[FFmpeg-user] How can I force a 360kHz time base?

Mark Filipak (ffmpeg) markfilipak at bog.us
Sat Feb 27 01:40:38 EET 2021 

On 2021-02-26 15:51, Paul B Mahol wrote:
> Ever looked at (a)settb filter
Thank you, Paul.

'ffmpeg -i input.mkv -vf "settb=expr=1/360000,showinfo" -codec:a copy -codec:s copy -dn output.mkv'
partial output shown below.

input.mkv is 30.1.001fps constant frame rate. I expected deltaPTS to be 12012.

Look at the 1st frame:
(0.033s/frame)*(360000ticks/s) = 11880ticks/frame,
instead of:
((1.001/30)s/frame)*(360000ticks/s) = 12012ticks/frame.

Why is that? It destroys the resolution improvement of the 1/(360000Hz) time base.

[Parsed_showinfo_1 @ 00000211128f2340] n:   1 pts:  11880 pts_time:0.033   pos:    10052 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:3CF10BFE plane_checksum:[64208370 00B13226 C5775659] 
mean:[25 126 131] stdev:[12.8 6.1 1.6]
[Parsed_showinfo_1 @ 00000211128f2340] n:   2 pts:  24120 pts_time:0.067   pos:     9213 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:23A8A65F plane_checksum:[90DC2AA6 37E908C8 779972F1] 
mean:[27 125 132] stdev:[14.8 7.1 1.9]
[Parsed_showinfo_1 @ 00000211128f2340] n:   3 pts:  36000 pts_time:0.1     pos:    11086 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:1CDF7A80 plane_checksum:[089DE80E C537F4C0 8C4E9D94] 
mean:[29 125 132] stdev:[15.2 6.6 2.3]
[Parsed_showinfo_1 @ 00000211128f2340] n:   4 pts:  47880 pts_time:0.133   pos:     7431 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:119710AA plane_checksum:[D43E9018 B24CC548 E7AABB2C] 
mean:[31 124 133] stdev:[17.0 7.3 2.6]
[Parsed_showinfo_1 @ 00000211128f2340] n:   5 pts:  60120 pts_time:0.167   pos:    15291 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:DD84243C plane_checksum:[DC606F90 0745C015 944BF479] 
mean:[33 124 134] stdev:[17.3 7.0 3.0]
[Parsed_showinfo_1 @ 00000211128f2340] n:   6 pts:  72000 pts_time:0.2     pos:    14140 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:DC5702F7 plane_checksum:[58664923 D8779F91 07D31A34] 
mean:[35 123 135] stdev:[19.0 7.5 3.4]
[Parsed_showinfo_1 @ 00000211128f2340] n:   7 pts:  84240 pts_time:0.234   pos:    15885 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:982F77C4 plane_checksum:[F9629DEA F0FC9662 7B844369] 
mean:[37 123 135] stdev:[18.5 6.3 3.9]
[Parsed_showinfo_1 @ 00000211128f2340] n:   8 pts:  96120 pts_time:0.267   pos:    11959 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:E1FE3E48 plane_checksum:[D4B07602 1B8663D0 32DC6467] 
mean:[39 122 136] stdev:[21.1 7.8 4.2]
[Parsed_showinfo_1 @ 00000211128f2340] n:   9 pts: 108000 pts_time:0.3     pos:    18831 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:3E3AB9E7 plane_checksum:[62FDF2C3 E42D414E 4F1C85C7] 
mean:[40 121 137] stdev:[21.8 7.4 4.6]
[Parsed_showinfo_1 @ 00000211128f2340] n:  10 pts: 120240 pts_time:0.334   pos:    19527 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:D0BF9974 plane_checksum:[5C16D379 A215196E 670BAC7E] 
mean:[43 121 137] stdev:[24.9 9.6 5.0]
[Parsed_showinfo_1 @ 00000211128f2340] n:  11 pts: 132120 pts_time:0.367   pos:    16969 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:1FCDAD4B plane_checksum:[0873F57B 209AF8E2 FCD5BED0] 
mean:[44 120 138] stdev:[24.9 8.9 5.4]
[Parsed_showinfo_1 @ 00000211128f2340] n:  12 pts: 144000 pts_time:0.4     pos:    20576 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:6B674664 plane_checksum:[83DC7146 501EEC71 B06DE88F] 
mean:[46 120 138] stdev:[26.4 9.5 5.7]
[Parsed_showinfo_1 @ 00000211128f2340] n:  13 pts: 156240 pts_time:0.434   pos:    24416 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:4B39A727 plane_checksum:[7D7DCD8D 9002D009 66A90982] 
mean:[47 119 139] stdev:[27.6 9.2 6.1]
[Parsed_showinfo_1 @ 00000211128f2340] n:  14 pts: 168120 pts_time:0.467   pos:    25561 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:F6E060FD plane_checksum:[0ED972ED 6DF5BBA0 849B3261] 
