1. 19 Nov, 2018 1 commit
    • Niklas Haas's avatar
      film_grain: implement film grain synthesis · cfa986fe
      Niklas Haas authored
      This is using a slightly adapted version of my GPU-based algorithm. The
      major difference to the algorithm suggested by the spec (and implemented
      in libaom) is that instead of using a line buffer to hold the previous
      row's film grain blocks, we compute each row/block fully independently.
      
      This opens up the door to exploit parallelism in the future, since we
      don't have any left->right or top->down dependency except for the PRNG
      state. (Which we could pre-compute for a massively parallel / GPU
      implementation)
      
      That being said, it's probably somewhat slower than using a line buffer
      for the serial / single CPU case, although most likely not by much
      (since the areas with the most redundant work get progressively smaller,
      down to a single 2x2 square for the worst case).
      cfa986fe