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benyig
benyig
Known Participant
February 8, 2017
Answered

DNxHD HQ vs. QuickTime Animation - confused...

  • February 8, 2017
  • 1 reply
  • 2142 views

Hello,

I'm trying to pick the best intermediate codec for my fullHD project. I need it to be lossless if possible, but size is also a concern.

So far, QuickTime Animation seems to be the winner (which should be lossless) but I thought I'd give a try to DNxHD HQ too, which is slightly lossy AFAIK but should produce smaller files. Turns out, I was wrong, the DNxHD files are 40-50% larger than the Animation ones.

How is it possible? Is the Animation codec lossy? Is the newer DNxHD HQ codec lossless but have an inferior compression ratio? I'm confused.

    This topic has been closed for replies.
    Correct answer R Neil Haugen

    Doesn't work like that, as each codec has it's own methods of compression and of setting bitrates. And the method of compression matched with the bitrate of data written to file determine the resultant file size on disc.

    What he is saying is that the Animation codec, using a variable bit-rate, encodes some frames with a lot less data (as some frames can get by with less) while DNx uses a constant bit-rate per frame. Therefore in this case, DNx did produce a larger file.

    Which doesn't say anything really about the quality of each output, just the method used to get there.

    Between being lossless and variable bit-rate, it sounds like the Animation choice is probably better for your needs.

    Neil

    1 reply

    E
    excited_Genie16B8
    Legend
    February 8, 2017

    Animation is lossless, but variable bitrate.  DNx is lossy, but fixed bitrate.

    Bitrate is the determiner of file size, here.

    benyig
    benyigAuthor
    Known Participant
    February 8, 2017

    What do you mean exactly? That if two videos have the same resolution, bit depth, fps, and length, DNx will produce the same file size regardless of content?

    R Neil Haugen
    R Neil HaugenCorrect answer
    Legend
    February 8, 2017

    Doesn't work like that, as each codec has it's own methods of compression and of setting bitrates. And the method of compression matched with the bitrate of data written to file determine the resultant file size on disc.

    What he is saying is that the Animation codec, using a variable bit-rate, encodes some frames with a lot less data (as some frames can get by with less) while DNx uses a constant bit-rate per frame. Therefore in this case, DNx did produce a larger file.

    Which doesn't say anything really about the quality of each output, just the method used to get there.

    Between being lossless and variable bit-rate, it sounds like the Animation choice is probably better for your needs.

    Neil

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