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• How to implement FFMEG library for android video streaming

  10 mai 2014, par Kabir

  I am trying to create online streaming video player in android.
  I am trying to compile the appunite/AndroidFFmpeg library for android application to play HLS videos online. I am using linux-ubuntu OS I also have set the NDK path.
  I have executed all command one by one given on the link :

  https://github.com/appunite/AndroidFFmpeg

  But when I executed the following script :

  ./build_android.sh

  I got the following error :

  abi-gcc —sysroot=/home/singsys-063/android-ndk-r9d/platforms/android-5/arch-arm/
  checking whether the C compiler works... no
  configure : error : in
  /home/singsys-063/AndroidFFmpeg/FFmpegLibrary/jni/vo-amrwbenc :
  configure : error : C compiler cannot create executables
  See config.log for more details

• Real time livestreaming - RPI

  24 avril 2022, par Victor

  I work at a telehealth company and we are using connected medical devices in order to provide the doctor with real time information from these equipements, the equipements are used by a trained health Professional.

  


  Those devices work with video and audio. Right now, we are using them with peerjs (so peer to peer connection) but we are trying to move away from that and have a RPI with his only job to stream data (so streaming audio and video).

  


  Because the equipements are supposed to be used with instructions from a doctor we need the doctor to receive the data in real time.

  


  But we also need the trained health professional to see what he is doing (so we need a local feed from the equipement)

  


  How do we capture audio and video

  


  We are using ffmpeg with a go client that is in charge of managing the ffmpeg clients and stream them to a SRS server.
This works but we are having a 2-3 sec delay when streaming the data. (rtmp from ffmpeg and flv on the front end)

  


  ffmpeg settings :

  


  ("ffmpeg", "-f", "v4l2", `-i`, "*/video0", "-f", "flv", "-vcodec", "libx264", "-x264opts", "keyint=15", "-preset", "ultrafast", "-tune", "zerolatency", "-fflags", "nobuffer", "-b:a", "160k", "-threads", "0", "-g", "0", "rtmp://srs-url")


  


  My questions

  


  

  • Is there a way for this set up to achieve low latency (<1 sec) (for the nurse and for the doctor) ?

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  • Is the way I want to achieve this good ? Is there a batter way ?

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  Flow schema

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  Data exchange and use case flow

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• What does the left_block_options array represent in the fill_decode_neighbors function of FFmpeg？

  28 décembre 2024, par mike xu

  I am studying the source code of FFmpeg, specifically the fill_decode_neighbors function. I am trying to understand how the decoding process works, especially the usage of the left_block_options array.&#xA;Here is the relevant code snippet :

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  static const uint8_t left_block_options[4][32] = {
        { 0, 1, 2, 3, 7, 10, 8, 11, 3 + 0 * 4, 3 + 1 * 4, 3 + 2 * 4, 3 + 3 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 5 * 4, 1 + 9 * 4 },
        { 2, 2, 3, 3, 8, 11, 8, 11, 3 + 2 * 4, 3 + 2 * 4, 3 + 3 * 4, 3 + 3 * 4, 1 + 5 * 4, 1 + 9 * 4, 1 + 5 * 4, 1 + 9 * 4 },
        { 0, 0, 1, 1, 7, 10, 7, 10, 3 + 0 * 4, 3 + 0 * 4, 3 + 1 * 4, 3 + 1 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 4 * 4, 1 + 8 * 4 },
        { 0, 2, 0, 2, 7, 10, 7, 10, 3 + 0 * 4, 3 + 2 * 4, 3 + 0 * 4, 3 + 2 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 4 * 4, 1 + 8 * 4 }
    };


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  While I understand that this array plays a role in determining neighboring blocks for decoding, I am unclear about :

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  The specific meaning of the array values.&#xA;How this array interacts with the decoding process, especially in relation to intra-prediction or block positioning.&#xA;Instead of a detailed explanation, I would greatly appreciate :

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  Any keywords I can look up to understand this topic better (e.g., terms from the H.264 standard or FFmpeg documentation).&#xA;Links to related documentation, articles, or sections in the H.264 specification.&#xA;Suggestions on where I might find similar examples or detailed discussions about intra-block neighbor handling in FFmpeg.&#xA;Thank you for any resources or pointers you can provide !

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