The High Definition Multimedia Interface ushers in new levels of audio and video performance. Compared to component video, however, these performance improvements have less to do with the cable itself and everything to do with the hardware to which it connects. Component video still offers high-end performance on non-HDMI equipment, with video supported all the way to 1080p on certain devices. Nonetheless, for the best in audio and video and ease of setup on Blu-ray and other select devices, HDMI remains the go-to interconnect.
HDMI and HDCP
The vibrant images and uncompressed, lossless sound provided by HDMI might make you forget that those performance qualities are not the sole reasons why HDMI exists. The primary function is copy protection. HDMI is a digital protocol, which means that without High Definition Content Protection authentication at any point in the signal chain, the signal is lost. This is designed to prevent high-definition copies and curb piracy. Component video's ability to play video at 1080p and beyond is on par with HDMI but offers an analog loophole that offered pirates a way to make HD duplicates. This is the primary reason why HDMI and component video-enabled devices limit the available resolution over component video, normally all the way to 480p.
While the audio and video benefits provided to the consumer and the copy protection elements satisfying content producers are great, another practical benefit is the reduction of cabling required. Each HDMI device only needs a single cable to carry top-flight audio and video, reducing cable clutter and potentially cabling costs. Component video in contrast requires the three individual red, blue and green video feeds, with a separate RCA, optical or digital coaxial audio cable for sound. However, digital coaxial and optical audio do not possess the bandwidth to play back lossless audio formats such as DTS Master Audio and Dolby TrueHD. HDMI therefore reduces the amount of wiring needed while performing at a higher level overall.
Since Blu-ray is now predominantly HDMI-only, these connections let the audio and videophile format truly shine. Identical to the master recordings, uncompressed audio formats such as DTS Master Audio and Dolby TrueHD play at far higher bit rates than conventional Dolby Digital and DTS formats on DVD. Additionally, 1080p video, although possible on component video, is never reduced over HDMI. Future formats such as 4K resolution are possible over HDMI, providing over twice the resolution of 1080p. Although only found in its true form in commercial theaters as of 2012, 4K is slated for consumer release.
HDMI Limitations and Conveniences
Despite the copy protections in place over HDMI, there are instances where users are limited in terms of video resolution settings. For example, many video enthusiasts prefer to send DVD video as untainted 480i over HDMI to an external video processor. Most Blu-ray and upconverting DVD players prohibit this. However, HDMI does allow a feature known as display detection, whereby the connected source component detects the resolution capabilities of the television or projector and setting the video output for best results. By comparison, component video-only sources allow users to send out video any way they choose, within the limitations of that device. Since component video devices are analog in nature, consumer-restricting digital copy protection schemes are normally not in place.
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