WebRTC視頻流渲染中插入自己的圖片幀渲染

WebRTC revision 8146

2015年初,戴維營里上了WebRTC框架進行音視頻通話項目,由于一個無聊的主意,想要在WebRTC視頻聊天的過程中,在本地視頻畫面添加一個水印圖片的渲染,但是希望不要改動代碼太多,最后還是沒有實現視頻幀和圖片的融合渲染,只測試了把一個寫死的圖片文件數據當成一幀數據渲染出來.這里為這個無聊的行為做個簡單的記錄:

把一個JPEG圖片用jpeg2yuv命令處理轉成yuv格式,然后把yuv格式的二進制轉為一個C語言頭文件,放到下面這個路徑

#include "webrtc/modules/video_render/watermark_yuv.h"

然后就只要修改文件:
webrtc/modules/video_render/incoming_video_stream.cc
中的視頻幀渲染函數為這樣:

int32_t IncomingVideoStream::RenderFrame(const uint32_t stream_id,
                                         I420VideoFrame& video_frame) {
  CriticalSectionScoped csS(&stream_critsect_);
  WEBRTC_TRACE(kTraceStream, kTraceVideoRenderer, module_id_,
               "%s for stream %d, render time: %u", __FUNCTION__, stream_id_,
               video_frame.render_time_ms());

  if (!running_) {
    WEBRTC_TRACE(kTraceStream, kTraceVideoRenderer, module_id_,
                 "%s: Not running", __FUNCTION__);
    return -1;
  }

  // Mirroring is not supported if the frame is backed by a texture.
  if (true == mirror_frames_enabled_ && video_frame.native_handle() == NULL) {
    transformed_video_frame_.CreateEmptyFrame(video_frame.width(),
                                              video_frame.height(),
                                              video_frame.stride(kYPlane),
                                              video_frame.stride(kUPlane),
                                              video_frame.stride(kVPlane));
    if (mirroring_.mirror_x_axis) {
      MirrorI420UpDown(&video_frame,
                       &transformed_video_frame_);
      video_frame.SwapFrame(&transformed_video_frame_);
    }
    if (mirroring_.mirror_y_axis) {
      MirrorI420LeftRight(&video_frame,
                          &transformed_video_frame_);
      video_frame.SwapFrame(&transformed_video_frame_);
    }
  }

  // Rate statistics.
  num_frames_since_last_calculation_++;
  int64_t now_ms = TickTime::MillisecondTimestamp();
  if (now_ms >= last_rate_calculation_time_ms_ + KFrameRatePeriodMs) {
    incoming_rate_ =
        static_cast<uint32_t>(1000 * num_frames_since_last_calculation_ /
                              (now_ms - last_rate_calculation_time_ms_));
    num_frames_since_last_calculation_ = 0;
    last_rate_calculation_time_ms_ = now_ms;
  }

  // Insert frame.
  CriticalSectionScoped csB(&buffer_critsect_);
  if (render_buffers_.AddFrame(&video_frame) == 1)
    deliver_buffer_event_.Set();

#if 0
#else
  //修改,插入渲染自己的圖片幀
  const uint32_t renderDelayMs = 50;
  static I420VideoFrame videoFrame0;
  const int width = 480;
  const int height = 640;
  const int half_width = (width + 1) / 2;
  const int stride_y = width;
  const int stride_uv = half_width;
  const uint8_t* buffer_y = watermark_yuv;
  const uint8_t* buffer_u = buffer_y + stride_y * height;
  const uint8_t* buffer_v = buffer_u + stride_uv * ((height + 1) / 2);
  videoFrame0.CreateFrame(width*height,buffer_y,width*height/2, buffer_u,width*height/2, buffer_v, width, height, stride_y,
                     stride_uv, stride_uv);
  videoFrame0.set_render_time_ms(TickTime::MillisecondTimestamp() + renderDelayMs);
  videoFrame0.set_ntp_time_ms(video_frame.ntp_time_ms()+renderDelayMs);
  if (TickTime::MillisecondTimestamp()%30000<=3000&&render_buffers_.AddFrame(&videoFrame0) >= 1) {
    deliver_buffer_event_.Set();
//    fprintf(stderr,"%s:diveinedu logo\n",__FUNCTION__);
  }
#endif
  return 0;
}

修改的文件的變化用svn diff的結果如下:

Index: webrtc/modules/video_render/incoming_video_stream.cc
===================================================================
--- webrtc/modules/video_render/incoming_video_stream.cc    (revision 8146)
+++ webrtc/modules/video_render/incoming_video_stream.cc    (working copy)
@@ -9,6 +9,7 @@
  */
 
 #include "webrtc/modules/video_render/incoming_video_stream.h"
+#include "webrtc/modules/video_render/watermark_yuv.h"
 
 #include <assert.h>
 
@@ -135,6 +136,27 @@
   if (render_buffers_.AddFrame(&video_frame) == 1)
     deliver_buffer_event_.Set();
 
+#if 0
+#else
+  const uint32_t renderDelayMs = 50;
+  static I420VideoFrame videoFrame0;
+  const int width = 480;
+  const int height = 640;
+  const int half_width = (width + 1) / 2;
+  const int stride_y = width;
+  const int stride_uv = half_width;
+  const uint8_t* buffer_y = watermark_yuv;
+  const uint8_t* buffer_u = buffer_y + stride_y * height;
+  const uint8_t* buffer_v = buffer_u + stride_uv * ((height + 1) / 2);
+  videoFrame0.CreateFrame(width*height,buffer_y,width*height/2, buffer_u,width*height/2, buffer_v, width, height, stride_y,
+                     stride_uv, stride_uv);
+  videoFrame0.set_render_time_ms(TickTime::MillisecondTimestamp() + renderDelayMs);
+  videoFrame0.set_ntp_time_ms(video_frame.ntp_time_ms()+renderDelayMs);
+  if (TickTime::MillisecondTimestamp()%30000<=3000&&render_buffers_.AddFrame(&videoFrame0) >= 1) {
+    deliver_buffer_event_.Set();
+//    fprintf(stderr,"%s:diveinedu logo\n",__FUNCTION__);
+  }
+#endif
   return 0;
 }
 

然后重新編譯項目,生成框架即可在視頻通話建立之后每隔30s顯示一幀自定義圖3s.