With all the different 3D Formats that are out there, understanding all the terminology and how all the different 3D formats work can seem like an impossible task. Even more puzzling, is whether any given 3D format will work with your 3D TV or 3D Home Theater system. This guide has been written to provide you with an overview of all the different 3D formats out there. We have also linked to more in-depth articles on specific formats if you wish to learn more about any of the new 3D formats that have been introduced along with the HDMI 1.4 specification. A combination of the information in this guide and our 3D Compatibility Guide will provide you all the information and knowledge you need to understand everything about current 3D formats and compatibility. With the help of these guides you can be sure that all your 3D home theater components will play along nicely with each other.
Frame Sequential 3D Format
The Frame Sequential 3D Format consists of a sequence of alternating frames where each frame is typically at HD resolution where each successive frame contains the image for one or the other eye. So if the first frame carries the Left eye image, the next one will have the Right eye image, then the left eye image again, and so on and so forth. The key point to note is that practically all 3D TVs currently (all Active Shutter based, as well as some Passive 3D Displays) display the final 3D content on the screen in a Frame Sequential manner so as to work with Active Shutter 3D glasses. All HDMI 1.4 3D displays will be able to take a number of different 3D formats (see below) as inputs and convert them into the Frame Sequential format for final display on the screen. Be sure to read our 3D Frame Sequential Guide for more information and details.
The Side-by-Side 3D format consists of a single frame that actually contains sub-frames for both the left and right eye. In this format, the left eye sub-frame and right-eye sub-frame are stacked side by side, giving this format its name. When a 3D TV receives a Side-by-Side 3D frame, it splits the frame into its left and right sub-frames, upscales the sub-frame back to HD dimensions using an upscaling algorithm (if the original Side-by-Side content had half the horizontal resolution) and then displays these sub-frames in a Frame Sequential manner to achieve the 3D effect.
The most common use of the Side-by-Side 3D format is in what is called Frame Compatible format (more on this below) or “Side-by-Side Half” wherein, each sub-frame is sampled such that they have only half the horizontal resolution of a true HD frame (for example 960×1080 instead of 1920×1080 for 1080p content). This allows each frame to have the same size as regular 2D HD, thus making it easier to transmit and compatible with HDMI 1.3 equipment. This is the main reason why DIRECTV and ESPN have adopted the Side-by-Side 3D (half) Frame Compatible format for their 3D content. Be sure to read our article on Side-By-Side 3D for more details about this 3D format.
It is important to note that Side-By-Side 3D does not have to have a loss in horizontal resolution. It is possible to stack too full HD frames side-by-side for Full HD 3D, but this format is not mandatory as part of the HDMI 1.4 specification. Instead, the Full HD 3D format relies on the top-and-bottom format (more details below).
Top-and-Bottom 3D or Over-Under 3D Format
The top-and-bottom or Over-Under 3D format is very similar to the Side-by-Side 3D format described above, except that instead of each sub-frame being combined along the horizontal axis, they are stacked vertically with the left eye frame stacked above the sub-frame for the right eye. Similar to the case of Side-by-Side 3D, 3D TVs that receive 3D content in the Top-Bottom format, process the frame and split it to extract each sub-frame that is meant for each eye and then display these sub-frames in a frame-sequential manner.
The Top-and-Bottom 3D format with half the vertical resolution for each sub-frame (Frame Compatible) is supported under the HDMI 1.4 specification and is a popular choice for displaying sports in 3D at 720p and 60fps. On the other hand, a lossless stacking of full 1080p or 720p sub-frames in a top-and-bottom format is the standardized format for enabling true HD in 3D under the HDMI 1.4 specification. The 1080p Full HD 3D format (details below) is the standard for 3D BluRay players while the Full HD 3D 720p format will be primarily used by gaming consoles such as the PS3. Be sure to read more about this format in our Top-and-Bottom 3D format guide.
Full High Definition 3D (FHD3D) Format
As mentioned above, the FHD3D format is the only loss less 3D format that provides true HD. This is a Frame Packing format (see below for more about Frame Packing) wherein a single frame consists of two sub-frames meant for each eye, stacked using the Top-and-Bottom 3D format. The key feature of this format is that each sub-frame is at full HD resolution, i.e. 1920×1080 in the case of 1080p content and 1280×720 in the case of 720p content. This is a new format that was defined under the HDMI 1.4 specification and as such, is incompatible with HDMI 1.3 devices since they were not designed to handle a single frame with such large dimensions. To learn more about the Full HD 3D Format, be sure to read our FHD3D Format Guide.
Frame Packing 3D Format
An important point to note is that Frame Packing by itself is not so much a format, but rather a reference to the way in which the frames of a 3D signal are put together. The term “Frame Packing” is used to refer to 3D content whose sub-frames for left and right eye are combined into a single frame using either the Top-and-Bottom 3D or Side-by-Side 3D formats without any halving of the vertical or horizontal resolution of individual sub-frames in each format respectively. Thus, the Frame Packing format preserves the fidelity and quality of the video since each sub-frame still exists at full HD resolution, resulting in the total frame of the Frame Packing 3D content to be double the size of 2D HD content. Under the HDMI 1.4 specification, Top-and-Bottom 3D is the preferred method for Frame Packing as seen in the Full HD 3D specification. For more details about Frame Packing, check out our guide on Frame Packing 3D.
Frame Compatible 3D Format
Just like Frame Packing 3D, the term “Frame compatible” doesn’t refer directly to a format as much as refer to the manner in which individual sub-frames are combined together to form a single frame for a given 3D format. In the case of Frame Compatible 3D content, the net resolution and size of a given frame is the same as a single frame of regular 2D HD content. This compatibility with regular 2D HD content specifications is the reason for the term “Frame Compatible”. In order to achieve this, the fidelity of each sub-frame for each eye has to be reduced by halving the resolution of individual sub-frames along the horizontal axis (in the case of Side-by-Side Frame Compatible 3D) or along the vertical axis (in the case of Top-and-Bottom or Over-Under Frame Compatible 3D). Be sure to read our Frame Compatible 3D guide for more details and diagrams that help illustrate the working of this format.
Hopefully this article has given you a good idea of the various 3D formats that are currently being utilized for providing 3D content to the consumer. Be sure to read the detailed guides on each of these formats to learn more and see some illustrative diagrams that help explain how these formats work. 3D content providers are using a number of different formats to provide 3D to consumers. We have listed the most common use of each type of format below:
Blu-ray movies in 3D: 1080p @ 24fps, Frame Packing (Top-and-Bottom), i.e., FHD3D
Satellite, Cable and Broadcast 3D content: 1080p@24fps Top-and-Bottom (Half) for Movies; 720p@60fps Top-and-Bottom and Side-by-Side for Sports; 1080i @ 60fps Side-by-Side (Half) for Documentaries.
Gaming Consoles like the PS3: 720p @ 60fps, Frame Packing (Top-and-Bottom)