receiver: Provides excellent audio quality and video pass thru
  • Video Processor: Performs deinterlacing and scaling to 720p
  • Display: Provides excellent black level, detail and color accuracy.

Scenario 2 simply has each component performing to the best of its ability in a way that makes fiscal and "system" sense. Having the entry level 480i player provides a solid source for the video processor to work with. The receiver is focused on audio and the display was purchased so that the processed signal would be displayed with all of its maximized potential. Scenario 2 is a smart system and the owner didn't spend "redundant" money on processing that wasn't needed.


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Recent Forum Posts:

bandphan posts on December 09, 2008 11:24
^^ have you checked ant test patterns ?
ouchakov posts on December 09, 2008 10:45
DTR 8.9 Reon processing of native source

As a follow up on my earlier post, I had a chance to connect my DTR 8.9 to my Sony changers. It appears that via HDMI output, the best option is to feed the 8.9 1080i signal, otherwise, the picture appears blotchy on my TV. I have 8.9 outputting 720p to my TV. I don't see much difference on my Samsung between 1080i and 720p, so I went with native resolution. I will post my impressions of the receiver as a separate thread. I hope Clint and the gang will have a chance to review new Integra receivers. It looks like there are a lot of options that are available to professional installers to calibrate all home theater sources. I would be interested in Audioholics opinions on those.

Thanks for advice, Clint, but my Sony changers don't output clean 480i via HDMI … ;-(


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Clint DeBoer posts on December 03, 2008 12:17
480i is best with the only exception being with HD sources. Some set-top boxes will output 480i and then output 1080i automatically when an HD signal is received. Cjeck the user manual (you might have to track it down online). Ideally, you want the native output on all sources with a good processor like yours.

With that said, your TV is likely 720p native and merely supports 1080i. As a result, set the AV receiver to output 720p.
ouchakov posts on December 03, 2008 11:25
So many output formats, what's to use ?

Good article. I liked how it was laid out.

I am still a bit confused on processing options. I recently bought a new Integra DTR 8.9 Receiver, and I am looking forward to using its Reon chip with my DVD changers, but was should I set the output to?

My DLP TV is a 720p / 1080i TV, and I usually leave it at 720p.
My Dish outputs 1080i (I tried outputting 720p and it looks worse)
My DVD changers can output anything (480i, 720p, 1080i), but their scaling/processing was rated subpar

I am contemplating having the receiver output of 720p, but I am not sure what I should feed it from the sources if I want to utilize the power of Reon chip.

I am thinking outputting 480i from all sources to have my receiver to do all the work, as recommended in the article, the question is, will this limit the amount of details (data) output from my Dish and DVDs if I limit output to 480i, shouldn't I feed my receiver 1080i and let it do video processing?

I wanted to see what smart people think

I will, of course, tinker with the settings when I set it up and pick the best one and report on it, but I wanted to see what people think.


- O
thegreenline posts on June 09, 2007 09:48
How about CRT RPTV's

I have a Hitachi 46F500 RP CRT TV, this will not be replaced in the near future. My question is does all the stuff in the article apply to RP CRT?

Also how would I find out what the native resolution is for this TV?

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