4:3 stretch to 16:9 based on WSS (2 Viewers)

[marttoma]

Hello,

this is more question the bug report, does MP (i.e.TV cards based on BDA driver) support WSS signal?

Almost all new TVs can stretch 4:3 content in 16:9 format automatically very fast based on WSS (AFAIK) and I would like to know if WSS can be aupported in MP as well.

IFC is fine, but due to "monitoring" algorithm the stretch decision is not 100% perfect.

Thanks for any feedback.

marttoma

 

[mm1352000]

Hello marttoma

In short the answer is no, WSS is not supported.
A fuller answer would be to say that WSS is digital metadata embedded within the analog TV vertical blanking interval (VBI). Since you mention BDA and your system specs say you have DD C/T tuners it seems like you're talking about digital TV. Digital TV does not have a VBI. Having said that, it is possible for providers to include a private data stream with VBI data in the MPEG 2 transport stream. Such is/was sometimes done for VBI subtitles and/or teletext with digital TV... but I don't know whether providers would also include WSS data. Usually the signalling of aspect ratio etc. is done in completely different ways for digital TV...

Regards,
mm

 

[marttoma]

Hello mm,

Thank you for explanation. You are right, I am talking about digital TV without knowledge the WSS is related to analog TV only.

In my case the Digital TV cable setop-box (DBV-C) provided by UPC can somehow get information about the 4:3 size content which is broadcasted in 16:9 screen size -> as the setop-box switchs between 4:3 and 16:9 automatically and very fast (this change is not even visible on the TV screen).

My knowledge in this area is weak, my understading is it can be done somehow if the setop-box can hanle it, may be by one of the following option:

• DBV-C broadcasted mpeg file with 16:9 content contains information about content size 4:3 and based on this information the setop-box can automatically stretch the 4:3 content to 16:9 (the TV screen is all time 16:9 only)
• Information about the 4:3 resolution is available on Scart or HDMI connector and the automaticall stretch of 4:3 content is done by TV

How is usually the signalling of aspect ratio done for digital TV?

Thank you

marttoma

 

[mm1352000]

...without knowledge the WSS is related to analog TV only

But to be clear, I didn't say that WSS is 100% not available for digital TV. In fact, there are standards for transferring VBI teletext, subtitles, WSS etc. into the digital MPEG 2 transport stream: EN 301 775.
http://www.etsi.org/deliver/etsi_en/301700_301799/301775/01.02.01_60/en_301775v010201p.pdf

So the question is whether your provider does that, and to know that I would need log files.

How is usually the signalling of aspect ratio done for digital TV?

Too complex to explain in detail, but basically the video encoding usually includes this kind of information.

 

[marttoma]

Thank you.

So the question is whether your provider does that, and to know that I would need log files.

Let me try to figure out this information.

Too complex to explain in detail, but basically the video encoding usually includes this kind of information.

Is there any ETSI or whatever standard, which describes this?

 

[mm1352000]

Is there any ETSI or whatever standard, which describes this?

Yes, the ISO standards for MPEG program (ISO/IEC 11172 part 1) and transport streams (ISO/IEC 13818 part 1), and also the ISO standards for video encoding (eg. MPEG 1 = ISO/IEC 11172 part 2, MPEG 2 = ISO/IEC 13818 part 2, h.264/AVC = ISO/IEC 14496 part 10 etc.) describe it. Unfortunately those standards are not freely available.

You can see an example of sequence header parsing in code that I wrote for the TsMuxer here:
https://github.com/MediaPortal/Medi...tShowFilters/TsMuxer/source/TsMuxer.cpp#L1649

You can see the aspect ratio is included there... though in that case, not with the same detail as WSS, which allows you to specify that the content aspect ratio is different to the video aspect ratio.
Note the above code only handles MPEG 1 and 2.

 

[marttoma]

So the question is whether your provider does that, and to know that I would need log files.

I was speaking to the UPC technical support and I got some new information:

• UPC as a cable provider does not add any information into the content about the content resolution, such information is delivered in mpeg stream directly from TV companies (they add such information directly into the SDI studio signal)
• some TV companies are using WSS, some VII signals, but I dont have information about the rest of TV companies
• setop boxes are following for resolution switching the EN 300 294 standard

Some more info:

• in case of SCART there is pin 8, which contains high or low voltage and this is a driver for TV devices to change the resolution (not my case)
• in case of HDMI the resolution is alway 16:9 (my case)

 

[marttoma]

Yes, the ISO standards for MPEG program (ISO/IEC 11172 part 1) and transport streams (ISO/IEC 13818 part 1), and also the ISO standards for video encoding (eg. MPEG 1 = ISO/IEC 11172 part 2, MPEG 2 = ISO/IEC 13818 part 2, h.264/AVC = ISO/IEC 14496 part 10 etc.) describe it. Unfortunately those standards are not freely available.

I found out on the web:

• ISO/IEC 11172 - see attachment
• ISO/IEC 13818 - see attachment
• IEC 14496 part 10 - see attachment

 

[marttoma]

So the question is whether your provider does that, and to know that I would need log files.

Can you implement support for WSS and VII signals? Which log files you would need?

 

[mm1352000]

Can you implement support for WSS and VII signals?

No, sorry. I have no time. Also, this would need to be implemented on the client side. Probably mainly in TsReader. I have very little experience with that code.

Which log files you would need?

TV Server TsWriter and TVService log files. Please also specify the names of the channels that you want me to look at. All I would do is check whether those channels have VBI sub-streams which might contain WSS signalling.