Review Zenith DVD DVB318 component HD Scaling
Posted: Tue May 17, 2005 12:35 am
Originally published 12/23/2004, HDTV Magazine, editor Dale Cripps
By Richard Fisher
Due to the graphical nature of this column you may experience delays as the images are being downloaded.
Zenith DVB318 DVI/component HD Scaling DVD Player
There has been considerable buzz on the internet about this DVD player so it seemed fitting to make this our first review. There is ample written about this unit yet there is little specifically defining just what it can or cannot do to give the end-user seeking image accuracy any satisfaction.
This player is also available in Canada as the LG DV7832NXC. The main reason so many are ga ga over this unit is because it will output component video at HD scan rates--specifically 720p and 1080i--at the astounding MSRP of $249. It also provides a DVI connection with HDCP capacity but your display's DVI connector must support that if your DVI is to work. Unfortunately, I was unable to test that portion of the unit. That said, DVI presents a real challenge to the work we are trying to perform with this column as it is nearly impossible to test in an open manner due to all the security issues involved. The last time I investigated it I was informed that a very expensive computer is used to determine what the real response is for a DVI signal. True or not, the fact is that there is no inexpensive solution to test it, much less view it. It is so bad that all of us with analog-only video inputs may very well be blocked or down rezzed in the future HD-DVD world. At this time no outlet has been provided for legacy HDTV display owners who would like to be able to use DVI gear regardless of price. That situation, along with the inexpensive price, is the key to this unit?s popularity.
The reason this is important is because a number of the better known manufacturers changed their CRT displays from dual native scan rates to one single native HD scan rate. That means any other scan rate must be converted by the internal scaler of the display. To this day those scalers are inducing artifacts into the image. By feeding a display its native scan rate you bypass the internal scaler in most-all cases. That eliminates those artifacts. The twist, of course, is now your response is directly related to the scaling performance of the DVD player and its ability to generate correct video signals. Based on the last 3 years DVD scaling is likely to be the least of our worries as DVD players, in general, have been doing a far better job than their internal scaling cousins. Generating the correct signals for an accurate response is another matter entirely and that is the gist of this column.
Another point is that technically this DVD player is not supposed to allow HD scan rates via analog component video due to copy protection requirements on Hollywood movies for the U.S. market and the Zenith DVB318 was designed and destined for the U.S. market. While this is beyond the scope of this column, the reader should be aware that this capability with this player is a quirk and competing brands do not offer such. That said, there are gray market players destined for other countries which do provide this capability and they can be acquired by a U.S. resident via the internet.
Our review sample was purchased from Amazon.com for $200, received well packed and in good condition. The DVB318 sports the currently popular cosmetic silver with the slim chassis, meaning it is only 1.7? high. Compared to my older models this was a relief as there was enough room between the shelves to simply throw it on top of the pile. The front panel provides only the most simple of functions so, needless to say, don?t lose the remote! The remote is well designed in terms of size and ergonomics except for the location of the FF and RW functions, which is a shuttle dial at the bottom. The remote also provides glow-in-the-dark buttons which can be a bit irritating in a dark room. It was set face down once the movie started. The back panel sports DVI, component, s-video and composite video jacks with the NTSC video always active regardless of output scan rate. For digital audio you have both optical and coax plus one L/R analog output.
Setup is simple as there is little provided for you to adjust. Out of the box I did find the DRC, dynamic range compression and vocal setting was turned on and recommend you turn them off unless you really wanted those features active. On playback you have special search and playback control functions but curiously not the first sign of picture adjustments. There is not one single picture control on this unit and that was disconcerting as most provide at least a black level setup.
Scaling
We begin the review with scaling...
Using a Faroudja chip this product was quite astounding in it?s delivery of 1080I images. The 1080I scaling was simple and straightforward. Unfortunately, there is a snag when viewing 4:3 or letterboxed 4:3 content. Most displays do not have picture formatting available with an HD scan rate leaving you with no choice but to watch a stretched image in 4:3. The player does have an interesting zoom feature which allows you to stretch the image vertically or horizontally, but it does not allow you to squeeze the image, leaving you with stretching it vertically and cropping the top and bottom of a 4:3 image for some form of accurate geometry. I say form because it is completely variable rather than fixed and without a test pattern you will be hard pressed to set this accurately. For the movie portion of 16:9 enhanced masters this presents no problem so for these rare birds and extra features you could drop the scan rate to 480P regaining the display formatting controls except for one problem--the 480P scan rate is chock full of scaling artifacts. The following scenes are from the original Star Trek TV series.
