[opendtv] Re: 3D compressed formats

So far, yes. According to ITU-R, DVB, and EBU, we should expect a future of "service-compatible" 3D with full spatial & temporal resolution. 

But don't hold your breath.

Thanks!

TTFN,
Mark


On 12/17/2010 2:19 PM, Mike Tsinberg wrote:


Thanks Mark!

As usual you have a wealth of information!
So for broadcasting most popular are side-by-side compression format that is decoded and delivered through HDMI in one of the HDMI "mandatory" 3D side-by-side display formats. Since there are only five of such HDMI "mandatory" formats is it safe to assume that incoming compressed format will be is the same or similar format as display format? The Blu Ray, for example, uses "frame packing" HDMI display format. That probably means that compressed files on the disk are also done in frame packing style. Although for motion compensated compression encoding that will be a problem. 

Mike Tsinberg

------------------------------------------------------------------------
*From:*opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] *On Behalf Of *Mark Schubin 
*Sent:* Friday, December 17, 2010 1:30 PM
*To:* opendtv@xxxxxxxxxxxxx
*Subject:* [opendtv] Re: 3D compressed formats

Hoo-Boy!  What a can of worms!
There are literally dozens of 3D compression formats. You can download a poster of some of the pros & cons, as described by Ateme, here (it's the lower left): http://www.ateme.com/news_events.php5?Arg=153
Before I get into all the options, let me start by saying that almost all of the 3D being transmitted today uses a straight side-by-side squeeze: both views squeezed horizontally by a factor of two and placed side-by-side in a single frame. That's one of the HDMI 1.4a formats. The compression of those side-by-side images is standard.
Of course, there's a loss of 50% of the horizontal resolution, so Dolby recommends a variation in which the left-eye image takes alternating columns of pixels starting with the leftmost, and the right-eye-image takes alternating columns of pixels starting with the next column. That way, for portions of the image with no disparity, there's at least the possibility that the two eyes' resolution can be additive (although, once the temporal element of shuttered glasses is added, all bets are off.
Although that's the most common, it's just one form of "frame-compatible" compression. In side-by-side, alone, in addition to the simple squeeze, there are: squeeze & mirror; rotate & squeeze; and rotate, squeeze, & mirror. Then there are side-by-side versions based rotated 720p in a 1080p frame, thus losing both horizontal & vertical resolution, but less of each, and there are mirrored versions of those, too. There is also over-under (with mirrored version), alternating field, alternating frame, column interleave, line interleave, and quincunx, plus the Sisvel tile format (a full-sized, left-top, 720p image in a 1080p frame with the right-eye view broken into pieces surrounding it), something that allows set-top boxes to deliver 2D from a 3D transmission without doing image processing. Finally (in frame-compatible compression), there is anaglyph, with MANY color-pair combinations, of which the most popular are red-cyan, green-magenta (Trioscopics), and blue-amber (ColorCode 3D & SpaceSpex).
That brings us to non-frame-compatible (sometimes called service compatible). One form takes any of the (non-anaglyph) versions above and adds a helper signal for restoring the missing resolution. Then there is 2D+delta (the difference signal representing the disparity of the two views), 2D+delta+graphics, 2D+depth, 2D+depth+graphics, and 2D+depth+graphics+graphics occlusion. The +depth formats are useful for multiview autostereoscopic displays. 

Then there are various versions of MVC.
All of these are being experimented with, but the VAST majority of current 3D is simply squeezed side-by-side feeding a single video channel to an ordinary compression encoder. According to recent press reports, the frame-compatible tile format is also picking up steam.
You can find more in slides 106-111 of one of my 3D tutorials, which may be downloaded here: http://schubincafe.com/blog/2010/11/more-than-you-ever-wanted-to-know-about-3d/ 

TTFN,
Mark


On 12/17/2010 9:46 AM, Mike Tsinberg wrote:
What are compressed video formats that are used for 3D broadcasting on cable and satellite? Is there a formal definition or description of compressed 3D format? HDMI has described 3D only in baseband. 

Mike Tsinberg

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