In guppyplex.py you have a formula for mean read calculation:
def get_read_mean_quality(record):
return -10 * log10((10 ** (pd.Series(record.letter_annotations["phred_quality"]) / -10)).mean())
Although this is technically correct if one wants to get the mean on the probability scale, aren't these scores meant to be averaged at the log-scale (phred scale)? This severely biases the value towards lower qualities, for example the sequence of bases [10,10,10,10,10,10,10,10,2,1] would have 8.3 score on a linear scale, but has 6.53 as a result for your calculation.
None of my reads pass your default filter of 7, for example:
[4, 7, 6, 10, 3, 6, 14, 3, 3, 11, 5, 7, 5, 3, 3, 11, 6, 11, 2, 4, 4, 2, 5, 2, 3, 3, 7, 10, 3, 15, 15, 4, 3, 4, 13, 4, 4, 15, 2, 5, 8, 10, 3, 4, 3, 3, 2, 4, 5, 5, 5, 5, 2, 2, 5, 3, 3, 6, 4, 3, 2, 3, 9, 2, 5, 9, 4, 3, 4, 5, 5, 11, 10, 2, 4, 9, 2, 2, 2, 3, 5, 4, 4, 3, 10, 7, 3, 6, 5, 5, 3, 6, 10, 4, 4, 4, 4, 3, 8, 3, 9, 5, 9, 2, 7, 6, 3, 7, 4, 4, 3, 4, 2, 4, 4, 11, 4, 6, 2, 3, 3, 4, 6, 3, 4, 6, 4, 3, 5, 4, 2, 2, 4, 4, 3, 7, 2, 7, 3, 7, 8, 8, 4, 2, 8, 3, 4, 3, 4, 2, 2, 3, 10, 3, 3, 2, 7, 5, 8, 11, 3, 4, 4, 1, 2, 2, 4, 6, 2, 5, 5, 2, 3, 4, 3, 8, 2, 3, 4, 3, 4, 8, 6, 13, 13, 6, 10, 20, 17, 8, 4, 6, 7, 8, 5, 4, 3, 4, 4, 3, 3, 6, 3, 7, 6, 6, 7, 5, 3, 3, 5, 2, 3, 10, 6, 5, 3, 4, 5, 5, 7, 4, 4, 13, 7, 2, 3, 5, 2, 7, 10, 3, 4, 5, 5, 4, 10, 7, 4, 3, 8, 4, 2, 2, 1, 4, 5, 15, 6, 4, 3, 4, 3, 3, 7, 10, 4, 4, 8, 6, 5, 2, 3, 3, 3, 8, 6, 5, 6, 6, 10, 7, 11, 10, 11, 10, 8, 6, 8, 4, 6, 2, 4, 7, 8, 2, 4, 6, 3, 12, 9, 4, 10, 10, 4, 8, 4, 3, 3, 9, 12, 5, 12, 1, 3, 6, 2, 3, 1, 2, 3, 3, 2, 7, 9, 3, 9, 13, 9, 3, 8, 6, 7, 2, 8, 7, 2, 9, 7, 3, 2, 5, 3, 4, 2, 3, 2, 3, 3, 4, 4, 4, 2, 7, 2, 3, 7, 8, 3, 4, 4, 2, 5, 7, 5, 4, 4, 3, 7, 5, 7, 5, 12, 13, 3, 14, 12, 6, 8, 8, 12, 5, 4, 5, 7, 5, 8, 4, 6, 11, 8, 16, 17, 12, 3, 6, 4, 3, 3, 1, 5, 14, 20, 13, 7, 4, 3, 2, 6, 3, 2, 5, 7, 10, 3, 2, 7, 3, 6, 5, 4, 10, 5, 4, 5, 2, 3, 2, 3, 9, 3, 4, 3, 5, 4, 6, 8, 8, 10, 4, 3, 1, 4, 2, 5, 3, 5, 3, 4, 3, 5, 4]
In the meantime, this is my quality tab from MinKNOW:
![image](https://user-images.githubusercontent.com/16489606/105224895-16a68f80-5b5e-11eb-8f41-54be0bff323d.png)
Is this intended?