[img]http://www.hdtvmagazine.com/images/forum/1DVB318.jpg[/img]
From left to right the first image has black streaks coming off of the edge, the middle has red pieces missing on two edges and one edge for last one. All of these artifacts were clearly visible in the image and occurred with other colors and edges as well with red being the most notorious. This player is not recommended for 480P applications, period. As for letterboxed 4:3 you can still vertically stretch it and while not accurate, it will satisfy most. The scaling of this kind of content was equally phenomenal, appearing very much like a 16:9 enhanced master.
Pixel cropping was checked with 15 pixels on the left and right sides, 9 pixels at the top and 0 pixels at the bottom. This equates to about 2% overscan and would only be an issue for those displays capable of less than 2%, which are very few.
Color Decoding
Unfortunately the DVB318 failed the color decoder test. The overall level is off requiring a recalibration of the color control, which is not a sever issue at all. What is a severe issue is the green channel.
[img]http://www.hdtvmagazine.com/images/forum/2DVB318.jpg[/img]
Overlooking the artifacts in the image note that the blue and red fields from Digital Video Essentials show very-little-to-no-shading while green shows a significant problem. Using Avia I find the green saturation is -20 to -25%, which is a huge error. What that means is that not only will green objects such as grass and trees appear lower in intensity, any other color that uses green as part of its mix will also be incorrect. If you are put off by red push then this error should be equally disturbing.
Waveforms 1080i
If you recall there were no picture controls to speak of. This creates a problem because the component video output is setup for NTSC video which uses 7.5 IRE as the black level instead of 0 IRE.
[img]http://www.hdtvmagazine.com/images/forum/3DVB318.jpg[/img]
The left image is the DVB318 and the error is right next to A=5us. The correct response is on the right. What this means is instead of putting out 700mv for video it is putting out 647.5mv and also raising the black level. While you can turn down the brightness on the display to compensate for this it will goof up the overall gamma response. For accurate component video response the black level must be set at 0 IRE. Besides that an accurate 1 volt peak to peak response was provided.
The next set of waveforms deals with frequency response and severe waveform distortion using the sweep and multiburst patterns from Avia and Digital Video Essentials.
[img]http://www.hdtvmagazine.com/images/forum/4DVB318.jpg[/img]
The left side is the DVB318 with the top being the sweep and the bottom the multiburst. The images to the right are the correct response. Note: the right image is not flat on the bottom. This is a small error from that DVD player. What this means for the DVB318 is the finer the line the higher the light output. While inaccurate, many will perceive this player to have a sharper image due to this artifact.
The next set of waveforms are of the same type but from Digital Video Essentials, DVE, which extends these patterns out to about 6Mhz rather than the 5Mhz used by Avia.
[img]http://www.hdtvmagazine.com/images/forum/5DVB318.jpg[/img]
The top two and bottom left are the DVB318. Just like the previous waveforms we are looking for a flat response. The bottom left is an extended frequency response multiburst from 5-6Mhz and shows severe distortion besides a rolled off response. This particular pattern will not pass correctly on any DVD player that I have. The one on the bottom right is from another DVD player and while it is not rolled off it has the same type of distortion. I am told this is caused by the MPEG decoder. Bottom line is a gain error of +2.5db for the peak and -4db for the roll off. Bear in mind prior to DVE there would not have been a roll off to document and this player would have been reported as having a +2.5db peak only.
[img]http://www.hdtvmagazine.com/images/forum/6DVB318.jpg[/img]
This distortion shows up as shading in the multiburst as shown above. The rolled off response reduces the light output of the mulitburst as well where the burst all the way left is brighter than the burst all the way right.
Finally, the color difference signals.
[img]http://www.hdtvmagazine.com/images/forum/7DVB318.jpg[/img]
The top left is the green channel and that is exactly what it should like. The top right is the blue color channel and the bottom left is the red color channel. The bottom right is another DVD player and a box has been drawn around the waveform to illustrate that here too we are looking for a flat response. What this represents is the color resolution or detail and is no different from the previous line or frequency response waveforms. The DVB318 is rolled off and while the other DVD player is providing a much better response it is also creating severe waveform distortion in the finest line count on the left side of the pattern that may be seen as a shading artifact similar to the luminance waveform and screen picture.
