Talk:HDMI

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This article uses American English dialect and spelling.
According to the WP:ENGVAR, this should not be changed without broad consensus.

Specification defines an HDMI cable as having only HDMI connectors on the ends[edit]

Adaptor cables contravene current HDMI spec, and may not be "allowed" to be sold? http://www.techradar.com/news/home-cinema/thousands-of-apple-hdmi-cables-must-be-withdrawn-976455 http://www.pcmag.com/article2/0,2817,2388289,00.asp http://mobile.pcauthority.com.au/Article.aspx?CIID=263280&type=News It looks like old news but when I was trying to find out why HDMI to DVI cables are currently nearly impossible to obtain (in rural Australia, at least), I could find no useful information anywhere. If anyone is up to date on this perhaps the subject would be worth a sentence or two? HuwG 203.208.123.81 (talk) 07:43, 29 October 2012 (UTC)

The requirement is that certified HDMI cables must have a HDMI plug connection on both ends of the cable. The press section of the HDMI website gives an explanation about that requirement and it states that dongles that convert from a different cable type to a HDMI receptacle connection are allowed. While DVI to HDMI cables can't be certified I still see them for sale on the internet, and at retail stores, so I don't think that HDMI licensing is trying that hard to get rid of them. --GrandDrake (talk) 00:09, 25 May 2013 (UTC)

What is RedMere and how does it work?[edit]

I've heard of a technology called RedMere it is supposed to allow "up to 65 feet (20 meters) at the full 10.2 Gbps data throughput" (http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10240&cs_id=1025501&p_id=9167&seq=1&format=2). What is it? How does it work? Does anyone know? — Preceding unsigned comment added by 68.228.41.185 (talk) 22:01, 19 December 2012 (UTC)

RedMere HDMI cables use active amplification which allows them to have much longer cable lengths than passive HDMI cables. Active HDMI cables contain a small chip that boosts the HDMI signal. Active HDMI cables are usually more expensive than passive HDMI cables but are useful if you need a HDMI cable longer than 5 meters. --GrandDrake (talk) 00:14, 25 May 2013 (UTC)

Critical omission in not mentioning severe limitations[edit]

This article comes off as a sales piece, since it is essentially silent on what makes HDMI so costly and difficult for consumers to use, and practically impossible to use over many distances needed in typical home uses. For example, HDMI is crippled in its ability to transmit over anything longer than just a few meters because it uses a parallel signal transmission method, instead of serial communications used in every other modern transmission protocol.

Until this article addresses all such significant consumer issues, I will continue to assume that firms with a financial interest in HDMI will continue to control the article content. — Preceding unsigned comment added by 67.171.190.119 (talk) 23:23, 20 May 2013 (UTC)

The limits of HDMI are due to the high data rate that it uses combined with the low cost signalling method. HDMI at full bandwidth works with passive cables at up to about 5 meters in length. DisplayPort has a higher data rate but at full bandwidth works with passive cables that are up to about 3 meters in length. Neither standard uses serial data transmission since that would either reduce the data rate or increase the price. --GrandDrake (talk) 04:44, 24 May 2013 (UTC)
You may want to have a word with the manufacturer of the cable that I use to connect my PC's HDMI port to my AV unit in my living room. The cable is 20 metres long. It seems that both the manufacturer and the cable are unaware of this limitation. DieSwartzPunkt (talk) 08:53, 24 April 2014 (UTC)
The maximum HDMI cable length depends on bandwidth, cable quality, and whether the cable includes a signal amplifier. --GrandDrake (talk) 19:17, 27 April 2014 (UTC)
I thought the same thing (article is a sales piece). The critical omissions are how much HDMI is prone to power surges, and bad image quality with the smallest interference around. Many articles around the web about those two points. Atriel (talk) 03:24, 19 March 2015 (UTC)
Have to agree with above, in that whenever I've tried to use HDMI to interface a device with a display there have always been problems. Like so many new designs, it's all features and no functionality. Issues range from loss of display resolution each time the lead is reconnected, to no signal at all. Also, you find nonstandard submin sockets that are misleadingly labelled 'HDMI' but after buying a costly HDMI lead you find it will not fit the 'HDMI' socket. DVI connections almost always work first time, HDMI is a disaster. Maybe reliability reports are outside the scope of WP (not sure) but then this article makes it sound far better than it is. --Anteaus (talk) 09:04, 30 May 2015 (UTC)

My hope was to learn some technical details of the specification. It appears, but is not 100% clear from this article, that to even read the specification you have to be a member of the forum ($15 grand sign up?!). It would be helpful if this was spelled out up front one way or the other, so that people didn't waste their time looking for information that does not exist. — Preceding unsigned comment added by 184.71.25.218 (talk) 21:20, 23 October 2013 (UTC)

Error in version comparison table (HDMI 2.0 refresh rates)[edit]

I am pretty sure that there is an error in the table listing the maximum resolution for HDMI 2.0 at different color depths. Specifically, I think anything more than 24 bits per pixel can not be shown at 60 frames per second at 4k resolutions (e.g. 4096×2160p60 at 48 bits per pixel would take 4096*2160*60*48/1e9 = 25.5 Gbits/second excluding overhead, well in excess of what HDMI 2.0 can deliver).

