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• FFMPEG libav gdigrab capturing with wrong colors

  7 mars 2018, par user1496491

  I’m capturing screen with code below, and it gets me the picture with wrong colors.

  

  The picture on left is raw data which I assumed in ARGB the picture in right is encoded as YUV. I’ve tried different formats, the pictures slighly changing, but it’s never looks ow it should be. In what format gdigrab gives its output ? What’s the right way to encode it ?

  #include "MainWindow.h"
  
  
  
  #include <qguiapplication>
  
  #include <qlabel>
  
  #include <qscreen>
  
  #include <qtimer>
  
  #include <qlayout>
  
  #include <qimage>
  
  #include <qtconcurrent></qtconcurrent>QtConcurrent>
  
  #include <qthreadpool>
  
  
  
  #include "ScreenCapture.h"
  
  
  
  MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
  
  {
  
      resize(800, 600);
  
  
  
      label = new QLabel();
  
      label->setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);
  
  
  
      auto layout = new QHBoxLayout();
  
      layout->addWidget(label);
  
  
  
      auto widget = new QWidget();
  
      widget->setLayout(layout);
  
      setCentralWidget(widget);
  
  
  
      init();
  
      initOutFile();
  
      collectFrame();
  
  }
  
  
  
  MainWindow::~MainWindow()
  
  {
  
      avformat_close_input(&amp;inputFormatContext);
  
      avformat_free_context(inputFormatContext);
  
  
  
      QThreadPool::globalInstance()->waitForDone();
  
  }
  
  
  
  void MainWindow::init()
  
  {
  
  
  
      av_register_all();
  
      avcodec_register_all();
  
      avdevice_register_all();
  
  
  
      auto screen = QGuiApplication::screens()[1];
  
      QRect geometry = screen->geometry();
  
  
  
      inputFormatContext = avformat_alloc_context();
  
  
  
      AVDictionary* options = NULL;
  
      av_dict_set(&amp;options, "framerate", "30", NULL);
  
      av_dict_set(&amp;options, "offset_x", QString::number(geometry.x()).toLatin1().data(), NULL);
  
      av_dict_set(&amp;options, "offset_y", QString::number(geometry.y()).toLatin1().data(), NULL);
  
      av_dict_set(&amp;options, "preset", "ultrafast", NULL);
  
      av_dict_set(&amp;options, "probesize", "10MB", NULL);
  
      av_dict_set(&amp;options, "pix_fmt", "yuv420p", NULL);
  
      av_dict_set(&amp;options, "video_size", QString(QString::number(geometry.width()) + "x" + QString::number(geometry.height())).toLatin1().data(), NULL);
  
  
  
      AVInputFormat* inputFormat = av_find_input_format("gdigrab");
  
      avformat_open_input(&amp;inputFormatContext, "desktop", inputFormat, &amp;options);
  
  
  
  //    AVDictionary* options = NULL;
  
  //    av_dict_set(&amp;options, "framerate", "30", NULL);
  
  //    av_dict_set(&amp;options, "preset", "ultrafast", NULL);
  
  //    av_dict_set(&amp;options, "vcodec", "h264", NULL);
  
  //    av_dict_set(&amp;options, "s", "1280x720", NULL);
  
  //    av_dict_set(&amp;options, "crf", "0", NULL);
  
  //    av_dict_set(&amp;options, "rtbufsize", "100M", NULL);
  
  
  
  //    AVInputFormat *format = av_find_input_format("dshow");
  
  //    avformat_open_input(&amp;inputFormatContext, "video=screen-capture-recorder", format, &amp;options);
  
  
  
      av_dict_free(&amp;options);
  
      avformat_find_stream_info(inputFormatContext, NULL);
  
  
  
      videoStreamIndex = av_find_best_stream(inputFormatContext, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
  
  
  
      inputCodec = avcodec_find_decoder(inputFormatContext->streams[videoStreamIndex]->codecpar->codec_id);
  
      if(!inputCodec) qDebug() &lt;&lt; "Не найден кодек входящего потока!";
  
  
  
      inputCodecContext = avcodec_alloc_context3(inputCodec);
  
      inputCodecContext->codec_id = inputCodec->id;
  
  
  
      avcodec_parameters_to_context(inputCodecContext, inputFormatContext->streams[videoStreamIndex]->codecpar);
  
