Why Does HDMI Recording Require External Power?¶
When recording from HDMI sources, RecDual Dongle requires external power. This article explains why.
The Technical Reason¶
HDMI doesn’t provide power:
HDMI is a video/audio signal standard only
It does not carry power to connected devices
HDMI sources (game consoles, etc.) don’t supply power to outputs
RecDual Dongle needs power to:
Process incoming HDMI signal
Encode video in real-time (H.264)
Write data to TF card
Drive LED indicators
Comparison: HDMI vs Type-C DP¶
Type-C DP Connection:
Type-C port carries video, audio, AND power
Connected device provides power to RecDual Dongle
No external adapter needed
HDMI Connection:
HDMI carries video and audio only
No power delivery through HDMI
External power must be provided
How to Provide Power¶
Connect a power adapter:
Use a USB-C power adapter
Connect to Type-C PWR port on RecDual Dongle
Minimum: 5V/2A (10W)
Recommended: PD adapter for best stability
Compatible adapters:
Phone chargers with USB-C output
Laptop USB-C chargers
Dedicated USB-C power adapters
Power banks with USB-C output
What Happens Without Power?¶
If you try HDMI recording without external power:
RecDual Dongle won’t turn on
LED indicators remain off
No signal detection
No recording possible
Power Consumption¶
During HDMI recording:
RecDual Dongle draws power for signal processing
Video encoding requires significant power
TF card writing adds to consumption
A stable power source ensures reliable recording.
Tips for HDMI Recording¶
Use quality power adapter - Reliable adapters prevent issues
Verify power first - Ensure LEDs light up before expecting operation
Avoid underpowered sources - Some USB ports may not provide enough power
Use wall adapter when possible - More reliable than laptop USB ports
Power Bank Use¶
Power banks can power RecDual Dongle:
Must have USB-C output (or use adapter)
Minimum 5V/2A output
Monitor power bank charge level
Good for portable HDMI recording