VideoHelp Forum
+ Reply to Thread
Results 1 to 7 of 7
Thread
  1. Member budwzr's Avatar
    Join Date
    Apr 2007
    Location
    City Of Angels
    Search Comp PM
    So my thinking now is that changes to contrast, color, brightness, sharpening, etc. are best done "before" upscaling low-def to hi-def. Is this in fact the correct procedure?

    I want to start collecting some of the free public domain stuff that's still somewhat interesting. I found some old gold mine maps online, so I want to enlarge some of the details. The maps are hand drawn, but quite detailed. But the resolution is 72dpi on a monitor.

    I would ideally like to print out sections on separate pages, like a regular atlas. Probably like to print at 300dpi to 8.5X11 pages, however many it takes.
    Quote Quote  
  2. I usually do most of the filtering before upscaling. For the most part, I only upscale animated material. Hand drawn maps would probably fit in that category.
    Quote Quote  
  3. Member budwzr's Avatar
    Join Date
    Apr 2007
    Location
    City Of Angels
    Search Comp PM
    OK. Thanks. As a side note, is there any benefit to convert to grayscale?
    Quote Quote  
  4. Most black and white material has a color cast or noise in the chroma channels. I usually convert to pure greyscale. You get slightly better compression when the chroma channels are flat.
    Quote Quote  
  5. Member budwzr's Avatar
    Join Date
    Apr 2007
    Location
    City Of Angels
    Search Comp PM
    Okey Dokey.
    Quote Quote  
  6. Originally Posted by budwzr View Post
    OK. Thanks. As a side note, is there any benefit to convert to grayscale?
    depends how this will be performed - if chroma plane will be clipped to 128 (YCbCr) then seem to be fine but if some fancy grayscale method is used then it can reintroduce chroma noise in luminance channel. I would recommend or "desaturate" or under Avisynth simple Limiter(0, 255, 128, 128) for YCbCr.
    Quote Quote  
  7. I usually use ColorYUV(cont_u=-256, cont_v=-256) because I'm usually using ColorYUV() anyway. GreyScale() works fine too.

    Beware, some other filters cause chroma problems. For example Stab() causes chroma to bounce up and down by a unit.
    Quote Quote  
Visit our sponsor! Try DVDFab and backup Blu-rays!