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• How is video decoding corruption debugged ?

  20 novembre 2013, par TopGunCoder

  I just started working for a new company and my new role demands that I help debug the video corruption that they are receiving through decoding frames. As much as I intend on digging down deep into the code and looking into the specifics of my problem, it made me think about video debugging in general.

  Since handling videos is very new to me, the whole process seems pretty complex and it seems there are a lot of places for corruption to present itself. The way I see it there is at least three places where corruption could pop up (barring memory corruption from the machine) :

  • Transporting the data before it is decoded
  • decoding implementation that perpetuates corruption once it is encountered, or is all together incorrect (Which seems to be my problem)
  • Transportation to the monitor(which seems unlikely but possible)

  So what i'm really curious about is if/how people debug their video streams to determine the location of any potential corruption they are encountering. I'm sure there is no sure fire method but I am curious to see what problems are even possible and how they can be identified and triaged.

  P.S. - I'm not sure of the differences between different decoding methods but, if this question seems too vague maybe it helps to mention I am using ffmpeg and avcodec_decode_video2 for the decoding.

• How is video decoding corruption be debugged ?

  17 septembre 2013, par TopGunCoder

  I just started working for a new company and my new role demands that I help debug the video corruption that they are receiving through decoding frames. As much as I intend on digging down deep into the code and looking into the specifics of my problem, it made me think about video debugging in general.

  Since handling videos is very new to me, the whole process seems pretty complex and it seems there are a lot of places for corruption to present itself. The way I see it there is at least three places where corruption could pop up (barring memory corruption from the machine) :

  • Transporting the data before it is decoded
  • decoding implementation that perpetuates corruption once it is encountered, or is all together incorrect (Which seems to be my problem)
  • Transportation to the monitor(which seems unlikely but possible)

  So what i'm really curious about is if/how people debug their video streams to determine the location of any potential corruption they are encountering. I'm sure there is no sure fire method but I am curious to see what problems are even possible and how they can be identified and triaged.

  P.S. - I'm not sure of the differences between different decoding methods but, if this question seems too vague maybe it helps to mention I am using ffmpeg and avcodec_decode_video2 for the decoding.

• How to stop FFMPEG from running if connection to input stream is lost ?

  12 septembre 2018, par Ryan Griggs

  I am capturing thumbnails from a webcam RTMP stream every 1 second to JPG files. Here’s my command line :

  ffmpeg -i rtsp://192.168.1.89:554/11 -f image2 -r 1 thumb%03d.jpg

  How can I make FFMPEG die with an error if the input RTMP stream is lost for a given timeout period ? Currently, if I lose connection to the webcam, FFMPEG starts throwing "Unknown error" messages, but when the network reconnects, ffmpeg appears to reconnect to the stream, but does not output any more captured frames. I have to manually kill the process and restart it to again start capturing frames.

  It would be nice to simply have ffmpeg die when it loses connection for a specific timeout period. Then I could monitor the process and restart when it ends.

  Any ideas ?