edcase
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Dont then. :banana:
cs vm on dbox? need a team
- Thread starter JIMMYQ
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Dont then. :banana:
Now, just for laughs...
Is it possible to capture some encrypted stream? Using a DreamBox or something? I'm not sure whether there is a way to get at the data when it is being descrambled and decoded. Does the CPU have any access to copy it around in memory?
If the case was that it can't be gotten at, would feeding the same (incorrect) CW in over and over result in something useful to look at coming out of the decoder?
Slight thread hijack :blushing:, applicable to DBox I suppose though.
Humour me
.
Is it possible to capture some encrypted stream? Using a DreamBox or something? I'm not sure whether there is a way to get at the data when it is being descrambled and decoded. Does the CPU have any access to copy it around in memory?
If the case was that it can't be gotten at, would feeding the same (incorrect) CW in over and over result in something useful to look at coming out of the decoder?
Slight thread hijack :blushing:, applicable to DBox I suppose though.
Humour me
.
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Thanks, I had a quick look at that yesterday and it is interesting. I think it may be more applicable to DVB-S, though I don't know what (if anything) differs between than and DVB-C as far as the transport stream is concerned.
This paragraph:
"When using DVB2000 software on a Nokia Mediamaster receiver and a PC equipped with a SCSI bus and DVBEdit, it's possible to capture the recontstructed video directly out of the MPEG-2 decoder's buffer memory. In the following screen shots from Dish Network, you can see how each of the individual components of the picture are transmitted and how pan/scan is used to interpolate both the base video and chroma information."
From: tsreader.com/mpeg/index.html#beforebuying
That's what I want but without buying hardware (Ah! Mediamaster is a DBox?). Our little issue, of course, is that it will be encrypted. That is, if our system reconstructs the video before it is decrypted. Anyone any ideas on that?
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Answer to my last question here:
"When a scrambled packet arrives, before it passed through to the demultiplexor, it's first sent through the CAM or Conditional Access Module. The CAM is the descrambling engine and can be either built directly into the receiver or inserted into the receiver via a PC Card (aka PCMCIA) connector. At the start of each MPEG-2 packet is a 2-bit field called the TSF or Transport Scrambling Flags - if zero or one, the packet is passed through the CAM onto the demux for display since this value indicates an un-scrambled stream. If the TSF is set to either two or three, then the packet is passed through to the CAM, which takes the key obtained from the smartcard and uses it to turn the packet packet back into an MPEG-2/DVB transport packet which can then be processed by the rest of the system."
"When a scrambled packet arrives, before it passed through to the demultiplexor, it's first sent through the CAM or Conditional Access Module. The CAM is the descrambling engine and can be either built directly into the receiver or inserted into the receiver via a PC Card (aka PCMCIA) connector. At the start of each MPEG-2 packet is a 2-bit field called the TSF or Transport Scrambling Flags - if zero or one, the packet is passed through the CAM onto the demux for display since this value indicates an un-scrambled stream. If the TSF is set to either two or three, then the packet is passed through to the CAM, which takes the key obtained from the smartcard and uses it to turn the packet packet back into an MPEG-2/DVB transport packet which can then be processed by the rest of the system."
With a dvb-c card you can capture as much encrypted streamdata as you want. You can also do it easily enough on dreambox/dbox using a program like dvbsnoop though you haven't got too much space to play with if you want full TS data.
There's plenty of tools for examing data. TSReader (as suggested above) is pretty good if you want to check out the dvb headers and sections whilst if you want to look at TS PID level then MPeg packet analyser (free) is pretty good. You can also use dvbsnoop on a PC to analyse captured data.
I believe theres also a prgram called something like offline CSA descrambler, where you can feed the encrypted data in, along with the relevant cw, and see the decrypted data come out. Using such a program you would be able to compare encrypted data with decrypted data.
There's plenty of tools for examing data. TSReader (as suggested above) is pretty good if you want to check out the dvb headers and sections whilst if you want to look at TS PID level then MPeg packet analyser (free) is pretty good. You can also use dvbsnoop on a PC to analyse captured data.
I believe theres also a prgram called something like offline CSA descrambler, where you can feed the encrypted data in, along with the relevant cw, and see the decrypted data come out. Using such a program you would be able to compare encrypted data with decrypted data.
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neathdrew
Inactive User
i'm currently using dvb-c, floppydtv, tt1500 and tt2100c so if anyone wants stream data give me a shout what they want and a few pointers how to do it and i'll give it a go.....:err:
That sounds interesting. I'm sure the compression will make any re-assembly of the data without the CW impossible but I'm sure this is more entertaining than FTA.
I wonder if there are any MATLAB tools for MPEG-2, there's bound to be.
Nicked from elsewhere and not tested...
