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Troubleshooting for running

Introduction​

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Questions and answers​

Fail to decode first frame​

  • Question: Why is the first frame not able to be decoded correctly? The returned frame is totally black.

  • Answer: This problem often occurs when using MpegClient, especially when demuxing the RTSP stream. In some video codec formats, there are I, P, and B frames. The I frame is required for decoding other frames. If the first received frame from the remote stream is not an I frame, you could not decode the frame correctly. This problem should be fixed if you let your client running for a while.

Fail to encode frames​

  • Question: When encoding frames, why does mpegCoder collapse?

  • Answer: You may send incorrect data to MpegEncoder.EncodeFrame(). The input value should be a 3D np.ndarray. The size of this array requires to be consistent with the configuration of the encoder.

Bad output video​

  • Question: I am working with MpegEncoder. Why is the output video broken?

  • Answer: There are two typical cases for the bad output video. Please check whether you meet such cases:

    • The video tail is not written correctly. This problem is often caused by a sudden termination of the program.
    • Some of the input frames are not correctly written.

Stuck of the streamer​

  • Question: When using MpegClient or MpegServer, why is the program stucked?

  • Answer: This problem is often caused by streamer.FFmpegSetup(), especially when the remote server program is not launched, or the stream protocol is not accepted by the server. I have to admit that I should add a timeout option in the future.

Fail to push the stream​

  • Question: I could connect the server by MpegServer.FFmpegSetup() successfully. Why am I not able to serve the first frame by MpegServer.ServeFrame()?

  • Answer: This problem is often caused by using a wrong codec. Not all codecs are supported for the online streaming. We recommend users to use libx264.

Set log level​

  • Question: I do not want the logs shown in the prompt, how to disable them?

  • Answer: We provide a global configuration method to do that:

    mpegCoder.setGlobal(dumpLevel=0)

    This value could be 0 (only show errors), 1 (show basic logs), 2 (show detailed logs).

Reuse the instances​

  • Question: Can I reuse the same instance of mpegCoder, for example, the mpegCoder.MpegDecoder?

  • Answer: Of course. Remember to call clear() before reusing the instance.