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Discussion Starter · #1 ·
I have noticed a few articles have stated that 1080p120 was a requirement including the Electronic House article that was recently linked to on the main page of AVS Forum. Here are two of the mistakes that were made in that article:

Quote:
Other lower resolutions outside of Full HD 3D may be added in the HDMI 1.4a spec, but that's mostly speculation.

The HDMI group released the 3D specification for HDMI 1.4 weeks before this article was released describing 720p120 (720p60 per eye) as one of the mandatory 3D formats. Also the HDMI website released on the same day as this article a press release listing the mandatory 3D formats for HDMI 1.4a .


Quote:
If and how the PS3 will meet the 1080p120 requirement without HDMI 1.4 is yet to be seen.

Which won't be much of an issue since 1080p120 is not a mandatory 3D format for HDMI 1.4a.
 

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Quote:
Originally Posted by Richard Paul /forum/post/18301380


Which won't be much of an issue since 1080p120 is not a mandatory 3D format for HDMI 1.4a.

And, since even most HDMI 1.4 chips currently available top out at around 220 MHz, it will be a while before we see any products with 1080p120 or 3D-FramePacking-1080p60, at 297 MHz.
 

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Richard,

The 120hz requirement is for the frame rate capability of the HDTV/Display required in order to play Full 3D blu-ray received content over HDMI 1.4 in order that the content for each eye can be refreshed at a minimum of 60fps.
 

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Discussion Starter · #4 ·

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Originally Posted by walford /forum/post/18302559


Richard,

The 120hz requirement is for the frame rate capability of the HDTV/Display required in order to play Full 3D blu-ray received content over HDMI 1.4 in order that the content for each eye can be refreshed at a minimum of 60fps.

There may be a refresh rate requirement for HDMI 1.4a 3D displays but I was referring to the fact that I have seen several articles which state that there is a requirement to support a 1080p120 (1080p60 per eye) video signal over HDMI 1.4a. The author of the Electronic House article makes that mistake as seen in the following statements:

Quote:
There are other more technical issues regarding LCD response time and processing power, but the 120Hz input requirement is the main consideration. Other lower resolutions outside of Full HD 3D may be added in the HDMI 1.4a spec, but that's mostly speculation.

...

If and how the PS3 will meet the 1080p120 requirement without HDMI 1.4 is yet to be seen.

...

Chances are, HDMI 1.3a cabling won't have the bandwidth to carry 1080p120 signals required for Full HD 3D.
 

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What I don't understand is why people even keep talking about 120hz.


I would agree that I would prefer displays have 120hz input capability so I can send a 120hz signal from my htpc. I would agree that 120hz is optimal for 3d gaming, as this would give 60hz per eye, typically thought in the gaming community as minimum refresh rate for smooth gaming without eyestrain/headache. There are already 120hz monitors for 3d pc gaming, they've been out for like a year.


But 3d bluray does not need 120hz. 3d blurays as I understand it will have 2x 1080p24 streams, one 1080p24 stream for each eye. (for the most part. I'm sure some 3d titles could come in the future at 30 frames or even 1080i60) So, the display should simply accept a 48hz signal and then do the frame doubling internally. Granted, the 3d player could do this and send a 120hz signal to the display, but its unnecessary in my opinion. I would rather the display do this personally.


3d bluray will not have 120fps or even 60 progressive fps on the disc. Bluray doesn't even support 1080p60: only 1080p24, 1080p30, 1080i60, and 3d bluray does not change this.
 

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Quote:
Originally Posted by Lazarus Dark /forum/post/18303364


What I don't understand is why people even keep talking about 120hz.


I would agree that I would prefer displays have 120hz input capability so I can send a 120hz signal from my htpc. I would agree that 120hz is optimal for 3d gaming, as this would give 60hz per eye, typically thought in the gaming community as minimum refresh rate for smooth gaming without eyestrain/headache. There are already 120hz monitors for 3d pc gaming, they've been out for like a year.


But 3d bluray does not need 120hz. 3d blurays as I understand it will have 2x 1080p24 streams, one 1080p24 stream for each eye. (for the most part. I'm sure some 3d titles could come in the future at 30 frames or even 1080i60) So, the display should simply accept a 48hz signal and then do the frame doubling internally. Granted, the 3d player could do this and send a 120hz signal to the display, but its unnecessary in my opinion. I would rather the display do this personally.


3d bluray will not have 120fps or even 60 progressive fps on the disc. Bluray doesn't even support 1080p60: only 1080p24, 1080p30, 1080i60, and 3d bluray does not change this.

3D BD supports 1080x24P and 108060i. BD does not support 30P. Not in the specs.
 

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Quote:
Originally Posted by Lee Stewart /forum/post/18303433


3D BD supports 1080x24P and 108060i. BD does not support 30P. Not in the specs.

Exactly, 1080p60 per eye isn't supported by Blu-ray so why would HDMI 1.4 make it mandatory.


It does serve as a word of warning to those who can't wait for 3D broadcasts. The VP at Moto believe we'll have 1080p60 per eye broadcasts within three years which means that 3DTVs made today won't be able to take advantage of this (this was confirmed by a Panasonic engineer). The new cable boxes (existing boxes don't support frame sequential 3D or H.264) will probably be able to convert the signal to all kinds of formats including 1080p30 per eye that the current 3DTVs do support.
 

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Quote:
Originally Posted by bdraw /forum/post/18304250


Exactly, 1080p60 per eye isn't supported by Blu-ray so why would HDMI 1.4 make it mandatory.

To allow the Blu-ray player or a video processor to do the de-interlacing of 1080/60i or upconversion of 720p60 per eye and other formats? To be ready for when TV broadcasts are 1080p60 per eye?


