I'll support BPM180 4/4.
There'll be a few choices: BPM180 4/4, BPM90 2/4 and BPM90 4/4.
Firstly, the song has a strong simple quadruple character over the simple duple one. This is indicated by the repetition length of vocal and melody. If it's a duple metre the main beat will be re-emphasized in a much frequent way. However in this song every accent is re-accumulated instead of a clear-cut accent. (e.g. through 01:37:913 - to 01:38:413 - ). This is theoratically a very poor choice on 2/4, and therefore the song should be a 4/4.
Now if we have to choose between BPM180 and BPM90 4/4, the easiest way is to fit the count into the beatings.
In usual practice 1/2 is used as the slightest regular beatings with 1/1 beatings a noticible one. In such way to judge BPM180 would be a suitable one.
In a song if 1/4 is used as regular beatings it should be intentional with a clear rapid sense than the BPM should have, but it's not the case here.
Another indicator is the repetition of the melody. In usual practice the melody is written in the manner that every bar is an unit, connecting and echoing each other. In the song the melody repeats every bar under the BPM180 4/4 scale.
When we decide where the bar ends, the accent on the note as well as the bridging towards the accent is very important. It should be uniquely used at the end of the bar. Take 01:38:413 - again as example, the syncopation is a sign of accumulating accent towards 01:38:413 - --- and this will never occur in the second beat of the bar, which is the case under BPM90 4/4 scale.
Moreover, BPM90 does not imply BPM180 is wrong. This is very vague when musicians write their transcripts. As a result it's very common to say BPM = 80-160, meaning that you can either treat it as BPM80 4/4 or BPM160 8/4. Of course this is not the problem on musical sheet because it's clearly written but this is the footnote for performance, the way you present it, and both is fine.
There'll be a few choices: BPM180 4/4, BPM90 2/4 and BPM90 4/4.
Firstly, the song has a strong simple quadruple character over the simple duple one. This is indicated by the repetition length of vocal and melody. If it's a duple metre the main beat will be re-emphasized in a much frequent way. However in this song every accent is re-accumulated instead of a clear-cut accent. (e.g. through 01:37:913 - to 01:38:413 - ). This is theoratically a very poor choice on 2/4, and therefore the song should be a 4/4.
Now if we have to choose between BPM180 and BPM90 4/4, the easiest way is to fit the count into the beatings.
In usual practice 1/2 is used as the slightest regular beatings with 1/1 beatings a noticible one. In such way to judge BPM180 would be a suitable one.
In a song if 1/4 is used as regular beatings it should be intentional with a clear rapid sense than the BPM should have, but it's not the case here.
Another indicator is the repetition of the melody. In usual practice the melody is written in the manner that every bar is an unit, connecting and echoing each other. In the song the melody repeats every bar under the BPM180 4/4 scale.
When we decide where the bar ends, the accent on the note as well as the bridging towards the accent is very important. It should be uniquely used at the end of the bar. Take 01:38:413 - again as example, the syncopation is a sign of accumulating accent towards 01:38:413 - --- and this will never occur in the second beat of the bar, which is the case under BPM90 4/4 scale.
Moreover, BPM90 does not imply BPM180 is wrong. This is very vague when musicians write their transcripts. As a result it's very common to say BPM = 80-160, meaning that you can either treat it as BPM80 4/4 or BPM160 8/4. Of course this is not the problem on musical sheet because it's clearly written but this is the footnote for performance, the way you present it, and both is fine.
