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Thread: Ip camera video delay after G.711 transcoding

  1. #1
    Join Date
    Mar 2012
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    5

    Default Ip camera video delay after G.711 transcoding

    Hi!

    I've got a Sunell Ip camera which has got H264 and G.711 alaw/mulaw audio output format.
    I would like to stream the video+audio live. I tried the transcoder but it isnt working.

    The problem is that the video and audio is not synchronised,the video plays more slow (about half speed) and there is a strange "do-re-mi" sound in the audio signal. If i set the audio bitrate to lower eg:8000bps the video speed become normal, but there is no sound. If I set the bitrate to eg: 96000bps the video slows down again.
    Have you ever seen this problem?

    my conf/application.xml and transcode.xml are the following:

    http://cruisher.digitaltrip.hu/nenez...pplication.xml
    http://cruisher.digitaltrip.hu/nenez...scodeAudio.xml

  2. #2
    Join Date
    Dec 2007
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    21,962

    Default

    The do re mi is the Wowza Transcoder audio watermark.

    Are you playing the source stream instead of one of the transcoded streams output by Wowza Transcoder?

    Richard

  3. #3
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    Mar 2012
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    Quote Originally Posted by rrlanham View Post
    The do re mi is the Wowza Transcoder audio watermark.

    Are you playing the source stream instead of one of the transcoded streams output by Wowza Transcoder?

    Richard
    No, I'm playing the camera.stream_rtp. This is the transcoded stream.

  4. #4

    Default

    Looks like you're trying to upsample the audio from 8kbps to 64kbps in your template, which you probably don't want to do. Try lowering the bitrate in your transcoder template to equal to or less than your source bitrate or use: <Bitrate>${SourceAudioBitrate}</Bitrate>

  5. #5
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    Mar 2012
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    Quote Originally Posted by randall View Post
    Looks like you're trying to upsample the audio from 8kbps to 64kbps in your template, which you probably don't want to do. Try lowering the bitrate in your transcoder template to equal to or less than your source bitrate or use: <Bitrate>${SourceAudioBitrate}</Bitrate>
    I tried with many bitrate. If I set to 8000 or more, i hear the watermark and the camera microphone sound, but the video goes about half speed.
    If I set the bitrate to 5000 or below, there is no sound but the video speed is correct.

  6. #6

    Default

    Where are you setting the bitrate? Try setting the bitrate on your camera to 64k, and setting the template to <Bitrate>${SourceAudioBitrate}</Bitrate>.

    The bitrate should not be above the bitrate of your encoding, generally speaking.

  7. #7
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    Mar 2012
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    I set the bitrate in the transcodeAudio xml file :
    <Audio>
    <!-- AAC, PassThru -->
    <Codec>AAC</Codec>
    <Bitrate>${SourceAudioBitrate}</Bitrate>
    </Audio>

    In the camera menu there isn't any possibility to set the bitrate, only the encoding type.
    The video delay is very high, about 10-20sec, the audio delay is about 3sec.

  8. #8
    Join Date
    May 2011
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    456

    Default

    Set the bitrate in the template instead of using a variable.
    <Audio>
    <!-- AAC, PassThru -->
    <Codec>AAC</Codec>
    <Bitrate>96000</Bitrate>
    </Audio>
    You can log extra debug information to the log file regarding the RTSP handshake between Wowza Media Server and the IP camera (RTSP/RTP source) by adding the following property to the MediaCaster/Properties container in [install-dir]/conf/[application]/Application.xml:
    <Property>
        <Name>debugRTSPSession</Name>
        <Value>true</Value>
        <Type>Boolean</Type>
    </Property>
    Also check to see if there is a firmware update for your camera. If problems persist, email support@wowza.com with a zip of [install-dir]/conf and logs directories, URL to your live camera feed if possible, and please reference this thread.

    -Lisa
    Last edited by lisa_w; 03-27-2012 at 09:41 AM.

  9. #9
    Join Date
    Mar 2012
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    Default

    I put the debugRTSPSession, but i don't see any information wich can cause the low video speed.
    I think I let these Sunell cameras, i will use Vivotek instead.
    Thanks for the help!

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