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Discussion Starter · #1 ·
One of the factors in my decision to get a Replay over a Tivo was the comparison over at pvrcompare.com which stated that Replay's picture quality was higher at most settings.


In a few weeks of owning a 5060, I've been reasonably happy with the picture quality, but when I do a side-by-side comparison, even on high quality, the Replay picture does not seem true to the original. It's not that anything looks terribly compressed or showing any kind of artifacts, but it's almost as if the Replay has some kind of a "softening" or "smoothing" effect.


It's very noticable when I switch back and forth between my raw cable signal and my Replay's output (on a "live" non-recorded stream.) I can definitely see that a lot of the sharpness and detail of the cable signal is softened. It's especially noticable if there are any kind of computerized graphics on the screen, like titles, sports scores, etc. but can also be seen easily in regular scenes with limited camera motion and regions of sharp colors. Obviously a "softening" effect is harder to pick up on when there's a lot of motion in the scene, or where the scene is already "soft" visually.


Just to be sure I'm not imagining it, I conducted a "blind" test where I didn't know which input was chosen (raw cable or Replay) and I picked the right one six times in a row.


Now, I haven't seen anything written about any kind of intentional smoothing/softening effect, nor do I see a lot of compaints about the "high" quality setting on the Replay. So I'm just curious if anyone else has noticed anything like this. Am I asking too much to expect the high quality to be almost perfectly true to the source? That's what the PVR comparison said one could expect, and that's not what I'm seeing.


Oh, the source for both inputs is the same (analog cable) and I've tested to make sure the coax cables themselves aren't at fault. The wiring is like such:


Cable (Wall) -> Splitter

Splitter Output 1 -> Replay RF IN -> Replay Tuner -> Replay S-Video Out -> TV S-Video In

Splitter Output 2 -> TV RF IN -> TV Tuner
 

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I know what you mean. It's the soft filter effect like Lifetime network employs on their aging actresses. To my knowledge replay doesn't even acknowledge the 5000 picture quality needs work.
 

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One of the "tricks" for good compression is to remove some of the "sharpness" from the picture. If the image is sharper (more detail) it's more detail the encoder must try to preserve on the encode. If you soften the image there is less detail for the encoder to deal with.


But, is the soften done before the encode? I don't know, I don't suspect that, but it's tough to say. What you could see is a bunch of other things all added up.


If you are comparing the cable you got a couple of things...

1) ReplayTV tuner isn't the best there could be a tuning issue with the way the TV and replay tune the channel.

2) With the replay there is a lot of signal processing, the tuner, the encoder, the decoder all play a part in the output image quality. If you are using progressive output from the replay you'll have a decomb filter on the replay too.

3) cable, the s-video cable could be a factor too. S-video is about the best you can get short of component video. But, your cable can make a difference. RF and composite are both single line cables, so the picture shouldn't be as nice as the dual coax s-video cable.

4) Less likely, but still could be a factor. Check the splitter and make sure the output levels are the same for the two compared signals, generally the 2 way splitters both lines have a -3.5dB loss.
 

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And to add, my feelings on the 5k image quality. It's "ok" not even "good" it's just ok. I think there are issues with the encoder that need to be addressed. I'm most unhappy with the chroma loss on encoded dark scenes. Skin tones going to grey isn't cool.
 

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The sharpness settings can be controlled throughout the video path, but it is a very subjective judgement to decide what the "best" setting is. I think that MPEG compression will, by definition, benefit from SOME softening, since it is breaking the image up into blocks. You can tweak the sharpness in the output stages of the MPEG decoder, as well as in the NTSC encoder (for that matter, you can tweak the NTSC decoder and MPEG encoder settings too), but then you can end up with other artifacts.


I think another part of this is that it really depends on what TV you are using to look at the image. If you tweak things to look good on a progressive-scan TV (where you'd probably want a bit more softness), the composite output might start to look TOO soft. I know that when we were testing the 4000s, we used HDTVs to check the output, as well as lower-end sets and Trinitrons. We could have 5 people in the room, and each one would have a different opinion.


That being said, there is ALWAYS room for improvement. MPEG encoder firmware gets updated frequently by the semiconductor vendors, and perhaps Replay could add a set of picture controls in the menu (at least for the output stages) to address some of the TV-specific concerns.
 

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Quote:
Originally posted by JustDave
That being said, there is ALWAYS room for improvement. MPEG encoder firmware gets updated frequently by the semiconductor vendors, and perhaps Replay could add a set of picture controls in the menu (at least for the output stages) to address some of the TV-specific concerns.


