If you‘ve ever felt confused trying to connect your television, game console, Blu-ray player or other devices using HDMI cables, you‘re not alone. Understanding the difference between HDMI inputs and outputs is key to making sure your devices are connected properly for the best audio/video quality.
In this guide, we‘ll explain what HDMI inputs and outputs are, why the distinction matters, how they work together, and how to identify the type you need. Let‘s clear up the confusion once and for all!
What Does Input and Output Mean?
Simply put, inputs receive signals and outputs send out signals.
For HDMI, the input is the connection port where the HDMI cable is plugged into on a TV or other display device to receive the audio/video signal from a media source. The output is the port where the HDMI cable connects to the media source to transmit or output the signal to the display‘s input.
So HDMI inputs receive signals and HDMI outputs send signals. Knowing whether your device needs to receive or transmit HDMI signals is the key to understanding whether you need an input or an output.
A Brief History of HDMI
To appreciate the difference between HDMI inputs and outputs, it helps to understand what HDMI is and how it evolved.
HDMI (which stands for High Definition Multimedia Interface) was created in the early 2000s to replace the confusing mess of analog video connection standards that existed previously like composite video, S-Video, VGA, DVI and component video.
By 2002, high definition televisions were gaining popularity. But transitioning from analog to digital HD video signals wasn‘t easy with a hodgepodge of cable options.
So leading media and tech companies including Toshiba, Sony, Hitachi, Panasonic, Philips and others collaborated to create a new digital standard that could handle the demands of HD video along with multi-channel surround sound audio.
The HDMI 1.0 specification was released in December 2002 with the first HDMI-capable products hitting the market in 2003. By combining advanced uncompressed video formats and audio signals over a single cable, HDMI revolutionized home theater connections.
Over 425 million HDMI devices were sold by 2008. Today, over 5 billion HDMI products have been sold worldwide. It‘s the undisputed standard for high quality A/V connections.
HDMI Input Devices
HDMI inputs are required on devices like televisions, monitors, projectors and audio amplifiers that need to receive video and audio from a media source. These "display devices" rely on media sources feeding them video through an HDMI connection.
Some examples of products that need HDMI inputs include:
- Computer monitors and displays
- Video projectors
- Surround sound receivers
- AV preamplifiers
- Gaming monitors and displays
- Car entertainment displays
- Video processors
- Video capture cards
The number of HDMI inputs can vary. Basic televisions may only have 1 or 2 while advanced home theater receivers offer 6 or more. It depends on the number of media sources you want to be able to display.
Having multiple HDMI inputs makes it easy to connect multiple media sources like game consoles, streaming sticks, cable boxes etc. and switch between them.
HDMI Output Devices
On the flip side, media sources like Blu-ray players, gaming consoles and set-top boxes require HDMI outputs to send HDMI signals to displays and AV receivers.
Some common examples of products with HDMI outputs include:
- Blu-ray and DVD players
- Gaming consoles like Playstation and Xbox
- Streaming media devices like Roku, FireTV, Apple TV
- Cable, satellite and OTA set-top TV boxes
- Laptop and desktop computers
- Smartphones and tablets
- Camcorders and DSLR cameras
- Media streamers like Plex
- Laser projectors
- Video game capture cards
HDMI outputs provide the ability to output video and audio from the source to an external display. Even smartphones and tablets include HDMI outputs via MHL or USB-C alt mode to mirror their screens on larger displays.
Connecting HDMI Inputs and Outputs
HDMI cables are designed to transmit signals in one direction only – from an HDMI output to an HDMI input. The output of your media source must always be connected to the input of your display.
Here are some examples:
- Connect Blu-ray player HDMI output to TV HDMI input
- Connect game console HDMI output to AV receiver HDMI input
- Connect laptop HDMI output to external monitor HDMI input
HDMI cables and ports are keyed so you can‘t connect an output-to-output or input-to-input incorrectly.
Trying to connect two HDMI inputs or two HDMI outputs together directly won‘t work and can damage electronics. The signal can only travel from an output to an input.
Some devices like AV receivers can have both inputs and outputs to connect multiple media sources to a display. For example, you can connect your cable box and Blu-ray player HDMI outputs into a receiver, then connect the receiver HDMI output to your TV input.
But in general, remember that displays use inputs and media sources use outputs when connecting your home theater. This ensures proper signal flow from source to display.
HDMI Cable Bandwidth and Versions
The HDMI specifications define the bandwidth and resolutions supported to transmit signals from outputs to inputs. Higher bandwidth allows HDMI cables and ports to transmit higher resolution, higher framerate and higher bitrate video and audio.
