DVB-C radio not working

Discussion in '1.3.x' started by torrinha, April 10, 2013.

  1. torrinha

    torrinha Portal Pro

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    MediaPortal Version: 1.3.0

    Description
    As the title suggests, the DVB-C radio channels are not outputting any audio.
    When I try to preview the radio channel inside TV-Server configuration, the SetupTV seems to hang for some minutes, then a preview window is open and there's no audio.
    When I try to open the channel radio inside MediaPortal client, the system again seems to hang and after some time it shows the "now playing" info (with time 0:00) and no audio again.
    The radio channels are not scrambled, and I can play them fine with ProgDVB.
    I attached two log archives, from both tests.

    Steps to Reproduce:
    Try to listen to any DVB-C radio channel.


     

    Attached Files:

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  3. hello_joe

    hello_joe Portal Member

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    Hello torrinha

    The problem is a codec issue. LAV does not seem to be capable of handling the audio for some reason, and so it is removed from the graph:
    Probably TV Server preview is also using an incompatible codec.
    Aside from that nothing is wrong.
    So make sure you are using the latest version of LAV (check the MP extension installer) or just try a different codec...

    Joe
     
    Last edited: April 10, 2013
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  4. torrinha

    torrinha Portal Pro

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    Hi, Joe!

    Thanks for the answer.
    I just tried to change the codec from LAV to Microsoft DTV and ffdshow, but I got the same results (there's a "- remove done" on the log too).

    Also, in the TSReader log I got a lot of "EOF ..." stuff.
    It seems to me that the TSWriter from the TV Server is not writing the file...

    Do you know if I can test the TV Server using GraphStudioNext?
    Or do you have another suggestion to try?


    Thanks again.
     
  5. hello_joe

    hello_joe Portal Member

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    I think I see what you mean...
    Have you checked the size of the file in your timeshift folder?
    Probably GraphStudioNext will not help to solve problems with TsWriter.

    ...in fact...

    Ahhhh, I see the problem.
    The PCR PID for these channels is 0x1fff (the NULL packet PID).
    TsWriter throws away these packets in DiskRecorder.cpp OnTsPacket().
    TsWriter only starts writing to the timeshift file after it sees the first PCR packet in WriteTs().
    Since the packets are thrown away before WriteTs(), TsWriter will never start writing to the timeshift file for these channels.

    So this is a bug that the @Developers will need to fix.

    Nice find! :)
     
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  6. torrinha

    torrinha Portal Pro

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    Holy sh*t!!

    The file size is 0...
    And this whole "NULL packet PID" seems like an "error" or "non-conformance" from my network provider.... right?!?!

    I don't have a development environment set here right now, so I guess I'll have to wait to someone kindly compile a test version for me.... ;)


    Thanks again!
     
  7. hello_joe

    hello_joe Portal Member

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    It could be non-conformant -yes. It is certainly very questionable. :)



    I'd like to help, but I don't have a development environment either. I just checked the code on github online. Hopefully somebody else can help you with this...
     
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  8. torrinha

    torrinha Portal Pro

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    Thanks anyway!

    I'll try to setup my things here as wait for some dev to take a look at it...
    (y)
     
  9. HomeY
    • Team MediaPortal

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    @Owlsroost what does your wisdom think of the above? ;)
     
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  10. Owlsroost
    • Team MediaPortal

    Owlsroost Development Group

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    Show System Specs
    The MPEG spec is quite clear on PCR PIDs - "NOTE – The transport packets with PID values 0x0000, 0x0001, and 0x0010-0x1FFE are allowed to carry a PCR" i.e. PID 0x1FFF is not allowed, so the stream is non-compliant.

    However, to check if this is really the problem, attached is a TsWriter that should allow through 'null' packets when PCR PID = 0x1FFF and they have an adaption field (which means they might carry a PCR). Just stop TV service and replace the current TsWriter.ax with the new one, then start TV service again.
     

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  11. torrinha

    torrinha Portal Pro

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    Just as I thought... :mad:
    I'm at work right know, but I'll test as soon as I get home.


    Thanks for the help so far!!
     
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