Monday, December 10, 2012

Set Top Box Overview


A set-top box is a device that enables a television set to become a user interface to the Internet and also enables a television set to receive and decode digital television (DTV)
broadcasts. DTV set-top boxes are sometimes called receivers. A set-top box is necessary to television viewers who wish to use their current analog television sets to receive digital broadcasts.
Before Digital TV was invented, TV’s decoded broadcast analogue channels, initial STB’s simply converted one type of analogue TV channel signal to one the TV could understand.
Initial STBs had very little security and the ownership of a STB and the feed (Cable ,Satellite or Terrestrial  meant a consumer could have access to the video content.
As multi-channel TV started to expand the move to Digital TV allowed some major changes:

  • Basic features of the STB are to Receive Demodulate, Demultiplexer, and decode the incoming Digital signal and convert it into the Analog format
  • Input digital stream to STB may be from satellite ,cable or terrestrial medium.
  • It can also de-scramble the received signal and thus provide conditional access to the STB.
  • Conditional access is the key feature for Pay TV system
  • If STB is used for satellite applications then input frequency range is 950 to 2150 MHZ and modulation technique used is QPSK
  • If STB is used for cable applications then input frequency range is 110 to 862 MHZ and modulation technique used is QAM
  • If STB is used for Terrestrial applications then input frequency range is  47 to 860 MHZ and modulation technique used is COFDM

STB’s were constantly evolving, as the battle between the satellite and cable broadcasters heated in any given region.
Many new features were add to the STB since then:

  • nVOD – Near Video on Demand, a broadcaster plays out a video many time starting every 15 mins
  • VOD (Video on Demand – the broadcaster just plays a video when a customer wants to watch it)
  • Internet Access on TV
  • PVR/DVR – secure video recording on internal hard disks
  • High Definition TV – more pixels better quality TV
  • 3D TV
  • Personalize-able ‘Apps’ similar to smart-phones 
etc. etc

The STB has now become a highly complex software based system requiring years of development effort for each new feature.
The consumer is quite happy for his mobile smart phone to crash every now and then, or his PC to slow down and need fixing,
but historically they expect their TV  to work all the time or they will call the broadcaster and complain.
However the next technology development is to the Connected TV, this moves into the arena of the PC, smart phone and games console.
Content will be obtainable from many sources and not just the traditional broadcaster Also the software running on these devices will be obtained from many developers.

Most of the content is known to all of us and used from some of the major provider and vendors in the industry
Stay tuned for more updates on the STB Middleware and other STB stuff.

Monday, December 3, 2012

Linux Study Material

Kernel compilation:
Developing Kernel modules/Device drivers:

Implementing System calls in Linux:
Improtant Documentation:   

Applying a patch:
  • Linuxdocs:
The GCC compiler, the GNU Make, and the KBuild:
The Kernel Development: 

The Kernel Debugger:
Kernel Support for Faster Web Proxies

H.265 High Efficiency Video Coding to be Help or Headache for Online Video?

H.264 is still, pretty much, the de facto for online video. But there could be a shift very soon as MPEG and VCEG have announced they've got H.265 in the works (still in draft) and could see it implemented for phones next year. Why? Because it's said to be twice as efficient at H.264. So what's that mean for the industry?
H.265, MPEG-H Part 2, the High Efficiency Video Coding, is said to be 2x as effective as H.264 which pretty much means you could see file sizes half the size with the same quality soon. It could also mean upgraded resolution in the same file size. It's great news for mobile users who want to stream video but have bandwidth limitations on their data plans or are stuck at 3G speeds. That could even mean some very high quality video for tablets with the screen resolution and real estate to make it noticeable.

How high or low can you go?

H.265 is said to support resolution up to 7680 × 4320! Yowza! Meanwhile, bit rate reduction was aimed to be 50% with the same quality as it would have in H.264. It's said to be aimed as low as QVGA (320x240) up to that massive resolution above and to improve noise levels, color gamut and dynamic range.