Waveforms 720p
The stair step pattern was identical to the 1080I response. The frequency response is another story.
[img]http://www.hdtvmagazine.com/images/forum/8DVB318.jpg[/img]
These are from DVE and there are serious problems
[img]http://www.hdtvmagazine.com/images/forum/9DVB318.jpg[/img]
These are from Avia. In either series you can see that we have nothing even remotely flat, much higher waveform distortion and the higher frequencies from DVE are significantly rolled off. The image to the right is the same waveform with an adjustment on the scope so I can see the whole pattern to take measurements, not a good sign. Bottom line here is a gain error of +3db for the peak with a severe -4db for the roll off based on Avia and a whopping -9db for the roll off based on DVE.
[img]http://www.hdtvmagazine.com/images/forum/10DVB318.jpg[/img]
This is the color response from DVE showing the green and blue channel. The red channel is not shown as it had the same response. The green is clean like 1080I but the blue channel shows more waveform distortion.
DVI Performance
While I was unable to test this function of the player it seems the response is identical to component based on what I was able to find. According to that the original firmware crushes the peak white using the DVI output so if you have an older player that allows component output you should download the new firmware to fix that error for DVI applications but understand this will shut down the HD scaling dropping the player to 480P.
Uh oh!
While the player allowed HD scaling using the calibration DVDs it switched to 480P using any Hollywood movie due to copy protection. This would have greatly limited the subjective review of this test and also defeated the purpose of this review which was to research an economical alternative for those with analog only inputs and only a native HD scan rate. Further research led me to the Keohi HDTV website led by Michael Chen, a well known calibrator. My thanks to Michael for assisting me with getting the old firmware installed to get the HD component outputs turned back on. A link with full documentation on this procedure is provided at the end of this review. A complete series of waveforms was taken with the new and old firmware using 1080i and no difference was found.
Subjective Review
A number of discs were viewed in the Zenith DVB318 and directly compared to a Panasonic DVDRP91 feeding a Lumagen Vision external scaler via 480I analog and also feeding a Lumagen Vision HDP external scaler via SDI or digital video input. Both scalers have been calibrated with a scope for accurate waveform reproduction. The brightness level had to be turned down for the DVB318 due to the black level problem and also the color reduced 3 clicks lower due to the hotter color output.
No matter what I was watching two slightly different images. Due to the color decoder error greens were down in level and many hues did not match. Due to the black level error requiring readjustment of the brightness which goofs up the gamma response of the display the luminance seemed darker on the DVB318 burying differences in light output. Picture sharpness goes to the DVB318 but that is a no brainer due to the peaked response right in the area where we perceive sharpness, the fine line counts. Color detail goes to the DVB318 due to a clean chroma response in comparison to the external scalers even though it was rolled off.
I just happened to watch Shreck 2 from our local rental store which was scratched and the DVB 318 had far more trouble navigating those scratches then my Panasonic DVDRP91. While both players stuttered the Zenith was dropping far more content than the Panasonic.
The track functions also tended to hang up intermittently requiring pushing the button multiple times. There are notes on the internet that this may resolved by setting the auto playback feature to off but that appeared to have no effect on our review sample. While this was highly frustrating with the calibration discs it was far less of an issue with actual movies.
Conclusion
If accuracy is your passion you won?t find it here. Regardless of the 1080I scaling quality there are simply too many video signal errors in the wrong places and 720p only makes this worse. Perceptually, I still liked the player yet found myself frustrated with the incorrect color decoding and black level for the impact that had on the image. While subtle they none-the-less left their mark. Every time I went back to the external scalers I was greeted with a better overall image although with ever-so slightly less detail and most noticeable in the color. For me I will take that hit instead and have correct gamma and overall color response. That said if only the color decoder and black level were right I could have lived with the peaked response. I would happily use this player myself and recommend it far and wide for its mere $200 but, alas, it was not to be. One question is why would a manufacturer provide a DVD player with these errors? The black level I believe was a goof up. The peaked sweep response and the color decoder error, though, could easily be used to promote the product and it should be noted that my Zenith HDR230 DVR HDTV receiver has the exact same type of error. These errors are introduced to make the product appear different. Having less green and an artificially sharper image are certainly sales tools that can trick the buyer's perceptions.
