RK3399平台ffmpeg-VPU硬编码录制USB摄像头视频、H264或MJPEG编码 - 指南
1 前言
在某项目中需要在RK3399平台实现USB摄像头画面的实时预览、视频录制、拍照存储等功能。
先来看需要实现的最终效果。
ffmpeg USB摄像头 H264编码录视频拍照
本项目使用了搭载了RK3399芯片的嵌入式平台，操作系统Debain10，调用ffmpeg-rkmpp库进行H264硬编码。
本项目需要外接一个支持 2592x1944，1080p，720p，480p的USB摄像头。
2 项目内容详细说明
2.0 功能
（1）实时预览；
（2）摄像头分辨率设置，可设置为480p，720p，1080p；
（3）编码格式设置，可按照H264格式编码，或直接存MJPEG；
（4）存储文件格式，可设置为.avi或者.mp4格式；
（5）录制视频时，显示当前录制时间以及“REC”闪烁字样；
（6）拍照功能，拍摄照片分辨率为2592x1944（500万像素）；
（7）通过F3、F4键移动光标，通过 ↑ 按键实现“开始、停止”录视频，通过 → 按键实现“确定”，通过 ← 按键实现“拍照”。
2.1 工程文件夹说明
工程文件夹结构如下：
在cameraModule文件夹内的是视频相关内容，可单独编译成库，在cameravideowidget.cpp中实现代码的调用。
3 代码
3.1 CameraThread类
CameraThread类为视频录制、拍照实现的关键类，其接口如下表所示。
| 成员类型 | 名称 | 描述 |
| 构造函数 | CameraThread() | 初始化 CameraThread 对象 |
| 析构函数 | ~CameraThread() | 释放 CameraThread 对象的资源。 |
| 函数 | int CheckUSBCamera() | 检查 USB 相机是否正常工作。返回值为 0 表示正常，其他值表示错误代码。 |
| void setParamter(int, int, int) | 设置视频参数（分辨率、编码格式、封装格式）。必须在 OpenCamera() 之前调用。 | |
| int OpenCamera() | 开启相机。返回值为 0 表示成功，其他值表示错误代码。 | |
| int CloseCamera() | 关闭相机。返回值为 0 表示成功，其他值表示错误代码。 | |
| int TakePhoto(QString name) | 拍照接口，调用该函数使用相机拍摄一张照片并保存至指定路径。返回值为 0 表示成功，其他值表示错误代码。 | |
| int DeletPhoto() | 删除照片接口，调用该函数删除当前拍摄的照片。返回值为 0 表示成功，其他值表示错误代码。 | |
| int StartTakeVideo(QString name) | 开始视频录制并保存到指定路径。返回值为 0 表示成功，其他值表示错误代码。 | |
| int StopTakeVideo() | 停止当前视频录制操作，并完成所有未完成任务。返回值为 0 表示成功，其他值表示错误代码。 | |
| 信号 | void sendPhoto(QImage img) | 当拍摄照片后发出此信号，传递一个 QImage 类型的图像用于UI绘制。 |
| 信号 | void sendRealTimePhoto(QImage img) | 发送实时图像帧信号，用于传递实时预览图像。 |
| 公有变量 | bool isOpen | 标志相机是否已打开。 |
| 公有变量 | bool isRecording | 标志是否正在录制视频。 |
| 公有变量 | std::unique_ptr impl | 使用 PIMPL 设计模式隐藏实现细节的实现类指针。 |
camerathread.cpp实现如下所示。
#include "camerathread.h"
#include "camerathreadimpl.h"
CameraThread::CameraThread() :
impl(std::make_unique<CameraThreadImpl>
())
{
connect(impl.get(), &CameraThreadImpl::sendPhoto, this, &CameraThread::sendPhoto);
connect(impl.get(), &CameraThreadImpl::sendRealTimePhoto, this, &CameraThread::sendRealTimePhoto);
qDebug()<<
"libcamerathread.so_version_20250731_";
}
CameraThread::~CameraThread()
{
}
int CameraThread::CheckUSBCamera()
{
int ret = 0;
qDebug()<<
"CheckUSBCamera!";
if(isOpen==true)
{
ret = 0;
}
else
{
ret = impl->
CheckUSBCamera();
}
return ret;
}
void CameraThread::setParamter(int resolution, int encodeformat, int containerformat)
{
qDebug()<<
"resolution: "<<resolution<<
" encodeformat: "<<encodeformat<<
"containerformat "<<containerformat;
impl->
setParamter(resolution, encodeformat, containerformat);
}
int CameraThread::OpenCamera()
{
int ret = 0;
qDebug()<<
"Camera Open!";
ret=impl->
OpenCamera();
if(!ret)
{
isOpen = true;
}
qDebug()<<
"OpenCamera isOpen: "<<isOpen;
return ret;
}
int CameraThread::CloseCamera()
{
int ret = 0;
qDebug()<<
"Camera Close!";
qDebug()<<
"CloseCamera isOpen: "<<isOpen;
if(isOpen == true)
{
ret = impl->
CloseCamera();
}
if(!ret)
{
isOpen = false;
}
ret = StopTakeVideo();
return ret;
}
int CameraThread::TakePhoto(QString name)
{
int ret = 0;
ret=impl->
TakePhoto(name);
return ret;
}
int CameraThread::DeletPhoto()
{
int ret = 0;
qDebug()<<
"Delete Photo";
ret=impl->
DeletPhoto();
return ret;
}
int CameraThread::StartTakeVideo(QString name)
{
int ret = 0;
qDebug()<<
"StartTakeVideo: "<<name;
ret=impl->
StartTakeVideo(name);
isRecording = true;
return ret;
}
int CameraThread::StopTakeVideo()
{
int ret = 0;
if(isRecording)
{
ret=impl->
StopTakeVideo();
}
isRecording = false;
return ret;
}3.1 CameraThreadImpl类
CameraThread类中使用CameraThreadImpl类作为内部实现类，可使得CameraThread接口不暴露具体实现方法。
camerathreadimpl.cpp具体实现如下所示。
#include "camerathreadimpl.h"
CameraThreadImpl::CameraThreadImpl()
{
initParam();
