Is it still 1920x1080 if it's widescreen?

Discussion in 'Displays' started by Ken Burkstrum, Nov 22, 2005.

  1. Ken Burkstrum

    Ken Burkstrum Stunt Coordinator

    Joined:
    Dec 19, 2003
    Messages:
    149
    Likes Received:
    0
    I'm curious about the relation between aspect ratio and pixel count. I'm not sure if pixel counts are just pixel counts or if they really do have a native resolution. Basing on computers, am I correct in thinking 1600x1200 is a 4:3 pixel count, 1920x1080 is a 16:9 pixel count and 1920x1200 is a 16:10 pixel count? I know TVs can scale this up or down but how come TVs don't know how to take something like widescreen and stretch it to fill a whole 4:3 screen? On my 1920x1200 computer monitor for instance, I can use Divx to take 4:3 or 16:9 material and change it to a 16:10 so I can full screen it, I know there's something not right about that method but hey, the picture doesn't look weird to me.

    I'm kind of confused how it all works. If you have a 1920x1080 resolution, is it any aspect the filmmaker wants it to be, 16:9, 2.35:1 etc, or is it native to one aspect and TVs scale up/down to fit it. I've seen these videos online that are supposed to be 1920x1080p but according to their properties they are only 1920x816p because of 2.35:1 aspect ratio. Why would you call a 2.35:1 video 1920x1080 if it's not really 1920x1080?
     
  2. Ken Burkstrum

    Ken Burkstrum Stunt Coordinator

    Joined:
    Dec 19, 2003
    Messages:
    149
    Likes Received:
    0
    oops, I meant to put this in Display Devices, admins if you'd be so kind.
     
  3. Roger_R

    Roger_R Second Unit

    Joined:
    Nov 6, 2003
    Messages:
    372
    Likes Received:
    1
    HDTVs and the forthcoming HD-DVD/Blu-ray players are set to work with specific resolutions, one of them being 1920x1080. When a movie's in 2.35:1, there's black bars added to the top and bottom when it's encoded into a 16:9 area like 1920x1080.

    The reason why those so-called 1080p trailers you download on the net not always are in 1920x1080 is because a PC can display a video of any resolution. Encoding a trailer intended to be shown on PC in 1920x1080 if it's in 2.35:1 would therefore be a waste of harddrive space since you'd have black pixels on the top and bottom. However, the same trailer would have to be encoded in 1920x1080 if it's put on a HD-DVD or Blu-ray because of the limitations I mentioned earlier.
     
  4. Ken Burkstrum

    Ken Burkstrum Stunt Coordinator

    Joined:
    Dec 19, 2003
    Messages:
    149
    Likes Received:
    0
    Wait, so with HD-DVDs and Blu-rays they are wasting some of the 1080 scan lines with top and bottom bars or do they scrunch it so the 2.35:1 so the source picture is 1920x1080? Or better yet, all DVDs are 720x480 right? Are they 720x480 in 4:3, 16:10, 16:9 and 2.35:1, or are some scan lines wasted on black bars? If that were so, 16:9 TVs wouldn't actually be watchin 480p and I dont think that's correct.
     
  5. Roger_R

    Roger_R Second Unit

    Joined:
    Nov 6, 2003
    Messages:
    372
    Likes Received:
    1
    Yeah, in effect there are some lines wasted when watching movies not in 16:9 with HDTV. Same goes for movies in 4:3 on HDTV where there's black bars on the sides of the image.

    With movies in 4:3, all the lines are used. When it comes to movies in 16:9, all the lines are used if it is anamorphically enhanced which means that the picture is stretched vertically to avoid having any black pixels. With movies wider than 16:9, there are black bars added to the top and bottom. Also, movies wider than 16:9 can be anamorphically enhanced, but there will still be black bars.
    On a 16:9 TV, anamorphically enhanced movies are simply stretched horizontally so that they appear as intended and on a 4:3 TV, the DVD player squeezes the picture back to its original shape and adds black bars to the top and bottom.
     
