Waveform: min and max values are 0

[gnuletik]

On new items, when loading the waveform, the server's response contains only 0 values in the min and max arrays.

Request URL example : https://sandbox.wasabi.telemeta.org/timeside/api/items/67dbad2e-b054-4070-9cd2-b81b712edcd9/waveform/

Response:

(not pasted to avoid a huge payload of 0)

The waveform image generated from the server is flat. e.g. :

The player will show the following message in this case : The waveform do not seems valid. Please check your browser's console logs..

This will be printed to the console : Unexpected waveform: waveform.min has constant values .

This issue already occured in a previous issue : #167