Recherche avancée

Sur d’autres sites (13544)

• arm : Use .data.rel.ro for const data with relocations

  16 novembre 2014, par Martin Storsjö

  arm : Use .data.rel.ro for const data with relocations
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] configure
  • [DH] libavcodec/arm/fft_fixed_neon.S
  • [DH] libavcodec/arm/fft_neon.S
  • [DH] libavcodec/arm/fft_vfp.S
  • [DH] libavutil/arm/asm.S

• How to create video with dynamic pictures like Facebook Friend's Day video

  21 février 2019, par Vinicius

  How to create a video with pictures from a user just like Facebook does with their Facebook Friend’s day video ?

  Example : https://www.youtube.com/watch?v=mNWJ_XxfQfU

  The intention is to generate this sort of video with images that a visitor will upload to a website. FFMPEG does support images animation but it seems that a bit of 3d animations like the above needs ages to be done with FFMPEG. I wonder if there is an alternative to FFMPEG that can generate this sort of animations, or maybe a software like After Effects that can either generate a template that can be used on ffmpeg (or any command line alternative) or has its own command-line interface that can be executed in a linux machine to do such thing.

  Basically, the user would upload the pictures, the server would crop them to have the same size and then it would convert it to a video like the one mentioned above.

• Rendering YUV420P ffmpeg decoded images on QT with OpenGL, only see black screen

  17 février 2019, par Lucas Zanella

  I’ve found this QT OpenGL Widget which should render a 420PYUV image on screen. I’m feeding a ffmpeg decoded buffer into its paintGL() function but I see nothing. Neither noises or correct images, only a black screen. I’m trying to understand why.

  I want to exclude the possibilities of other things being wrong, but I need to be sure first that my code will produce anything. I std::couted some bytes from the ffmpeg just to see if they were arriving and they were. So I should see at least some noise.

  Can you see anything wrong with my code that wouldn’t make it able to render images on screen ?

  This is the widget that should output the image :

  #include "XVideoWidget.h"
  
  #include <qdebug>
  
  #include <qtimer>
  
  #include <iostream>
  
  //自动加双引号
  
  #define GET_STR(x) #x
  
  #define A_VER 3
  
  #define T_VER 4
  
  
  
  //顶点shader
  
  const char *vString = GET_STR(
  
      attribute vec4 vertexIn;
  
      attribute vec2 textureIn;
  
      varying vec2 textureOut;
  
      void main(void)
  
      {
  
          gl_Position = vertexIn;
  
          textureOut = textureIn;
  
      }
  
  );
  
  
  
  
  
  //片元shader
  
  const char *tString = GET_STR(
  
      varying vec2 textureOut;
  
      uniform sampler2D tex_y;
  
      uniform sampler2D tex_u;
  
      uniform sampler2D tex_v;
  
      void main(void)
  
      {
  
          vec3 yuv;
  
          vec3 rgb;
  
          yuv.x = texture2D(tex_y, textureOut).r;
  
          yuv.y = texture2D(tex_u, textureOut).r - 0.5;
  
          yuv.z = texture2D(tex_v, textureOut).r - 0.5;
  
          rgb = mat3(1.0, 1.0, 1.0,
  
              0.0, -0.39465, 2.03211,
  
              1.13983, -0.58060, 0.0) * yuv;
  
          gl_FragColor = vec4(rgb, 1.0);
  
      }
  
  
  
  );
  
  
  
  
  
  
  
  //准备yuv数据
  
  // ffmpeg -i v1080.mp4 -t 10 -s 240x128 -pix_fmt yuv420p  out240x128.yuv
  
  XVideoWidget::XVideoWidget(QWidget * parent)
  
  {
  
     // setWindowFlags (Qt::WindowFullscreenButtonHint);
  
    //  showFullScreen();
  
  
  
  }
  
  
  
  XVideoWidget::~XVideoWidget()
  
  {
  
  }
  
  
  
  //初始化opengl
  
  void XVideoWidget::initializeGL()
  
  {
  
      //qDebug() &lt;&lt; "initializeGL";
  
      std::cout &lt;&lt; "initializing gl" &lt;&lt; std::endl;
  
      //初始化opengl （QOpenGLFunctions继承）函数
  
      initializeOpenGLFunctions();
  
  
  
      this->m_F  = QOpenGLContext::currentContext()->functions();
  
  
  
      //program加载shader（顶点和片元）脚本
  
      //片元（像素）
  
      std::cout &lt;&lt; program.addShaderFromSourceCode(QOpenGLShader::Fragment, tString) &lt;&lt; std::endl;
  
      //顶点shader
  
      std::cout &lt;&lt; program.addShaderFromSourceCode(QOpenGLShader::Vertex, vString) &lt;&lt; std::endl;
  
  
  
      //设置顶点坐标的变量
  
      program.bindAttributeLocation("vertexIn",A_VER);
  
  
  
      //设置材质坐标
  
      program.bindAttributeLocation("textureIn",T_VER);
  
  
  
      //编译shader
  
      std::cout &lt;&lt; "program.link() = " &lt;&lt; program.link() &lt;&lt; std::endl;
  
  
  
      std::cout &lt;&lt; "program.bind() = " &lt;&lt; program.bind() &lt;&lt; std::endl;
  
  
  
      //传递顶点和材质坐标
  
      //顶点
  
      static const GLfloat ver[] = {
  
          -1.0f,-1.0f,
  
          1.0f,-1.0f,
  
          -1.0f, 1.0f,
  
          1.0f,1.0f
  
      };
  