What about you though? What if a better image rather than an accurate image is your goal? First place to start is your display. If it supports DVI/HDCP I would suggest looking at a different player with this feature due to the video signal errors. If you have a native 480P scan rate and are sitting at 4 screen heights or more then I suggest a 480p DVD player as there are accurately performing models available. That leaves us with folks who have only analog inputs and only one native 720P or 1080I scan rate. For 1080I this player may provide imaging nirvana at $200 since you will likely bypass far more artifacts from the internal scaler in the display. 720P is kind of an unknown since I could not subjectively review it and the waveform response is clearly worse. Another type of end user to consider this player, which is the same reason I even scale, is someone who is viewing a native 480P scan rate at less than 4 screen heights making the scan lines too evident. I watch 2.35 movies at 3.2 screen heights and 1.85 movies at 4. If getting rid of multiple artifacts from your internal scaler in exchange of three new ones works for you then this player is right up your alley!
A couple of things need to be pointed out though to any potential user. Most displays and systems are setup based on the source equipment providing the correct video signals or an external scaler in between to compensate for differences. What this means is if you have only one HD input or one HD internal calibration memory, which is nearly all of us, you will have to readjust the brightness control when switching back and forth. If some of you do not watch HDTV and instead use your display for DVD movies then depending on the display an ISF calibrator could feasibly compensate for most of the errors. Ditto if your display has more than one HD calibration memory or input that can be assigned its own user settings. It might be possible to get fairly accurate imaging out of this beast. Bear in mind that this input or the user settings example would not work correctly with any other source unless it had the same type of errors.
The purpose of this review has been successfully met which was to show you what artifacts and errors we will always have by inspecting the video waveforms. Over the next 30-60 days I will continue the subjective scaling review and may have an opportunity to test the DVI output during a calibration. Only time will tell if the scaling is really as flawless as my short time with the unit allowed me to verify. I will provide a follow up review if necessary. While highly unlikely maybe we will get lucky and LG/Zenith will provide a fix for the black level and color decoder.
LINKS
Zenith Website DVB318 specifications and information
Zenith Website owners manual
click on service/parts and then owners manuals
Zenith DVB318 firmware files
Click and Buy at Amazon.com
<a href="http://www.amazon.com/exec/obidos/redirect?path=ASIN/B00023CDL4&link_code=as2&camp=1789&tag=hdtvforum0c-20&creative=9325"><img border="0" src="http://images.amazon.com/images/P/B00023CDL4.01._AA_SCMZZZZZZZ_.jpg"></a><img src="http://www.assoc-amazon.com/e/ir?t=hdtvforum0c-20&l=as2&o=1&a=B00023CDL4" />
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By Richard Fisher
Due to the graphical nature of this column you may experience delays as the images are being downloaded.
Zenith DVB318 DVI/component HD Scaling DVD Player
There has been considerable buzz on the internet about this DVD player so it seemed fitting to make this our first review. There is ample written about this unit yet there is little specifically defining just what it can or cannot do to give the end-user seeking image accuracy any satisfaction.
This player is also available in Canada as the LG DV7832NXC. The main reason so many are ga ga over this unit is because it will output component video at HD scan rates--specifically 720p and 1080i--at the astounding MSRP of $249. It also provides a DVI connection with HDCP capacity but your display's DVI connector must support that if your DVI is to work. Unfortunately, I was unable to test that portion of the unit. That said, DVI presents a real challenge to the work we are trying to perform with this column as it is nearly impossible to test in an open manner due to all the security issues involved. The last time I investigated it I was informed that a very expensive computer is used to determine what the real response is for a DVI signal. True or not, the fact is that there is no inexpensive solution to test it, much less view it. It is so bad that all of us with analog-only video inputs may very well be blocked or down rezzed in the future HD-DVD world. At this time no outlet has been provided for legacy HDTV display owners who would like to be able to use DVI gear regardless of price. That situation, along with the inexpensive price, is the key to this unit?s popularity.
The reason this is important is because a number of the better known manufacturers changed their CRT displays from dual native scan rates to one single native HD scan rate. That means any other scan rate must be converted by the internal scaler of the display. To this day those scalers are inducing artifacts into the image. By feeding a display its native scan rate you bypass the internal scaler in most-all cases. That eliminates those artifacts. The twist, of course, is now your response is directly related to the scaling performance of the DVD player and its ability to generate correct video signals. Based on the last 3 years DVD scaling is likely to be the least of our worries as DVD players, in general, have been doing a far better job than their internal scaling cousins. Generating the correct signals for an accurate response is another matter entirely and that is the gist of this column.
