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HDMI/Composite Conversion Question...

post #1 of 10
Thread Starter 
My parents just got a new HDTV and a Blu Ray player. However, they have a TVGuardian box to block foul language, and the box only has composite inputs and outputs. (The box connects in between the dvd or blu ray player and the tv.) My question is, if I got a couple adapters or cables to convert the HDMI Blu Ray player output to composite for the box, then had another adapter/cable after the box to upconvert it back to HDMI for the tv, am I going to lose picture quality by the end of the chain?
post #2 of 10
If you convert the video to composite you will lose MASSIVE video quality to the point where you might as well get rid of the HDTV and Blu-ray player and just use VHS. If you do audio-only you might be able to use RCA audio cables from the Blu-ray player to route the audio through the silly TVGuardian box and into the TV, and keep the HDMI connection for video-only if your hardware allows it.
post #3 of 10
Why did your parents get a Blu-Ray player and a new HDTV? Seems a waste if all they are going to do is to watch standard definition through a single composite video cable.

Then the second question is why didn't your parents get a Blu-Ray player that had a component video ouput? Those are still made and will provide the best possible video signal for standard definition composite video as opposed to trying to find an HDMI to component converter (not just a cable) which may not be the best signal and will cost more money. Can you return the Blu-Ray player and get one with component video output?

It seems a shame to buy all HD equipment and then downgrade everything to standard definition (actually poor standard definition through a composite video cable).

If you didn't get the answer to your last question from the above, you will lose all of the benefits of high definition and actually have a worse picture than ones in the 1980s. That is because the all-important number-of-lines that you'll get will actually be less than what was available in the late 1980s since you'll be sending a widescreen picture with bars on the top and bottom taking up some of the available lines. Not a good choice for picture quality. The information is already lost at the end of the chain, so upconverting to HDMI (more expense) will not restore a single line.
Edited by alk3997 - 12/2/12 at 10:06am
post #4 of 10
Thread Starter 
Thanks for the replies. The Blu Ray player was a cheap Black Friday deal, hence the lack of component outputs. I actually just checked TVGuardian's website, and they don't filter Blu Rays, so that question is moot, I guess. However, my parents actually watch mostly DVDs anyways, so if they got a blu ray player or an upconverting DVD player with component outputs, would the down conversion into the TVG box and the subsequent up conversion give better results using component outputs and inputs (being that component and composite are both analog---e.g. no digital to analog conversion taking place)? Would DVDs still be up converted to 1080p, or does down converting to composite lose the data permanently no matter what cable/converter you use to downconvert or upconvert on the other side? In other words, is going from component--->composite--->component going to be any better, worse, or the same as going from HDMI--->composite--->HDMI?
Edited by imqboy - 12/2/12 at 11:32am
post #5 of 10
Downconverting to composite destroys the video data and you can't get any of it back by re-converting it to another type. You can't magically recreate what was lost when converting from HD to sub-480i composite.
post #6 of 10
Thread Starter 
post #7 of 10
OK, I think I understand your question. Think of your picture as lines of resolution. This is the number of vertical pixels in a still image but with TVs we talk about the full line. The best standard defintion video was 480 lines in the U.S. For something like VHS, the number of lines was around 240 to 300 lines. No matter what you did with those old tapes there was no way to get those missing 240 lines back. They just weren't on the tape and certainly no processor at the time could interpolate the missing lines. However, there were some tricks such as doubling the number of lines that kind-of sort-of made the picture look better. The lines were just duplicates but the picture looked a bit better.

Now going to the present day, high definition is either 1080 or 720 lines of resolution. So, compare that against the best standard definition and you'll see that the difference is as much as 600 lines (well over double). Now that yellow composite single cable was, at best, able to carry 480 lines of resolution and it combined the color and luminosity (brightness) signal all as one, which also caused some issues. As soon as you convert to composite video, you are throwing away those 600 lines as well as combining other information into one signal. That information is all gone.

