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  1. Member
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    HI
    i imported video files from my sony HDR-XR150 ( whis is HD AVCHD handycam) to vegas pro.12
    and vegas recognizes it as 1920x1080x12, what does 12 mean here?
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  2. Member DB83's Avatar
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    Look at your clip in mediainfo text mode and I suspect it simply means the bit-resolution of each pixel i.e.12-bit.
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  3. Probably 12 bits per pixel (8 bit YUV with 4:2:0 chroma subsampling). 1920x1080 luma with 960x540 chroma.
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  4. Member
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    tnx for your answers
    i dont know what does " bit-resolution" mean but media info for my file goes like this:
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Bits/(Pixel*Frame) : 0.410

    i think jagabo's answer makes sense
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  5. Member Cornucopia's Avatar
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    Background info:

    RGB (in standard 4:4:4 mode) uses 8 bits for each color primary for each and every pixel: 8 + 8 + 8 = 24bits
    YUV, in full 4:4:4 color sampling mode also uses 24 bits in the same way (just organized differently since no color primaries).
    YUV, in standard professional 4:2:2 color sampling mode uses 8bits for the Y (luma), 8bits for every other U and 8bits for every other V (the 2 chroma values), or (averaged) 8 + 8/2 + 8/2 = 8 + 4 + 4 = 16bits
    YUV, in standard consumer 4:2:0 color sampling mode uses 8 for Y, 8 for every other U and V, but on every other line, so that averages out to 8 + (8/2 /2) + (8/2 /2) = 8 + 2 + 2 = 12bits
    **

    Hopefully that will clear everything up. There are other real-world examples beyond these (<8-10-12-14-16-32> bits per color, other sampling options, addition of Alpha, etc), but these are currently the most commonly found.

    Scott

    **(Actually the 2nd & 3rd YUV numbers correspond to the H and V siting of BOTH the U and V sampling, not to separate respective U and V, but for illustration purposes, it ought to get the point across).
    Last edited by Cornucopia; 17th Apr 2014 at 02:37.
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  6. Member
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    tnx but are more or less bits any different?
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  7. DECEASED
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    ^ Yes, less bits = less "information" = less quality

    See this: http://en.wikipedia.org/wiki/Chroma_subsampling
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  8. Originally Posted by darknesslord View Post
    tnx but are more or less bits any different?
    As I indicated in my previous post, YUV 4:2:0 (aka YV12) has 1/2 (each dimension) the color resolution of YUV 4:4:4 or RGB 4:4;4. But most video formats are YV12 because the human eye has less color resolution than luma resolution. And most camera CCD sensors are similar.
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  9. Member
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    thank you guys
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  10. If you want to see the practical repercussions of 4:2:0 chroma subsampling see the image in this post:

    http://forum.videohelp.com/threads/278330-video-quality-on-SD-TV?p=1674987&viewfull=1#post1674987

    White text on a black background (or vice versa) would look the same with both 4:4:4 and 4:2:0 because greyscale information is stored at the same resolution.
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