Transport Stream Dumping
dvbstreamexplorer.dk/dvbstreamexplorer.php
coolstf.com/tsreader
stuffware.co.uk/stufftv
Offline CSA
joshyfun.peque.org/OfflineDescrambler/index.html
dvbsoft.net/download.php?list.40
dvbsoft.net/download.php?view.56
Remux
offeryn.de/dv.htm
lucike.info/index.htm?
lucike.info/index.htm?http://www.lucike.info/page_projectx.htm
tmpgenc.net/e_main.html
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Also in use is the reed-solomon algorithm to ensure data is correct. This would be the same one as used in quickpar ironically for making sure files are put together properly.
This is available as open source in various flavours, this may be or may not be of use but thought it was worth a mention as its being used.
This is available as open source in various flavours, this may be or may not be of use but thought it was worth a mention as its being used.
PaphosAL
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I think dvbsnoop can be run on a dbox or DM with it's output log file directed to an internal HDD (if it has one), or to a shared mount on your PC via ethernet. So space shouldn't be an issue.
Cheers- AL
For TS capture on a dvb card Twinhan do a nice free capture tool which will run with most BDA compatible cards.
The Twinhan utility is getting a little difficult to find now so i've included it along with a copy of the Mpeg2 Packet Analyser program and a PC version of DVBSnoop in the following attachment.
To run the capture utility you will need to have your dvb card bda compatible drivers installed (most modern cards have bda type drivers). For cable, you would need to enter your frequency (default frequency for area is usually good to start with), symbol rate (6952 or 6800), and Constallation (usually 64 - for QAM64 mode). You will also want to enter a path to a file for the capture storage and you may want to limit the capture as the files get huge very quickly. For general playing around and learning 50Meg will probably be ok. The capture utility will also work with sat and terrestrial cards if you fancy capturing data from those and playing.
An alternative for an interesting look is the TSreader program. You can download it from the coolst link above for free for an evaluation period. Its quite a nice program if you want to get a feel for how TS streams are put together although it does seem to have limitations when t comes to cable cards. You can however, use a fiddle called a TSloop driver which will effectively play back the TS files you captured using the Twinhan utility so you dont actually need TSReader to have a compatible hardware driver.
The Twinhan utility is getting a little difficult to find now so i've included it along with a copy of the Mpeg2 Packet Analyser program and a PC version of DVBSnoop in the following attachment.
To run the capture utility you will need to have your dvb card bda compatible drivers installed (most modern cards have bda type drivers). For cable, you would need to enter your frequency (default frequency for area is usually good to start with), symbol rate (6952 or 6800), and Constallation (usually 64 - for QAM64 mode). You will also want to enter a path to a file for the capture storage and you may want to limit the capture as the files get huge very quickly. For general playing around and learning 50Meg will probably be ok. The capture utility will also work with sat and terrestrial cards if you fancy capturing data from those and playing.
An alternative for an interesting look is the TSreader program. You can download it from the coolst link above for free for an evaluation period. Its quite a nice program if you want to get a feel for how TS streams are put together although it does seem to have limitations when t comes to cable cards. You can however, use a fiddle called a TSloop driver which will effectively play back the TS files you captured using the Twinhan utility so you dont actually need TSReader to have a compatible hardware driver.
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I think we need some data for everybody to play with. Then even those who haven't got the equipment can still play with it on the computer and the various reader programmes mentioned. It might help as we will all be looking at the same bit.
So if anybody has any ideas on what size file, what to record hopefully somebody can post it.
So if anybody has any ideas on what size file, what to record hopefully somebody can post it.
Might be worth a look:
http://www.pjdaniel.org.uk/mpeg/index.php
http://www.pjdaniel.org.uk/mpeg/index.php
If you need info on how dvb packets are stiched together etc then a read of the ETSI EN300-468 document (Specification for Service information (SI) in DVB Systems) is well worth the time spent. V1.9.1 was the latest release version a few weeks back. You can download it directly from the ETSI web site.
Thats a newer version of one of the proggies I included above. Looks good !
I had a look for some MATLAB MPEG-2 tools but I didn't come up with much. Thought it might have been useful for analysis since it was designed for manipulating matrices.
That tool might be able to dump interesting bits out though.
I see much staring at meaningless data... Intelligent frame re-assembly without using keys at all? I'd be happy with a single off-line frame.
I've only briefly fiddled with ANNs in MATLAB for character recognition:
http://en.wikipedia.org/wiki/Artificial_neural_network
That tool might be able to dump interesting bits out though.
I see much staring at meaningless data... Intelligent frame re-assembly without using keys at all? I'd be happy with a single off-line frame.
I've only briefly fiddled with ANNs in MATLAB for character recognition:
http://en.wikipedia.org/wiki/Artificial_neural_network
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