Modern A/V guide
Native DC outputs
The Dreamcast's multi-AV port supports several video outputs. These are, in ascending order of quality:
- Composite video (yellow RGB connector)
- S-video (mini-DIN with separate luminescence and chroma (Y/C) signals)
- RGB (separate signals for red, green, and blue colors, plus a sync signal)
- VGA (PC-style connection for use with a monitor)
The Dreamcast also supported RF connection to older TVs using a cable which converts composite video and audio signals to a single signal which connects to a TV's antenna or VCR input. Nowadays RF and composite should be ignored entirely.
You should use VGA or RGB signals whenever you can. These provide the best possible video signal with less color bleeding, cross-talk, and "fuzz".
Composite video
Composite is the most common way to connect a DC to a TV, as this cable was included in the box in most regions. This yellow RCA cable's video looks acceptable on a smaller CRT display. But on a larger model it looks bad. And on a flat-panel display like a LCD, it looks absolutely awful.
Avoid composite video wherever possible.
S-video
S-video (sometimes erroneously called S-VHS) uses two signals, rather than composite's one. This greatly increases quality, as black-and-white video is carried on one path and color is carried on another. High-end CRTs and early flat panel TVs support S-video.
This was the easiest way to improve picture fidelity in North America during the DC's lifetime.
RGB
While S-video uses two signals for video, RGB uses three. This allows for amazing video quality.
There are several standards for RGB video around the world. You need to research which one is right for your location and equipment. The most common are:
- SCART (used heavily in Europe)
- JP-21 (RGB-21, used in Japan and Korea)
- RGB-S (4 RCA or BNC connectors, with the 4th cable being used for sync)
- SoG (Sync-on-green, a rarer alternative to RGB-S)
There is no difference in video quality between these standards when used correctly.
SCART
SCART can carry high quality RGB signals as well as lower quality ones. Composite to SCART adapters were common during the DC's life (such as a SCART plug with RCA connectors). These provide composite video quality, but RGB SCART cables were also available as aftermarket accessories. These are very rare nowadays, so people with a compatible TV should look into converting other, more common cables.
JP-21
JP-21 (or RGB-21) was most commonly used in Japan and Korea. It uses the same connector as SCART but with a different pinout. This means that it is not compatible with SCART, and the connectors cannot be used interchagably.
As a rule, if a new old stock product is listed in Japanese and/or Korean, it is JP-21. If it is written in English and/or other European languages, it is SCART.
RGB-S
RGB-S is a video signal which uses 4 cables to transit Red, Green, Blue, and a Synchronization signal. SCART and JP-21 both use the same signals, so "RGB-S" usually implies connecting with 4 distinct RCA or BNC cables.
Some PVMs, projectors, and other high end equipment used RGB-S connections, but it is rare. Although the RCA jack colors are the same, RGB-S and component video are not compatible. Component video will be covered later in this guide.
Sync-on-green
Rather than use a separate sync signal, some displays can get that information from the green color channel. This is also very rare, and is of little interest unless you have a display which accepts it.
VGA
In the Dreamcast context, VGA can refer to a particular video signal (640x480@60Hz) or the connector used on monitors (commonly called DE-15 or D-Sub.)
Compared to TV signals like S-video or even RGB, VGA has a higher picture quality because it is progressive scan rather than interlaced (each line is drawn at the same time, not alternating.) This results in a much sharper image, equivalent to 480p.
The Dreamcast supports VGA output natively, but a small minority of games do not. Some of these unsupported games can be "tricked" into outputting VGA using mods, cheat codes, ODE overrides, or simply switching cables once the game has started.
Sega's official "VGA box" for the Dreamcast is now quite rare and expensive, but many third party alternatives exist. These may vary in quality and features. Most will have either a 3.5mm audio jack or stereo RCA cables for audio, as VGA does not carry audio.
Common alternatives
RF
RF combines composite video with audio in a single coaxial cable, and was commonly used with OTA TV antennas and VCRs. The signal is often noisy and is the worst quality possible. RF should only be used on an old TV with no better options available.
Component
Also known as YPbPr or D-terminal (in Japan), component video is similar to RGB, but uses a different color conversion so the signals are not directly compatible.
Because component video became very popular after the Dreamcast, there has been a demand to convert RGB signals to YPbPr component. Most converters or purpose-built cables will use RGB signals as a source, so the video is limited to 480i rather than the 480p offered with VGA.
HD Retrovision has announced a Component video cable for Dreamcast with support for both 480i and 480p video, but there has been little news since 2020.
HDMI
Most Dreamcast HDMI cables are adapters which convert a VGA signal from the DC to HDMI.
There is a wide variety of different cables or adapters which have varying levels of quality and features. Some may upscale the video to a higher resolution, introduce video latency, or alter the color saturation and contrast.
Generic VGA-HDMI adapters also exist, but may be less suitable for gaming and be incompatible with some Dreamcast-TV combinations. Ensure any adapter is VGA to HDMI and not HDMI to VGA - the conversion is unidirectional.
TODO: Reviews?
HDMI mods
A HDMI adapter which connects to the DC's multi-AV output still uses the DC's native VGA output before converting it to HDMI. This introduces latency and reduces quality because it is converting to analog video and then back to digital.
A HDMI mod, on the other hand, directly connects to the DC's video chipset and grabs the signal straight from the source. This allows for perfect video quality, no added lag, and flexible scaling options.
However they are quite expensive and require significant delicate soldering to your system. Most installations also remove the Serial port from the Dreamcast, which may be undesirable if you want to use a Coder's Cable or NGPC link cable.
RetroGEM
Formerly DCDigital and DCHDMI, RetroGEM is now a multi-system modification which supports Dreamcast and other consoles.
Recommendations
For the best, most authentic Dreamcast experience, use a CRT PC monitor, preferably with Trinitron (or equivalent). This has the progressive scan resolution which other CRTs do not, and does not have scaling or conversion issues like newer flat panel displays (LCD, OLED) do. It is the best of both worlds.
With a modern TV or display which only accepts HDMI, RetroGEM is by far the best option, although its price and installation is an understandable barrier for many. A standard Dreamcast HDMI cable such as Kaico or Retrobird will deliver a great experience.
For older displays without HDMI or VGA, choose RGB, S-video, composite, and RF in decreasing order of preference.
For dedicated gamers or those with unique setups, a frame scaler may be a good investment but the DC has enough output options that it is rarely necessary to use a scaler.