TV chips in 2011 had USB 2.0 hosts fully integrated into the TV’s
SoC. This allowed TV makers to incorporate a single standard chip.
Low-end TVs used the same chip, but did not provide the USB 2.0
ports on the outside of the TV. For the high-end TVs with USB ports,
consumers could buy a USB video camera and mount it on their TV.
Usually, the video camera was a specific model, sold only by the TV
manufacturer. The same USB ports could be used to connect the TV to
the internet with a WiFi USB dongle, or connect a digital camera or
flash memory to view pictures or video. The Hisense TV allowed use
of four applications at once.
More, faster data transfer requires USB 3.0
Fast forward to today. All major TV makers offer a built-in video
camera for video conferencing. These systems use USB internally to
connect the TV chip and the camera. For example, Figure 2
below taken at CES 2013, you can see this Panasonic TV has three
external USB ports.
Figure 2: Panasonic TV with three USB Ports
as seen at CES 2013
It is likely there is a 4th port used internally for a USB to WiFi
connection. In at least one case, Samsung’s Smart Interaction
feature uses the camera for gesture control and face recognition,
and its microphone for voice control.
While USB 2.0 throughput is sufficient for video conferencing, the
higher demands of gesture control require USB 3.0. Why? Gesture
control improves with higher resolution cameras, and at least two
cameras. If you’ve seen a teardown of the Microsoft Kinect USB Video
Camera, which is used for gesture control in video gaming, you’ll
see that it includes at least two imaging sensors. One camera
captures a full-color image of the action and displays the user on
the screen. The second camera, which is infrared, coordinates with
data from the video camera to map out the human body. The two data
streams together make a 3D model of the body for fairly accurate
mapping and fine gesture control.
However, gamers will tell you that this interface isn’t sensitive
enough. Improved sensor control requires more data from multiple
angles. With more video data delivered at 1080p, 30 frames per
second would need 1.7 Gigabits throughput per second. This is at
least five times faster than the effective throughput of USB 2.0
Trying to move this much video data through a USB 2.0 connection
requires compression next to the image sensor, transmission over USB
2.0, and then decompression when it reaches the central processor.
Compressing and decompressing the video produces unwanted delays due
to the additional CPU cycles. For gamers, it means slower motion
sensing and more lag—basically, slow response times between the
gamer’s motion and the TV/game’s response.
Connections outside the TV
Moving forward, at least two USB 3.0 ports will be available on the
outside of TVs, such as those found on the Panasonic Viera. Using
these ports, consumers can connect a USB 3.0 hard drive to the TV
for direct recording. Attaching USB 3.0 drives will allow recording
of up to four high-definition (HD) channels at once. A 3 terabyte
(TB) USB 3.0 hard drive will hold 300 hours and a 6 TB USB 3.0 hard
drive can hold 600 hours of HD TV shows. The second port can be used
for connecting to a USB 3.0 video camera for the transfer and
display of HD or 4K videos.
USB 2.0 can’t support recording multiple channels of HD,
uncompressed, encrypted content, so USB 3.0 is required. While TVs
can currently record four channels, future TVs will easily record
more. Recording multiple HD channels requires high throughput.
Compressed video might be handled with slower speeds, but minimizing
compression allows for faster display on the screen. Faster USB 3.0
throughput reduces lag and provides more reliable delivery of
content to display and to storage. Faster delivery to storage also
reduces the RAM required. If the TV has to wait to write data into
storage (or hold data for display when reading from storage) then
more RAM is required for buffering the video data. Reducing RAM has
a direct impact on reducing the cost of a TV since RAM is not
designed by the TV manufacturer—it is purchased from a third party.
Removing a single bank of RAM can save more than $1USD per unit in
the cutthroat TV market.