Chosen Solution

I have an iphone 6 that I am trying to fix, and it has a problem where it would not play any videos(it would say an error has occurred for any video tried to play through youtube safari ect…) and audio would not work either through things like phone calls, on speaker or headset mode. I first tried erasing all content and settings, which did nothing. I then tried disconnecting the battery, pressing the power button a few times, then booting it back up. This kinda fixed the problem, as when I tried to play a video, no error would occur, but it would just load the first frame and never actually play, and the audio is now working through the headset, but not on speaker. Does anyone know what is causing this? thanks!

When you press the volume up and down buttons does the volume go up and down or does it say Headphones even when there are no headphones plugged in??? It sounds more like an issue with Audio probably the main Audio IC itself, was the phone dropped or water damaged? Audio ic having a fault I think could cause the problems your having, ie no sound video not playing or crashing when it tries to play back the audio element of the video. Does voice recording work and play back?