)]}'
{
  "commit": "470efbcf01b452d365618b1dfb1f3b4eb1479c6f",
  "tree": "2a4da776a18e6f1b8ac64c03ca75169a293f5594",
  "parents": [
    "32658e2ab84df9855491fabc8f2ae07aecb38f70"
  ],
  "author": {
    "name": "Guillaume Martres",
    "email": "gmartres@mozilla.com",
    "time": "Tue Aug 23 01:16:35 2016 -0700"
  },
  "committer": {
    "name": "Yaowu Xu",
    "email": "yaowu@google.com",
    "time": "Tue Oct 18 14:40:15 2016 -0700"
  },
  "message": "Remove rd_variance_adjustment\n\nThis function is called after `super_block_yrd` and assumes that the dst\nbuffer is correct but that is no longer always the case after\ndaf841b4a10ece1b6831300d79f271d00f9d027b since we don\u0027t call\n`txfm_rd_in_plane` after the RDO loop in `choose_tx_size_from_rd`.\nWe could fix this by always saving and restoring the dst buffer but\nremoving `rd_variance_adjustment` is a better solution:\n- Getting the dst buffer always right is tricky as demonstrated by the\n  fact that it is wrong now, even if we fix it now we could break it later\n  and not notice\n- Perceptual weighting is a good idea but `rd_variance_adjustment` is the\n  wrong approach as it weights both the rate and the distortion:\n  to get meaningful units you should only weight the distortion,\n  weighting rate means that we pretend some bits cost less than other\n  bits, this is not the case. The distortion weighting approach is\n  implemented by Daala in `od_compute_dist` and we plan to experiment\n  with this in AV1 too.\n- Removing `rd_variance_adjustment` improves coding efficiency on all\n  metrics, here are the results for objective-1-fast using the Low\n  Latency settings:\n\n      PSNR Y:     -0.14%\n     PSNRHVS:     -0.17%\n        SSIM:     -0.12%\n      MSSSIM:     -0.12%\n   CIEDE2000:     -0.07%\n\nChange-Id: I74b26b568ee65f56521646b8f30dd53bcd29fce3\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "bd5ae7ea45cc5a6a03ae01cdb0ab2c415c4f6f68",
      "old_mode": 33188,
      "old_path": "av1/encoder/rdopt.c",
      "new_id": "6f4a0d723a3021534c762e28516800fa8ecf16b0",
      "new_mode": 33188,
      "new_path": "av1/encoder/rdopt.c"
    }
  ]
}