WebRTC视频流渲染中插入图片帧

WebRTC视频流渲染中插入自己的图片帧渲染

WebRTC revision 8146

2015年初,戴维营里上了WebRTC框架进行音视频通话项目,由于一个无聊的主意,想要在WebRTC视频聊天的过程中,在本地视频画面添加一个水印图片的渲染,但是希望不要改动代码太多,最后还是没有实现视频帧和图片的融合渲染,只测试了把一个写死的图片文件数据当成一帧数据渲染出来.这里为这个无聊的行为做个简单的记录:

把一个JPEG图片用

jpeg2yuv

命令处理转成yuv格式,然后把yuv格式的二进制转为一个C语言头文件,放到下面这个路径

#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

中的视频帧渲染函数为这样:

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,插入渲染自己的图片帧
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;
}

修改的文件的变化用svn diff的结果如下:

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;
}

然后重新编译项目,生成框架即可在视频通话建立之后每隔30s显示一帧自定义图3s.

文／戴维营教育（简书作者）

原文链接：http://www.jianshu.com/p/c126c4831e8b

著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。