Nikon D7000, Playback

There are a couple of options for reviewing your video once you have finished recording. The first, and probably the easiest, is to press the Image Review button to bring up the recorded image on the rear LCD, and then use the OK button to start playing the video. The Multi-selector acts as the video controller and allows you to rewind and fast-forward as well as stop the video altogether

If you would like to get a larger look at things, you will need to either watch the video on your TV or move the video files to your computer. To watch low-res video on your TV, you can use the video cable that came with your camera and plug it into the small port on the side of the camera body (Figure 10.3). To get the full effect from your HD video, you will need to buy an HDMI cable (your TV needs to support at least 720HD and have an HDMI port to use this option). Once you have the cable hooked up, simply use the same camera controls that you use for watching the video on the rear LCD.

If you want to watch a video on your computer, you will need to download it using Nikon software or an SD card reader attached to the computer. The video file will have the extension .avi at the end of the filename. These files should play on either a Mac or a PC using software that came with your operating system (QuickTime for Mac and Windows Media Player for PC).

Plug your cable into
Figure 10.3 Plug your cable into this port to watch videos on your television.

 

Nikon D7000, Video Quality

The best quality your D7000 is capable of is high-definition video with a resolution of 1920 x 1080 pixels, aka 1080p. The 1080 represents the height of the video image in pixels, and the P stands for progressive, which is the method the camera uses to draw the video on the screen (more on this later). You can select a lower resolution video depending on your needs.

The other two video resolutions are 1280 x 720 and 640 x 424 (standard definition). For high-definition television and computer/media station viewing, you will be best served by using 1920 x 1080. If you plan on recording for the Internet or portable media devices, first check the appropriate upload to that medium or device. Many social sites such as YouTube and Facebook support HD video, as do the iPad, iPod touch, and competing devices. But before you decide to render HD video you should know the key benefit of using the lower resolutions: Lower resolution video requires less physical storage due to a smaller pixel count. This means you can fit more video on the storage card, as well as take less time to upload the video to the Internet.

What’s the difference between 1080p and 1080i?

When it comes to video, two terms describe its quality and how it is captured and displayed on a monitor or screen: progressive and interlaced. Unlike a photo, a video frame is not displayed all at once but instead is drawn sequentially. Interlaced video first draws the odd-numbered lines and then the even-numbered lines. This odd-even drawing is what we sometimes call screen flicker. In progressive video, the type your D7000 produces, the lines are drawn in sequence from top to bottom, usually resulting in better image quality and less screen flicker. For viewing purposes progressive video is preferred, especially with higher definition images.

Setting Movie Quality

Setting Movie Quality

Setting Movie Quality

  1. Start by pressing the Menu button. Using your Multi-selector, navigate to the Shooting menu.
  2. Using the Multi-selector, highlight Movie Settings and press OK (A).
  3. Highlight Movie Quality and press OK (B).
  4. Select the video quality of your choice and press OK (C).
  5. Press the Menu button twice to exit Menu mode and return to shooting, or rotate the Live View switch to the right to jump to the Live View/Movie mode.

 

Beware, Not All Black Friday Deals Are Good Deals

Everyone I talk to seems to be getting really excited about the upcoming deals at most major retailers this Friday (known as Black Friday). I am no exception to this excitement. But at the same time I can’t deny that I become saddened when I think about how many people are going to get a bargain basement price on a technology gadget this Friday that in reality is a piece of junk.I’m not saying that everything with a bargain basement price is a piece of junk. What I am saying is that some of them are. And my fear stems from the fact that noobies usually can’t tell them apart.For instance, do you know that an DVD player that upconverts to high definition is not the same as a Blu-ray high definition DVD player? Most noobies don’t. But a $60 or $70 price tag on a DVD player with the words “HD” on it sure looks like a deal! In this particular example an upconverting DVD player is not necessarily a piece of junk. In fact, they actually do a nice job of making standard DVDs look nicer on high definition televisions. But they aren’t Blu-ray, which is true 1080p high definition quality and the idea that most people think they just bought an high definition DVD player upsets me.Easy to hide inadequacies on computers and laptopsDeals on computers and laptops are another notorious rip-off. If you think you’re getting a good computer or laptop for $200 this Friday, you’re not. It may look nice on the outside but most techies would know to look for things such as how much memory it has, what the processor speed is and what kind of graphics card it has inside. A $200 laptop would fail all three of these tests.I could go on and on but I think you get the idea. But I will give you one last word of caution. Occasionally you really will find a great deal on a great technology product. But beware of the bait and switch. Most stores only carry one or two of these in their inventory. And when they run out you can bet they won’t tell you to come back another day. No, instead they will sell you on the “other” technology products still available that coincidentally aren’t all that good of a deal.So my parting advice to you is this. Trust your gut just like you would anything else. If it sounds too good to be true, it probably is. Either that or look for a good return policy.

