Hey there ritika92,
Thanks for reaching out to Apple Support Communities. I understand you’re having issues playing audio from videos in your car stereo. You’ve done some great troubleshooting so far and I’ll be happy to help with this.
You mention you disconnected/connected Bluetooth. When you did this, did you unpair your iPhone and car stereo? If not, go to Settings > Bluetooth, find the device you want to unpair, and tap the small i next to your car stereo , then Forget this Device.
Check for any iOS updates once you’ve done this. Go to Settings > General > Software Update. If you see an update available, back up your iPhone and install the update:
Update your iPhone, iPad, or iPod touch
If there’s not an update available, restart your iPhone and pair your iPhone and car stereo together again:
Connect Bluetooth devices to iPhone
If that doesn’t work, reach out to your car manufacturer and see if there are any firmware updates available for your car stereo.
Best wishes.