mean:[49 119 140] stdev:[29.2 9.7 6.5]
[Parsed_showinfo_1 @ 00000211128f2340] n:  15 pts: 180360 pts_time:0.501   pos:    22146 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:6C3D4C60 plane_checksum:[D0A87196 9AB1975E 4494435D] 
mean:[50 118 140] stdev:[30.3 9.6 6.9]
[Parsed_showinfo_1 @ 00000211128f2340] n:  16 pts: 192240 pts_time:0.534   pos:    29758 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:B80E35AE plane_checksum:[3EEE2D48 B4148D20 9EEF7B37] 
mean:[52 118 141] stdev:[31.8 10.0 7.3]
[Parsed_showinfo_1 @ 00000211128f2340] n:  17 pts: 204120 pts_time:0.567   pos:    28824 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:E02EB74A plane_checksum:[C9839D7E 70D47B70 E2C89E4D] 
mean:[54 118 142] stdev:[32.7 9.2 7.7]
[Parsed_showinfo_1 @ 00000211128f2340] n:  18 pts: 216360 pts_time:0.601   pos:    30300 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:DE1E3F2D plane_checksum:[C8B7238E A1D25AA7 F52CC0E9] 
mean:[56 117 142] stdev:[34.7 10.3 8.2]
[Parsed_showinfo_1 @ 00000211128f2340] n:  19 pts: 228240 pts_time:0.634   pos:    26532 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:04DA490F plane_checksum:[0FCB36A9 40BA3BF4 9FABD663] 
mean:[57 117 143] stdev:[35.7 10.2 8.6]
[Parsed_showinfo_1 @ 00000211128f2340] n:  20 pts: 240120 pts_time:0.667   pos:    33345 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:B27FEF95 plane_checksum:[B411D21D 52F61823 32E10555] 
mean:[59 116 144] stdev:[37.4 10.8 9.1]
[Parsed_showinfo_1 @ 00000211128f2340] n:  21 pts: 252360 pts_time:0.701   pos:    31240 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:33AAFEA0 plane_checksum:[7945E1E2 4DF0022A B0801A94] 
mean:[60 116 144] stdev:[38.3 10.4 9.4]
[Parsed_showinfo_1 @ 00000211128f2340] n:  22 pts: 264240 pts_time:0.734   pos:    38152 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:BCCBA0B6 plane_checksum:[1F165EA3 BE8CFC55 FA1A45AF] 
mean:[62 116 145] stdev:[39.6 10.8 9.7]
[Parsed_showinfo_1 @ 00000211128f2340] n:  23 pts: 276120 pts_time:0.767   pos:    36999 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:2C47A2CA plane_checksum:[DCB94D3D A49BDC55 52257929] 
mean:[64 115 146] stdev:[40.9 10.6 10.2]
[Parsed_showinfo_1 @ 00000211128f2340] n:  24 pts: 288360 pts_time:0.801   pos:    39218 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:2910BBE9 plane_checksum:[E4705C5F 9BB7BCCD 5575A2AE] 
mean:[66 114 146] stdev:[42.7 11.0 10.6]
[Parsed_showinfo_1 @ 00000211128f2340] n:  25 pts: 300240 pts_time:0.834   pos:    34109 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:495B2593 plane_checksum:[B62FC80E 12CA9E04 2511BF63] 
mean:[68 114 147] stdev:[44.1 11.0 11.1]
[Parsed_showinfo_1 @ 00000211128f2340] n:  26 pts: 312480 pts_time:0.868   pos:    44416 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:F3D875F1 plane_checksum:[EA0508D3 A5C68F7A 1FB0DD95] 
mean:[69 114 147] stdev:[45.3 11.4 11.3]
[Parsed_showinfo_1 @ 00000211128f2340] n:  27 pts: 324360 pts_time:0.901   pos:    43409 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:95CF8E78 plane_checksum:[C7B319BE 35EC8591 A12FEF1A] 
mean:[71 113 148] stdev:[46.3 10.8 11.5]
[Parsed_showinfo_1 @ 00000211128f2340] n:  28 pts: 336240 pts_time:0.934   pos:    45167 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:8D724A43 plane_checksum:[CD1CE198 DC377EA5 3D51E9E8] 
mean:[70 113 148] stdev:[46.3 11.6 11.5]
[Parsed_showinfo_1 @ 00000211128f2340] n:  29 pts: 348480 pts_time:0.968   pos:    40163 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:P checksum:8F6C0D42 plane_checksum:[385DA9F1 7EA37D5A AD78E5D9] 
mean:[70 113 148] stdev:[46.6 11.6 11.5]
[Parsed_showinfo_1 @ 00000211128f2340] n:  30 pts: 360360 pts_time:1.001   pos:    50467 fmt:yuv420p 
sar:32/27 s:240x236 i:P iskey:0 type:B checksum:B511B7BA plane_checksum:[9C9A49A0 B1D583BA FA0EEA51] 
mean:[70 113 148] stdev:[46.5 11.4 11.6]

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