Also would be a nice feature:
As for changing the aspect aspect ratio: Yet, there is only one option you can try: Got to Settings->Playback, and there you can set the "Maintain Aspect Ratio" to eighter "Full screen" (strech to your TV's) or "Keep ratio" (leaves source aspect as it is). However it would be nice to have this feature also in Himedia Player's on-the fly menu, and change it during playback, so you don't have to always quit from KODI (or whatever browser GUI you use) and set it in the main Setting menu again, to fit the ratio depending on the source you wish to play next time. This would be a much confy solution, if one's have relatively lot of videos with different aspect ratios (like 1920x1080 vs 1080x800 vs 720 x576, 640x480 (4:3) or even lower SD 4:3 resolutions). And so it also would be also more practial sometimes this way, to switch while the picture is visible during playing the video, to see if the "Full Screen" setting suits the video's quality, or if the "streching" is tool much than set it easily back to it's default aspect ratio at any time, without always stopping the playback, quitting the media software (e.g. KODI) and head back to the Settings->Playback menu.
(This one feature request came in mind while answering to a question in an another Topic, but I guess it may was usefull to happen.)