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Tests

a guest Nov 4th, 2015 13 Never
  1. [Filesize Experiments]
  2.  
  3.  
  4. 1.00 [SEPARATION]
  5. 1.01 Separate the audio for video-only data size.
  6. 1.02 I'll just round it down to 21.5 MB [In Video Only], henceforth referred to as IVO.
  7.  
  8. 2.00 [AUDIO BITRATE]
  9. 2.01 Also important is the current audio bitrate and the final audio bitrate which will be changed.
  10. 2.02 Changing the audio bitrate from 85k to 64k: This is just a step from not recording in 64k in the first place, which I suggest.
  11. 2.03 I know, it makes the music aspect sound worse, but that's why you include music files at 128k on their own
  12. 2.04 It saves overall space (from recording at 128k) and introduces a controllable audio balance.
  13.  
  14. 3.00 [NEW FILE SIZES]
  15. 3.01 We will be basing all the experiments on the new files, so disregard any filesizes mentioned prior.
  16. 3.02 [AUDIO] 7.50 MB (Previously 9.50 MB]
  17. 3.03 [Video] 21.0 MB (Previously 31.4 MB] (Mere video/audio separation) 21 + 7.5 = 28.5.
  18.  
  19. 4.00 [TESTS BASED ON NEW FILE SIZES]
  20. 4.01 All tests will be done on the video-only file, in future this won't be necessary, the file just wasn't recorded in 64k audio this time.
  21. 4.02 As base, the IVO number for video-only file is 21.0MB, remember this.
  22.  
  23. 4.020 [FFMPEG CONSTANT RATE FACTOR (CRF) TESTS]
  24. 4.021 [SEE THE INCLUDED FFMPEG OUTPUT FOR MORE DETAILED RESULTS.]
  25. 4.022 [Former number is kb/s, latter is file size (STILL VIDEO ONLY 21.0MB;for simplicity, add 7.5MB to get the true file size.]
  26.  
  27. 4.023 CRF 51 [5.29 @ 677KB] (51 is the highest (worst) quality available)
  28. 4.024 CRF 50 [5.87 @ 745KB]
  29. 4.025 CRF 49 [6.54 @ 823KB]
  30. 4.026 CRF 48 [7.21 @ 901KB]
  31. 4.027 CRF 47 [7.92 @ 985KB]
  32. 4.028 CRF 46 [8.74 @ 1.1MB]
  33. 4.029 CRF 45 [9.65 @ 1.2MB]
  34.  
  35. 4.030 At this point, I am getting a bit tired of going down single numbers at a time, just rest assured at CRF45 is nowhere near good enough.
  36. 4.031 I will be doing skips of 5 for now.
  37.  
  38. 4.032 CRF 40 [15.1 @ 1.8MB]
  39. 4.033 CRF 35 [23.0 @ 2.8MB]
  40. 4.034 CRF 30 [34.2 @ 4.1MB]
  41. 4.035 CRF 25 [51.1 @ 6.0MB]
  42. 4.036 CRF 20 [74.8 @ 8.8MB]
  43. 4.037 CRF 15 [107  @ 12.7MB]
  44. 4.038 CRF 10 [142  @ 16.7MB]
  45. 4.039 CRF 05 [168  @ 19.8MB]
  46.  
  47. 4.040 So at this point, we have reached the filesize of the original quality, making it larger for no reason would be a waste of time.
  48. 4.041 For this file at least, we can say CRF 05 is the limit.
  49. 4.042 But this is not about looking the best, it's quality/size tradeoffs.
  50.  
  51. 5.00 [THE TRADEOFF]
  52. 5.01 Obviously, CRF5 looks as good as (indistinguishable) from the source video.
  53. 5.02 So let's go down by 5 until we stop seeing a difference.
  54. 5.03 CRF 40 @ 1.8MB [Somewhat blurry, actually tolerable if you don't have high standards, but I don't have high standards, so.]
  55. 5.04 CRF 35 @ 2.8MB [A bit less blurry, I think the general population would be alright with having something on this level.]
  56. 5.05 CRF 30 @ 4.1MB [I can only see a slight improvement over 35, will need confirmation on this.]
  57. 5.06 CRF 25 @ 6.0MB [Same as above.]
  58. 5.07 CRF 20 @ 8.8MB [Same as above.]
  59. 5.08 CRF 15 @ 13~MB [Same as above.]
  60. 5.09 CRF 10 @ 17~MB [Same as above.]
  61. 5.10 CRF 05 @ 20~MB [Same as above.]
  62.  
  63. 6.00 [TRADEOFF RESULTS]
  64. 6.01 As you can see from my opinion (I also want your opinion on what is 'tolerable'), diminishing returns below 30.
  65. 6.02 I would go with 30, I would be able to tolerate 35, but I think the general audience would want something at least 30 quality.
  66. 6.03 But I don't think they're that different in the first place, all the same, an additional MB of video file for a happier audience is fine.
  67.  
  68. 7.00 [YOUR OPINION]
  69. 7.01 I want to hear whether you want CRF 35 or CRF 30, maybe you're picky and want CRF 25? I need input on what looks good.
  70. 7.02 I, myself, have never watched HD video or anything, so my perspective is skewed about what makes a good video.
  71.  
  72. 8.00 [Screenshot examples, file uploads]
  73. 8.01 I have uploaded screenshots for 5 decreasing incremental, it's not quite the same as an in motion video (especially on sub-35)
  74. 8.02 As well as some videos, I won't upload all tests as like I said, only down to 25 really matters.
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