Following libraries are required to build this code.
clang++ mjpeg_clock_main.cc mongoose.c <link flags for OpenCV and Abseil> \
-o mjpeg_clock
./mjpeg_clock
This serves web interface at http://localhost:8000. Opening the browser at this address shows a simple autogenerated MJPEG video.
| /* | |
| MIT License: | |
| Permission is hereby granted, free of charge, to any person | |
| obtaining a copy of this software and associated documentation | |
| files (the "Software"), to deal in the Software without restriction, | |
| including without limitation the rights to use, copy, modify, | |
| merge, publish, distribute, sublicense, and/or sell copies of | |
| the Software, and to permit persons to whom the Software is | |
| furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be | |
| included in all copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | |
| EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES | |
| OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | |
| NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS | |
| BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN | |
| AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR | |
| IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
| THE SOFTWARE. | |
| Copyright 2018 Punit Soni <[email protected]> | |
| */ | |
| #include <chrono> | |
| #include <fstream> | |
| #include <iostream> | |
| #include <thread> | |
| #include "absl/strings/str_format.h" | |
| #include "opencv2/opencv.hpp" | |
| #include "mongoose.h" | |
| using std::cout; | |
| using std::endl; | |
| void GenerateFrame(cv::Mat *img, const std::string &text, int frameid, | |
| int timestamp_ms) { | |
| // clear image | |
| *img = cv::Scalar::all(0); | |
| int baseline = 0; | |
| int thickness = 3; | |
| int fontscale = 6; | |
| auto fontface = cv::HersheyFonts::FONT_HERSHEY_PLAIN; | |
| // Draw text | |
| cv::Size textsize = | |
| cv::getTextSize(text, fontface, fontscale, thickness, &baseline); | |
| cv::Point text_origin((img->cols - textsize.width) / 2, | |
| (img->rows + textsize.height) / 2); | |
| putText(*img, text, text_origin, fontface, fontscale, cv::Scalar::all(255), | |
| thickness, cv::LINE_AA); | |
| // Draw frame id | |
| fontscale = 2; | |
| thickness = 1; | |
| const std::string frameid_text = absl::StrFormat("Frame %6d", frameid); | |
| cv::Size frameid_text_size = | |
| cv::getTextSize(frameid_text, fontface, fontscale, thickness, nullptr); | |
| cv::Point frameid_text_origin(img->cols - frameid_text_size.width - 10, | |
| frameid_text_size.height + 10); | |
| putText(*img, frameid_text, frameid_text_origin, fontface, fontscale, | |
| cv::Scalar::all(255), thickness, cv::LINE_AA); | |
| // Draw timestamp | |
| fontscale = 1; | |
| thickness = 1; | |
| const std::string timestamp_text = absl::StrFormat("%8d ms", timestamp_ms); | |
| cv::Size timestamp_text_size = | |
| cv::getTextSize(timestamp_text, fontface, fontscale, thickness, nullptr); | |
| cv::Point timestamp_text_origin(img->cols - timestamp_text_size.width - 10, | |
| img->rows - 10); | |
| putText(*img, timestamp_text, timestamp_text_origin, fontface, fontscale, | |
| cv::Scalar::all(255), thickness, cv::LINE_AA); | |
| } | |
| void http_handle_root(struct mg_connection *conn, struct http_message *req) { | |
| const std::string res = | |
| "<html><body>" | |
| "<p><h2>Test MJPEG Stream</h2>" | |
| "<img src=\"test_mjpeg\"></p></body></html>"; | |
| mg_send_head(conn, 200, res.size(), "Content-Type: text/html"); | |
| mg_printf(conn, "%.*s", (int)res.size(), res.c_str()); | |
| } | |
| class TestFrameGen { | |
| public: | |
| TestFrameGen() : img(cv::Mat::zeros(480, 640, CV_8UC3)) {} | |
| std::vector<uint8_t> GenerateNextFrame() { | |