  
  
      //材质
  
      static const GLfloat tex[] = {
  
          0.0f, 1.0f,
  
          1.0f, 1.0f,
  
          0.0f, 0.0f,
  
          1.0f, 0.0f
  
      };
  
  
  
      //顶点
  
      glVertexAttribPointer(A_VER, 2, GL_FLOAT, 0, 0, ver);
  
      glEnableVertexAttribArray(A_VER);
  
  
  
      //材质
  
      glVertexAttribPointer(T_VER, 2, GL_FLOAT, 0, 0, tex);
  
      glEnableVertexAttribArray(T_VER);
  
  
  
      //glUseProgram(&amp;program);
  
      //从shader获取材质
  
      unis[0] = program.uniformLocation("tex_y");
  
      unis[1] = program.uniformLocation("tex_u");
  
      unis[2] = program.uniformLocation("tex_v");
  
  
  
      //创建材质
  
      glGenTextures(3, texs);
  
  
  
      //Y
  
      glBindTexture(GL_TEXTURE_2D, texs[0]);
  
      //放大过滤，线性插值   GL_NEAREST(效率高，但马赛克严重)
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      //创建材质显卡空间
  
      glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, 0);
  
  
  
      //U
  
      glBindTexture(GL_TEXTURE_2D, texs[1]);
  
      //放大过滤，线性插值
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      //创建材质显卡空间
  
      glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width/2, height / 2, 0, GL_RED, GL_UNSIGNED_BYTE, 0);
  
  
  
      //V
  
      glBindTexture(GL_TEXTURE_2D, texs[2]);
  
      //放大过滤，线性插值
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      //创建材质显卡空间
  
      glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width / 2, height / 2, 0, GL_RED, GL_UNSIGNED_BYTE, 0);
  
  
  
      ///分配材质内存空间
  
      datas[0] = new unsigned char[width*height];     //Y
  
      datas[1] = new unsigned char[width*height/4];   //U
  
      datas[2] = new unsigned char[width*height/4];   //V
  
  }
  
  
  
  //刷新显示
  
  void XVideoWidget::paintGL(unsigned char**data)
  
  //void QFFmpegGLWidget::updateData(unsigned char**data)
  
  {
  
      std::cout &lt;&lt; "painting!" &lt;&lt; std::endl;
  
      memcpy(datas[0], data[0], width*height);
  
      memcpy(datas[1], data[1], width*height/4);
  
      memcpy(datas[2], data[2], width*height/4);
  
  
  
      glActiveTexture(GL_TEXTURE0);
  
      glBindTexture(GL_TEXTURE_2D, texs[0]); //0层绑定到Y材质
  
      //修改材质内容(复制内存内容)
  
      glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, datas[0]);
  
      //与shader uni遍历关联
  
      glUniform1i(unis[0], 0);
  
  
  
  
  
      glActiveTexture(GL_TEXTURE0+1);
  
      glBindTexture(GL_TEXTURE_2D, texs[1]); //1层绑定到U材质
  
                                             //修改材质内容(复制内存内容)
  
      glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width/2, height / 2, GL_RED, GL_UNSIGNED_BYTE, datas[1]);
  
      //与shader uni遍历关联
  
      glUniform1i(unis[1],1);
  
  
  
  
  
      glActiveTexture(GL_TEXTURE0+2);
  
      glBindTexture(GL_TEXTURE_2D, texs[2]); //2层绑定到V材质
  
                                             //修改材质内容(复制内存内容)
  
      glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width / 2, height / 2, GL_RED, GL_UNSIGNED_BYTE, datas[2]);
  
      //与shader uni遍历关联
  
      glUniform1i(unis[2], 2);
  
  
  
      glDrawArrays(GL_TRIANGLE_STRIP,0,4);
  
      qDebug() &lt;&lt; "paintGL";
  
  }
  
  
  
  
  
  // 窗口尺寸变化
  
  void XVideoWidget::resizeGL(int width, int height)
  
  {
  
      m_F->glViewport(0, 0, width, height);
  
  
  
      qDebug() &lt;&lt; "resizeGL "&lt;code></iostream></qtimer></qdebug>

  Here’s a bit of code from my MainWindow :

  MainWindow::MainWindow(QWidget *parent):
  
      QMainWindow(parent)
  
      {
  
          FfmpegDecoder* ffmpegDecoder = new FfmpegDecoder();
  
          if(!ffmpegDecoder->Init()) {
  
              std::cout << "problem with ffmpeg decoder init"  << std::endl;
  
          } else {
  
              std::cout << "fmmpeg decoder initiated"  << std::endl;
  
          }
  
          XVideoWidget * xVideoWidget = new XVideoWidget(parent);
  
          ffmpegDecoder->setOpenGLWidget(xVideoWidget);
  
  
  
          mediaStream = new MediaStream(uri, ffmpegDecoder, videoConsumer);//= new MediaStream(uri, ffmpegDecoder, videoConsumer);
  
          //...
  
      }
  
      void MainWindow::run()
  
      {
  
          mediaStream->receiveFrame();
  
      }

  My main.cpp makes sure my window run() method runs in the background.

      MainWindow w;
  
      w.setFixedSize(1280,720);
  
      w.show();
  
      boost::thread mediaThread(&MainWindow::run, &w);
  
      std::cout << "mediaThread running"  << std::endl;

  If someone wants to view the entire code, please feel free to visit the commit I just did : https://github.com/lucaszanella/orwell/tree/bbd74e42bd42df685bacc5d51cacbee3a178689f