Sur d’autres sites (12446)

• "Format" or style the output of showwaves/showwavespic in ffmpeg

  9 avril 2020, par flomei

  I'm trying to get my head wrapped around ffmpeg and its functions and filters.

  



  showwaves and showwavespic already create nice output, but I'm looking to style it even more. Lots of audioplayers for example create a "waveform" like the following, which would be a job for showwavespic, I think. (I think soundcloud for example does create a form like this with actual data.)


  



  I wonder if I can use ffmpeg to create something like this directly from my raw input data. I thought I might need to split my audio track into X parts, calculate the average distance from the Y-axis and then create a bar. But I'm not sure if I can manage to do that with ffmpeg or if I need to build more of a toolchain for that.

  



  If I could create the output of showwaves to look like that above, that would be great. On the other hand I'd already be happy if I could just increase the stroke width of the showwaves output.

  



  Didn't found anything about the in the documentation or I looked at the wrong places, because I don't yet get the big picture of ffmpeg.

  


• Can not use the jsmpeg in react "Unexpected use of 'self'"

  5 mai 2020, par Muhammad Anas Khan

  code that i want to convert in React

  



   &#xA;    &#xA;    <code class="echappe-js">&lt;script type=&quot;text/javascript&quot; src='http://stackoverflow.com/feeds/tag/jsmpeg.min.js'&gt;&lt;/script&gt;&#xA;&#xA;    &lt;script type=&quot;text/javascript&quot;&gt;&amp;#xA;      var canvas = document.getElementById(&quot;videoCanvas&quot;);&amp;#xA;      console.log(document.location.hostname);&amp;#xA;     var url = &quot;ws://localhost:9999/&quot;;&amp;#xA;    &lt;/script&gt;&#xA;    &#xA;&#xA;

  



  Can not change it to react format.When i try to convert it is giving jsmpeg error 
i.e

  



  code that i tried but get an error

  



  import React from &#x27;react&#x27;;&#xA;import ReactDOM from &#x27;react-dom&#x27;;&#xA;import "./jsmpeg.min.js"&#xA;const App =()=>{&#xA;    return(&#xA;        <h1>Hello</h1>&#xA;    )&#xA;}&#xA;&#xA;&#xA;ReactDOM.render(<app></app>,document.getElementById(&#x27;root&#x27;));&#xA;

  



  Error

  



  /src/jsmpeg.min.js
Line 606:9 : Unexpected use of 'self' no-restricted-globals
 Line 2771:13 : Expected an assignment or function call and instead saw an expression no-unused-expressions

  



  Search for the keywords to learn more about each error.

  


• Error of FFmpeg on Java in "av_image_copy_to_buffer" method during decoding H.264 stream

  26 mai 2020, par maru2213

  I'm trying to decode H.264 stream, which is sent over Socket from an Android application to a computer. And I also want to show the decoded stream using JavaFX. I searched for a long time, and decided to use JavaCV / FFmpeg. However I got error from FFmpeg. (I was inspired by this code.)

  



  Questions :

  



  

  • Why does FFmpeg make error ?

  


  • Is it a correct way to convert AVFrame to javafx.scene.image.Image ?

  


  



  I'm using :

  



  

  • javacv-platform 1.4.4

  


  • ffmpeg-platform 4.1-1.4.4

  


  



  Code :

  



  This is a part of import and class fields, and method which runs once at the first time. (Actually the content of initialize() is wrapped by try catch.)

  



      import javafx.scene.image.Image;

    private avcodec.AVCodec avCodec;
    private avcodec.AVCodecContext avCodecContext;
    private avutil.AVDictionary avDictionary;
    private avutil.AVFrame avFrame;

    public void initialize() {
        avCodec = avcodec_find_decoder(AV_CODEC_ID_H264);
        if (avCodec == null) {
            throw new RuntimeException("Can't find decoder");
        }
        avCodecContext = avcodec_alloc_context3(avCodec);
        if (avCodecContext == null) {
            throw new RuntimeException("Can't allocate decoder context");
        }
        int result = avcodec_open2(avCodecContext, avCodec, (AVDictionary) null);
        if (result < 0) {
            throw new RuntimeException("Can't open decoder");
        }
        avFrame = av_frame_alloc();
        if (avFrame == null) {
            throw new RuntimeException("Can't allocate frame");
        }
    }


  



  And this is a method which is called every time when I receive a packet from Android. byte[] data is the packet data starting with 0x00, 0x00, 0x00, 0x01.

  



  The place where I get error is number_of_written_bytes. It always gets <0.

  &#xA;&#xA;

      private void decode(byte[] data) {
        AVPacket avPacket = new AVPacket();
        av_init_packet(avPacket);
        avPacket.pts(AV_NOPTS_VALUE);
        avPacket.dts(AV_NOPTS_VALUE);
        BytePointer bytePointer = new BytePointer(data);
        bytePointer.capacity(data.length);
        avPacket.data(bytePointer);
        avPacket.size(data.length);
        avPacket.pos(-1);

        avcodec_send_packet(avCodecContext, avPacket);
        int result = avcodec_receive_frame(avCodecContext, avFrame);
        if (result >= 0) {
            int bufferOutputSize = av_image_get_buffer_size(avFrame.format(), avFrame.width(), avFrame.height(), 16);
            Pointer pointer = av_malloc(bufferOutputSize);
            BytePointer outputPointer = new BytePointer(pointer);
            int number_of_written_bytes = av_image_copy_to_buffer(outputPointer, bufferOutputSize, avFrame.data(), avFrame.linesize(), avFrame.chroma_location(), avFrame.width(), avFrame.height(), 1);
            if (number_of_written_bytes < 0) {
                //The process always come here.
                throw new RuntimeException("Can't copy image to buffer");
            }

            System.out.println("decode success");
            Image image = new Image(new ByteArrayInputStream(outputPointer.asBuffer().array()));
        } else {
            System.out.println("decode failed");
        }
    }


  &#xA;&#xA;

  Anything is helpful for me. Thanks.

  &#xA;