Another point is that technically this DVD player is not supposed to allow HD scan rates via analog component video due to copy protection requirements on Hollywood movies for the U.S. market and the Zenith DVB318 was designed and destined for the U.S. market. While this is beyond the scope of this column, the reader should be aware that this capability with this player is a quirk and competing brands do not offer such. That said, there are gray market players destined for other countries which do provide this capability and they can be acquired by a U.S. resident via the internet.
Our review sample was purchased from Amazon.com for $200, received well packed and in good condition. The DVB318 sports the currently popular cosmetic silver with the slim chassis, meaning it is only 1.7? high. Compared to my older models this was a relief as there was enough room between the shelves to simply throw it on top of the pile. The front panel provides only the most simple of functions so, needless to say, don?t lose the remote! The remote is well designed in terms of size and ergonomics except for the location of the FF and RW functions, which is a shuttle dial at the bottom. The remote also provides glow-in-the-dark buttons which can be a bit irritating in a dark room. It was set face down once the movie started. The back panel sports DVI, component, s-video and composite video jacks with the NTSC video always active regardless of output scan rate. For digital audio you have both optical and coax plus one L/R analog output.
Setup is simple as there is little provided for you to adjust. Out of the box I did find the DRC, dynamic range compression and vocal setting was turned on and recommend you turn them off unless you really wanted those features active. On playback you have special search and playback control functions but curiously not the first sign of picture adjustments. There is not one single picture control on this unit and that was disconcerting as most provide at least a black level setup.
Scaling
We begin the review with scaling...
Using a Faroudja chip this product was quite astounding in it?s delivery of 1080I images. The 1080I scaling was simple and straightforward. Unfortunately, there is a snag when viewing 4:3 or letterboxed 4:3 content. Most displays do not have picture formatting available with an HD scan rate leaving you with no choice but to watch a stretched image in 4:3. The player does have an interesting zoom feature which allows you to stretch the image vertically or horizontally, but it does not allow you to squeeze the image, leaving you with stretching it vertically and cropping the top and bottom of a 4:3 image for some form of accurate geometry. I say form because it is completely variable rather than fixed and without a test pattern you will be hard pressed to set this accurately. For the movie portion of 16:9 enhanced masters this presents no problem so for these rare birds and extra features you could drop the scan rate to 480P regaining the display formatting controls except for one problem--the 480P scan rate is chock full of scaling artifacts. The following scenes are from the original Star Trek TV series.
[img]http://www.hdtvmagazine.com/images/forum/1DVB318.jpg[/img]
From left to right the first image has black streaks coming off of the edge, the middle has red pieces missing on two edges and one edge for last one. All of these artifacts were clearly visible in the image and occurred with other colors and edges as well with red being the most notorious. This player is not recommended for 480P applications, period. As for letterboxed 4:3 you can still vertically stretch it and while not accurate, it will satisfy most. The scaling of this kind of content was equally phenomenal, appearing very much like a 16:9 enhanced master.
Pixel cropping was checked with 15 pixels on the left and right sides, 9 pixels at the top and 0 pixels at the bottom. This equates to about 2% overscan and would only be an issue for those displays capable of less than 2%, which are very few.
Color Decoding
Unfortunately the DVB318 failed the color decoder test. The overall level is off requiring a recalibration of the color control, which is not a sever issue at all. What is a severe issue is the green channel.
[img]http://www.hdtvmagazine.com/images/forum/2DVB318.jpg[/img]
Overlooking the artifacts in the image note that the blue and red fields from Digital Video Essentials show very-little-to-no-shading while green shows a significant problem. Using Avia I find the green saturation is -20 to -25%, which is a huge error. What that means is that not only will green objects such as grass and trees appear lower in intensity, any other color that uses green as part of its mix will also be incorrect. If you are put off by red push then this error should be equally disturbing.
Waveforms 1080i
If you recall there were no picture controls to speak of. This creates a problem because the component video output is setup for NTSC video which uses 7.5 IRE as the black level instead of 0 IRE.
[img]http://www.hdtvmagazine.com/images/forum/3DVB318.jpg[/img]
The left image is the DVB318 and the error is right next to A=5us. The correct response is on the right. What this means is instead of putting out 700mv for video it is putting out 647.5mv and also raising the black level. While you can turn down the brightness on the display to compensate for this it will goof up the overall gamma response. For accurate component video response the black level must be set at 0 IRE. Besides that an accurate 1 volt peak to peak response was provided.