Current Blu-ray players don't support decoding of 1080p60 in 2D, but HDMI supports 1080p60 for 2D allowing current players to de-interlace 1080/60i or output 1080p24 content at 1080p60 in 2D.
 

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Joe,

The problem is bandwidth since 1080p/60 requires twice the banddwidth as 1080i/60 or 720p/60 so transmiting two 1080p/60 frames concurently from a player would require over twice the bandwith as transmiting two 1080p/24 frames.

The whole reason ESPN and DirectTV pressured the HDMI standards committee to include packed 720p frames in the HDMIa 1.4 specification was so that they could broadcast live content especially sporting events to STBs. And of course disk players do not have to concern themselves with live content but they do concert themselves with high resoluton film content so packed 1080p/24 is sufficient for Full 3D Blu-Ray.
 

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Quote:
Originally Posted by Lee Stewart /forum/post/18303433


3D BD supports 1080x24P and 108060i. BD does not support 30P. Not in the specs.

holy crap. You're right it doesn't. I could have sworn it did, but I looked it up and only HD-DVD supported 30p. Wow, all this time I've been wrong...
 

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Quote:
Originally Posted by walford /forum/post/18306529


Joe,

The problem is bandwidth since 1080p/60 requires twice the banddwidth as 1080i/60 or 720p/60 so transmiting two 1080p/60 frames concurently from a player would require over twice the bandwith as transmiting two 1080p/24 frames.

The whole reason ESPN and DirectTV pressured the HDMI standards committee to include packed 720p frames in the HDMIa 1.4 specification was so that they could broadcast live content especially sporting events to STBs. And of course disk players do not have to concern themselves with live content but they do concert themselves with high resoluton film content so packed 1080p/24 is sufficient for Full 3D Blu-Ray.

Are you saying HDMI 1.3 doesn't have the bandwidth to support 1080p60 x2?


According to http://en.wikipedia.org/wiki/Hdmi

HDMI 1.3 can support 2560×1600p75.


2560*1600*75=307,200,000. 1920x1080p60 x2 is less than that (1920*1080*60*2=248,832,000)


So it seems that the bandwidth needed for 1920x1080p60 x2 is within that supported by the HDMI 1.3 & 1.4 specs. All they needed to do was add it as a supported standard if it isn't already.


Or do you mean there would be a problem making players that could support that bandwidth (even though that bandwidth is within the HDMI 1.3 & 1.4 specification).
 

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Quote:
Originally Posted by walford /forum/post/18304178


The HDMI 1.4 spec for 3D requires the support of two 1280x720 frames contained in a Packed 1280x1470 buffer at 60fps. See the followiing link:

http://hdguru.com/3d-hdtv-and-hdmi-explained/1336/
Quote:
Originally Posted by bdraw /forum/post/18304250


Exactly, 1080p60 per eye isn't supported by Blu-ray so why would HDMI 1.4 make it mandatory.


It does serve as a word of warning to those who can't wait for 3D broadcasts. The VP at Moto believe we'll have 1080p60 per eye broadcasts within three years which means that 3DTVs made today won't be able to take advantage of this (this was confirmed by a Panasonic engineer). The new cable boxes (existing boxes don't support frame sequential 3D or H.264) will probably be able to convert the signal to all kinds of formats including 1080p30 per eye that the current 3DTVs do support.

Many people seem to be confusing what is an appropriate display rate for 3D images with what signal format a Blu-ray 3D player will output. These are certainly not the same thing. Blu-ray 3D players and other 3D sources are only required to output in one of the signal formats defined as mandatory by the HDMI 1.4a spec. For Blu-ray 3D the only required format for 24fps source material (all movies) is full resolution 1080p/24 for each the right and left images and the only signal format for outputing this is the "Frame Packing" format. The HDMI 1.4a spec. does also define a 720p/60 Frame Packing format but this is intended for 60Hz 720p source material and in any case Frame Packing is not a simple alternating sequential right/left frame mode (i.e., it requires preocessing by the 3D HDTV to convert it into that type of display format if that's how that HDTV wants to display it). Any BD player manufacturer can decide to support multiple output formats if they want to, but they are not required to do so. The burden in placed upon the 3D HDTV to accept the input signal in any of the standard (mandatory) formats defined by the HDMI 1.4a then process this signal to create and image stream at the resolution and refresh rate the manufacturer deems best for that specific display.
 

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Joe,

Excellent HDMI specifications link, very informative.

Thank you for pointing out that I was wrong about the bandwidth being the restrcition. The link does, point out, however, that the HDMI 1.3 spec does not support the packed buffer format wheras HDMI 1.4 does.
 

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Quote:
Originally Posted by walford /forum/post/18309112


Joe,

Excellent HDMI specifications link, very informative.

Thank you for pointing out that I was wrong about the bandwidth being the restrcition. The link does, point out, however, that the HDMI 1.3 spec does not support the packed buffer format wheras HDMI 1.4 does.

Which is probably why they are able to upgrade the CBL and SAT STBs for their choosen 3D formats and why the 1.3 receivers won't pass a 3D BD signal
 

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Quote:
Originally Posted by Lee Stewart /forum/post/18303433


3D BD supports 1080x24P and 108060i. BD does not support 30P. Not in the specs.

The 1080i60 support in the specification was dropped. 1080i60 is a needed support for DVB broadcast specification. OTOH 720p 50/60 is supported under 3D BD.
 

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Quote:
Originally Posted by mainakb /forum/post/18337647


The 1080i60 support in the specification was dropped. 1080i60 is a needed support for DVB broadcast specification. OTOH 720p 50/60 is supported under 3D BD.

So I guess they will use 1080x24P stereo camera rigs to shoot 3D concerts (as they have in the past) and not use 1080i stereo camera rigs as many concerts were shot and presented on BD in 1080i HD - 2D single camera of course.
 
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