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blank screen no audio/video - please read this

Discussion in 'Digital TV - United States & Canada' started by zappp64, Jan 24, 2007.

  1. zappp64

    zappp64 Regular member

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    ok so one day you come home sit down to watch Sky Sports but all you get is a blank screen with no video or audio - however the FTA (free to air) channels like BBC1 and Channel 4 are ok

    well lets start by explaining a bit about how the dbox descrambles the cable signal

    The DBOX descrambles the cable signal - The actual fundamentals of the image do not decode the channels - the image is simply a standard linux operating system.

    There are two types of stream sent out by the cable company:

    FTA - These channels are broadcast 'in the clear' and are not scrambled in any way. Typically this is BBC1, BBC2, ITV1 and Cbeebies (maybe a few others). In other words they are the freeview channels; and anybody can stick a box on the end and obtain them.

    Nagra Encrypted - These channels are broadcast as 'scrambled'. In other words, they need to be decoded before you will see a sound and picture. It needs to be decrypted first via use of a 'key' The cable system works similar to this.

    The 'keys' are sent down the video/audio stream, but the box needs to know what to do with them, how to recognise them, and how to process them. This is where a softcam comes in. The encrypted channels are the subscription ones that they want you to pay for - for example the Movies and Sports channels.

    In a standard/legitimate box, you have a digital smartcard which processes all the data and reacts to it. The smartcard is the one that looks for, receives, and processes these 'keys' which will decode the channel. But we don't use a card with the DBOX2 do we, so whats going on there then??

    On top of the image is a 3rd party program which we refer to as a 'softcam' - it emulates a smartcard. You would have heard of it as evocamd, newcamd, mgcamd, or maybe even gbox. This programs work by simulating an inserted card and processing commands in the stream. They were written by studying the smartcards and their processors, and working out what commands do what function. By doing this, a softcam is essentially a digital clone of a smartcard in an unphysical form.

    The 'softcam' grabs the keys from the stream and saves them into a file on the box [a real smartcard would store these in permanent memory]. Whenever you change channel, this file is then read, and the stream is decoded using these sets of keys or passwords.

    The cable company send 'commands' down the stream called ECMs which tell boxes that the key has changed, and that the systems need to be updated. The softcam receives this command and compares the two sets of keys - if the newer keys are different then it saves those instead. This is known as 'autoroll' or 'autoupdate'. If the softcam didnt recognize and save the newer keys then the encrypted channels would not be able to be displayed, because the 'key' to unlock them would not be correct and the stream would still be encoded. Therefore you see a blank screen.

    To view this ECM information, using FTP go to the tmp folder on the dBox
    and look for a file called ecm.info - this is a standard text file with the 'key' to descramble the channel.

    Therefore to update or autoroll the key - all you need to go to is go to a channel like Sky Sporst 1 - wait for a while (a minute at the most) and this ecm.info file will be updated with the new key.
     
  2. Sipper

    Sipper Member

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    Excellent desciption, thanks for the info.


    Sipper
     
  3. Sandy1379

    Sandy1379 Member

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    Ok, thanks for this awesum decription, one thing i am wondering though is which of the following should i use?

    evocamd, newcamd, mgcamd

    how are they different? which would be best for telewest uk? etc...

    Many thanks zappp64, you've been a great help to these forums.

     
  4. zappp64

    zappp64 Regular member

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    evocamd is the most common one for Nagra1 encryption, as used by TW and enTeeeL 0- I have not tried the others but I am sure they do the same job.
     
  5. pedro105

    pedro105 Member

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    hi i have the same problem with the scrambled channels but i cant connect my box to the computer. is there a way of manually updating keys on the box or do i have to wait for the next time a key change signal gets sent to the box? regards.
     
  6. zappp64

    zappp64 Regular member

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    as per my original post and towards the end, you need to go to a channel like sky sports 1 and leave it on that channel for 1 minute - the keys will be autoupdated
     
  7. pedro105

    pedro105 Member

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    thanks tried that left it on there for 5 min still nothing.this has happend to me before and after about two weeks it all came back. weird.
     
  8. bal247

    bal247 Member

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    happened to me - you need to make sure your emu Autoupdate setting is automatic, took around 10 mins but did sort it out. (for some reason when the setting was on "on" it didnt work) Thanks to Zappp64 for an excellent post, always good to know how things actually work! Makes it easier when you're trying to solve problems!
     
  9. Iainang

    Iainang Member

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    Hi mate, very good description, but when i did my re-scan, the only channels that appear are, bbc1, 2, 3, itv etc, i also pick up setanta, sky sports xtra, some music ones, the adult ones, but for some reason i dont see sky sports 1, 2, or 3, or any movie channels, any idea as to why this is?
     
  10. zappp64

    zappp64 Regular member

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    if you have channels missing one thing to look out for it a file called myservices.xml - this is located inthe same folder on the dbox as the services.xml and bouquet.xml - delete the file and all channels should appear
     
  11. kasuku

    kasuku Member

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    sorry if this is a stupid question but .....

    if the keys are autoupdated then why do some guides say that it is important to have a valid keys file for your provider when installing the softcam?
    Isn't this key file going to be updated anyway with new codes?
     
  12. Fekker

    Fekker Regular member

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    Depends on what key system your provider is using, no point in having keys from a German provider if you are in the UK as they won't update ;-)
     
  13. shawn736

    shawn736 Member

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    i dont understand wat yr sayin bout how 2 fix the blank channels can u explain just how 2do tht plz...

    thanks in advance
     
  14. zappp64

    zappp64 Regular member

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    to sum up my original post

    when you get a blank screen, the ecm or keys for encryption channels have not been updated via the evocam process - in order to do this go to sky sports 1 leave it on for 1 minute and then channel should be viewable.

    if this fails, restart the cam.
     
  15. shawn736

    shawn736 Member

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    i did tht and it didnt wrk. im using commando 7.5 by the way
     
  16. zappp64

    zappp64 Regular member

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    r u using the original command 7.5 as the official release does not include the keys and roms for subscription channel therefore you wont get sky sports 1 or any other sjy channels only ones you will get is FTA one,.
     
  17. shawn736

    shawn736 Member

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    ahh k can u send me the best commando, i cant dwnlaod from rapitshare
     
  18. shawn736

    shawn736 Member

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    is comando 7 beta any gd and will i get the channels if i flash wit it?
     
  19. Fekker

    Fekker Regular member

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    It does not have any keys in it so you will have to get them somewhere and FTP them to your box.
     

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