Repository restructuring in AEM 6.4 moved video profiles from /etc/dam/video to /conf/<tenant>/settings/dam/video as documented in .
The method VideoProfile#get(ResourceResolver resolver, String name) is marked as deprected and it is supposed to use VideoProfile#get(ResourceResolver resolver, ConfigurationResourceResolver configResolver, String name) instead .
Tests with current AEM6.5 and io.wcm.handler.media-1.8.0 didn't create a markup, as DamVideoMediaMarkupBuilder is not able to load a video profile in .
should be solved in next version, you can give it a try with snapshot version 1.9.0-SNAPSHOT
the problem was two-fold:
the default profile names for the build-in profiles changed between AEM 6.3 and 6.4
the AEM 6.4 API introduced a new API method to get video profiles, and only this supports the new paths at /libs, /apps, /conf