FFmpeg学习（二）-- ffmpeg 摄像头

《 FFmpeg学习（一） 》
《FFmpeg学习（二）》
《FFmpeg学习（三） 》

工程的ffmpeg的的开发

开发工具和库：VS2013 + ffmpeg-4.0 + SDL2.0.8

Git的学习请看我这篇：《Git上传代码到github上》

码云的工程地址：https：//gitee.com/harray/MyQtFFmpegStudy

摄像头显示：https：//gitee.com/harray/MyQtFFmpegStudy/tree/cammer_computer/

myqtffmpegstudy.cpp

#include "myqtffmpegstudy.h"
#include "mediamsg.h"
#include 

HWND g_hwnd_widget_camera;
MyQtFFmpegStudy::MyQtFFmpegStudy(QWidget *parent)
	: QWidget(parent)
{
	ui.setupUi(this);
	this->setFixedSize(629, 410);
	m_bIsOpen = false;
	getDeviceInfoToList();
	foreach(QVariant qvar, m_qlistCameraInfo)
	{
		QString qstrCamera = qvar.value();
		addCameraToComboBox(qstrCamera);
	}
	connect(ui.btnOpenCamera, &QPushButton::clicked, this, &MyQtFFmpegStudy::SlotOpenCamera);
	connect(ui.btnCloseCamera, &QPushButton::clicked, this, &MyQtFFmpegStudy::SlotCloseCamera);
	connect(ui.comboBox_Camera, SIGNAL(currentIndexChanged(int)), this, SLOT(SlotGetCameraComboBoxText(int)));
	connect(this, &MyQtFFmpegStudy::signal_send_open_camera, MediaMsgIns, &MediaMsg::SlotOpenCamera);
	connect(this, &MyQtFFmpegStudy::signal_send_close_camera, MediaMsgIns, &MediaMsg::SlotCloseCamera);
	g_hwnd_widget_camera = (HWND)ui.widget_show->winId();
}

MyQtFFmpegStudy::~MyQtFFmpegStudy()
{

}

QVariant MyQtFFmpegStudy::getCameraListInfo()
{
	return QVariant::fromValue(m_qlistCameraInfo);
}

void MyQtFFmpegStudy::getDeviceInfoToList()
{
	/// ȡͷϢ
	foreach(const QCameraInfo cameraInfo, QCameraInfo::availableCameras())
	{
		m_qlistCameraInfo.append(QVariant::fromValue(cameraInfo.description()));
	}
}

void MyQtFFmpegStudy::addCameraToComboBox(QString qstrCamera)
{
	ui.comboBox_Camera->addItem(qstrCamera);
}

void MyQtFFmpegStudy::SlotGetCameraComboBoxText(int index)
{
	QString qstrCamera = ui.comboBox_Camera->itemText(index);
	qDebug(qstrCamera.toLocal8Bit().data());
}

void MyQtFFmpegStudy::SlotOpenCamera()
{
	if (m_bIsOpen)
	{
		return;
	}
	VideoAudio videoaudio;
	QString qstrCamera = "video=";
	qstrCamera.append(ui.comboBox_Camera->currentText());
	g_hwnd_widget_camera = (HWND)ui.widget_show->winId();
	videoaudio.qstrCamera = qstrCamera;
	MediaMsgIns->SetVideoAudio(videoaudio);
	MediaMsgIns->SetCamWidgetSize(ui.widget_show->width(), ui.widget_show->height());
	videoaudio.lwinid = (long)ui.widget_show->winId();
	emit signal_send_open_camera();
	m_bIsOpen = true;
}

void MyQtFFmpegStudy::SlotCloseCamera()
{
	m_bIsOpen = false;
	emit signal_send_close_camera();
	QTimer::singleShot(100,this,&MyQtFFmpegStudy::SlotUpdateWnd);
}

void MyQtFFmpegStudy::SlotUpdateWnd()
{
	update();
}

mediamsg.cpp

#include "mediamsg.h"

extern HWND g_hwnd_widget_camera;
//Refresh Event
#define REFRESH_EVENT  (SDL_USEREVENT + 1)
//Break
#define BREAK_EVENT  (SDL_USEREVENT + 2)

bool thread_exit = false;

int RefreshVideo(void *opaque)
{
	thread_exit = false;
	while (!thread_exit)
	{
		SDL_Event event;
		event.type = REFRESH_EVENT;
		SDL_PushEvent(&event);
		SDL_Delay(40);
	}
	thread_exit = false;
	//Break
	SDL_Event event;
	event.type = BREAK_EVENT;
	SDL_PushEvent(&event);
	return 0;
}

MediaMsg * MediaMsg::m_Instance = NULL;
MediaMsg::MediaMsg(QObject *parent)
: QObject(parent)
{
	m_bIsClose = false;
	addToThread();
	InitMedia();
}

MediaMsg::~MediaMsg()
{
	m_pThread->quit();
	m_pThread->wait();
}

void MediaMsg::InitMedia()
{
	av_register_all();
	avformat_network_init();
	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
	{
		char buf_err[1024] = { 0 };
		sprintf(buf_err, "Could not initialize SDL - %s\n", SDL_GetError());
		qDebug(buf_err);
		exit(1);
	}