Here‘s a quick summary of HDMI versions and max resolutions:
HDMI 1.0 – Released 2002, max resolution 1080p 60Hz
HDMI 1.3 – Released 2006, added support for higher resolutions up to WQXGA (2560×1600)
HDMI 1.4 – Released 2009, added support for 4K 30Hz
HDMI 2.0 – Released 2013, supports 4K 60Hz video
HDMI 2.1 – Released 2017, supports resolutions up to 10K and bandwidth up to 48Gbps
To achieve maximum performance, you need HDMI cables rated for the version of HDMI ports on your devices. Lower bandwidth cables may limit resolution or frame rate.
Using HDMI 2.1 cables won‘t improve performance if your devices only have older HDMI 2.0 or 1.4 ports. But higher rated cables are backwards compatible with older standards.
Identifying HDMI Inputs and Outputs
HDMI inputs and outputs are clearly labeled on devices and connection ports. But it helps to know what to look for:
Inputs labeled as "HDMI In" or "HDMI Input"
Outputs labeled as "HDMI Out" or "HDMI Output"
On HDMI Ports:
Input ports denoted with "HDMI In" or an input symbol
Output ports denoted with "HDMI Out" or an output symbol
HDMI cables are directional with different connector ends for input and output
Arrows on connectors indicate signal direction from outputs to inputs
As long as your cable connects the output port of the source to the input port of the display, you have the correct directionality.
Real-World Examples of HDMI Inputs and Outputs
To help reinforce the difference between inputs and outputs, let‘s look at some real world examples:
Playstation to TV
The Playstation game console acts as an HDMI source, so it needs an HDMI output to send video to the TV.
The TV acts as an HDMI display, so it requires an HDMI input to receive the video signal from the Playstation.
By connecting the Playstation HDMI output to the TV HDMI input, the signal flows properly from source to display.
Blu-ray Player to AV Receiver
The Blu-ray player is the source device, so it uses an HDMI output.
The AV receiver will transmit video to a TV display downstream, so it needs HDMI inputs to receive video from sources like the Blu-ray player.
Connecting the Blu-ray HDMI output to the AV receiver HDMI input allows the video signal to flow from player to receiver.
Laptop to External Monitor
For displays, laptops utilize an HDMI output to send video.
External monitors require HDMI inputs to receive video from a laptop or other source.
Connecting the laptop‘s HDMI output to the monitor‘s HDMI input allows the laptop to send video and audio to the external display.
Why Understanding Inputs vs Outputs Matters
Hopefully the examples help illustrate why properly matching HDMI inputs and outputs is important.
Connecting devices incorrectly can stop signals from being transmitted. And forcing connections between two inputs or two outputs can damage ports.
A few final tips:
Displays use inputs, sources use outputs
Outputs always connect to inputs for proper signal direction
Match HDMI cable versions to port versions
Labels indicate input or output ports
HDMI cables are directional
More advanced resolutions require higher bandwidth
As long as you remember the difference between inputs and outputs and follow basic signal flow, you‘ll be able to connect your home theater devices successfully.
Frequently Asked Questions
Here are answers to some common questions about HDMI inputs and outputs.
Can I connect two HDMI devices together if they both only have outputs?
No, this will not work since the signal can only travel from an output to an input. At least one device needs an input.
Do all HDMI cables work the same in both directions?
No. HDMI cables are directional and can only send signals from an output to an input port. Reversing their direction won‘t work.
Can I split one HDMI output to multiple displays?
Yes, you can use an HDMI splitter to take a single HDMI output and split it to multiple displays. Each display would need to have an HDMI input.
My Blu-ray player only has one HDMI port. How do I connect it?
If a source device only has one HDMI port, it will always be an output that needs to connect to a display input. Having only one port makes the needed connection obvious.
What happens if I connect two HDMI outputs together?
Connecting two outputs can potentially damage the electronics by sending signals to a port meant to only receive them. HDMI cables and ports are keyed to prevent this.
Can I improve picture quality by upgrading HDMI cables?
Maybe. If your current cables are not rated for the bandwidth your devices support, higher rated cables may allow better resolutions and frame rates. But cables alone can‘t improve quality beyond what your devices are capable of.
Do I need the latest HDMI 2.1 cables for best quality?
Not necessarily. You need HDMI cables rated for the versions of your devices‘ HDMI ports. For example, HDMI 2.1 cables won‘t provide any benefit for older HDMI 2.0 or 1.4 devices. Match cable and port versions.
Understanding the distinct purposes of HDMI inputs and outputs is key to making sure your home theater devices are connected properly.
Inputs receive audio/video signals while outputs transmit them. Displays use inputs to receive signals from media sources. Media devices use outputs to send signals to a display input. Proper signal flow matters.
Following the simple principles covered in this guide will help you successfully connect your HDMI devices. Just remember outputs always link to inputs for crystal clear audio and sharp high definition video.