What's it All Mean?

In a nutshell, it means you could start shooting video at a much higher resolution in the near future, 7680 × 4320 or 16x full HD (sometimes called SuperHD, 8K UltraHDTV, UHDTV2 and 4320p) is 33.2 megapixels at up to 120 frames per second. That is, if you could afford the $1 million camera! OK, so maybe not quite yet. But it's coming. The original implementation plan for 8K had a time frame of 2015 to 2020. It seems that the industry in general is trying to shorten it.
First off, there are almost no commercial displays for the format and secondly, there are only about four cameras in the world. There was an 85" display shown off by Sharp and the NHK, Japan's public broadcaster, is working with Panasonic for a 145" display.
So don't worry about any of that 8K stuff just yet. But if you are making SD or HD content and hoping to have it viewed on tablets and smart or superphones, then this should be of particular interest. With the plethora of TV commercials that talk about bandwidth restrictions on mobile plans, this could seriously change the game, next year. H.265 could also help the industry fight against cable companies bandwidth metering and restrictions. If files sizes drop by 50% but quality remains the same, that should help alleviate the alleged bandwidth problem that they are facing, and using as a way to hike up rates on US consumers. If H.265 delivers on its promise, it could mean some serious streaming improvements for end-users and for video content producers it could mean a great deal of savings in storage and bandwidth costs.
But it could also be a major, long-lived headache. Let's face it, H.264 hasn't exactly been controversy free. While MPEG-LA has stated that H.264 will be royalty free until the end of 2015, it could decide that H.265 requires a license fee meaning everyone, from hardware manufacturers, software and service developers all the way down to end-userscould see a price hike because of it. They've already called for patents essential to the HEVC coding.
“By starting the joint license facilitation process now, the market can enjoy the earliest opportunity to plan for deployment of this promising new technology,” said MPEG LA President and CEO Larry Horn. “MPEG LA is pleased to assist in facilitating a convenient, independently administered, one-stop patent licensing alternative to assist users with implementation of their technology choices and invites all patent holders to participate.”
In order to participate in the initial facilitation effort for the creation of a joint HEVC License, MPEG LA invites any party that believes it has patents that are essential to the HEVC Draft 7 standard (or subsequent revisions that may issue) to submit an initial patent by September 7, 2012...
So they're already working on the monetization side of the license and patents, before the standard is even in place. That's how lucrative the H.265 coding could be it seems. So it's definitely going to cost someone something. However, if they are interested in the overall progress of digital video they'll offer the same deal as they have on H.264 where they "will not charge royalties on Internet Video using the codec, when that video is free to end-users, for the lifetime of that license."
If could end up being that they decide on a licensing fee that would impact end-users and that could do things like reduce competition, because of high licensing, etc. Hopefully, they'll take it the way of H.264 and it will have the same deal.
For now, it's wait and see, but it certainly does seem quite promising for us all. Less bandwidth, same or better quality and the potential for the online video industry to continue steamrolling onward and upward.
Source: H.265 High Efficiency Video Coding to be Help or Headache for Online Video? 

Browser Adoption of HTML5 Video Continues to Grow

LongTail Video just released the update to their longstanding State of HTML5 Video which gives everyone a clear cut, easy to read guide to what parts of the HTML5 <video> tag are supported, by what browser and to what extent. At present, 79% of the market can now play HTML5 video, that's a pretty good percentage and shows that if you've been dragging your feet it's time to think about compatibility.
Aside from the old versions of Internet Explorer (6-8) and some mobile phone browsers, HTML5 video will play just about everywhere. Chrome and Firefox lead the way with 49% of the market and the non-Flash platforms make up for just 17% (iOS, Android and other mobile phones).
Browser/DeviceMarket ShareHTML5 VideoFlash Video
Internet Explorer 916%YesYes
Internet Explorer 6/7/813%NoYes
Other (feature phones)8%NoNo
Connected TVs and game consoles aren't included in the report. They say it's because the first has too small an install base and the second doesn't have adequate browsing. Additionally, both are more app based anyway.