  
  
      if(avcodec_open2(inputCodecContext, inputCodec, NULL)) qDebug() &lt;&lt; "Не удалось открыть входной кодек!";
  
  }
  
  
  
  void MainWindow::initOutFile()
  
  {
  
      const char* filename = "C:/Temp/output.mp4";
  
  
  
      if(avformat_alloc_output_context2(&amp;outFormatContext, NULL, NULL, filename) &lt; 0) qDebug() &lt;&lt; "Не удалось создать выходной контекст!";
  
  
  
      outCodec = avcodec_find_encoder(AV_CODEC_ID_MPEG4);
  
      if(!outCodec) qDebug() &lt;&lt; "Не удалось найти кодек!";
  
  
  
      videoStream = avformat_new_stream(outFormatContext, outCodec);
  
      videoStream->time_base = {1, 30};
  
  
  
      const AVPixelFormat* pixelFormat = outCodec->pix_fmts;
  
      while (*pixelFormat != AV_PIX_FMT_NONE)
  
      {
  
          qDebug() &lt;&lt; "OUT_FORMAT" &lt;&lt; av_get_pix_fmt_name(*pixelFormat);
  
          ++pixelFormat;
  
      }
  
  
  
      outCodecContext = videoStream->codec;
  
      outCodecContext->bit_rate = 400000;
  
      outCodecContext->width = inputCodecContext->width;
  
      outCodecContext->height = inputCodecContext->height;
  
      outCodecContext->time_base = videoStream->time_base;
  
      outCodecContext->gop_size = 10;
  
      outCodecContext->max_b_frames = 1;
  
      outCodecContext->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
      if (outFormatContext->oformat->flags &amp; AVFMT_GLOBALHEADER) outCodecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      if(avcodec_open2(outCodecContext, outCodec, NULL)) qDebug() &lt;&lt; "Не удалось открыть выходной кодек!";
  
  
  
      swsContext = sws_getContext(inputCodecContext->width,
  
                                  inputCodecContext->height,
  
  //                                inputCodecContext->pix_fmt,
  
                                  AV_PIX_FMT_ABGR,
  
                                  outCodecContext->width,
  
                                  outCodecContext->height,
  
                                  outCodecContext->pix_fmt,
  
                                  SWS_BICUBIC, NULL, NULL, NULL);
  
  
  
      if(avio_open(&amp;outFormatContext->pb, filename, AVIO_FLAG_WRITE) &lt; 0) qDebug() &lt;&lt; "Не удалось открыть файл!";
  
      if(avformat_write_header(outFormatContext, NULL) &lt; 0) qDebug() &lt;&lt; "Не удалось записать заголовок!";
  
  }
  
  
  
  void MainWindow::collectFrame()
  
  {
  
      AVFrame* inFrame = av_frame_alloc();
  
      inFrame->format = inputCodecContext->pix_fmt;
  
      inFrame->width = inputCodecContext->width;
  
      inFrame->height = inputCodecContext->height;
  
  
  
      int size = av_image_alloc(inFrame->data, inFrame->linesize, inFrame->width, inFrame->height, inputCodecContext->pix_fmt, 1);
  
      qDebug() &lt;&lt; size;
  
  
  
      AVFrame* outFrame = av_frame_alloc();
  
      outFrame->format = outCodecContext->pix_fmt;
  
      outFrame->width = outCodecContext->width;
  
      outFrame->height = outCodecContext->height;
  
  
  
      qDebug() &lt;&lt; av_image_alloc(outFrame->data, outFrame->linesize, outFrame->width, outFrame->height, outCodecContext->pix_fmt, 1);
  
  
  
      AVPacket packet;
  
      av_init_packet(&amp;packet);
  
  
  
      av_read_frame(inputFormatContext, &amp;packet);
  
  //    while(av_read_frame(inputFormatContext, &amp;packet) >= 0)
  
  //    {
  
          if(packet.stream_index == videoStream->index)
  
          {
  
  
  
              memcpy(inFrame->data[0], packet.data, size);
  
  
  
              sws_scale(swsContext, inFrame->data, inFrame->linesize, 0, inputCodecContext->height, outFrame->data, outFrame->linesize);
  
  
  
              QImage image(inFrame->data[0], inFrame->width, inFrame->height, QImage::Format_ARGB32);
  
              label->setPixmap(QPixmap::fromImage(image).scaled(label->size(), Qt::KeepAspectRatio));
  