Canon EOS 60D, Composition

When creating movies, most of the same rules of composition you use with still photography apply. The rule of thirds is one important rule to keep in mind when shooting video. The 60D’s grid overlay feature places a grid over the LCD Monitor to help you frame your shot properly. Changes to this menu item will apply to both Live View and videorecording modes.(FIGURE 9.4)

You can set your camera to display a grid overlay on the LCD Monitor in video mode and Live View.
FIGURE 9.4 You can set your camera to display a grid overlay on the LCD Monitor in video mode and Live View.

SETTING THE GRID DISPLAY FOR VIDEO RECORDING

SETTING THE GRID DISPLAY FOR VIDEO RECORDING

  1. Set the camera to video mode using the Mode dial on the top of the camera.
  2. Press the Menu button and use the Main dial to get to the second camera tab. Use the Quick Control dial to scroll down to Grid Display and press Set (A).
  3. Using the Quick Control dial, select the grid of your choice (B). Press the Set button to lock in your change.
  4. Press the Menu button to go back into Movie shooting mode. You will now see a semitransparent grid over the LCD Monitor on the back of your camera.

Quick Control dial

When you are in video mode, you will notice a semitransparent mask covering parts of the LCD Monitor (FIGURE 9.5 and FIGURE 9.6). The space within the mask is the area that will be recorded; the semitransparent mask on either the top and bottom (HD) or left and right (SD) will not be recorded. This is extremely helpful when composing images for movies, because you will know where the edges of the frame will be.

In HD resolutions (720p and 1080p), your camera will display a semitransparent mask over the top and bottom portions of your LCD Monitor.
FIGURE 9.5 In HD resolutions (720p and 1080p), your camera will display a semitransparent mask over the top and bottom portions of your LCD Monitor.
n SD resolution (640 x 480), your camera will display a semitransparent mask over the left and right portions of your LCD Monitor.
FIGURE 9.6 In SD resolution (640 x 480), your camera will display a semitransparent mask over the left and right portions of your LCD Monitor.

If you place your camera on a tripod to record your movies, one very useful feature is the electronic level, “Landscape Photography” (FIGURE 9.7). It can sometimes be difficult to see the horizon line in your scene, and the electronic level will help you keep your camera leveled horizontally. With still photography you can always go in and straighten the photo in editing software, but with video you don’t have as much wiggle room, so it’s always best to get it correct in-camera. Note that if you set the autofocus mode to “Face detection Live mode,” the electronic level won’t appear. Be sure to set it to either “Live mode” or “Quick mode” for it to show (please read the next section for more information on focus settings for video recording).

The electronic level is a helpful feature to use when placing your camera on a tripod.
FIGURE 9.7 The electronic level is a helpful feature to use when placing your camera on a tripod.

USING A TRIPOD

To get the best-possible quality when recording video with your camera, it’s a good idea to have a sturdy tripod and a fluid video head. I use a Manfrotto 501HDV video head with my Canon 60D when I use it on a tripod (Figure 9.8). There are also other options for stabilizing your camera, including handheld rigs and additional equipment.

A sturdy tripod and a fluid video head are good tools to have when shooting video with your 60D.
FIGURE 9.8 A sturdy tripod and a fluid video head are good tools to have when shooting video with your 60D.

 

 

Canon 7D, Composition

When creating movies, most of the same rules of composition you use with still photography apply (see Chapter 8). The rule of thirds is one important rule to keep in mind when shooting video. The 7D’s grid overlay feature places a grid over the LCD Monitor to help you frame your shot properly. Changes to this menu item will apply to both Live View and video recording modes (Figure 9.5).

You can set your camera to display a grid overlay on the LCD Monitor in video mode and Live View.
FIGURE 9.5 You can set your camera to display a grid overlay on the LCD Monitor in video mode and Live View.

