hoglet67
Possible Mode 7 Calibration Bug
This may not be a bug, but there is room for improvement.
This calibration came from Lurkio: https://stardot.org.uk/forums/viewtopic.php?p=340203#p340203
I've attached the whole file: Log.txt
It's the final calibration run in the file that's a sub-optimal:
INFO: A B C D E F total
INFO: value = 0: metrics = 0 0 2627 96 0 290 3013
INFO: value = 1: metrics = 0 0 95 0 2310 16 2421
INFO: value = 2: metrics = 4156 0 15 0 209 0 4380
*PLL
INFO: value = 3: metrics = 253 0 7876 0 19 0 8148
INFO: value = 4: metrics = 0 0 313 0 0 0 313
INFO: value = 5: metrics = 0 0 15 0 0 0 15
Optimizing calibration
phases = 5 5 5 5 5 5; half = 0; pix h offset = 0; mult = 3; rate = 0
Calibration pass complete, retested errors = 20
Current minimum: Phase = 5, Half = 0
INFO: A B C D E F total
INFO: value = 6: metrics = 0 0 0 0 0 0 0
INFO: value = 7: metrics = 0 0 0 0 0 0 0
INFO: value = 8: metrics = 0 0 0 0 0 0 0
INFO: value = 9: metrics = 0 0 64 0 0 0 64
INFO: value = 10: metrics = 1535 50 0 970 46 0 2601
INFO: value = 11: metrics = 20 0 0 0 0 36 56
phases = 7 7 7 7 7 7; half = 0; pix h offset = 0; mult = 3; rate = 0
Calibration pass complete, retested errors = 0
Current minimum: Phase = 7, Half = 0
INFO: A B C D E F total
INFO: value = 0: metrics = 152 0 348 0 5 0 505
INFO: value = 1: metrics = 0 0 319 0 0 0 319
INFO: value = 2: metrics = 0 0 57 0 0 0 57
INFO: value = 3: metrics = 0 0 0 0 0 0 0
INFO: value = 4: metrics = 17 0 0 0 0 0 17
INFO: value = 5: metrics = 0 0 0 0 0 0 0
phases = 3 3 3 3 3 3; half = 1; pix h offset = 0; mult = 3; rate = 0
Calibration pass complete, retested errors = 0
Current minimum: Phase = 3, Half = 1
INFO: A B C D E F total
INFO: value = 6: metrics = 0 0 161 0 0 0 161
INFO: value = 7: metrics = 268 2 0 4821 73 0 5164
INFO: value = 8: metrics = 19 0 0 0 0 3 22
INFO: value = 9: metrics = 0 1166 45 0 0 0 1211
INFO: value = 10: metrics = 10000 10024 10000 10000 10000 10000 60024
INFO: value = 11: metrics = 0 0 0 15 0 49 64
Optimizing calibration
phases = 9 8 8 8 8 8; half = 1; pix h offset = 0; mult = 3; rate = 0
Calibration pass complete, retested errors = 42
Testing mode 7 alignment
counter 0 = 3666
counter 1 = 648
counter 2 = 648
counter 3 = 3832
counter 4 = 4077
counter 5 = 3737
counter 6 = 3621
counter 7 = 4117
counter 8 = 4108
counter 9 = 3562
counter 10 = 3699
counter 11 = 3923
minima at index: 1
Characters aligned to word boundaries
phases = 3 3 3 3 3 3; half = 1; pix h offset = 11; mult = 3; rate = 0
Calibration complete, errors = 0
In this calibration, there is a three position wide error free band at half=0 phase= 6,7,8 but this is not used as the final calibration. Instead, a one position wide error free band at half=1 phase=3 is picked instead.
Somehow we should include the width of the error free band, when there are multiple choices that appear error free.
I think I've fixed this in this commit: https://github.com/IanSB/RGBtoHDMI/commit/61494c94a40296ca715c24a39ef45cb21404d21a If a three wide zero error window is detected, the error count is set to -1 instead of 0 and as that is lower than zero it will be selected in preference to a single 0 error count. The error value shows as -1 in the logs but is displayed as "0,0,0" in the calibration summary so you can tell at a glance if you have a good three sample window or just a single zero count.
I haven't been able to confirm this works in the above example as I can't reproduce the specific results but is does display the 0,0,0 for normal calibrations that have a three wide zero error band.
I'm wondering if this is this making too much of a special case of 0,0,0.
Wouldn't it be better to make use of the three-wide window metric value to resolve ties like this?
I'm wondering if this is this making too much of a special case of 0,0,0. Wouldn't it be better to make use of the three-wide window metric value to resolve ties like this?
Yes, I already decided to improve it by incorporating the 3 sample window in the decision and it's in https://github.com/IanSB/RGBtoHDMI/commit/c9690050e7cd1a940ebfab092c9297c0cb7885e3
so 12,0,34 will be selected in preference to 2345,0,1234
Also the 3 sample window total is included in the calibration display