the whole point of this music in my opinion is to learn it as much as one can by ear,
so whether a videos is blurred is hardly relevant to the concertina which when i am playing ,i am in fact playing as if i cannot see the fingerboard, it is done by feel,
now it is necessary to point out that there are different correct ways of harmonising a tune, at the time i was attempting in my explanation to keep the chords or dyads relatively simple.