  
  
              AVPacket outPacket;
  
              av_init_packet(&amp;outPacket);
  
  
  
              int encodeResult = avcodec_receive_packet(outCodecContext, &amp;outPacket);
  
              while(encodeResult == AVERROR(EAGAIN))
  
              {
  
                  if(avcodec_send_frame(outCodecContext, outFrame)) qDebug() &lt;&lt; "Ошибка отправки фрейма на кодирование!";
  
  
  
                  encodeResult = avcodec_receive_packet(outCodecContext, &amp;outPacket);
  
              }
  
              if(encodeResult != 0) qDebug() &lt;&lt; "Ошибка во время кодирования!" &lt;&lt; encodeResult;
  
  
  
              if(outPacket.pts != AV_NOPTS_VALUE) outPacket.pts = av_rescale_q(outPacket.pts, videoStream->codec->time_base, videoStream->time_base);
  
              if(outPacket.dts != AV_NOPTS_VALUE) outPacket.dts = av_rescale_q(outPacket.dts, videoStream->codec->time_base, videoStream->time_base);
  
  
  
              av_write_frame(outFormatContext, &amp;outPacket);
  
  
  
              av_packet_unref(&amp;outPacket);
  
          }
  
  //    }
  
  
  
      av_packet_unref(&amp;packet);
  
  
  
      av_write_trailer(outFormatContext);
  
      avio_close(outFormatContext->pb);
  
  }
  
  </qthreadpool></qimage></qlayout></qtimer></qscreen></qlabel></qguiapplication>

• FFMPEG transcoding.c example produces wrong video frame rate [on hold]

  24 juillet 2018, par Poldon

  I am attempting to get this transcoding.c example to work :

  I had to fix some initialization issues, but the remaining issue I have so far is that the resulting video frame rate is 1/2 of what it should be in the output file. Here is the relevant part of the code :

    /* read all packets */
  
    while (1) {
  
      if ((ret = av_read_frame(ifmt_ctx, &packet)) < 0)
  
        break;
  
      stream_index = packet.stream_index;
  
      type = ifmt_ctx->streams[packet.stream_index]->codecpar->codec_type;
  
      av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n",
  
             stream_index);
  
  
  
      if (filter_ctx[stream_index].filter_graph) {
  
        av_log(NULL, AV_LOG_DEBUG, "Going to reencode&filter the frame\n");
  
        frame = av_frame_alloc();
  
        if (!frame) {
  
          ret = AVERROR(ENOMEM);
  
          break;
  
        }
  
        av_packet_rescale_ts(&packet, ifmt_ctx->streams[stream_index]->time_base,
  
                             stream_ctx[stream_index].dec_ctx->time_base);
  
        dec_func = (type == AVMEDIA_TYPE_VIDEO) ? avcodec_decode_video2
  
                                                : avcodec_decode_audio4;
  
        ret = dec_func(stream_ctx[stream_index].dec_ctx, frame, &got_frame,
  
                       &packet);
  
        if (ret < 0) {
  
          av_frame_free(&frame);
  
          av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");
  
          break;
  
        }
  
  
  
        if (got_frame) {
  
          frame->pts = frame->best_effort_timestamp;
  
          ret = filter_encode_write_frame(frame, stream_index);
  
          av_frame_free(&frame);
  
          if (ret < 0)
  
            goto end;
  
        } else {
  
          av_frame_free(&frame);
  
        }
  
      } else {
  
        /* remux this frame without reencoding */
  
        av_packet_rescale_ts(&packet, ifmt_ctx->streams[stream_index]->time_base,
  
                             ofmt_ctx->streams[stream_index]->time_base);
  
  
  
        ret = av_interleaved_write_frame(ofmt_ctx, &packet);
  
        if (ret < 0)
  
          goto end;
  
      }
  
      av_packet_unref(&packet);
  
    }

  I’m using the libraries from ffmpeg 3.4.2 (which is from Ubuntu 18.04). I appreciate any help someone could offer.

• make : *** No rule to make target 'jni/../third_party/lame/libmp3lame/VbrTag.c', needed by 'obj/local/arm64-v8a/objs/lame/VbrTag.o'. Stop

  29 mars 2020, par Pradeep Simba

  my jni folder
  

  

  when I build ndk it comes like this.

  How can I solve this ?