}

MediaMsg * MediaMsg::Instance()
{
	if (m_Instance == NULL)
	{
		m_Instance = new MediaMsg;
	}
	return m_Instance;
}

void MediaMsg::addToThread()
{
	m_pThread = new QThread;
	this->moveToThread(m_pThread);
	m_pThread->start();
}

void MediaMsg::SetVideoAudio(VideoAudio videoaudio)
{
	m_videoAudioDevice = videoaudio;
}

void MediaMsg::SetCamWidgetSize(int nWidth, int nHeight)
{
	m_nWinCamWidth = nWidth;
	m_nWinCamHeight = nHeight;
}

void MediaMsg::SlotOpenCamera()
{
	AVFormatContext *pFormatCtx;
	int             i, videoindex;
	AVCodecContext  *pCodecCtx;
	AVCodec         *pCodec;
	AVPacket        packet;
	m_bIsClose = false;// 处于打开状态
	qDebug("SlotOpenCamera");
	pFormatCtx = avformat_alloc_context();
	//Register Device  
	avdevice_register_all();
	AVInputFormat *ifmt = av_find_input_format("dshow");
	//窗口
	SDL_Window *sdlScreen = NULL;
	//渲染器
	SDL_Renderer* sdlRenderer = NULL;
	//纹理
	SDL_Texture* sdlTexture = NULL;
	//矩形结构
	SDL_Rect sdlRect;
	SDL_Thread *sdlThread = NULL;
	SDL_Event event;
	uint8_t *out_buffer;
	int             frameFinished;
	//Set own video device's name  
	if (avformat_open_input(&pFormatCtx, m_videoAudioDevice.qstrCamera.toLocal8Bit().data(), ifmt, NULL) != 0)
	{
		qDebug("Couldn't open input stream.");
		return;
	}
	if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
	{
		qDebug("Couldn't find stream information.");
		return;
	}
	videoindex = -1;
	for (i = 0; i < pFormatCtx->nb_streams; i++)
	{
		if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
		{
			videoindex = i;
			break;
		}
	}
	if (videoindex == -1)
	{
		qDebug("Couldn't find a video stream.");
		return;
	}
	pCodecCtx = pFormatCtx->streams[videoindex]->codec;
	pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
	if (pCodec == NULL)
	{
		qDebug("Codec not found.");
		return;
	}
	if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
	{
		qDebug("Could not open codec.");
		return;
	}
	AVFrame *pFrame, *pFrameYUV;
	pFrame = av_frame_alloc();
	pFrameYUV = av_frame_alloc();
	int screen_w = 0, screen_h = 0;
	SDL_Surface *screen;
	screen_w = pCodecCtx->width;
	screen_h = pCodecCtx->height;
	// AV_PIX_FMT_YUV420P（新版本） PIX_FMT_YUV420P（旧版本）
	out_buffer = (uint8_t *)av_malloc(avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));
	avpicture_fill((AVPicture *)pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);
	struct SwsContext *img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
		pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
	// Make a screen to put our video  
	sdlScreen = SDL_CreateWindowFrom(g_hwnd_widget_camera);
	if (!sdlScreen) {
		char buff_err[1024] = { 0 };
		sprintf(buff_err, "SDL: could not create window - exiting:%s", SDL_GetError());
		return;
	}
	sdlRenderer = SDL_CreateRenderer(sdlScreen, -1, 0);
	Uint32 pixformat = 0;
	//IYUV: Y + U + V  (3 planes)  
	//YV12: Y + V + U  (3 planes)  
	pixformat = SDL_PIXELFORMAT_IYUV;
	sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);

	// Read frames and save first five frames to disk  
	while (av_read_frame(pFormatCtx, &packet) >= 0) {
		// Is this a packet from the video stream?  
		if (m_bIsClose)
		{
			// Free the packet that was allocated by av_read_frame  
			av_free_packet(&packet);
			break;
		}
		if (packet.stream_index == videoindex) {
			// Decode video frame  
			int ret = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
			if (ret < 0){
				printf("Decode Error.\n");
				return;
			}
			// Did we get a video frame?  
			if (frameFinished)
			{
				sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);
				SDL_UpdateTexture(sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0]);
				//FIX: If window is resize
				sdlRect.x = 0;
				sdlRect.y = 0;
				sdlRect.w = m_nWinCamWidth;
				sdlRect.h = m_nWinCamHeight;
				SDL_RenderClear(sdlRenderer);
				SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
				SDL_RenderPresent(sdlRenderer);

				av_free_packet(&packet);
				SDL_Delay(20);//延迟一下，防止播放太快  
			}
		}
		else 
		{
			// Free the packet that was allocated by av_read_frame  
			av_free_packet(&packet);
		}

		SDL_PollEvent(&event);
		switch (event.type) {
		case SDL_QUIT:
			thread_exit = true;
			SDL_Quit();
			exit(0);
			break;
		default:
			break;
		}

	}
	avcodec_close(pCodecCtx);
	// Close the video file  
	avformat_close_input(&pFormatCtx);

}

void MediaMsg::SlotCloseCamera()
{
	m_bIsClose = true;// 关闭摄像头
	qDebug("SlotCloseCamera");
}

void MediaMsg::SlotStartRecordVideo()
{

}

void MediaMsg::SlotPauseRecordVideo()
{

}

void MediaMsg::SlotEndRecordVideo()
{

}

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