Re: TV stream and scrambled channels

Thanks a lot for your reply. It was extremly helpful! Just a couple of more questions though... ;)

Peter Feldbaumer skrev:
If I understand you correctly, you're communication with your smart-card by some kind of SC-Interface _other_ than a CA-Module?

Exactly! I'm using a smart card reader which was included with a laptop I purchased a couple of years ago...

It certainly is possible, e.g. using the sample-grabber or a custom transform-filter. You would have to insert it after your BDA-capture-filter (not the bda-tuner), or possibly behind the MPEG2-Demux-filter, but certainly before any MPEG2/Audio-Decoder.

This way you can access the raw TS (including all information scrambling-information ca-sections, scrambled packets) or only specific PIDs (if you insert your filter behind the demux).

You will however have to "read" any information you need out of the "raw" ts-packets - MS-Digital-TV infrastructure knows nothing about ca-systems/scrambling.

Ok, this makes sense! I just need to study the mpeg TS specifications to recognize certain interesting packets.

So for your "software CI" to work you will also have to do the actual descrambling yourself (which is basically nothing but a simple xor-operation) - there are some dvb-s programs out there that implement an interface for software-cams - you could have a look at their source-codes (basically they take each 188byte-packet coming in with the TS, examine it if it has to be processed/process it and then pass on the modified packet) ...

But what if I have a DVB tuner with embedded mpeg-decoding? Will such a tuner even allow scrambled packets to leave the BDA driver if the tuner isn't able to decode them? Or will all packets be sent along to the filter graph and, if neccessary, be handled by my and all other filters and then fed back to the hardware decoder by a filter further down the filter graph?

I guest that, if I really had a DVB tuner with hardware mpeg decoding, I could test what kind of filters a filter graph that displays a TV station from the DVB stream is made up of this using GraphEdit?

Best regards
/ David Olsson
.

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