  6. Ken Burkstrum

    Ken Burkstrum Stunt Coordinator

    Joined:
    Dec 19, 2003
    Messages:
    149
    Likes Received:
    0
    So, 1920x1080 doesn't mean 16:9 right? It CAN be shrunken and stretched any which way? the whole 1080p can be in smushed into all aspects? I notice when I open videos on my computer that not only does it assume an aspect ratio, it'll fit itself relative to my screen. Like I have 1920x1200 so if it's 1920x1080, when I open it up it'll stretch from end to end, and leave alittle room on the top and bottom. See thats what bothers me though, you did say computers work different. When I opened this supposed 1920x1080 it didn't assume the 1920x1080 aspect with little black bars on top and bottom, it assumed 1920x816, with big black bars. Computers don't smush the resolution in the aspect right? So I was looking at 1920x816 on 1920x816 not 1920x1080 smushed into 1920x816, right?

    So on computers, videos have a fixed aspect ratio until you tamper with them, so that does prove that every resolution has a native aspect, but unlike TVs, on computers you can manually tamper with them. Am I right on this?
     
  7. Roger_R

    Roger_R Second Unit

    Joined:
    Nov 6, 2003
    Messages:
    372
    Likes Received:
    1
    Yeah, with editing software and some players too you can stretch the video all you want on computers. It'll look weird though if you deviate from the original aspect ratio. [​IMG]
     
  8. Ken Burkstrum

    Ken Burkstrum Stunt Coordinator

    Joined:
    Dec 19, 2003
    Messages:
    149
    Likes Received:
    0
    So unless a video has 1920 pixels on each line, I'm watching video that has been scaled on account of it's ratio? Like 1440x816 isn't going to be as tall as 1920x816 right? Or would it only scale one way and stretch 1440 pixels into 1920 and leave the 816 alone?

    Finally, do any 1920x1200 videos exist? [​IMG]
     
  9. Roger_R

    Roger_R Second Unit

    Joined:
    Nov 6, 2003
    Messages:
    372
    Likes Received:
    1
    That'd be something with an aspect ratio of 1.6:1. The closest film format is 1.66:1. I have no idea where they came up with 16:10, but I've seen a lot of monitors in that format.
     
  10. Ken Burkstrum

    Ken Burkstrum Stunt Coordinator

    Joined:
    Dec 19, 2003
    Messages:
    149
    Likes Received:
    0
    So one more time, 1280x720 is 16:9, you watch it on a 1280x720 16:9 TV. If the HD-DVD your watching is 2.35:1 it won't squeeze 1280x720 into 2.35:1, it'll take the image and fill out the viewable area with what is it, 1024x464? So instead of watching 1280x720 in a 1024x464 screen are, your watching 1280x720 that was scaled down to 1024x464 and viewed in a 1024x464 area? Or is it one in the same, it's so confusing to me. Wow high definition is a loose term. I know when you scale up from say 1280x720 to a 1920x1080 screen, it takes 1280x720 source stretches it and fills in the rest of pixels the best it can, it's scaling down that's got my mind in knots.
     
  11. Ken Chan

    Ken Chan Producer

    Joined:
    Apr 11, 1999
    Messages:
    3,301
    Likes Received:
    0
    DVD uses 720x480 pixels for either a 4:3 frame or a 16:9 frame; in neither case are the pixels square. HD uses 1920x1080 or 1280x720 for 16:9 only; the pixels are always square. For either format, if the image does not match the frame, you have black pixels to fill the frame.

    That may not be the question you really wanted to ask. I don't know of any standard video formats that uses that frame size. (To confuse things though, widescreen LCD computer monitors in the 24" range are that size. You might think of such a screen as being capable of displaying a full 1920x1080 frame, pixel-for-pixel, with an extra strip for controls on the top/bottom.) But of course you can take any video and crop/scale/fill it to any pixel frame/shape.
     

Share This Page