SETTING THE GRID DISPLAY FOR VIDEO RECORDING

SETTING THE GRID DISPLAY FOR VIDEO RECORDING

  1. Set the camera to video mode using the Movie shooting switch.
  2. Press the Menu button and use the Main dial to get to the fourth camera tab. Use the Quick Control dial to scroll down to Grid Display and press Set (A).
  3. Using the Quick Control dial, once again select the grid of your choice (B). Press the Set button to lock in your change.
  4. Press the Menu button to go back into Movie shooting mode. You will now see a semi-transparent grid over the LCD Monitor on the back of your camera.

When you are in video mode, you will notice a semi-transparent mask covering parts of the LCD Monitor (Figures 9.6 and 9.7). The space within the mask is the area that will be recorded; the semi-transparent mask on either the top and bottom (HD) or left and right (SD) will not be recorded. This is extremely helpful when composing images for movies, because you will know where the edges of the frame will be.

In HD resolutions, your camera will display a semi-transparent mask over the top and bottom portions of your LCD Monitor.
FIGURE 9.6 In HD resolutions, your camera will display a semi-transparent mask over the top and bottom portions of your LCD Monitor.
 In SD resolution, your camera will display a semi-transparent mask over the left and right portions of your LCD Monitor.
FIGURE 9.7 In SD resolution, your camera will display a semi-transparent mask over the left and right portions of your LCD Monitor.

If you place your camera on a tripod to record your movies, one very useful feature is the electronic level, which you learned about in Chapter 5 (Figure 9.8). It can sometimes be diffi cult to see the horizon line in your scene, and the electronic level will help you keep your camera leveled both vertically and horizontally. With still photography you can always go in and straighten the photo in editing software, but with video you don’t have as much wiggle room, so it’s always best to get it correct in-camera. Note that if you set the autofocus mode to “Face detection Live mode,” the electronic level won’t appear. Be sure to set it to either “Live mode” or “Quick mode” for it to show (please read the next section for more information on focus settings for video recording).

The electronic level is a helpful feature to use when placing your camera on a tripod.
FIGURE 9.8 The electronic level is a helpful feature to use when placing your camera on a tripod.

USING A TRIPOD

To get the best possible quality when recording video with your camera, it’s a good idea to have a sturdy tripod and a fluid video head. I use a Manfrotto 501HDV video head with my Canon 7D when I use it on a tripod (Figure 9.9). There are also other options for stabilizing your camera, including handheld rigs and additional equipment.

A sturdy tripod and a fluid video head are good tools to have when shooting video with your 7D.
FIGURE 9.9 A sturdy tripod and a fluid video head are good tools to have when shooting video with your 7D.

Canon 7D, Getting Started

Before you jump into making movies of your own, let’s go over some of the basic settings you’ll use in order to ensure that you’re getting the quality you want.

VIDEO QUALITY

The fi rst setting that’s important to understand is resolution. You’ll need to know what movie-recording size you want to use, along with the frame rate, or frames per second (fps). The fi les are recorded as .mov fi les, and the quality and the resolution (size) of each fi le is measured in pixels. The fps rate is defi ned as how many frames (images) the camera records in a 1-second timeframe.

The 7D has three different sizes you can choose from:

  • 1920 x 1080: This is the full High Defi nition (HD) setting (16:9 aspect ratio). You have the option to record in 30, 25, or 24 fps. Using this setting at 24 fps is the standard for recording motion pictures. This setting is often referred to as “1080p.”
  • 1280 x 720: This is another HD setting with an aspect ratio of 16:9, but in a smaller resolution. It records movies at 50 or 60 fps and is often referred to as “720p.” This is good for shooting Web-sized videos or if you want to create a high-quality slow-motion effect with your movies using editing software. Using this setting will take up the same amount of space on your CF card as the 1080p setting since it records twice as many fps.
  • 640 x 480: This setting is for Standard Defi nition (SD) recording and records at a 4:3 aspect ratio.

FRAME RATES

The frame rate numbers listed on your camera are an approximate number of what the camera actually records. The true frame rates are as follows: 24: 23.976, 25: 25.00, 30: 29.97, 50: 50.00, and 60: 59.94.

