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in this forum most of the discussion about what mainly determines quality in DVD players relates to the quality of the progressive scan output on NTSC players, and this is determined mainly by the hardware used for the deinterlacer circuitry ( from Genesis/Sag/Faroudja and ilImage/DVDO) .


i havnt seen much specific discussion about the mpeg decoder chips used in the different brand DVD players in the usa or europe.

- does this mean that most current DVD players all use the same chip ?

- or does this mean that there is very little quality difference between various brands mpeg decoder chips ?

- do the latest mpeg decoder chips in current cheap DVD players (like the panasonic mpeg decoder chip MN677531KA in the latest panasonic RP-82 ) outperform a mpeg decoder used in a 1500$ DVD player that is 18 months old ?


my DVD player is for use with a european CRT tv (pal standard) with RGB video connections, and i want the best possible picture. (audio quality for CD play is also important but is secondery, and DVD-A or SACD are not important at all to me, neither is ntsc progresive scan).


i am considering a just superceded toshiba 900E DVD player (replaced by the 9500 model) based on the "zoran vadis" mpeg decoder chip, or the Denon 2800-MK2 (unknown chipset). the panasonic RP-82 is only available here with component out, and i dont want to use an addon converter to turn it into RGB out.


one of the main authors of the "secrets" webpage review, uses i believe a panasonic RP-82 DVD player where he has a HighEnd SDI output board connected directly to the mpeg decoder output, thus bypassing all the processing and manipulation that occurs afterwards, and creating a digital output. is this something i/we should consider and just focus on the best quality mpeg-2 decoder chip ?


can somebody explain the quality differences in mpeg decoder chip's ?, or point me to information sources on this, and what their strength/weaknes are ? have any comparetive tests been done that directly focus on this aspect of dvd players ?
 

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Discussion Starter #2
bump



this seems a ligitimate question to me :)


can somebody explain the types/brands of mpeg decoder chips used in DVD players ? and the quality differences for these different decoder chip's ?
 

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It is a legitimate question, but the problem is that hard answers are difficult to come by. There are certainly differences between different MPEG decoders, some of them more subtle than others. The competition is fierce, and many chip makers have stopped designing new chips because it's so hard to make money.


The MPEG decoder manufacturers sell to the box manufacturers, who care mostly about:


- Basic chip cost

- Implementation cost (does it require extra memory chips, does it need a more expensive motherboard design, etc.)

- Flexibility for adding distinctive UI features


I believe that most box manufacturers think of MPEG decoders as commodity items, or close to it. So they're likely to choose the chipset that's going to be cheapest to stick a box around. This is what's driving the popularity of the newer "all in one" chipsets that have a DAC, a deinterlacing engine, and a decoder (and in some cases a DVD controller) all on one chip. Certainly output quality enters the equation somewhere, but it's less important (most of the time) than driving down the costs. Most of the money is in mass-market players at Wal-Mart.


From the consumer's perspective, the kinds of things that matter are:


- Robust handling of discs with encoding errors and/or complicated options like multi-angle, seamless branching, etc.

- Chroma upsampling (lack of chroma bug, but also quality of upsampling algorithms)

- Quality deinterlacing (if the chip includes a deinterlacer)

- 4x3 downconversion quality

- Scaling/zooming ability and quality of scaling algorithms


Evaluating who makes the "best" decoders is a complicated business.


Panasonic makes excellent decoders, but they don't have internal deinterlacing, their downconversion is good but not spectacular, and they don't scale.


Mediamatics (National Semiconductor) makes a line of all-in-one chips with spectacular scaling and upsampling and excellent DACs, but lackluster deinterlacing.


Zoran makes a new all-in-one similar to the Mediamatics, with somewhat better deinterlacing, but it still has the chroma bug (why, Zoran, why????).


ESS makes mainly inexpensive bare-bones chips, but they aren't bad, and recently they've fixed the chroma bug because of pressure from Denon.


That's just off the top of my head. There are many other manufacturers. I don't think any of them makes a "perfect" chip. Personally, I don't take any chip maker seriously if they still have the chroma bug. The bug has been known long enough for them to fix it.


Ultimately, though, the implementation of a player makes a huge difference. Often two players with the same MPEG decoder will be very similar, but in some cases a manufacturer will completely mess up the implementation and make a bad DVD player out of a good chip. In other cases, manufacturers will find clever ways to work around the limitations of a lackluster chip. So while it's interesting to know what chip a player is using, in the end it's the final output that counts.


Don
 

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dmunsil,


thank you for your extensive answer, it explained the issues very well.


your information combined with the information i found in a recent posting by "sspears" in another thread ( ... Honest and accurate.....) have given me a much better understanding.


rather than having tunnel vision and just focussing on the presence/absence of a particular "bug" , i am now more able to judge the significance of these various errors in the overall performance of a particular dvd player.
 
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