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Analogto digital conversion comparisons???

Discussion in 'Archived Threads 2001-2004' started by Scott_AH, Oct 7, 2002.

  1. Scott_AH

    Scott_AH Stunt Coordinator

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    I'm looking into many different HD RPTVs and have come across one important question that no salesman can answer for me: Do different brands of HD RPTVs convert an analog antenna or cable signal to digital differently? All these TVs claim to have a better method of conversion than their competitors but what exactly is done during the conversion? Does the signal go from 480i to 480p? My Best Buy saleswoman claimed that Mitsubishi has the best method but I don't know how much she really knows or if she just wants to make a sale. I'm pretty new to all this so any info would be very helpful.

    Scott
     
  2. Jan Strnad

    Jan Strnad Screenwriter

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    They have line doublers that do indeed convert 480i to 480p or to 540p (Toshiba, Hitachi, maybe some others).

    You will lose some sharpness in the very top end if the set upconverts to 540p. However, you won't notice it outside of a test pattern on the new Toshibas; I don't know about the new Hitachis. The benefit: no scan lines, even on ordinary broadcast material.

    Balancing out the upconversion, and outweighing it substantially IMO, is that the line doubler in Toshibas does an excellent job with mediocre cable or satellite signals, whereas Sony (for instance) gives a great picture with a great signal but their line doubler doesn't do well with mediocre signals. So I've read here and elsewhere.

    Best Buy has started carrying Mitsubishi, so they're getting a lot of attention lately. They are supposed to have excellent pictures, but poor stretch modes. So check out how a cable feed looks "stretched" on all the sets and make sure you can live with it for casual viewing.

    Panasonic is also well thought of, as is Pioneer. You'll find individuals boosting or bashing any brand, but all of the majors have their supporters, all of the sets involve some kind of trade-off, and chances are, as with adopting a puppy, you'll love whichever one you take home.

    Jan
     
  3. Allan Jayne

    Allan Jayne Cinematographer

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    There are many ways of de-interlacing (line doubling), there are many ways of getting from interlaced analog 480i to the final display on an HDTV monitor. Quality can vary widely and I don't know what makes and models do what.
    If everything ultimately ends up as 1080i so the picture tube scanning is always the same, it is better to go from 480i to 480p first and then to 1080i (540p) rather than 480i directly to 1080i. The latter is really a 240p to 540p conversion and is noticeably inferior.
    In my opinion an HDTV with two speed scanning (960i and 1080i) does a better display of 480p than a 1080i only scan. The only difference between 960i and 480p is a slight staggering of alternate frames on the picture tube done by the final stages of the video electronics. This stagger is mandatory for HDTV otherwise you lose half the vertical resolution.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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