HTML5 Video File Format

Over the past year we've seen support for WebM dwindle. Android, Google's own OS, only supports MP4 which doesn't bode well for the upstart free media format. Currently only Firefox and Opera are listed as supporting only WebM while Chrome supports both. On the audio front it breaks down the same way, AAC and MP3 are supported on all but Opera and Firefox which are still pushing Vorbis. Meanwhile, Chrome supports all three.
The WebM project hasn't had a blog update since May 11th but over the last year gained hardware decoding and a lot of other support. It seems that everyone's energies have shifted from the MP4/WebM "war" to the HTML5/Flash "war." I know, I often call them wars myself but it's not really, all of them can co-exist and right now, need to because there are some things that can't be done in HTML5 and WebM, plus, competition is good for technology as it helps push things forward.
Browser/DeviceVideo FormatsAudio FormatsMultiple Sources
ChromeMP4, WebMAAC, MP3, VorbisYes
Internet ExplorerMP4AAC, MP3Yes
SafariMP4AAC, MP3Yes
AndroidMP4AAC, MP3Yes
View DetailsView DetailsView Details
From the LongTail report:
Note we have not included the Ogg video format in our tests. This format is not widely used and of lower quality than MP4 and WebM. Firefox 3.6, which is quickly phasing out, is the only browser version that supports Ogg but not WebM today.

What Is and Isn't Supported?

As I just mentioned there are some limitations in what each format can and cannot do and some things that browsers do and don't support. IE doesn't support Preload and it's completely ignored in iOS and Android, as is Autoplay. The mobiles usually skip some controls like volume, as they have buttons for it.
As for IE 9:
Internet Explorer ignores the preload=noneattribute, which prevent the desktop browsers from reaching a perfect score. The implication here is that IE9 loads a part of your MP4 upon each pageview, instead of waiting until a user actually starts the video. This may add to a substantial increase in your streaming costs.
The Javascript API is a bit more complex, still. Android? Nope. (Come on Google!) iOS? Sure, but not Playback or Volume (already discussed). Other than that, loading, buffering, playback, seeking and volume are all supported in the browsers.
Fullscreen is a mixed bag with Opera and IE skipping that control and playback function, everyone else is green light for go!.

HTML5 Text Tracks

Pretty much a major fail all around (except for Safari) is Text Track support. I have to believe there's a major push to get it implemented with the new mandates on closed captions for online video ramping.
Along with closed captions, keyboard control is also needed for accessibility compliance. Chrome and Safari haven't got it. iOS and Android don't always have keyboards which leaves FF, IE and Opera all supporting it. Shame on Chrome and Safari!

Live and Adaptive Streaming

Finally, live streaming is growing in popularity and its business uses, but none of the browsers support it except for Safari and iOS. Meanwhile on the adaptive streaming side....NONE support it. BOO! You would think that iOS and Android would be hard at work to support that. However, LongTail had this to say about it:
Note that every HTML5 browser supports seeking to not-yet-downloaded portions of the video by using HTTP 1.1 range-requests. Compared to Flash (which cannot do that), it reduces the need for adaptive streaming, as it enables the fast seeking feature.


The LongTail State of HTML5 doesn't address things like DRM which is a key capability if the major studios are going to get on board with allowing their content to flip over. Without DRM they lose control of their content and we all know how much they hate that. Adaptive bitrate streaming might not be a major deal anymore with faster mobile data networks and the abundance of Wi-Fi these days, but it, and live streaming, are still major pieces of the puzzle that need to be solved before HTML5 becomes the overall standard in my opinion. Additionally, there's still that thing about the MP4 license not being completely royalty free as it's owned by a licensing group. That means it's not a completely open and free protocol and that goes against the spirit and letter of the HTML standard.
Source: Browser Adoption of HTML5 Video Continues to Grow, But Still Not Complete
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