Now the box on the other end can receive this signal over the composite cable and fill in the missing lines. But it doesn't know the information in the lines so it has to "guess" at it by looking at adjacent lines and trying to figure out the missing pieces. With this conversion, in some cases, it is having to fill-in two adjacent lines. No matter what, this doesn't give you back your original picture. It gives you back the algorithm's best guess at your original picture.

If that wasn't true, we would all be using composite video cables since they are much easier to work with than HDMI. But, HDMI has other advantages that (maybe) make-up for its complexity.

Also keep in mind that any conversion between HDMI and something else (where it is allowed) requires a powered converter. The exception to this is DVI to HDMI, but that is another story. The bottom line is that once you add up the costs of these converters, your "Black Friday" special won't seem so special anymore. Really, if you want to give up HD (or any DVD upconversion) and use composite video, the best thing would be to return the Blu-Ray player (even if you got a great deal) and get something your parents can actually use.

I think the real question is whether your parents really care about HD or are just as happy with a standard def system. In which case return the Blu-Ray and get them a good DVD player, while the DVD players still exist. You'll then have a composite video output and it will be cheaper. Unfortunately, even the best 1080p HDTV will not be able to make a DVD look like high definition, although they are getting better at that. As far as upconversion is concerned, you realize your TV already does this, right? It has to in order to convert any standard definition picture to its high definition screen. It's really a question of whether the Blu-Ray player over HDMI is better at this or their new HDTV is better at it.

Now component video is a different story. Component video can handle up to 1080i and 720p. So it is a high definition interface. You said earlier that component video didn't include a digital conversion. That is incorrect. The video is stored on a Blu-Ray or DVD in digital format. The difference between component video output and HDMI output is that the digital to analog conversion is done in the player with component video and is done in the TV with HDMI. So, component would give you an excellent picture. However, as far as I know there are no longer any Blu-Ray players with high definition component video outputs. This was done by the industry because the movie studios were nervous and paranoid about someone copying their movies using the component video outputs. Only players that were designed before 2011 have high defintiion component video outputs.

So, bottom line - you have to choose between the TVGuardian box and High Definition. You can't have both. Once you choose, your path will be clear...
Edited by alk3997 - 12/2/12 at 8:56pm
post #8 of 10
Thread Starter 
Thanks for that very informative reply, alk3997.

So.....theoretically, if a DVD player's upscaler is superior to the HDTV's scaler, would using component cables (which perform the digital to analog conversion in the player) give a superior picture to HDMI? Or does the upscaling occur separate from the digital/analog conversion?
post #9 of 10
Originally Posted by imqboy View Post

Thanks for that very informative reply, alk3997.
So.....theoretically, if a DVD player's upscaler is superior to the HDTV's scaler, would using component cables (which perform the digital to analog conversion in the player) give a superior picture to HDMI? Or does the upscaling occur separate from the digital/analog conversion?

That's a good question. Normally the answer would be that HDMI and component video give the same quality (if good component video cables are used). However, because of the movie industry's paranoia that I mentioned previously, no DVD upscaling can occur over component video outputs. The only upscaling allowed from a DVD or Blu-Ray player is over HDMI. This is not a technical limitation but a legal limitation (having to do with industry agreements).

I believe the upscaling is always done on the digital side before any conversion to analog (either using component video, if allowed, or HDMI).

So, simplifying my answer, you can only upscale with HDMI. However, the upconversion is done in the digital domain before being sent out on HDMI.
post #10 of 10
Thread Starter 
Thanks for all the helpful answers! I think my parents are just going to upgrade their TVG model (the company actually offers an "HD capable" one now with HDMI---yay for them, I guess). Blu Rays aren't generally closed-captioned, so those are still out (TVG works using closed captioning), but my parents will be able to see language-free DVDs upscaled at least. smile.gif

Again, thanks for all the info!
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