I have a Samsung Galaxy S20 and a Roku Streaming Stick+ and I just figured out how to screen mirror on my tv. However, I can't figure out how to get the audio on my phone to play through my tv. Is this even possible? I tried using the Roku app but it doesn't put the sound on my tv, just through my phone and a connected bluetooth device. I do not have a Roku tv and my tv is not a smart tv. It's just a generic flat screen tv. Any help would be appreciated!
I win! It's not a ROKU problem. I now have HD video mirroring with audio to ROKU from Samsung S20 using either SmartView or DEX (proprietary Samsung software for Android, nee Miracast). This required 2 solid hours of Samsung tech line chat and several reboots.
First open smartview and connect to ROKU then open SmartThings settings to send audio to Roku. Verify that none of your devices (TV, ROKU, phone) are muted. Test with any video app you should have sound and audio from your TV.
Dex is different. It provides a MacOS or Windows10 desktop. You will need to adjust your TV picture settings to see the full screen. Then you use the Samsung TouchPad app to control an on screen cursor. In the lower left corner clicking on the checkerboard pattern opens your Android app icon folders and you can open the app you want to cast to ROKU.
I also opened the roku app on my phone. Connected to the device I wanted to fix. Turned on the headphone turned it off. Then I hit the setting cog in the upper right ( ios) and chose to check the audio delay. That seemed to fix it. But I did all the other things first:
you are experiencing no sound when mirroring your screen to Roku, you can try the following solutions
Set PCM-Stereo as the default audio mode on Roku.
Check the screen mirroring settings on Roku and adjust them as needed.
Disable and enable Wi-Fi on your device.
Set the mirroring mode of your Roku device to "Prompt".
Check Network settings and disable the Firewall.
Use SmartView or DEX to mirror your screen and send audio to Roku.