What is typical (horizontal lines) for these devices??? Also confuscious speaks...

Discussion in 'Archived Threads 2001-2004' started by Brad Craig, Feb 26, 2002.

  1. Brad Craig

    Brad Craig Stunt Coordinator

    Joined:
    Feb 1, 2002
    Messages:
    58
    Likes Received:
    0
    Trophy Points:
    0
    I know like progressive scan DVD = 480p
    Non progressive-scan dvd = 480i
    So what do you typically get(horizontal lines)out of the following???
    Satellite service like dish network or directTV???
    What is the difference between a digital satellite receiver and others???
    Typical CATV broadcast???
    VCR???
    High-Defintion TV broadcast???
    What gives you a 1080i picture???
    What looks better 480p or 960i??? Can u tell a difference???
    Does anything create 960i???
    Does a line doubler only double interlaced lines, and if so does it always double interlaced signals like TV broadcasts or how does that work??? Or do you tell it when to double a interlaced signal???
    Confuscious speaks...
    [​IMG]
    Thanks for you replies...
     
  2. Allan Jayne

    Allan Jayne Cinematographer

    Joined:
    Nov 1, 1998
    Messages:
    2,404
    Likes Received:
    0
    Trophy Points:
    0
    960i is fundamentally the same as 480p except that every other frame is painted on the picture tube a tad lower. 960i is a function of the TV, not of the source material. It is not a standard, and is used on large screens to hide the gaps between scan lines without having to use a fatter electron beam that detracts from ability to resolve fine side by side details (horizontal resolution). Currently there is no true 960i source material.
    The better 960i TV sets do some blending so the scan lines are not really paired duplicates. This blending makes diagonal lines and edges smoother.
    960i may also be an accidental byproduct on some HDTV sets where for 1080i it is mandatory that alternate scannings of the picture tube be staggered downward to keep the 1080i from degenerating into 540p.
    The typical line doubler is intended to take just one kind of input and deliver just one kind of output. For NTSC, the input is 480i and the output is 480p. Feeding a doubler with the wrong kind of input or connecting it to a TV that doesn't accept the output will produce unpredictable results. When the TV has just one set of component jacks to take 480p and 480i, it should detect which is which and cause 480p to skip the built in doubler. There are some multipurpose doublers, for example some also take PAL (convert 576i to 576p). Additional features such as convert interlaced NTSC to progressive PAL or convert NTSC to 1080i may or may not be present. If there are conversions other than doubling of the scan lines with or without deciding when to interpolate versus weave lines from the next field, the device is called a scaler rather than a doubler.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  3. Brad Craig

    Brad Craig Stunt Coordinator

    Joined:
    Feb 1, 2002
    Messages:
    58
    Likes Received:
    0
    Trophy Points:
    0
    So in essence are you saying line doublers will always take interlaced signals and change them to progressive signals???

    In 2006 when broadcasts in HDTV are suppose to be standard, what will be the supposed quality of the signal???

    Also are you saying that the only way to get 1080i in a picture is determined internally by the TV vs the signal being fed to the TV???

    I just don't understand how a NTSC signal of 480i can be converted to 1080i???

    Finally what kind of signal quality does a satellite give you??? The reason I ask is because I use to live w/ a friend who had one and the quality seemed better and also if the signal broke up, it was in squares so I assume it was a digital picture of sorts...
     
  4. Greg_R

    Greg_R Screenwriter

    Joined:
    Apr 9, 2000
    Messages:
    1,996
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Portland, OR
    Real Name:
    Greg
    It depends on which satellite & channel you're watching. You can get HD broadcasts (HD-HBO for example) but this requires special equipment (dish & decoder). DSS is a MPEG-2 encoded bitstream (digital). When the receiver loses information you'll see pixelation (just like watching a scratched DVD).
     
  5. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
    Sounds like a digital satellite signal-- the source is digital in transmission, but it is converted to an analog signal for display on a NTSC TV. I don't know the native res of Sat TV, but I assume it's close to the 25-300 level of Cable/VHS. Some sat services currently offer HD channels- with a special box and special dish.
    -Vince
     
  6. Brad Craig

    Brad Craig Stunt Coordinator

    Joined:
    Feb 1, 2002
    Messages:
    58
    Likes Received:
    0
    Trophy Points:
    0
    Do all HDTV's have scalers??? Because they must considering they claim being able to do 1080i right???

    Also do you tell it to scale the picture up internally in the TV menu???

    Finally is the picture quality twice as good when you scale 480i off a dvd player to 1080i lets say??? I mean is there any distortion???

    Also sounds like 480p (dvd quality) is about as good as a picture you can get...
     
  7. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    Trophy Points:
    0
     
  8. Larry Cole

    Larry Cole Auditioning

    Joined:
    Jan 30, 2002
    Messages:
    6
    Likes Received:
    0
    Trophy Points:
    0
    After years of poor reception living in the mountains of Colorado, I got the Dish Network in December. I've been disappointed with all the compression artifacts. During busy scenes, dissolves, or fades to black, it looks like I have bubblewrap taped in front of my screen. I work at a network uplink and know what this stuff looks like when it leaves playback and it's a lot better than what comes back. I know Charlie Ergen like to penny-pinch, but I sure hope he gets more satellites up (or merges with DirecTV) and quits compressing so aggressively. I have a friend that has the HDTV package from Echostar and it looks just like the stuff I've been seeing at NAB for the last few years - fabulous.
     
  9. Brad Craig

    Brad Craig Stunt Coordinator

    Joined:
    Feb 1, 2002
    Messages:
    58
    Likes Received:
    0
    Trophy Points:
    0
    What does DVHS and HTPC stand for???
     
  10. Allan Jayne

    Allan Jayne Cinematographer

    Joined:
    Nov 1, 1998
    Messages:
    2,404
    Likes Received:
    0
    Trophy Points:
    0
    HTPC -- Personal computer equipped with MPEG decoder card, sound card, DVD drive, and appropriate software to go with your home theater.

    DVHS -- A digital recording format that uses the same videocassettes we now use for VHS.

    By the way, all of the following are 480i in the U.S.:

    Regular VHS and S-VHS

    Most channels nowadays on CATV

    Satellite service, most dish and DirectTV channels today
     

Share This Page