News articles I have seen have said that 8 bit color (24 bpp) can be shown at 4k and 60 hz, and 48 bit color can be shown at 4k (but with an unspecified refresh rate). (e.g. see http://www.theregister.co.uk/2013/09/04/hdmi_20_spec_published/ )

I am not knowledgeable enough about this topic to make the appropriate changes, and it might be that more info will be forthcoming in the next few days. — Preceding unsigned comment added by 67.82.65.131 (talk) 00:51, 5 September 2013 (UTC)

I removed some unverifiable information from the table. --GrandDrake (talk) 01:14, 5 September 2013 (UTC)

Will HDMI 1.4 cables work with HDMI 2.0 devices?[edit]

Will HDMI 1.4 cables work with HDMI 2.0 devices? Thanks — Preceding unsigned comment added by 71.131.3.194 (talk) 02:57, 28 September 2013 (UTC)

This isn't that clear. You simply cannot put 600Mhz where before only 300Mhz would work. However, you may not need to. Tafinho (talk) 22:05, 19 June 2014 (UTC)

HDMI 1.4 and CEA-861-D vs CEA-861-E[edit]

The article says HDMI 1.4 uses the CEA-861-E video standard while referencing a SiI9389 datasheet that mentions HDMI 1.4 and CEA-861-E compliance. However, I'm reading the actual HDMI 1.4b specification and it makes no mention of CEA-861-E, but talks about CEA-861-D... Anssi (talk) 00:02, 31 October 2013 (UTC)

Accessibility[edit]

This article needs to address accessibility of the HDMI standards. It seems like audio description for the blind can be included on one of the audio channels. The HDMI standard does not include communication access though for people with hearing loss or non-native speakers of the primary language (no streams for closed captioning data whether for deaf and hard of hearing or anime/foreign language) so in order to use HDMI with captions, the originating equipment must decode the data and pass the generated pictures of text to the end equipment. This limits the accessibility for persons with hearing loss, especially those with visual impairments. Televisions in the United States are required to have closed caption decoder chips and the visibility can be changed to the user's liking for over the air or Video/Audio inputs but this does not work for HDMI inputs since they do not pass the caption data through. This limits the ease with which physically disabled persons can use captions since they cannot just turn their television caption decoder on once and be done, they must turn on captions on each piece of sending equipment when using HDMI. This makes it harder for children and the aged to gain ease of use for captions. This also increases costs for everyone as with HDMI all of the sending and receiving units must have decoder chips (receiving units/televisions for over the air caption data.) — Preceding unsigned comment added by 2602:30A:C049:EA80:4885:EA70:59A9:82AB (talk) 18:30, 9 June 2014 (UTC)

600Mhz Source and existing cables compatibility[edit]

There is no source for the 600Mhz TMDS frequency value. Also, there is no independent source for the compatibility for existing 1.4 cat 2 cables, apart from the HDMI forum. Tafinho (talk) 22:06, 19 June 2014 (UTC)

Several sources mention 18 Gbps for HDMI 2.0 so based on how HDMI works that would mean a TMDS clock rate of 600 MHz. I have added two references for the TMDS clock rate. As for compatibility with older cables it would depend on the cable but almost all HDMI cables are made out of copper cable. As long as the bits are correctly transferred over the copper cable it doesn't matter if the cable was designed for it. --GrandDrake (talk) 21:31, 28 June 2014 (UTC)

To this topic: the article says "Category 2-certified cables, which have been tested at 340 MHz" and that HDMI 2.0 introduces 600MHz. So how should one go about purchasing a cable? Blindly test many until one works? It there an unofficial label used by cable manufacturers? --193.169.48.48 (talk) 13:51, 19 February 2015 (UTC) (the above was by me)--Xerces8 (talk) 09:44, 22 February 2015 (UTC)

HDMI 2.0 references[edit]

Back when i added a section about HDMI 2.0, I added some references to convince everyone it was real. But since equipment with HDMI 2.0 is actually on the market right now, do we really need four references per statement in the HDMI 2.0 section? PizzaMan (talk) 18:40, 16 July 2014 (UTC)