| int ms_per_min = 1000 * 60; | |
| int ms_per_sec = 1000; | |
| int time_ms = millis; | |
| int time_min = time_ms / ms_per_min; | |
| time_ms = time_ms % ms_per_min; | |
| int time_sec = time_ms / ms_per_sec; | |
| time_ms = time_ms % ms_per_sec; | |
| const std::string text = | |
| absl::StrFormat("%02d:%02d:%03d", time_min, time_sec, time_ms); | |
| GenerateFrame(&img, text, frameid, millis); | |
| // encode the frame to jpeg | |
| std::vector<uint8_t> buffer; | |
| std::vector<int> params; | |
| params.push_back(cv::IMWRITE_JPEG_QUALITY); | |
| params.push_back(80); | |
| cv::imencode(".jpg", img, buffer, params); | |
| millis += int(1000 / fps); | |
| frameid++; | |
| return buffer; | |
| } | |
| float fps = 30.0; | |
| int millis = 0; | |
| int frameid = 0; | |
| cv::Mat img; | |
| }; | |
| void http_handle_test_mjpeg(struct mg_connection *conn, | |
| struct http_message *req) { | |
| double lastframe_time = mg_time(); | |
| mg_printf(conn, | |
| "HTTP/1.1 200 OK\r\n" | |
| "Cache-Control: no-cache\r\n" | |
| "Cache-Control: private\r\n" | |
| "Content-Type: multipart/x-mixed-replace; " | |
| "boundary=frame_boundary\r\n\r\n"); | |
| TestFrameGen *gen = new TestFrameGen(); | |
| absl::PrintF("sending frame %d\n", gen->frameid); | |
| std::vector<uint8_t> buffer = gen->GenerateNextFrame(); | |
| mg_printf(conn, | |
| "--frame_boundary\r\n" | |
| "Content-Type: image/jpeg\r\n" | |
| "Content-Length: %lu\r\n\r\n", | |
| buffer.size()); | |
| mg_send(conn, (const char *)&buffer[0], buffer.size()); | |
| mg_printf(conn, "\r\n"); | |
| // setup timer | |
| conn->user_data = (void *)gen; | |
| mg_set_timer(conn, lastframe_time + 0.030); // 30 ms | |
| } | |
| static void event_handler(struct mg_connection *conn, int ev, void *p) { | |
| if (ev == MG_EV_HTTP_REQUEST) { | |
| struct http_message *req = (struct http_message *)p; | |
| const std::string request_method(req->method.p, req->method.len); | |
| const std::string request_uri(req->uri.p, req->uri.len); | |
| const std::string request_query(req->query_string.p, req->query_string.len); | |
| const std::string proto(req->proto.p, req->proto.len); | |
| absl::PrintF("--------------------------------\n"); | |
| absl::PrintF("[HTTP Request]\n"); | |
| absl::PrintF("method: %s\n", request_method); | |
| absl::PrintF("uri: %s\n", request_uri); | |
| absl::PrintF("query: %s\n", request_query); | |
| absl::PrintF("--------------------------------\n"); | |
| absl::PrintF("conn=%p, conn->flags=%x\n", conn, conn->flags); | |
| if (request_uri == "/") { | |
| return http_handle_root(conn, req); | |
| } | |
| if (request_uri == "/test_mjpeg") { | |
| return http_handle_test_mjpeg(conn, req); | |
| } | |
| } else if (ev == MG_EV_TIMER) { | |
| double lastframe_time = *(double *)p; | |
| TestFrameGen *gen = (TestFrameGen *)(conn->user_data); | |
| absl::PrintF("sending frame %d\n", gen->frameid); | |
| std::vector<uint8_t> buffer = gen->GenerateNextFrame(); | |
| mg_printf(conn, | |
| "--frame_boundary\r\n" | |
| "Content-Type: image/jpeg\r\n" | |
| "Content-Length: %lu\r\n\r\n", | |
| buffer.size()); | |
| mg_send(conn, (const char *)&buffer[0], buffer.size()); | |
| mg_printf(conn, "\r\n"); | |
| mg_set_timer( | |
| conn, | |
| lastframe_time + 0.033); | |
| } | |
| } | |
| int main(int argc, char **argv) { | |
| cout << "MJPG Streaming server" << endl; | |
| struct mg_mgr mgr; | |
| mg_mgr_init(&mgr, NULL); | |
| struct mg_connection *conn = mg_bind(&mgr, "8000", event_handler); | |
| mg_set_protocol_http_websocket(conn); | |
| cout << "Starting server." << endl; | |
| while (true) { | |
| mg_mgr_poll(&mgr, 1000); | |
| } | |
| mg_mgr_free(&mgr); | |
| return 0; | |
| } |