1 /*
2  * Copyright (C) 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "host/frontend/webrtc/display_handler.h"
18 
19 #include <chrono>
20 
21 #include <libyuv.h>
22 
23 namespace cuttlefish {
DisplayHandler(std::shared_ptr<webrtc_streaming::VideoSink> display_sink,ScreenConnector * screen_connector)24 DisplayHandler::DisplayHandler(
25     std::shared_ptr<webrtc_streaming::VideoSink> display_sink,
26     ScreenConnector* screen_connector)
27     : display_sink_(display_sink), screen_connector_(screen_connector) {}
28 
Loop()29 [[noreturn]] void DisplayHandler::Loop() {
30   std::uint32_t frame_num = 0;
31   for (;;) {
32     auto have_frame = screen_connector_->OnFrameAfter(
33         frame_num, [&frame_num, this](std::uint32_t fn, std::uint8_t* frame) {
34           frame_num = fn;
35           std::shared_ptr<CvdVideoFrameBuffer> buffer(
36               new CvdVideoFrameBuffer(screen_connector_->ScreenWidth(),
37                                       screen_connector_->ScreenHeight()));
38           libyuv::ABGRToI420(frame, screen_connector_->ScreenStride(),
39                              buffer->DataY(), buffer->StrideY(),
40                              buffer->DataU(), buffer->StrideU(),
41                              buffer->DataV(), buffer->StrideV(),
42                              screen_connector_->ScreenWidth(),
43                              screen_connector_->ScreenHeight());
44           {
45             std::lock_guard<std::mutex> lock(last_buffer_mutex_);
46             last_buffer_ =
47                 std::static_pointer_cast<webrtc_streaming::VideoFrameBuffer>(buffer);
48           }
49         });
50     if (have_frame) {
51       SendLastFrame();
52     }
53   }
54 }
55 
SendLastFrame()56 void DisplayHandler::SendLastFrame() {
57   std::shared_ptr<webrtc_streaming::VideoFrameBuffer> buffer;
58   {
59     std::lock_guard<std::mutex> lock(last_buffer_mutex_);
60     buffer = last_buffer_;
61   }
62   if (!buffer) {
63     // If a connection request arrives before the first frame is available don't
64     // send any frame.
65     return;
66   }
67   {
68     // SendLastFrame can be called from multiple threads simultaneously, locking
69     // here avoids injecting frames with the timestamps in the wrong order.
70     std::lock_guard<std::mutex> lock(next_frame_mutex_);
71     int64_t time_stamp =
72         std::chrono::duration_cast<std::chrono::microseconds>(
73             std::chrono::system_clock::now().time_since_epoch())
74             .count();
75     display_sink_->OnFrame(buffer, time_stamp);
76   }
77 }
78 
79 }  // namespace cuttlefish
80