I don't know that much about electronics and stuff but I converted some videos from Youtube to MP3 where the videos involved some guys putting their fuzz pedals, which are Zvex Fuzz Factory and a DIY Calculator Fuzz, on the oscilloscope in order to see the waveforms. The waveforms are square waves as you can see in the pictures below.
But when I used the Audacity to see the waveforms after I converted the videos to MP3, the waveforms are different and the waveforms are not square waves. Notice the time I captured the waveforms, both are taken at the same time. For the Zvex Fuzz Factory, it was at 0:45 and for the Calculator Fuzz it was at 0:38, same goes for the waveforms in the Audacity.
Can someone explain why the differences? Is it possible that different brands of oscilloscope generate different waveforms from each other?