Interesting your comments on recordings as I've now managed to get mine to playback on Chromecast. I'm wondering if its a Video Codec issue? My details;
Working example from the Recording / Chromecast page which displays (have changed user/password);
Debug: uri "dvrfile/1b7a41bd30467559beb74cd3df2cbfa1"
fullurl is "http://user:password@192.168.1.183:9981/dvrfile/1b7a41bd30467559beb74cd3df2cbfa1?profile=chromecast"
This in turn will playback the recorded file;
"/home/hts/Cruising With Jane McDonald.mkv"
To get this to work I went into TVHeadEnd - Configuration / Recording and changed the Stream Profile to chromecast. This Stream Profile is setup to use the Video Codec "libx264: libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10".
Without doing this, the recorded file was saved with the extension .ts which would not play on Chromecast.
I should point out that I'm still on TVHeadEnd "HTS Tvheadend 4.2.8-36~g5bdcfd8ac" as I never was able to build a 4.3 version with working Video Codecs :-(
Hope this info helps.
EDIT: Now I'm lost, just tried to send a recording to chromecast and it will not work tonight!