Why does my microphone work in calls but not in media apps

So this just started recently when I call people thru the phone it works fine and speak to text works too i turned it off and on to ask "OK Google" it picked it up the first time but when I opened my camera and recorded a video no sound or anything I asked "OK Google" again and it didn't pick it up and same goes for apps such as Snapchat can anyone please help

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