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• why is streaming to an flv server with ffmpeg only showing black/blank video for clients ?

  6 septembre 2012, par rogerdpack

  When I stream to an flv server, like flash media server, using ffmpeg, like

   ffmpeg -i input -vcodec libx264 rtmp://hostname/streamname

  it turns out black. Why is that ?

• why ffmpeg frame to opengles texture is black

  5 juin 2012, par joe

  I'm trying to converted from a video using ffmpeg to an opengles texture in jni, but i just get a black texture. I have output the opengl with the glGetError(), there is any error.
  Here is my code :

  void*              pixels;    int err;
  
  int i;
  
  int frameFinished = 0;
  
  AVPacket packet;
  
  static struct SwsContext *img_convert_ctx;
  
  static struct SwsContext *scale_context = NULL;
  
  int64_t seek_target;
  
  
  
   int target_width = 320;
  
   int target_height = 240;
  
   GLenum error = GL_NO_ERROR;
  
   sws_freeContext(img_convert_ctx);  
  
  
  
  i = 0;
  
  while((i==0) && (av_read_frame(pFormatCtx, &packet)>=0)) {
  
      if(packet.stream_index==videoStream) {
  
          avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
  
  
          if(frameFinished) {
  
              LOGI("packet pts %llu", packet.pts);
  
              img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, 
  
                     pCodecCtx->pix_fmt, 
  
                     target_width, target_height, PIX_FMT_RGB24, SWS_BICUBIC, 
  
                     NULL, NULL, NULL);
  
              if(img_convert_ctx == NULL) {
  
                  LOGE("could not initialize conversion context\n");
  
                  return;
  
              }
  
              sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize);
  
              LOGI("sws_scale");
  
  
  
              videoTextures = new Texture*[1];
  
              videoTextures[0]->mWidth = 256; //(unsigned)pCodecCtx->width;
  
              videoTextures[0]->mHeight = 256; //(unsigned)pCodecCtx->height;
  
              videoTextures[0]->mData = pFrameRGB->data[0];
  
  
  
              glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  
  
  
              glGenTextures(1, &(videoTextures[0]->mTextureID));
  
              glBindTexture(GL_TEXTURE_2D, videoTextures[0]->mTextureID);
  
              glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); 
  
              glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  
  
              if(0 == got_texture)
  
              {
  
                  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, videoTextures[0]->mWidth, videoTextures[0]->mHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid *)videoTextures[0]->mData);
  
  
  
                  glTexSubImage2D(GL_TEXTURE_2D, 0, 0,0, videoTextures[0]->mWidth, videoTextures[0]->mHeight, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid *)videoTextures[0]->mData);
  
              }else
  
              {
  
                  glTexSubImage2D(GL_TEXTURE_2D, 0, 0,0, videoTextures[0]->mWidth, videoTextures[0]->mHeight, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid *)videoTextures[0]->mData);
  
  
  
              }
  
  
  
              i = 1;
  
              error = glGetError();
  
              if( error != GL_NO_ERROR ) {
  
                  LOGE("couldn't create texture!!");
  
                     switch (error) {
  
                      case GL_INVALID_ENUM:
  
                      LOGE("GL Error: Enum argument is out of range");
  
                      break;
  
                      case GL_INVALID_VALUE:
  
                          LOGE("GL Error: Numeric value is out of range");
  
                      break;
  
                      case GL_INVALID_OPERATION:
  
                          LOGE("GL Error: Operation illegal in current state");
  
                      break;
  
                      case GL_OUT_OF_MEMORY:
  
                          LOGE("GL Error: Not enough memory to execute command");
  
                      break;
  
                      default:
  
                          break;
  
                     }
  
              }
  
          }
  
      }
  
      av_free_packet(&packet);
  
  }

  i success to change pFrameRGB to a java bitmap， but i just want to change it to a texture in the c code,

• Black overlay appears when merging a transparent video to another video

  13 juin 2012, par RakeshS

  This is what I have done so far :

  Command to create a transparent PNG image :

  convert -size 640x480 -background transparent -fill blue \
  
  -gravity South label:ROCK image1-0.png

  Command to create a transparent video :

  ffmpeg -loop 1 -f image2 -i image1-0.png -r 20 -vframes 100 \
  
  -vcodec png -pix_fmt bgra mov-1.mov

  (as per this post) - I expect this video to be a transparent video.

  Command to overlay a video with another :

  ffmpeg -i final-video.mov -sameq -ar 44100 \
  
  -vf "movie=mov-1.mov [logo];[in][logo] overlay=0:0 [out]" \
  
  -strict experimental final-video.mov

  Above commands works perfect and I have not faced any problem, but I don't get what I expect which is kinda watermarking effect, I want mov-1.mov to be transparent with final-video.mov.

  Questions :

  1. Is there any way to verify if the generated video is transparent ? other than merging ?
  2. Not sure why the above mov-1.mov is not transparent when it is merged with final-video.mov, any info to solve this problem would be great.

  Please help.