SLOW MOTION

If you want to slow down your videos and create high-quality slow-motion videos, then you’ll want to start by shooting in 720p. This setting records the video at 60 fps so that when you bring it into an editing program you can set it to play back at 50 percent speed, or 30 fps. Your video will now play back half as fast as you originally recorded it without sacrificing image quality.

NTSC AND PAL

You can set your 7D to record video in one of two formats: NTSC (National Television Standards Committee) or PAL (Phase Alternate Line) (Figure 9.1). NTSC is the standard format for broadcasting in North America, South America, and Asia; and PAL is the standard format for most European countries and other parts of the world. The main difference between the two when shooting with the 7D is their frame rates (25/50 fps for PAL and 30/60 fps for NTSC). It’s recommended that you set your video format to the broadcasting standard for whatever country you’re located in.

The 7D can record video in one of two formats: NTSC or PAL.
FIGURE 9.1 The 7D can record video in one of two formats: NTSC or PAL.

SETTING THE MOVIE-RECORDING SIZE

SETTING THE MOVIE-RECORDING SIZE

  1. Set the camera to video mode using the Movie shooting switch (A).
  2. Press the Menu button and use the Main dial to get to the fourth camera tab (B) (you’ll notice a new icon at the top of this menu—this is because you are in video mode).
  3. Scroll down to Movie Rec. Size using the Quick Control dial, and press the Set button (C).
  4. Use the Quick Control dial to select your preferred movie-shooting mode, and press the Set button to lock in your changes.
  5. Press the Menu button to go back into Movie shooting mode.

SETTING THE MOVIE-RECORDING SIZE

The 7D is also limited in regard to the length of each individual movie fi le. The longest movie fi le you can record at a time is roughly 12 minutes for HD and 24 minutes for SD (a 4 GB fi le size). This typically should not be much of an issue since most videos are recorded in small segments and pieced together during the editing process, but it is good information to know since there may be times when you’ll want to have a movie fi le that is longer than usual.

OVERHEATING

When shooting video with the 7D, it’s a good idea to turn the camera off between shots, especially if you are outdoors on a warm or sunny day. The camera’s internal temperature is more likely to increase when using the video mode, and shooting for a prolonged period of time could degrade the image quality of your still photos and videos. So when you’re not recording, be sure to turn the camera off.

The next thing you’ll need to consider is the type of compact fl ash card you are using. Because the camera will be writing the movie quickly and needs to process the information as fast as possible, I recommend using a card that has a very fast write speed (anything greater than 8 MB a second).

IMAGE QUALITY—WHY DOES IT MATTER?

You might have noticed that an image quality setting (RAW/JPEG) displays when your camera is in the video mode (Figure 9.2). Whatever your image quality is usually set to, you’ll see that this setting stays the same on the Info screen in between recordings— if you typically shoot in the RAW format, that setting will appear on your screen before you start recording movies. Just to clarify, the camera does not have the capability to shoot each frame of the video in the RAW format, but this setting does have a purpose…trust me!

You can shoot still images while recording a movie— the image quality setting will appear on the rear LCD Monitor along with your video settings.
FIGURE 9.2 You can shoot still images while recording a movie— the image quality setting will appear on the rear LCD Monitor along with your video settings.

Let’s say you’re in the middle of doing a video recording and you want to take a quick still photo but you don’t want to stop the recording, go back to still shooting mode, change your camera mode and exposure settings, and so on. Instead of going through all of that trouble just to get one image, all you need to do is press the Shutter button down, even if you are still recording your movie. You’ll notice a pause in the recording, but after the camera takes the photo it will automatically return to recording your video. The drawback to this feature is that it creates 1 second of a still image in your movie, but it’s a nice feature to have if you need to jump to temporarily taking still photos.

SHOOTING AND PLAYBACK

So now that we’ve gone over some of the basics of getting started with video recording, I’m going to show you how to record your video and review it in the Playback mode. There are still a few other things to discuss in order to ensure that your videos are top-notch quality, but before we get to that, let’s put everything to the test—and the only way to do that is to actually shoot some video.

RECORDING A MOVIE

RECORDING A MOVIE

  1. Locate the Movie shooting switch on the back of the camera and turn it to the red video camera setting (A). The rear LCD Monitor will immediately go into Live View mode.
  2. Compose and focus your scene and press the START/STOP button to begin your recording. You’ll notice a red dot appears in the upper-right corner of the LCD Monitor (B). This indicates that video recording is in progress.
  3. When you are fi nished recording, press the START/STOP button. The red dot will disappear, indicating that you are no longer recording video.

