1. 29 5月, 2016 5 次提交
  2. 27 5月, 2016 5 次提交
  3. 26 5月, 2016 12 次提交
  4. 25 5月, 2016 4 次提交
  5. 24 5月, 2016 2 次提交
  6. 23 5月, 2016 10 次提交
  7. 19 5月, 2016 2 次提交
    • A
      nvenc: allow setting the number of slices · 3399a26d
      Anton Khirnov 提交于
      Based on a patch by Agatha Hu <ahu@nvidia.com>
      3399a26d
    • P
      nvenc: De-compensate aspect ratio compensation of DVD-like content. · 10545f84
      Philip Langdale 提交于
      For reasons we are not privy to, nvidia decided that the nvenc encoder
      should apply aspect ratio compensation to 'DVD like' content, assuming that
      the content is not BT.601 compliant, but needs to be BT.601 compliant. In
      this context, that means that they make the following, questionable,
      assumptions:
      
      1) If the input dimensions are 720x480 or 720x576, assume the content has
      an active area of 704x480 or 704x576.
      
      2) Assume that whatever the input sample aspect ratio is, it does not account
      for the difference between 'physical' and 'active' dimensions.
      
      From these assumptions, they then conclude that they can 'help', by adjusting
      the sample aspect ratio by a factor of 45/44. And indeed, if you wanted to
      display only the 704 wide active area with the same aspect ratio as the full
      720 wide image - this would be the correct adjustment factor, but what if you
      don't? And more importantly, what if you're used to lavc not making this kind
      of adjustment at encode time - because none of the other encoders do this!
      
      And, what if you had already accounted for BT.601 and your input had the
      correct attributes? Well, it's going to apply the compensation anyway!
      So, if you take some content, and feed it through nvenc repeatedly, it
      will keep scaling the aspect ratio every time, stretching your video out
      more and more and more.
      
      So, clearly, regardless of whether you want to apply bt.601 aspect ratio
      adjustments or not, this is not the way to do it. With any other lavc
      encoder, you would do it as part of defining your input parameters or do
      the adjustment at playback time, and there's no reason by nvenc should
      be any different.
      
      This change adds some logic to undo the compensation that nvenc would
      otherwise do.
      
      nvidia engineers have told us that they will work to make this
      compensation mechanism optional in a future release of the nvenc
      SDK. At that point, we can adapt accordingly.
      Signed-off-by: NPhilip Langdale <philipl@overt.org>
      Reviewed-by: NTimo Rothenpieler <timo@rothenpieler.org>
      Signed-off-by: NAnton Khirnov <anton@khirnov.net>
      10545f84