{"action":"created","issue":{"url":"https://api.github.com/repos/sqeazy/sqeazy/issues/4","repository_url":"https://api.github.com/repos/sqeazy/sqeazy","labels_url":"https://api.github.com/repos/sqeazy/sqeazy/issues/4/labels{/name}","comments_url":"https://api.github.com/repos/sqeazy/sqeazy/issues/4/comments","events_url":"https://api.github.com/repos/sqeazy/sqeazy/issues/4/events","html_url":"https://github.com/sqeazy/sqeazy/issues/4","id":166137662,"number":4,"title":"quantiser screws up lossy h264 ","user":{"login":"maweigert","id":11042162,"avatar_url":"https://avatars.githubusercontent.com/u/11042162?v=3","gravatar_id":"","url":"https://api.github.com/users/maweigert","html_url":"https://github.com/maweigert","followers_url":"https://api.github.com/users/maweigert/followers","following_url":"https://api.github.com/users/maweigert/following{/other_user}","gists_url":"https://api.github.com/users/maweigert/gists{/gist_id}","starred_url":"https://api.github.com/users/maweigert/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/maweigert/subscriptions","organizations_url":"https://api.github.com/users/maweigert/orgs","repos_url":"https://api.github.com/users/maweigert/repos","events_url":"https://api.github.com/users/maweigert/events{/privacy}","received_events_url":"https://api.github.com/users/maweigert/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":{"login":"psteinb","id":1465603,"avatar_url":"https://avatars.githubusercontent.com/u/1465603?v=3","gravatar_id":"","url":"https://api.github.com/users/psteinb","html_url":"https://github.com/psteinb","followers_url":"https://api.github.com/users/psteinb/followers","following_url":"https://api.github.com/users/psteinb/following{/other_user}","gists_url":"https://api.github.com/users/psteinb/gists{/gist_id}","starred_url":"https://api.github.com/users/psteinb/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/psteinb/subscriptions","organizations_url":"https://api.github.com/users/psteinb/orgs","repos_url":"https://api.github.com/users/psteinb/repos","events_url":"https://api.github.com/users/psteinb/events{/privacy}","received_events_url":"https://api.github.com/users/psteinb/received_events","type":"User","site_admin":false},"assignees":[{"login":"psteinb","id":1465603,"avatar_url":"https://avatars.githubusercontent.com/u/1465603?v=3","gravatar_id":"","url":"https://api.github.com/users/psteinb","html_url":"https://github.com/psteinb","followers_url":"https://api.github.com/users/psteinb/followers","following_url":"https://api.github.com/users/psteinb/following{/other_user}","gists_url":"https://api.github.com/users/psteinb/gists{/gist_id}","starred_url":"https://api.github.com/users/psteinb/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/psteinb/subscriptions","organizations_url":"https://api.github.com/users/psteinb/orgs","repos_url":"https://api.github.com/users/psteinb/repos","events_url":"https://api.github.com/users/psteinb/events{/privacy}","received_events_url":"https://api.github.com/users/psteinb/received_events","type":"User","site_admin":false}],"milestone":null,"comments":6,"created_at":"2016-07-18T16:37:17Z","updated_at":"2016-11-07T08:49:52Z","closed_at":null,"body":"The quantiser works strange for areas of high value, see image:\n![screen shot 2016-07-18 at 18 34 06](https://cloud.githubusercontent.com/assets/11042162/16922559/52f83cdc-4d16-11e6-964d-b4ac2a54557d.png)\nHere the difference between quantised (a sqy roundtrip with just a quantiser) and original should not be more than 4 (original has maximal value of ca 800) but is 150. This somehow makes the lossy h264 encoding giving bogus values (see right image). The lossless version however works fine on it. \n\nedit: Example data was Keller_TM0066_Droso_HisGFP.tif, z = 50 \n"},"comment":{"url":"https://api.github.com/repos/sqeazy/sqeazy/issues/comments/258777804","html_url":"https://github.com/sqeazy/sqeazy/issues/4#issuecomment-258777804","issue_url":"https://api.github.com/repos/sqeazy/sqeazy/issues/4","id":258777804,"user":{"login":"psteinb","id":1465603,"avatar_url":"https://avatars.githubusercontent.com/u/1465603?v=3","gravatar_id":"","url":"https://api.github.com/users/psteinb","html_url":"https://github.com/psteinb","followers_url":"https://api.github.com/users/psteinb/followers","following_url":"https://api.github.com/users/psteinb/following{/other_user}","gists_url":"https://api.github.com/users/psteinb/gists{/gist_id}","starred_url":"https://api.github.com/users/psteinb/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/psteinb/subscriptions","organizations_url":"https://api.github.com/users/psteinb/orgs","repos_url":"https://api.github.com/users/psteinb/repos","events_url":"https://api.github.com/users/psteinb/events{/privacy}","received_events_url":"https://api.github.com/users/psteinb/received_events","type":"User","site_admin":false},"created_at":"2016-11-07T08:49:52Z","updated_at":"2016-11-07T08:49:52Z","body":"couldn't resist doing a little study:\r\n```\r\n|--------------------------------------------+--------|\r\n|         ref=Keller_TM0066_Droso_HisGFP.tif | mse    |\r\n|--------------------------------------------+--------|\r\n|         Keller_TM0066_quant_h264_crf00.tif | 6.76   |\r\n|         Keller_TM0066_quant_h264_crf02.tif | 92.4   |\r\n|         Keller_TM0066_quant_h264_crf04.tif | 113.6  |\r\n|         Keller_TM0066_quant_h264_crf06.tif | 134.5  |\r\n|         Keller_TM0066_quant_h264_crf08.tif | 147.6  |\r\n|         Keller_TM0066_quant_h264_crf10.tif | 158.2  |\r\n|         Keller_TM0066_quant_h264_crf18.tif | 226.2  |\r\n|         Keller_TM0066_quant_h264_crf20.tif | 253.9  |\r\n|         Keller_TM0066_quant_h264_crf22.tif | 314.6  |\r\n|         Keller_TM0066_quant_h264_crf24.tif | 395.1  |\r\n|         Keller_TM0066_quant_h264_crf26.tif | 479.9  |\r\n|         Keller_TM0066_quant_h264_crf28.tif | 556.3  |\r\n|         Keller_TM0066_quant_h264_crf38.tif | 885.2  |\r\n|         Keller_TM0066_quant_h264_crf51.tif | 1320   |\r\n|                    Keller_TM0066_quant.tif | 6.76   |\r\n|--------------------------------------------+--------|\r\n```\r\n`crf=0` equals lossless compression. My take on this is that h264 does do some aggressive compression. looking at the stats of the individual files also reveals:\r\n\r\n```\r\n|----------------------------------------+-----+-----+------+--------+-----------+--------+------------|\r\n|                               filename | min | max | mean | stddev | .25*quant | median | .75*quant  |\r\n|----------------------------------------+-----+-----+------+--------+-----------+--------+------------|\r\n|         Keller_TM0066_Droso_HisGFP.tif | 0   | 885 | 51   | 72     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf00.tif | 0   | 502 | 51   | 72     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf02.tif | 0   | 502 | 51   | 72     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf04.tif | 0   | 502 | 51   | 72     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf06.tif | 0   | 502 | 51   | 71     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf08.tif | 0   | 502 | 50   | 71     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf10.tif | 0   | 502 | 50   | 71     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf18.tif | 0   | 502 | 50   | 70     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf20.tif | 0   | 502 | 50   | 70     | 5.5       | 14     | 80         |\r\n|     Keller_TM0066_quant_h264_crf22.tif | 0   | 502 | 50   | 70     | 6.5       | 13     | 80         |\r\n|     Keller_TM0066_quant_h264_crf24.tif | 0   | 502 | 50   | 69     | 6.6       | 12     | 80         |\r\n|     Keller_TM0066_quant_h264_crf26.tif | 0   | 502 | 50   | 69     | 7.6       | 10     | 82         |\r\n|     Keller_TM0066_quant_h264_crf28.tif | 0   | 502 | 50   | 68     | 7.7       | 10     | 82         |\r\n|     Keller_TM0066_quant_h264_crf38.tif | 0   | 502 | 49   | 64     | 8.7       | 10     | 84         |\r\n|     Keller_TM0066_quant_h264_crf51.tif | 0   | 502 | 52   | 54     | 16        | 18     | 91         |\r\n|                Keller_TM0066_quant.tif | 0   | 502 | 51   | 72     | 5.5       | 14     | 80         |\r\n|----------------------------------------+-----+-----+------+--------+-----------+--------+------------|\r\n```\r\nthe max is altered due to the quantiser that is for sure (the last bin of the quantisation is simply quite wide and has not many entries), looking at the stddev/mean/median I however feel that the observed differences are \"normal\". what do you think?"}}
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