PLAYING MOVIES

PLAYING MOVIES

PLAYING MOVIES

  1. Press the Playback button located on the back of the camera.
  2. Turn the Quick Control dial until you reach one of your videos. You’ll know it’s a movie when you see the video camera icon in the upper-left portion of the LCD Monitor (A). Then press the Set button.
  3. To begin playback, press the Set button (the Play option on the bottom of the LCD Monitor will be highlighted by default) (B).
  4. To stop or pause playback, press the Set button once again.
  5. To exit from the playback screen, use the Quick Control dial to select the Exit option and then press Set (C).

The 7D gives you several other options while in the playback screen. Figure 9.3 shows all of the options you have when playing movies on your camera.

Use the Quick Control dial to select the other options in the Playback mode. If you recorded sound with your movie, you can also use the Main dial to adjust the sound volume during playback.
FIGURE 9.3 Use the Quick Control dial to select the other options in the Playback mode. If you recorded sound with your movie, you can also use the Main dial to adjust the sound volume during playback.

A Exit
B Play
C Slow Motion
D First Frame
E Previous Frame
F Next Frame
G Last Frame
H Edit
I Sound Volume
J Main Dial

VIDEO PLAYBACK ON YOUR COMPUTER

Viewing movies on your computer that were recorded with your 7D is simple. Just download the .mov files to your computer from the memory card (you can also connect the camera to your computer using a USB cable). If you have a Mac, they will automatically play in QuickTime when you open the files (PC users can download this software online for free). The Canon Utility software that was included with your camera also has a program, ImageBrowser, that allows you to view still photos and play .mov files on your computer.

 

Blu-ray Disc Association (BDA)

The BDA announced the finalization and release of the Blu-ray 3D specification at the end of 2009. The specification for 3D-enhanced Blu-ray video is titled “Blu-ray 3D.” The specification, embodying the work of the leading Hollywood studios and consumer electronic and computer manufacturers, will enable the home entertainment industry to bring the stereoscopic 3D experience into consumers’ living rooms, on BDs, but will require consumers to acquire new players, HDTVs, and shutter glasses. The specification allows every Blu-ray 3D player and movie to deliver full HD 1080p resolution (1920 × 1080, progressive scan) to each eye, thereby maintaining the industry’s leading image quality, which further distances Blu-ray from high-definition options provided by Internet-based services. The release of a final specification based on H.264 should allow professional video editing tools such as Avid, Final Cut Studio, and Premiere author 3DV in a routine fashion. Note: Although announced at the end of 2009, the specification will actually be finalized in 2010.

The Blu-ray 3D specification is display-agnostic, meaning that Blu-ray 3D products will deliver the 3D image to any compatible 3D display, regardless of whether that display uses LCD, OLED, plasma, or other technology, and regardless of what 3D technology the display uses to deliver the image to the viewer’s eyes. The compulsory aspect for stereoscopic 3D is that those screens should support 120 Hz or higher refresh rate. The specification supports playback of 2D discs in forthcoming 3D players and can enable 2D playback of Blu-ray 3D discs on the large installed base of BD players currently in homes around the world. The Blu-ray 3D specification will encode 3DV using the MVC codec, an extension to the ITU-T H.264 AVC codec currently supported by all BD players. MPEG4-MVC compresses both left- and right-eye views with a typical 50% overhead compared to equivalent 2D content, according to BDA; and can provide full 1080p-resolution backward compatibility with current 2D BD players. The specification also incorporates enhanced graphic features for 3D. These features provide a new experience for users, enabling navigation using 3D graphic menus and displaying 3D subtitles positioned in 3DV.

By press time, observers were expecting to see demos of 3DTV sets using content from stereo–3D enabled Blu-ray players utilizing prototype implementations of the Blu-ray 3D. However, most of the players and many of the TVs will not be available until sometime later when new chips for the specifications are available.

