- Joined
- Jan 7, 2007
- Messages
- 9,626
- Reaction score
- 828
More HDMI info
Courtesy of this website:
http://hometheatermag.printthis.cli...m/hookmeup/hdmi_101/index.html&partnerID=3830
Courtesy of this website:
http://hometheatermag.printthis.cli...m/hookmeup/hdmi_101/index.html&partnerID=3830
[size=10pt]Hook Me Up
HDMI 101
By Joshua Zyber • March, 2009
How important is HDMI 1.3 anyway?
The HDMI standard was developed with noble intentions. Most people in the home theater hobby know the hazards of cable clutter. When you have a lot of equipment connected this way and that by separate audio and video cables, you wind up with a tangled mess of wires behind your equipment rack or entertainment center. The problem is compounded by component video (three cables just for picture) and multichannel analog audio (six to eight more cables!). Now factor in a DVR, a couple of DVD players, a Blu-ray player, a video processor, and an A/V receiver all interconnected in one theater room. If you want to add or remove any piece of equipment, you’ll have to squat behind the rack with a flashlight and trying to trace each cable from end to end. Which unit did this blue one come from? If I plug that red cable into here, will I get my picture back, or will my speakers start blaring obnoxious noises?
HDMI was supposed to help with all that. One cable carries both video and audio. Better yet, it carries high-definition video and high- resolution multichannel audio, plus it has all the latest copy-protection protocols that the Hollywood studios demand. In theory, it’s the perfect connection standard for Blu-ray. One HDMI cable out from the Blu-ray player to an A/V receiver, and another HDMI cable out from the receiver to an HDTV should be all it takes to get stunning 1080p picture and lossless audio, all fully encrypted with a minimum of cable clutter. So why are there so many different versions of HDMI? And which ones do you need to be concerned with?
HDMI is an evolving standard that first came to market before all of its features were finalized. The original HDMI version 1.0 established the basic parameters for transmitting high- definition video and uncompressed audio. This was followed by several revisions that added, among other features, support for the DVD-Audio format and some PC applications. For home theater purposes, any HDMI connection type from 1.0 to 1.2a will transmit 1080p picture and multichannel PCM sound equally well. However, at the very least, they will not carry the native digital bitstreams for the advanced Dolby TrueHD or DTS-HD Master Audio lossless audio formats.
The most significant revision to the HDMI spec came with version 1.3, which added support for a few new features that are useful for home theater applications. (Later versions such as 1.3a, 1.3b, and 1.3c add more remote control options and other improvements to their functionality, but they add nothing directly related to additional core audio or video.) In order to benefit from these new features, both ends of the signal chain—as well as any switches, splitters, or other intermediary devices—must be compliant with HDMI 1.3. As a result, HDMI 1.3 has become a marketing tool for many manufacturers to encourage consumers to upgrade their Blu-ray players, A/V receivers, and even all of their cables. You wouldn’t want to be noncompliant with all of the latest features, would you? Of course, this begs the question: Does a Blu-ray viewer really need HDMI 1.3 to get the most out of the format? The answer is a resounding maybe. To delve a little deeper, let’s take a look at what HDMI 1.3 offers that you can’t get in previous versions.
On the video side of things, HDMI 1.3 increases signal bandwidth and allows for the transmission of more color detail. Only HDMI 1.3+ can carry the Deep Color or x.v.YCC formats that promise billions of possible colors, smoother color gradients, and the elimination of banding artifacts. (Naturally, these will only work if both the source and the display are compatible.) That certainly sounds great, but there’s just one problem. The Blu-ray spec doesn’t support either Deep Color or x.v.YCC. Even if a Blu-ray player claims compatibility with these formats (and several do), no Blu-ray Discs are actually encoded with an extended color gamut. Those billions of new colors don’t exist in the Blu-ray source. Any standard HDMI connection can transmit the full video quality that’s available on a Blu-ray Disc.
Does that make HDMI 1.3 irrelevant for video? Not necessarily. At present, a few models of HD camcorders will record content with Deep Color or x.v.YCC. There has also been speculation that some video games may be encoded with one or the other in the future. Although Blu-ray Discs don’t contain the expanded color detail, some Blu-ray player models (such as the recent Pioneer BDP-51FD) may be able to interpolate those extra colors internally, which essentially upconverts the color signal. To take advantage of that, you’ll need HDMI 1.3 and a Deep Color–capable display. On the other hand, some displays may be able to perform that interpolation themselves, negating the need for the Blu-ray player to do it. In the end, there may be some cases where HDMI 1.3 is useful, but it is not strictly necessary for video.
The audio situation is more complicated. Blu-ray Discs can contain movie soundtracks in several possible formats. Regular DTS or Dolby Digital 5.1 work the same as they did on DVD. An S/PDIF cable or any version of HDMI can transmit those lossy codecs without issue. As I mentioned earlier, uncompressed multichannel PCM will also work just fine with any HDMI connection. (S/PDIF doesn’t have enough band- width for that.) Where things get tricky is the usage of the newer audio formats: Dolby Digital Plus, DTS- HD High Resolution Audio, Dolby TrueHD, and DTS-HD Master Audio. Dolby Digital Plus and DTS-HD High Resolution Audio are rarely used on Blu-ray these days, but Dolby TrueHD and DTS-HD Master Audio are very common. All four of these new audio formats have the same transmission limitations. In order to hear the full high-resolution soundtrack, your Blu-ray player must either decode the format internally or transmit its native bitstream to an A/V receiver or surround processor.
Players that decode the advanced audio codecs convert the audio to PCM. The decoded PCM should result in no loss of quality, and it can be output over any HDMI connection. (Some player models may also offer multichannel analog outputs.) In this case, HDMI 1.3 is not needed. Unfortunately, not all Blu-ray players are built with the ability to decode those high- resolution formats in full quality. Some Blu-ray players can only decode standard DTS or Dolby Digital 5.1. And a number of early players decode Dolby TrueHD but not DTS-HD Master Audio. In either case, you’ll need to transmit the codec’s native bitstream and let your A/V receiver or surround processor do the decoding. This will require HDMI 1.3 on both the Blu-ray player and the receiver or surround processor.
Either decoding to multichannel PCM or passing the native bitstream will give you high-quality lossless sound. The choice between letting the Blu-ray player decode the audio or transmitting the native bitstream will depend on the specifics of your equip- ment. For example, the Sony PlayStation 3 offers no bitstream option for the advanced audio formats, but it will decode them internally to PCM. On the other hand, the Panasonic DMP- BD30 will not decode Dolby TrueHD or DTS-HD Master Audio itself but can transmit their native bitstreams. Secondary audio from commentaries, Bonus View, and BD-Live content complicates this decision even further, as the only way to seamlessly mix disc and secondary audio is to let the player handle the decoding.
Older A/V receivers and surround processors may include HDMI inputs that can accept multichannel PCM but not the newer formats. And some A/V receivers and processors—even a few current models—have HDMI inputs that will not handle any type of audio at all over HDMI. Their HDMI inputs are strictly video. If yours is one of these, the only way you’ll be able to listen to the new high-resolution audio formats is from the player’s multichannel audio outputs to the multichannel analog inputs on your A/V receiver or surround processor. In either of these situations, the player must be able to perform the decoding. Every system will have its own particular needs.
For both video and audio, HDMI 1.3 is useful in some home theater applications, but it’s not necessarily required. If you buy new equipment today, the presence of HDMI 1.3 will help with future-proofing if nothing else. However, with a bit of care, it’s still possible to obtain the highest-quality video and audio available from Blu-ray even with older versions of HDMI.
[/size]