Multichannel decryption scenario (1 Viewer)

[alexandrecf]

I'm planning to implement the scenario shown in the attached figure in a project.

Can I simply multiplex the encrypted DVB TS from the 5 DVB-C tuners into a unique multichannel DVB TS, passes it through a SMiT multichannel CAM (with 3 PIDs for each channel) and after that demultiplex the decrypted multichannel TS into 5 decrypted DVB TS?

Is it possible to decrypt the 5 channels simultaneously in the same SMiT CAM?

 

[mm1352000]

Hello and welcome alexandrect

Sounds like an interesting project.

I'm planning to implement the scenario shown in the attached figure in a project.

Keep in mind that the CAM will have bitrate limitations. Not only for decrypting, but also for pass-through.

Can I simply multiplex the encrypted DVB TS from the 5 DVB-C tuners into a unique multichannel DVB TS, passes it through a SMiT multichannel CAM (with 3 PIDs for each channel) and after that demultiplex the decrypted multichannel TS into 5 decrypted DVB TS?

It entirely depends on the CAM capabilities and the way you intend to communicate with the CAM.

Is it possible to decrypt the 5 channels simultaneously in the same SMiT CAM?

Again, it depends on the CAM capabilities and the way that you communicate with it. Some CAMs can be instructed to decrypt multiple channels with CA PMT commands; some cannot. Some do not have the processing power to decrypt 5 channels.

mm

 

[alexandrecf]

Thanks for your reply mm!

I'm planning to use a SMiT Professional CAM for six channels. According with its specifications, it has a TS process bandwidth up to 96Mbps. So, I'll have, teorically, a limitation of 16 Mbps for each of the 6 channels. For one HD TS (H264) I think it is OK.

The communication with the CAM will be done using a FPGA. The same FPGA will be responsible for receive the 5 encrypted TS, multiplex them, pass this multiplexed TS through the CAM and then demultiplex the 5 decrypted TS.

For the decryption process am I need to provide the video and audio PIDs for each of the 5 TS, correct?

Do you see any problem in this scenario?

Best regards,
alexandrecf

 

[mm1352000]

Thanks for your reply mm!

No problem. Like I said, I think your project is interesting so I'll be interested to see the outcome.

I'm planning to use a SMiT Professional CAM for six channels. According with its specifications, it has a TS process bandwidth up to 96Mbps. So, I'll have, teorically, a limitation of 16 Mbps for each of the 6 channels. For one HD TS (H264) I think it is OK.

To be clear, as I understand it that "96 Mbps" is the bitrate limitation for the stream that you pass through the CAM, not just the bitrate limitation for decrypting. In other words, if each channel is 16 Mbps then you can only pass 6 channels through the CAM regardless of whether they are encrypted or not.

For the decryption process am I need to provide the video and audio PIDs for each of the 5 TS, correct?

Yes, sort of.
The FPGA will need to implement EN 50221 in order to send instructions to the CAM.
http://www.dvb.org/technology/standards/En50221.V1.pdf

In section 8.4.3.4 you can see the structure of the decrypt instructions that you would send to the CAM. This is called CA PMT (conditional access program map table). You must send one CA PMT for each service (channel) that you want to decrypt. Each CA PMT must contain the details of the video, audio and subtitle PIDs for the channel.

Do you see any problem in this scenario?

No problems.... only, I think this is quite a big project. If I started with nothing it could take... maybe one year working part time.
For me, the hardest thing would be establishing communication with the CAM. There is physical, transport and application layers to take care of...



mm