IPTV Concepts

As described in Ref. [1], IPTV deals with approaches, technologies, and protocols to deliver commercial-grade SD and HD entertainment-quality real-time linear and on-demand video content over IP-based networks, while meeting all prerequisite QoS, QoE, Conditional Access (CA) (security), blackout management (for sporting events), Emergency Alert System (EAS), closed captions, parental controls, Nielsen rating collection, secondary audio channel, picture-in-picture, and guide data requirements of the content providers and/or regulatory entities. Typically, IPTV makes use of MPEG-4 encoding to deliver 200–300 SD channels and 20–30 HD channels; viewers need to be able to switch channels within 2 s or less; also, the need exists to support multi-set-top boxes/multiprogramming (say 2–4) within a single domicile. IPTV is not to be confused with the simple delivery of video over an IP network (including video streaming) that has been possible for over two decades; IPTV supports all business, billing, provisioning, and content protection requirements that are associated with commercial video distribution. IP-based service needs to be comparable to that received over cable TV or Direct Broadcast Satellite. In addition to TV sets, the content may also be delivered to a personal computer. MPEG-4, which operates at 2.5 Mbps for SD video and 8–11 Mbps for HD video, is critical to telco-based video delivery over a copper-based plant because of the bandwidth limitations of that plant, particularly when multiple simultaneous streams need to be delivered to a domicile; MPEG-2 would typically require a higher bitrate for the same perceived video quality. IP Multicast is typically employed to support IPTV. There has been significant deployment of commercial-grade IPTV services around the world in the recent past, as seen in Table 5.1.

Partial List of IPTV Providers in the United States and Europe

One can anticipate several phases in the deployment of IPTV, as follows:

  • Phase 1: IPTV introduced by the telcos for commercial delivery of entertainment-grade video over their IP/MPLS (Multiprotocol Label Switching) networks (2007–2012).
  • Phase 2: IPTV introduced by the cable TV companies for commercial delivery of entertainment-grade video over their cable infrastructure (speculative, 2012+).
  • Phase 3: IPTV to morph to Internet TV for commercial delivery of any video content but of entertainment-grade quality over the Internet/broadband Internet access connections (2012+).

 

3DTV/3DV IPTV Transmission Approaches

IPTV services enable advanced content viewing and navigation by consumers; the technology is rapidly emerging and becoming commercially available. IPTV is being championed by the telecom industry in particular, given the significant IP-based infrastructure these carriers already own. IPTV may be an ideal technology to support 3DTV because of the efficient network pruning supported by IP Multicast. Developers are encouraged to explore the use of IPv6 to support evolving 3DTV needs. 3DTV is a forward-looking service and hence, it should make use of a forward-looking IP transport technology, specifically IPv6.

IP Multicast is also employed for control. While IP Multicast has been around for a number of years, it is now finding fertile commercial applications in the IPTV and DVB-H arenas. Applications such as datacasting (e.g., stock market or other financial data) tend to make use of large multihop networks; pruning is often employed and nodal store-and-forward approaches are completely acceptable. Applications such as video are very sensitive to end-to-end delay, jitter, and (uncorrectable) packet loss; QoS considerations are critical. These networks tend
to have fewer hops and pruning may be somewhat trivially implemented by making use of a simplified network topology.

IPTV services enable traditional carriers to deliver SD (Standard Definition) and HD video to their customers in support of their Triple/Quadruple Play strategies. With the significant erosion in revenues from traditional voice services on wireline-originated calls (both, in terms of depressed pricing and a shift to VoIP over broadband Internet services delivered over cable TV infrastructure), and with the transition of many customers from wireline to wireless services, the traditional telephone carriers find themselves in need of generating new revenues by seeking to deliver video services to their customers. Traditional phone carriers find themselves challenged in the voice arena (by VoIP and other providers); their Internet services are also challenged in the broadband Internet access arena (by cable TV companies); and, their video services are nascent and challenged by a lack of deployed technology.

3D Mastering Methods

For the purpose of this discussion we define a mastering method as the mechanism used for representing a 3D scene in the video stream that will be compressed, stored, and/or transmitted. Mastering standards are typically used in this process.

As alluded to earlier, a 3D mastering standard called “3D Master” is being defined by SMPTE. The high-resolution 3D master file is one that is used to generate other files appropriate for various channels; for example, theater release, media (DVD, Blu-ray Disc) release, and broadcast (e.g., satellite, terrestrial broadcast, cable TV, IPTV, and/or Internet distribution). The 3D Master is comprised of two uncompressed files (left- and right-eye files), each of which has the same file size as a 2D video stream. Formatting and encoding procedures have been developed to be used in conjunction with already-established techniques, to deliver 3D programming to the home over a number of distribution channels.