The next set of waveforms deals with frequency response and severe waveform distortion using the sweep and multiburst patterns from Avia and Digital Video Essentials.
[img]http://www.hdtvmagazine.com/images/forum/4DVB318.jpg[/img]
The left side is the DVB318 with the top being the sweep and the bottom the multiburst. The images to the right are the correct response. Note: the right image is not flat on the bottom. This is a small error from that DVD player. What this means for the DVB318 is the finer the line the higher the light output. While inaccurate, many will perceive this player to have a sharper image due to this artifact.
The next set of waveforms are of the same type but from Digital Video Essentials, DVE, which extends these patterns out to about 6Mhz rather than the 5Mhz used by Avia.
[img]http://www.hdtvmagazine.com/images/forum/5DVB318.jpg[/img]
The top two and bottom left are the DVB318. Just like the previous waveforms we are looking for a flat response. The bottom left is an extended frequency response multiburst from 5-6Mhz and shows severe distortion besides a rolled off response. This particular pattern will not pass correctly on any DVD player that I have. The one on the bottom right is from another DVD player and while it is not rolled off it has the same type of distortion. I am told this is caused by the MPEG decoder. Bottom line is a gain error of +2.5db for the peak and -4db for the roll off. Bear in mind prior to DVE there would not have been a roll off to document and this player would have been reported as having a +2.5db peak only.
[img]http://www.hdtvmagazine.com/images/forum/6DVB318.jpg[/img]
This distortion shows up as shading in the multiburst as shown above. The rolled off response reduces the light output of the mulitburst as well where the burst all the way left is brighter than the burst all the way right.
Finally, the color difference signals.
[img]http://www.hdtvmagazine.com/images/forum/7DVB318.jpg[/img]
The top left is the green channel and that is exactly what it should like. The top right is the blue color channel and the bottom left is the red color channel. The bottom right is another DVD player and a box has been drawn around the waveform to illustrate that here too we are looking for a flat response. What this represents is the color resolution or detail and is no different from the previous line or frequency response waveforms. The DVB318 is rolled off and while the other DVD player is providing a much better response it is also creating severe waveform distortion in the finest line count on the left side of the pattern that may be seen as a shading artifact similar to the luminance waveform and screen picture.
Waveforms 720p
The stair step pattern was identical to the 1080I response. The frequency response is another story.
[img]http://www.hdtvmagazine.com/images/forum/8DVB318.jpg[/img]
These are from DVE and there are serious problems
[img]http://www.hdtvmagazine.com/images/forum/9DVB318.jpg[/img]
These are from Avia. In either series you can see that we have nothing even remotely flat, much higher waveform distortion and the higher frequencies from DVE are significantly rolled off. The image to the right is the same waveform with an adjustment on the scope so I can see the whole pattern to take measurements, not a good sign. Bottom line here is a gain error of +3db for the peak with a severe -4db for the roll off based on Avia and a whopping -9db for the roll off based on DVE.
[img]http://www.hdtvmagazine.com/images/forum/10DVB318.jpg[/img]
This is the color response from DVE showing the green and blue channel. The red channel is not shown as it had the same response. The green is clean like 1080I but the blue channel shows more waveform distortion.
DVI Performance
While I was unable to test this function of the player it seems the response is identical to component based on what I was able to find. According to that the original firmware crushes the peak white using the DVI output so if you have an older player that allows component output you should download the new firmware to fix that error for DVI applications but understand this will shut down the HD scaling dropping the player to 480P.
Uh oh!
While the player allowed HD scaling using the calibration DVDs it switched to 480P using any Hollywood movie due to copy protection. This would have greatly limited the subjective review of this test and also defeated the purpose of this review which was to research an economical alternative for those with analog only inputs and only a native HD scan rate. Further research led me to the Keohi HDTV website led by Michael Chen, a well known calibrator. My thanks to Michael for assisting me with getting the old firmware installed to get the HD component outputs turned back on. A link with full documentation on this procedure is provided at the end of this review. A complete series of waveforms was taken with the new and old firmware using 1080i and no difference was found.
