DOC: Use video files for saving animations

Because the default is Base64-encoded frames of PNGs, this should save a
substantial amount of space in the resulting docs.

Author: QuLogic

doc/conf.py

@@ -195,6 +195,11 @@ def _check_dependencies():
         subsectionorder as gallery_order_subsectionorder)
     from sphinxext.util import clear_basic_units, matplotlib_reduced_latex_scraper
 
+if parse_version(sphinx_gallery.__version__) >= parse_version('0.17.0'):
+    sg_matplotlib_animations = (True, 'mp4')
+else:
+    sg_matplotlib_animations = True
+
 # The following import is only necessary to monkey patch the signature later on
 from sphinx_gallery import gen_rst
 
@@ -273,7 +278,7 @@ def tutorials_download_error(record):
     'image_scrapers': (matplotlib_reduced_latex_scraper, ),
     'image_srcset': ["2x"],
     'junit': '../test-results/sphinx-gallery/junit.xml' if CIRCLECI else '',
-    'matplotlib_animations': True,
+    'matplotlib_animations': sg_matplotlib_animations,
     'min_reported_time': 1,
     'plot_gallery': 'True',  # sphinx-gallery/913
     'reference_url': {'matplotlib': None},

requirements/doc/doc-requirements.txt

@@ -18,6 +18,7 @@ pydata-sphinx-theme~=0.15.0
 mpl-sphinx-theme~=3.9.0
 pyyaml
 sphinxcontrib-svg2pdfconverter>=1.1.0
+sphinxcontrib-video>=0.2.1
 sphinx-copybutton
 sphinx-design
 sphinx-gallery>=0.12.0