• How to fix missing frame rate issue when using Wowza Transcoder

    Some video encoders don't include frame rate information in stream metadata (SPS NAL unit VUI data and SDP data). Transcoder needs proper frame rate information to configure the encoding sessions. When frame rate information isn't available, Transcoder assumes the frame rate is 29.97 frames-per-second. When this happens, you'll see the following log statement:

    TranscoderWorkerVideoDecoder.handlePacket[stream-reference]: Source stream frame rate could not be calculated. Using default source stream frame rate: 29.97

    Transcoder uses the frame rate to properly encode the stream based on the target bitrate. If the frame rate isn't correct, the bitrate of the encoded video is either too high or too low.

    To adjust the default source frame rate to match your stream's frame rate, add the following property to the <Properties> container at the bottom of the transcoder template and set the value to the correct frame rate:
    <Property>
    	<Name>sourceStreamFrameRate</Name>
    	<Value>30</Value>
    	<Type>Double</Type>
    </Property>
    Note: The above property only alters the default frame rate of 29.97 used when a frame rate value can't be found within the stream itself. So it's used when the above error is encountered.

    Originally Published: 10-25-2012.

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