In addition to normal video encoding, 3D mastering/transmission requires additional encoding/compression, particularly when attempting to use legacy delivery channels. Additional encoding schemes for CSV include the following [6]: (i) spatial compression and (ii) temporal multiplexing.

Frame Mastering for Conventional Stereo Video (CSV)

CSV is the most well-developed and the simplest 3D video representation. This approach deals only with (color) pixels of the video frames captured by the two cameras. The video signals are intended to be directly displayed using a 3D display system. Figure 3.5 shows an example of a stereo image pair: the same scene is visible from slightly different viewpoints. The 3D display system ensures that a viewer sees only the left view with the left eye and the right view with the right eye to create a 3D depth impression. Compared to the other 3D video formats, the algorithms associated with CSV are the least complex.

A straightforward way to utilize existing video codecs (and infrastructure) for stereo video transmission is to apply one of the interleaving approaches illustrated in Fig. 3.6. A practical challenge is that there is no de facto industry standard
available (so that any downstream decoder knows what kind of interleaving was used by the encoder). However, there is an industry movement toward using an over/under approach (also called top/bottom spatial compression).

A stereo image pair. (Note: Difference in left-eye/right-eye views is greatly exaggerated in this and pictures that follow for pedagogical purposes.)

Stereo interleaving formats: (a) time multiplexed frames; (b) spatial multiplexed as side-by-side; and (c) spatial multiplexed as over/under.

Spatial Compression. When an operator seeks to deliver 3D content over a standard video distribution infrastructure, spatial compression is a common solution. Spatial compression allows the operator to deliver a stereo 3D signal (now called frame-compatible) over a 2D HD video signal making use of the same amount of channel bandwidth. Clearly, this entails a loss of resolution (for both the left and the right eye). The approach is to pack two images into a single frame of video; the receiving device (e.g., set-top box) will, in turn, display the content in such a manner that a 3D effect is perceived (these images cannot be viewed in a standard 2D TV monitor). There are a number of ways of combining two frames; the two most common are the side-by-side combination and the over/under combination. As can be seen there, the two images are reformatted at the compression/mastering point to fit into that standard frame. The combined frame is then compressed by standard methods and delivered to a 3D-compatible TV, where it is reformatted/rendered for 3D viewing.

The question is how to take two frames, a left frame and a right frame, and reformat them to fit side-by-side or over/under in a single standard HD frame. Sampling is involved, but as noted, with some loss of resolution (50% to be
exact). One approach is to take alternative columns of pixels from each image and then pack the remaining columns in the side-by-side format. Another approach is to take alternative rows of pixels from each image and then pack the remaining rows in the above/under format (Fig. 3.7).

Studies have shown that the eye is less sensitive to loss of resolution along a diagonal direction in an image than in the horizontal or vertical direction. This allows the development of encoders that optimize subjective quality by sampling
each image in a diagonal direction. Other encoding schemes are also being developed to attempt to retain as much of the perceived/real resolution as possible. One approach that has been studied for 3D is quincunx filtering. A quincunx is a geometric pattern comprised of five coplanar points, four of them forming a square (or rectangle) and a point fifth at its center, like a checkerboard. Quincunx filter banks are 2D two-channel nonseparable filter banks that have been shown to be an effective tool for image coding applications. In such applications, it is desirable for the filter banks to have perfect reconstruction, linear phase, high coding gain, good frequency selectivity, and certain vanishing-moment properties
[7–12]. Almost all hardware devices for digital image acquisition and output use square pixel grids. For this reason and for the ease of computations, all current image compression algorithms (with the exception of mosaic image compression for single-sensor cameras) operate on square pixel grids. It turns out that the optimal sampling scheme in the two-dimensional image space is claimed to be the hexagonal lattice; unfortunately, a hexagonal lattice is not straightforward in terms of hardware and software implementations. A compromise, therefore, is to use the quincunx lattice; this is a sublattice of the square lattice, as illustrated in Fig. 3.7. The quincunx lattice has a diamond tessellation that is closer to optimal hexagon tessellation than square lattice, and it can be easily generated by down-sampling conventional digital images without any hardware change. Because of this, quincunx lattice is widely adopted by single-sensor digital cameras to sample the green channel; also, quincunx partition of an image

Selection of pixels in (a) side-by-side, (b) over/under, and (c) quincunx approaches. (Note: Either black or white dots can comprise the lattice.)

was recently studied as a means of multiple-description coding [13]. When using quincunx filtering, the higher-quality sampled images are encoded and packaged in a standard video frame (either with the side-by-side or over/under arrangement). The encoded and reformatted images are compressed and distributed to the home using traditional means (cable, satellite, terrestrial broadcast, and so on).

