Your AVH-X7500BT reads DVD format. Your smart phone reads is most likely read MP4 format. You have to modify the video (convert the format to a compatible format on which your device can read. I looked up your AVH device and the specs reads;
Memory Card Slot MP3, CD-R, CD+R, DVD-R, DVD+RW
Media Playback Supported dvd. Get familiar with formats. You will be able to get it to work. Here is a link to a software that will convert MP4 to DVD (MPEG). https://www.wondershare.com/pro/video-converter-ultimate.html