There are only two secondary sources. I have marked primary sources and raw press releases. Perhaps those should be removed. ~KvnG 03:07, 23 July 2014 (UTC)
Sorry for the late response, but i agree, so i went ahead and removed them. This article has a *lot* of sources. Seems unnecesarry to me. It's not like the contents of this article will likely come under such debate that they require multiple refs for each sentence. PizzaMan (♨♨) 22:20, 8 December 2014 (UTC)
On a sidenote: is it too lazy for me to rely on bots for handling orphaned references or, for example, dating a [citation needed] tag? PizzaMan (♨♨) 11:12, 9 December 2014 (UTC)

1536kHz Audio[edit]

Although the press-release indicates a sampling rate of 1536kHz, this must be an error. The highest sampling rate I've ever heard of is 192khz and that's "audiophile" crazy-high quality that's 4x as high as the human ear can even deal with. 1536kHz is an order of magnitude higher than that! — Preceding unsigned comment added by 199.20.36.1 (talk) 16:53, 11 August 2014 (UTC)

That's 7.1 channels of 192 kHz each. PizzaMan (♨♨) 22:21, 8 December 2014 (UTC)
Then it's 1536 kHz "symbol rate", not "sample rate" - which we don't really add up for separate signals. A clear case of carefully crafted "marketese language" from the HDMI Association. --128.68.48.32 (talk) 23:05, 13 January 2016 (UTC)

Connector inconsistency[edit]

In the lead it says "all use same cable and connector."

Later in connectors all the different connectors are described.

Surely both cant be true :-)

Rpm13 (talk) 12:00, 5 January 2015 (UTC)

Type A receptacle should be female?[edit]

In the box a the top right of the article it shows an HDMI pin-out with the label "Type A receptacle HDMI (male)" connector. Shouldn't that be "Type A receptacle HDMI (female)"? — Preceding unsigned comment added by 71.81.180.160 (talk) 20:08, 19 January 2015 (UTC)

Royalties?[edit]

As perfectly acceptable HDMI cables can be obtained from Pound Shops, it would appear that the manufacturers of these cables are not paying any royalties. Should I be concerned about this? — Preceding unsigned comment added by 89.243.167.3 (talk) 22:20, 2 March 2015 (UTC)

CEC[edit]

In the article: "CEC wiring is mandatory, although implementation of CEC in a product is optional.[49]"

In the HDMI 1.3 spetification: "HDMI includes three separate communications channels: TMDS, DDC, and the optional CEC. "

Some cables does't have CEC wire. — Preceding unsigned comment added by Vagonoboev (talkcontribs) 07:43, 8 April 2015 (UTC)

Expanded table[edit]

The feature table counts 6 columns, explaining differences between consecutive HDMI versions, but does not distinguish 1.4 from 1.4a or 2.0 from 2.0a. Shouldn't this table be expanded to, say, 14 columns? The Seventh Taylor (talk) 17:52, 26 May 2015 (UTC)

Cost[edit]

> HDMI manufacturers pay an annual fee of US$10,000 plus a royalty rate of $0.15 per unit, reduced to $0.05 if the HDMI logo is used, and further reduced to $0.04 if HDCP is also implemented.

no one should pay asia/europe a dime for going lone star unless they first confirm "HDMI" is making payments to VGA, DVI, VESA etc al who they copied the bulk of their work from

Making several incompatible connectors and versions: all they have is a cable style and a sugguested use which is no better or worse than DVI-D beyond that of designating certain uses "packet headers", such as when data will be considered audio — Preceding unsigned comment added by 72.209.223.190 (talk) 18:19, 16 July 2015 (UTC)

History of Digital Audio/Video[edit]

I removed a section which was added by an unknown user, which was completely misplaced in the article, containing no references at all, and was of overall low quality. Soulhack (talk) 10:12, 21 July 2015 (UTC)

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What connector for 2.0 and 2.0a cable?[edit]

The subtitle of this section is self explanatory. The 2.0 cable has been existing (for customers anyway) since 2013 but in the section of connectors nothing is being noticed about which connector it will connect to. 145.132.75.218 (talk) 21:13, 15 January 2016 (UTC)

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Consoles[edit]

Do some consoles use HDMI? — Preceding unsigned comment added by 172.56.41.196 (talk) 15:47, 19 February 2016 (UTC)

What kind of console? Misty MH (talk) 11:07, 27 July 2016 (UTC)

input/output bi-directional usage[edit]

