Use factory method to create screen capturer

src/screen_capturer/macosx/screen_capturer_avf.cpp

@@ -0,0 +1,144 @@
+#include "screen_capturer_avf.h"
+
+#include <iostream>
+
+#include "log.h"
+
+#define NV12_BUFFER_SIZE 1280 * 720 * 3 / 2
+unsigned char nv12_buffer_[NV12_BUFFER_SIZE];
+
+ScreenCapturerAvf::ScreenCapturerAvf() {}
+
+ScreenCapturerAvf::~ScreenCapturerAvf() {}
+
+int ScreenCapturerAvf::Init(const RECORD_DESKTOP_RECT &rect, const int fps,
+                            cb_desktop_data cb) {
+  if (cb) {
+    _on_data = cb;
+  }
+
+  av_log_set_level(AV_LOG_QUIET);
+
+  pFormatCtx_ = avformat_alloc_context();
+
+  avdevice_register_all();
+
+  // grabbing frame rate
+  av_dict_set(&options_, "framerate", "60", 0);
+  av_dict_set(&options_, "pixel_format", "nv12", 0);
+  // show remote cursor
+  av_dict_set(&options_, "capture_cursor", "1", 0);
+  // Make the grabbed area follow the mouse
+  // av_dict_set(&options_, "follow_mouse", "centered", 0);
+  // Video frame size. The default is to capture the full screen
+  // av_dict_set(&options_, "video_size", "1280x720", 0);
+  ifmt_ = (AVInputFormat *)av_find_input_format("avfoundation");
+  if (!ifmt_) {
+    printf("Couldn't find_input_format\n");
+  }
+
+  // Grab at position 10,20
+  if (avformat_open_input(&pFormatCtx_, "Capture screen 0", ifmt_, &options_) !=
+      0) {
+    printf("Couldn't open input stream.\n");
+    return -1;
+  }
+
+  if (avformat_find_stream_info(pFormatCtx_, NULL) < 0) {
+    printf("Couldn't find stream information.\n");
+    return -1;
+  }
+
+  videoindex_ = -1;
+  for (i_ = 0; i_ < pFormatCtx_->nb_streams; i_++)
+    if (pFormatCtx_->streams[i_]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+      videoindex_ = i_;
+      break;
+    }
+  if (videoindex_ == -1) {
+    printf("Didn't find a video stream.\n");
+    return -1;
+  }
+
+  pCodecParam_ = pFormatCtx_->streams[videoindex_]->codecpar;
+
+  pCodecCtx_ = avcodec_alloc_context3(NULL);
+  avcodec_parameters_to_context(pCodecCtx_, pCodecParam_);
+
+  pCodec_ = const_cast<AVCodec *>(avcodec_find_decoder(pCodecCtx_->codec_id));
+  if (pCodec_ == NULL) {
+    printf("Codec not found.\n");
+    return -1;
+  }
+  if (avcodec_open2(pCodecCtx_, pCodec_, NULL) < 0) {
+    printf("Could not open codec.\n");
+    return -1;
+  }
+
+  const int screen_w = pFormatCtx_->streams[videoindex_]->codecpar->width;
+  const int screen_h = pFormatCtx_->streams[videoindex_]->codecpar->height;
+
+  pFrame_ = av_frame_alloc();
+  pFrameNv12_ = av_frame_alloc();
+
+  pFrame_->width = screen_w;
+  pFrame_->height = screen_h;
+  pFrameNv12_->width = 1280;
+  pFrameNv12_->height = 720;
+
+  packet_ = (AVPacket *)av_malloc(sizeof(AVPacket));
+
+  img_convert_ctx_ = sws_getContext(
+      pFrame_->width, pFrame_->height, pCodecCtx_->pix_fmt, pFrameNv12_->width,
+      pFrameNv12_->height, AV_PIX_FMT_NV12, SWS_BICUBIC, NULL, NULL, NULL);
+
+  return 0;
+}
+
+int ScreenCapturerAvf::Destroy() {
+  if (capture_thread_->joinable()) {
+    capture_thread_->join();
+  }
+
+  return 0;
+}
+
+int ScreenCapturerAvf::Start() {
+  capture_thread_.reset(new std::thread([this]() {
+    while (1) {
+      if (av_read_frame(pFormatCtx_, packet_) >= 0) {
+        if (packet_->stream_index == videoindex_) {
+          avcodec_send_packet(pCodecCtx_, packet_);
+          av_packet_unref(packet_);
+          got_picture_ = avcodec_receive_frame(pCodecCtx_, pFrame_);
+
+          if (!got_picture_) {
+            av_image_fill_arrays(pFrameNv12_->data, pFrameNv12_->linesize,
+                                 nv12_buffer_, AV_PIX_FMT_NV12,
+                                 pFrameNv12_->width, pFrameNv12_->height, 1);
+
+            sws_scale(img_convert_ctx_, pFrame_->data, pFrame_->linesize, 0,
+                      pFrame_->height, pFrameNv12_->data,
+                      pFrameNv12_->linesize);
+
+            _on_data((unsigned char *)nv12_buffer_,
+                     pFrameNv12_->width * pFrameNv12_->height * 3 / 2,
+                     pFrameNv12_->width, pFrameNv12_->height);
+          }
+        }
+      }
+    }
+  }));
+
+  return 0;
+}
+
+int ScreenCapturerAvf::Pause() { return 0; }
+
+int ScreenCapturerAvf::Resume() { return 0; }
+
+int ScreenCapturerAvf::Stop() { return 0; }
+
+void ScreenCapturerAvf::OnFrame() {}
+
+void ScreenCapturerAvf::CleanUp() {}