The complete header information of MPEG2-Transport stream

[imman]

dvb poster

Can anyone give me the complete header information of MPEG2-Transport stream?

I am trying to capture the MPEG2-TS stream and send ing to CPU for processing.
Do I need to send sync pulse also as a bit towards CPU?
How CPU can understand the start of frame.
MPEG2-TS stream says that 47H indicated start of frame, but if payload also has 47H how to find where frame starts??

Thanks in advance.
Regards,
imman

 

[Marcel Majoor]

Re: MPEG2-transport stream

A transport packet consist of 188-bytes and always start with the $47 sync byte. Like you indicate, the payload in that packet can also contain such a sync byte, so you do have to be aware of that.
If you capture a TS stream then they already contain the sync bytes and such, so you don't have to add anything to the data (except when the capture device provides 184 bytes, which the software of some DVB cards seem to do).
Depending on how the capture is done, the data is already sync based (thus the first data is the sync byte). When the data is not synchronized then it is relatively easy to get it synchronized, because the $47 sync byte occurs every 188 bytes. You basically discard all bytes until you find a $47. Then you check again after 188 bytes. If no $47, restart (discarding until next $47).

Header information and such can be found in ISO/IEC 13818-1 and related documents.
I suggest you have a look here, although these might not be the latest documents):
**broken link removed**

Note: Since I am not a regular visitor of this forum, when have additional questions for me, then go to www.majority.nl and use the email address there to respond ...

 

[joepr]

Re: MPEG2-transport stream

Not to be a pain in the ass, but TS packets can either be 188 or 204 bytes long.
Besides ISO 13818-1, I tend to use the very good Tektronix DVB poster if I want to know a detail about TS packets.
You can order it for free at:
https://www.tek.com/Measurement/cgi...istration/mpegposter.html&FrameSet=television

 

[Marcel Majoor]

Re: MPEG2-transport stream

To clarify this:
The 204 bytes is the transmitted number of bytes per packet. The Transport Stream packets are still 188 bytes in length. The 204-188=16 bytes additional bytes are parity bytes, and are themselves not part of the Transport Stream packet. These 16 bytes are used by the demodulator (in the tuner) and are typically not passed on.
Thus, when a Transport Stream packet is being transmitted (modulated; via air/cable/satellite) then 16 bytes parity bytes are added to help with error recovery.

 

[imman]

Re: MPEG2-transport stream

Hi Marcel Majoor,

I am looking for a 1SEG tuner chip to test my logic.

The problem is, I am capturing the 8 bit parallel TS and sending to CPU through serial interface. Hence I need a tuner chip which supports very low frequency say 250KHz to 333KHz. Can u suggest such a chip?

Thanks in advance.
Imman

 

[renato]

Re: MPEG2-transport stream

Hello imman,

1 seg tuner are you talking about ISBD-T oder DMB-T/H ? Or other standard (i don't know DVB) ?

Please specify better maybe more people could help you ...

Regards,