Hi Jason!
Found this potential solution on Screenly OSE’s GitHub (https://github.com/Screenly/screenly-ose/issues/1193):
"I had the same issue where my Screenly set up on Rpi with Balena Cloud would not play any of the H264 or normal videos.
This is what I tried to fix it:
I had the same issue where my Screenly set up on Rpi with Balena Cloud would not play any of the H264 or normal videos.
This is what I tried to fix it:
Adjust the GPU memory of your Raspberry Pi in order to optimize content playback.
To do this, click the “Fleet Configuration” tab on the left-side menu on the balenaCloud interface. On the Fleet Configuration menu, scroll down to find the RESIN_HOST_CONFIG_gpu_mem configuration item. Then, click “activate” to enable the item. Next, click the pencil icon on the right-hand side and change the value to 192. Restart the Pi to make this config work.
Hope that is helpful!"
Let me know if it works.