My views on Android and digital TV

 

This article will discuss the following topics with you:

1. Current situation and future of digital TV

2. Challenges for porting to digital TV

 

Status Quo and future of digital TV

 

Digital TVs use different operating systems, middleware, CA, and applications, making the entire software architecture significantly different.

In the face of the constantly evolving needs of users, consumers can not only watch the program, but also use TV as the portal platform to log on to the browser,

Search for more program content, install various applications, and develop and share various program software on your own.

Then the Android system is a good choice. Android is developed by google after several years and has invested hundreds of millions of dollars.

Relying on google's powerful development and media resources, the smart phone system will surely become the target of many mobile phone manufacturers.

As an excellent overall solution for open-source software, it applies to the mobile phone market, tablets, and digital TV,

The three screens are crossed.

 

 

Whether Android can be transplanted to digital TV, and a large number

Customization and modification. In the future, the software architecture level may be like this:

 

 

Illustration

 

 

Challenges for porting to digital TV

 

TVs on three screens (mobile phones, PCs, and TVs) are the slowest to change, such as smartTV and google TV, which proved to have failed in the market,

Whether it is technology or business model, there is still a certain distance from the true commercial success, but the trend of smart TV cannot be reversed,

Its large user base has made manufacturers and operators eager to try. So what challenges will android face when it is transplanted to digital TV?

 

Challenge 1: Graphic Display Effect and Performance

 

A. The TV resolution must be 720 p/p and the decoded frame rate must be greater than 25fps;

B. The OSD of TV requires 32-bit color depth. The default value is 16 bits. The image is not sufficiently refined.

C. TV is a large screen device that has higher performance requirements for 2D/3D graphics and must use hardware acceleration.

D. The screen size varies according to the specifications and the sizes of the display areas. adaptive adjustment is required.

 

This part involves modifications to the framebuffer and gfx Device Drivers (this part can be basically met by the set-top box vendors ),

However, many companies do not align the coordinate offset between the graphic layer and the video layer. As a result, some graphic layers are hidden.

Surfaceflinger and openGl ES interfaces are involved in the efficient implementation of 2D/3D hardware acceleration interfaces.

Make full use of GPU's big data computing functions

 

Challenge 2: User Experience

A. The TV user interface and content organization method must be suitable for remote operations and large screen layout.

B. TV users should use remote control instead of touch screen or keyboard;

 

This section involves webkit's focus control and libui input device modification, changing user input habits and various applications.

Operation Method, starting from the simplest "Up and down confirm return. Currently, mobile phones are often used as input devices on the market,

For example, "multi-screen interaction" enables screen interaction between different terminals such as TV, mobile phones, and PAD to achieve content sharing and "rejection ".

The simple "Drop" operation can send the "Drop Letter" Information on the mobile phone to the TV Terminal for playback experience.

 

Challenge 3: 2D/3D graphics acceleration performance is a key aspect of TV's overall performance

 

For 2D, skia and surfaceflinger can be optimized to accelerate the synthesis speed, that is, the copybit module is implemented,

In addition, the hardware decoder can be embedded here to replace the original image decoder, such as jpeg and gif hard decoding.

 

 

For 3D, in addition to hardware 3D acceleration (required), GPU can be used as the backend of skia.

 

 

For 2D/3D use cases, there is an image analogy: 3D is used for processing large amounts of data and regularly refreshed at a certain frequency,

It is like a bus, where many people are loaded and the sites are unified and operated cyclically. However, the interaction speed and response requirements are timely

It is like a taxi. From this point of view, this can be

In principle, find the optimized place (refer to the comments of lyre colleagues who think it is very good to use it as 'A ,:))

 

Challenge 4: suitable for large screen multimedia audio and video Experience

Whether it is an OpenCore or Stagefright Multimedia Framework, it supports fewer file formats and encoding standards, and requires

It is difficult to add other media formats and codec, And it is complicated to use the hardware decoding interface.

However, the use of existing open-source multimedia frameworks, such as Gstream or ffmpeg, has limitations and disadvantages.

 

Key issues to be solved: decoding speed (the hardware decoder of the set-top box must be used) and display speed.

Output Using the video layer and overlay

For audio, you need to consider a variety of output devices, high-quality audio quality, and multi-channel audio synthesis audio output.

 

Challenge 5: Integrate the digital TV Function

Up to now, Android has not integrated any protocol stacks related to digital TV protocols.

A, need to integrate DVB-C, DVB-T and DVB-H and other TV watching Functions

B. certain experience in developing a digital set-top box is required for definitions of digital TV interfaces (such as playing, recording, and on-demand video ).

 

Challenge 6: TV applications

For digital TV, the app is king. The operator is required to do a good job in app stores and develop TV-suitable apps,

Software Vendors and TV manufacturers jointly promote the development and prosperity of applications

 

Challenge 7: CA integration and content Encryption

For open systems such as android, how do I protect TV content?

The CA module is provided by various CA companies. The Integration Technology of the CA module is not a big problem, but the protection over the key is far from enough.

This may require the use of DRM to control copyright, but how does the operator deploy it?

 

Challenge 8: software updates are too fast

Basically, the software will be updated in 3-6 months, making it impossible for manufacturers to develop and increase development costs and reduce efficiency.

In addition, the Code of many branches needs to be maintained, which requires a lot of manpower and material resources.

 

Challenge 9: hardware costs

If you need to smoothly run BASIC 3D applications and video playback, at least 128 MHz or above clock speed is required, MB memory, MBflash, and the manufacturing cost will increase,

However, with this high configuration, the cost of high hardware is ultimately transferred to consumers. Currently, all mainstream set-top boxes require about RMB

 

Three-network convergence has entered the substantive pilot phase and achieved initial results. At the same time, triple play is not just

Physical convergence of telecommunication networks, computer networks, and cable television networks is also the business convergence of the three networks.

Android developed on the set-top box is far from the productization stage for TV. Maybe smart TV is a good direction.

 

Finally, Steve Jobs was quoted as saying:

"This has always been one of my secrets-focus and simplicity. Simplicity is more difficult than complexity: You must make great effort to simplify things.

But all of this is worthwhile in the end, because once you do it, you can create a miracle. "

 

Column of the author andyhuabing