Temporal Multiplexing. Temporal (time) multiplexing doubles the frame rate to 120 Hz to allow the sequential repetitive presentation of the left eye and right eye images in the normal 60-Hz time frame. This approach retains full resolution for each eye, but requires a doubling of the bandwidth and storage capacity. In some cases spatial compression is combined with time multiplexing; however, this is more typical of an in-home format and not a transmit/broadcast format. For example, Mitsubishi’s 3D DLP TV uses quincunx sampled (spatially compressed) images that are clocked at 120 Hz as input.

Compression for Conventional Stereo Video (CSV)

Typically, the algorithms to compress act to separately encode and decode the multiple video signals, as shown in Fig. 3.8a. This is also called simulcast. The drawback is the fact that the amount of data is increased compared to 2D video; however, reduction of resolution can be used as needed, to mitigate this requirement. Table 3.1 summarizes the available methods.

It turns out that the MPEG-2 standard includes an MPEG-2 Multi-View Profile (MVP) Coding that allows efficiency to be increased by combining temporal/inter-view prediction as illustrated in Fig. 3.6b.H.264/AVC was enhanced a few years ago with a stereo Supplemental Enhancement Information (SEI) message that can also be used to implement a prediction as illustrated in Fig. 3.8b. Although not designed for stereo-view video coding, the H.264 coding tools can be arranged to take advantage of the correlations between the pair of views of a stereo-view video, and provide very reliable and efficient compression performance as well as stereo/mono-view scalability [14].

For more than two views, the approach can be extended to Multi-view Video Coding (MVC) as illustrated in Fig. 3.9 [15]; MVC uses inter-view prediction by referring to the pictures obtained from the neighboring views. MVC has been standardized in the Joint Video Team (JVT) of the ITU-T Video Coding Experts Group (VCEG) and ISO/IEC MPEG. MVC enables efficient encoding of sequences captured simultaneously from multiple cameras using a single video stream. MVC is currently the most efficient way for stereo and MVC; for two views, the performance achieved by H.264/AVC stereo SEI message and MVC are similar [16]. MVC is also expected to become a new MPEG video coding standard for the realization of future video applications such as 3D Video (3DV) and Free Viewpoint Video (FVV). The MVC group in the JVT has chosen the

Stereo video coding with combined temporal/inter-view prediction. (a) Traditional MPEG-2/MPEG-4 applied to 3DTV; (b) MPEG-2 multi-view profile and H.264/AVC SEI message.

Compression MethodsCompression Methods

H.264/AVC-based MVC method as the MVC reference model, since this method showed better coding efficiency than H.264/AVC simulcast coding and the other methods that were submitted in response to the call for proposals made by the MPEG [15, 17–20].

Some new approaches are also emerging and have been proposed to improve efficiency, especially for bandwidth-limited environments. A new approach uses binocular suppression theory that employs disparate image quality in left- and right-eye views. Viewer tests have shown that (within reason), if one of the images of a stereo pair is degraded, the perceived overall quality of the stereo video will be dominated by the higher-quality image [16, 21, 22]. This concept
is illustrated in Fig. 3.10. Applying this concept, one could code the right-eye image with less than the full resolution of the left eye; for example, downsampling it to half or quarter resolution (Fig. 3.11). Some call this asymmetrical

Multi-view video coding with combined temporal/inter-view prediction.Use of binocular suppression theory for more efficient coding.

quality. Studies have shown that asymmetrical coding with cross-switching at scene cuts (namely alternating the eye that gets the more blurry image) is a viable method for bandwidth savings [23]. In principle this should provide comparable
overall subjective stereo video quality, while reducing the bitrate: if one were to adopt this approach, the 3D video functionality could be added by an overhead of say 25%–30% to the 2D video for coding the right view at quarter resolution.