This is perhaps the first time I've heard someone with "connections" on the inside at ReplayTV say this. AMEN Dave!


I've suggested it before that maybe there could be a very specific parameter settings adjustments for the TV decode, mpeg encode and mpeg decode stages.


It sounds like you've done a lot with the encoder. I've got a lot of experience with these pieces and parts too, and I may not know what works best, but I sure know what doesn't work!


Of course if there was a tweek these parameters option, there better be a restore to default!


I think the two toughest parts of the forumla are, the input and the display. Everyone's input is different. And the set's calibration. Some of us have ISF calibrated displays, others do dvd calibration, and others do the "looks good to me" adjustments. (Just to note, the third method is usually WRONG, unless you are an ISF tech, then your experience might get it close...) Too bad the replay Tuner adds another element to factor in, I think the 5k tuner is about as unreliable as you can get.
 

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It would be tricky to implement such controls, since there are literally hundreds of adjustable coefficients and parameters in the signal path. Perhaps (and please, don't misinterpret the word "perhaps" to mean that I have ANY inside info on future features) a subset of parameters could be adjusted, or they could be grouped into more generic (brightness, contrast, sharpness, etc.) controls.
 

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I would love to have the basics covered (brightness, contrast, sharpness, perhaps black level and color saturation). I have my cable S-video output running through a splitter/booster and feeding both my ReplayTV 5040 and my TiVo. There is no question but that the TiVo has a better image. The 5040 is both "warmer" and "softer" than the TiVo, whether I am viewing the raw, "pass-through" feed or watching a recorded program. Right now, the two units complement each other, so I will be keeping both, but I would be closer to dropping the TiVo if the 5040's video was higher quality...
 

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Dave, I totally understand you. Way too much to mess with.


Even if the encode/decode stages were skipped (and I'd like the ability) the user should have some level of control over the output. Just some ability to tweek the TL-850's display buffer that would be enough. I think the TL-850 has some settings for that kind of stuff.


Yeah, just the basics would be nice. I won't expect them to do anything like that any day soon. I think it would be faster to either hack the software. (I expect the loader is the only thing in the firmware, but I could be wrong.)


Damn all of us with good displays that actually allow you to see what you miss on the smaller tvs.
 

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I had the same issues with PQ on my 42" Plasma , comparing the RTV PQ to the direct feed and not satisfied. I bought a Iscan ultra pro and now run the RTV to the Iscan first and have adjusted the PQ settings so I cannot tell much difference at all. This made a huge difference in PQ from the RTV.


Rusty
 

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hi all...


after doing a search for words such as "no color" and "low channel", i figured this would be the best place to start figuring out whats wrong with my replay.


I have the "yellow, white & red" (i forget what its called) wire connection from my cable box into the replay and then the same way going out from the replay to my television. This was the best picture quality i could get out of the cable box (no s-video). My problem is that channel 2, the lowest channel on my cable system, is basically black & white, meanwhile channels 3 thru 90 something are all full color. I did have to adjust my television color settings to make the other channels look better, but channel 2 remains as bland and boring as black & white television is. To make it worse, this is the channel my local NFL team plays on every sunday, it kinda ruins the game and i'm forced to watch it live which is in complete and vibrant color...


any thoughst how to fix this? i'm stumped but figure it has something to do with the replays tuner, but for channel 2 to be black & white and channel 3 to be full color is odd. any help is appreciated!!!
 

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Check the picture using just the cable box. The composite video signal (yellow wire) should not be channel-dependent (i.e. it's not going through the Replay tuner). If the problem is not there when the cable box is used by itself, I think I'm stumped...
 

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dasmooth1, your idea about the tuner is off, if you are using RCA cables (that's the type of cable the Red-White-Yellow cables are. RCA is the connector on the ends of the cable. The video one (yellow) carries composite video.


I gotta agee with Dave, that's really odd. To add to Dave's test of trying the RCA cables to the TV directly. Can you try this too? Run your cable to the TV without the cablebox in the pat. What's channel 2 look like in both those configurations?
 

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thanks for the input guys..


I currently have picture in picture on my television, so the cable is already going directly into the television, and thats a beautiful clear color picture, in fact i can do a side by side comparison and the picture going thru the replay is no match, its black and white.


I'll try plugging the rca cables directly to the television and seeing how that goes..i'll let u know..and thanks again for the help!
 
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