What "reverse channel" features does HDMI offer? Can an HDMI display also include microphone audio input to a computer, for example? Can the display send back touch/multitouch data via HDMI? If such is possible, what are most common current examples and standards?-71.174.184.36 (talk) 13:43, 16 March 2016 (UTC)

seems 2.0b is launched, but what's going beside 2.1?[edit]

Nvidia GP104/geforce 1080 launch sheet data(click VIEW FULL SPEC) shows support HDMI 2.0b with DP 1.4, and 2.0b page from HDMI LLC says "Bandwidth up to 18Gbps". so, 2.0b is same as (former)2.1?--Hong620 (talk) 05:15, 7 May 2016 (UTC)

good question, what is going on here? — Preceding unsigned comment added by 193.107.156.62 (talk) 13:43, 6 June 2016 (UTC)

Official 2.0b?[edit]

If there is an official HDMI 2.0b, can someone with access and savvy add the features that differentiate it to the article? Thank you! (HDMI 2.0b) Misty MH (talk) 11:06, 27 July 2016 (UTC)

USB / HDMI Alt Mode[edit]

There is a new USB Type-C to HDMI spec. Although it's "not backwards compatible with existing devices" and "only supports the older HDMI 1.4b standard" so "4K (UHD) video will work, but only at 30FPS" 40.129.236.30 (talk) 06:32, 6 September 2016 (UTC)

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Digital or analog?[edit]

Among the very first words in the lead is "is a proprietary audio/video interface", without even a mention if it's a digital or analog interface. While I _think_ it's a digital interface, suggesting "is a proprietary digital"... would be correct, I don't know. I'd appreciate if someone knowing HDMI could fix the lead. 83.252.234.134 (talk) 08:02, 2 December 2016 (UTC)

HDMI 2.1 packetization and embedded clock[edit]

Regarding, "The sources suggest that the new mode isn't really TMDS any more; we will need to wait until the official specification to clarify the details. (The packet-based format is to facilitate the embedded clock, it's not a separate point.))" [1] by C0nanPayne (talk):

I guess by 'packetization' you are mentioning these references:

Reference 127, "HDTV Expert - HDMI 2.1: The Need For Speed Continues". hdtvmagazine.com: "But HDMI 2.1 adds another lane for TMDS data (although it’s not really TMDS anymore) by taking over the clock lane and embedding clock data within the existing signal, much the same way it’s done with packet-based signaling systems."

Reference 128, "HDMI 2.1 To Bring Robust Home Theater Experience". hdguru.com: "The connector includes three twisted pairs and a clock – which translates to four twisted pairs but sending basically RGB or Y and Cb and Cr. HDMI 2.1 can be run in inverted clock mode, which uses all four lanes and is packetized – This is said to be similar to though not the same as DisplayPort."

DisplayPort and MHL uses certain techniques to derive the data clock from the data stream itself. They don't use a separate clock lane (except in MHL 1.3) and there are only data lanes. Numerous digital coding methods -- on data -- enables them to do this.

Until HDMI 2.0, each of the 3 data lane carried one of the 3 colour component (e.g. Blue on TMDS D0 channel) and this was a fixed mapping. But when you have less than 3 data lanes or more that 3 data lanes the fixed mapping cannot be used any more and data has to be sent as fragments over the lanes. They use packetization to flexibly partition and distribute the AV data over the data lanes. This kind of packetization is used in MHL/superMHL and DisplayPort.

They probably use both embedded clock and packetization on HDMI 2.1. But, embedding of clock signal in data lane is a separate point from packetized structure of data stream.

louisnells (talk) 05:32, 12 February 2017 (UTC)

My point was to aid the reader in understanding that the packet-based format is how the clock is able to be embedded (in addition to being a means to distribute the three streams over a non equal number of lanes). Otherwise the reader is left with the impression that packetization is just another unrelated change, something like 16b/18b. (Both references talk about the embedded clock in the context of packetization.)
Given that DisplayPort explicitly makes use of data packets (called micro packets) to embed the clock signal within the data stream, how does making it a standalone point help explain it? C0nanPayne (talk) 17:27, 12 February 2017 (UTC)
The packetization does not always imply embedding of the clock signal. For example with superMHL there are 6 data lanes and they use packetization, but still they have a separate clock line (they use eCBUS as clock line). Packetization and embedded clock are just two separate techniques. One does not imply the other one. Packetization works in data level and embedding of clock signal works in line coding level (like they are in 2 different layers).
louisnells (talk) 08:30, 13 February 2017 (UTC)

Specifications[edit]

The link to HDMI 1.3a Specifications is redirected to Uncompressed video.64.47.214.68 (talk) 08:24, 7 March 2017 (UTC)