ValueError: unknown file extension: .mp4 in bloch sphere animation notebook along with deprecation error.

[mjhajharia]

matplotlib.animation:MovieWriter avconv was unavailable and Pillow is being used instead, which does not support mp4 files, possibly making anim an FFMpegWriter object would help

[ajgpitch]

Thanks for raising this.
Please refer to and link the Notebook that is causing the error.

[ajgpitch]

I think you will find that the error is caused by a usage error in
https://github.com/qutip/qutip/blob/master/qutip/ipynbtools.py
please do investigate further

[mjhajharia]

matplotlib.animation:MovieWriter avconv was unavailable and Pillow is being used instead, which does not support mp4 files, possibly making anim an FFMpegWriter object would help

The relevant notebook is https://github.com/qutip/qutip-notebooks/blob/master/examples/bloch-sphere-animation.ipynb