@tron4 I had a problem with anime buffering. Figured out it was due to it being encoded with a bit depth of 10 (instead of the 'normal' 8bit in other shows).
Unfortunately the Chromecast doesn't support playing h264 with a bit depth of 10, so what I did was convert the videos from 10 to 8 bit.
To do this I just used a free tool called HandBrake. I had some problems with video needing transcoding (which causes buffering, and also a lot of strain on your computer), even after converting it to 8bit - but after a few trials and errors I found out which settings to use. I'll post some screenshots on how to set it up to do a rather simple 10>8 conversion with little quality loss.
Note; any re-encode or transcoding will reduce quality - similar to encoding lossy music over and over.
Now, here are my settings in handbrake that did the trick for me.
Under "tools" open options, here you can make ajustments as you like but noteworthy options are under "Output Files" > Default Path - I set this to a folder on my desktop named Videostream for simplicity. Also check automatically name output files.
Also remember to tick this to automatically pull the subtitles into the new file. The rest of the preferences are optional.
These are in the main editor, I would highly recommend you import a file (click source > file/folder then import a video) then set up the output settings and save as a preset. (bottom right; click add).
Picture - default settings work fine.
Filter - default settings work fine.
Video - the most important ones are H.264 profile settings, apart from the speed preset (set at medium for me)
The h.264 preset slider basically means how fast it will encode versus compression. (faster = bigger file size, slower = smaller file size) for anime medium works fine, I end up with files averaging 3-400mb which play very nice and look super fine on my tv (this size also depends on your Constant Quality sider. 20 is the default but for HD videos you can put it at 24 to get a smaller file size (at the slight loss of quality).
Audio - AAC ffmpeg 128kbs works fine for me.
Subtitles - they should import automatically (due to the checkbox in the preferences) if not click add and pick "english" (or what other language you want). (Note; sometimes it says "unknown" or otherwise, and (SSA/ASS) in parentheses - those are usually the ones you want.)
Leave Chapters and Advanced as is if you don't know what you're doing.
Now; click add to queue (if you have 1 file) or click the arrow next to it and add the whole batch if you have multiple. Followed by clicking start to start encoding. For me each file takes about 15minutes in the cooker like this and work with zero effort on the computer playing it on the chromecast and no buffering at all.
Hope this works, good luck and enjoy!