Subjective Review
A number of discs were viewed in the Zenith DVB318 and directly compared to a Panasonic DVDRP91 feeding a Lumagen Vision external scaler via 480I analog and also feeding a Lumagen Vision HDP external scaler via SDI or digital video input. Both scalers have been calibrated with a scope for accurate waveform reproduction. The brightness level had to be turned down for the DVB318 due to the black level problem and also the color reduced 3 clicks lower due to the hotter color output.
No matter what I was watching two slightly different images. Due to the color decoder error greens were down in level and many hues did not match. Due to the black level error requiring readjustment of the brightness which goofs up the gamma response of the display the luminance seemed darker on the DVB318 burying differences in light output. Picture sharpness goes to the DVB318 but that is a no brainer due to the peaked response right in the area where we perceive sharpness, the fine line counts. Color detail goes to the DVB318 due to a clean chroma response in comparison to the external scalers even though it was rolled off.
I just happened to watch Shreck 2 from our local rental store which was scratched and the DVB 318 had far more trouble navigating those scratches then my Panasonic DVDRP91. While both players stuttered the Zenith was dropping far more content than the Panasonic.
The track functions also tended to hang up intermittently requiring pushing the button multiple times. There are notes on the internet that this may resolved by setting the auto playback feature to off but that appeared to have no effect on our review sample. While this was highly frustrating with the calibration discs it was far less of an issue with actual movies.
Conclusion
If accuracy is your passion you won?t find it here. Regardless of the 1080I scaling quality there are simply too many video signal errors in the wrong places and 720p only makes this worse. Perceptually, I still liked the player yet found myself frustrated with the incorrect color decoding and black level for the impact that had on the image. While subtle they none-the-less left their mark. Every time I went back to the external scalers I was greeted with a better overall image although with ever-so slightly less detail and most noticeable in the color. For me I will take that hit instead and have correct gamma and overall color response. That said if only the color decoder and black level were right I could have lived with the peaked response. I would happily use this player myself and recommend it far and wide for its mere $200 but, alas, it was not to be. One question is why would a manufacturer provide a DVD player with these errors? The black level I believe was a goof up. The peaked sweep response and the color decoder error, though, could easily be used to promote the product and it should be noted that my Zenith HDR230 DVR HDTV receiver has the exact same type of error. These errors are introduced to make the product appear different. Having less green and an artificially sharper image are certainly sales tools that can trick the buyer's perceptions.
What about you though? What if a better image rather than an accurate image is your goal? First place to start is your display. If it supports DVI/HDCP I would suggest looking at a different player with this feature due to the video signal errors. If you have a native 480P scan rate and are sitting at 4 screen heights or more then I suggest a 480p DVD player as there are accurately performing models available. That leaves us with folks who have only analog inputs and only one native 720P or 1080I scan rate. For 1080I this player may provide imaging nirvana at $200 since you will likely bypass far more artifacts from the internal scaler in the display. 720P is kind of an unknown since I could not subjectively review it and the waveform response is clearly worse. Another type of end user to consider this player, which is the same reason I even scale, is someone who is viewing a native 480P scan rate at less than 4 screen heights making the scan lines too evident. I watch 2.35 movies at 3.2 screen heights and 1.85 movies at 4. If getting rid of multiple artifacts from your internal scaler in exchange of three new ones works for you then this player is right up your alley!
A couple of things need to be pointed out though to any potential user. Most displays and systems are setup based on the source equipment providing the correct video signals or an external scaler in between to compensate for differences. What this means is if you have only one HD input or one HD internal calibration memory, which is nearly all of us, you will have to readjust the brightness control when switching back and forth. If some of you do not watch HDTV and instead use your display for DVD movies then depending on the display an ISF calibrator could feasibly compensate for most of the errors. Ditto if your display has more than one HD calibration memory or input that can be assigned its own user settings. It might be possible to get fairly accurate imaging out of this beast. Bear in mind that this input or the user settings example would not work correctly with any other source unless it had the same type of errors.
The purpose of this review has been successfully met which was to show you what artifacts and errors we will always have by inspecting the video waveforms. Over the next 30-60 days I will continue the subjective scaling review and may have an opportunity to test the DVI output during a calibration. Only time will tell if the scaling is really as flawless as my short time with the unit allowed me to verify. I will provide a follow up review if necessary. While highly unlikely maybe we will get lucky and LG/Zenith will provide a fix for the black level and color decoder.
LINKS
Zenith Website DVB318 specifications and information
Zenith Website owners manual
click on service/parts and then owners manuals
Zenith DVB318 firmware files
Click and Buy at Amazon.com
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