/***************************分配缓冲队列**************************************/
video_packet_queue = new AVPacketQueue();
video_packet_queue_output = new AVPacketQueue();
/***************************分配缓冲队列**************************************/
video_frame_queue = new AVFrameQueue();
fmtConvert_queue_output = new AVFrameQueue();
}
CameraThreadImpl::~CameraThreadImpl()
{
delete demux_thread;
delete decode_thread;
delete save_thread;
delete video_packet_queue_output;
delete video_packet_queue;
}
void CameraThreadImpl::initParam()
{
// 读取INI配置文件
QString configFilePath = QCoreApplication::applicationDirPath() + "/config.ini";
QSettings settings(configFilePath, QSettings::IniFormat);
/************************确认配置文件路径以及是否存在配置文件***************/
// qDebug()<<"configFilePath: "<<configFilePath;
// qDebug()<<"File Exists: " << QFile::exists(configFilePath); // 确保文件存在
// qDebug()<<"QSettings file path: " << settings.fileName();
/*********************************************************************/
// 设置默认值
QString defaultCameraUrl;
QString defaultSavePath;
#ifdef Q_OS_WIN
// defaultCameraUrl = "video=Rmoncam FHD 1080P"; // Windows 平台默认相机名称
defaultCameraUrl = "video=USB Video Device";
// Windows 平台默认相机名称
defaultSavePath = "C:\\Users\\chao8\\Desktop\\";
// Windows 默认保存路径
#else
// defaultCameraUrl = "/dev/video10"; // Forlinx 平台默认相机名称
// defaultSavePath = "/home/forlinx/Desktop/"; // Forlinx 默认保存路径
defaultCameraUrl = "/dev/video0";
// Debain11平台默认相机名称
defaultSavePath = "/mnt/ums/data/";
// Debain11 默认保存路径
#endif
double defaultRemainingSpace = 0.8;
int defaultRecordIntervalMinutes = 1000;
QString defaultResolution = "1920x1080";
QString defaultBitrate = "40M";
// 从INI文件读取配置值，如果没有配置则使用默认值
savePath_ = settings.value("Parameters/savePath", defaultSavePath).toString().toStdString();
url_ = settings.value("Parameters/url", defaultCameraUrl).toString().toStdString();
remainingSpace = settings.value("Parameters/remainingStorageSpace", defaultRemainingSpace).toDouble();
recordIntervalMinutes = settings.value("Parameters/recordIntervalMinutes", defaultRecordIntervalMinutes).toInt();
Resolution = settings.value("Parameters/resolution", defaultResolution).toString();
Bitrate = settings.value("Parameters/bitrate", defaultBitrate).toString();
// 设置定时器时间，定时处理视频信息，每隔一段时间自动记录视频
timer = new QTimer(this);
timer->
setInterval(recordIntervalMinutes * 60 * 1000);
connect(timer, &QTimer::timeout, this, &CameraThreadImpl::handleVideoData);
/*****************************打印各参数配置数值*****************************/
// qDebug()<<"savePath_: "<<QString::fromStdString(savePath_);
// qDebug()<<"url_: "<<QString::fromStdString(url_);
// qDebug()<<"remainingSpace: "<<remainingSpace;
// qDebug()<<"Resolution: "<<Resolution;
// qDebug()<<"Bitrate: "<<Bitrate;
// qDebug()<<"recordIntervalMinutes: "<<recordIntervalMinutes;
/**************************************************************************/
}
int CameraThreadImpl::CheckUSBCamera()
{
avdevice_register_all();
std::string url_str = url_;
AVFormatContext *ifmt_ctx = avformat_alloc_context();
char err2str[256] = {
0
};
AVDictionary *options = nullptr;
av_dict_set(&options, "fflags", "nobuffer", 0);
av_dict_set(&options, "probesize", "4096", 0);
av_dict_set(&options, "framerate", "30", 0);
av_dict_set(&options, "video_size", "1920x1080", 0);
av_dict_set(&options, "input_format", "mjpeg", 0);
#ifdef Q_OS_WIN
const AVInputFormat *m_inputFormat = av_find_input_format("dshow");
#else
const AVInputFormat *m_inputFormat = av_find_input_format("v4l2");
#endif
int ret = avformat_open_input(&ifmt_ctx, url_str.c_str(), m_inputFormat, &options);
// qDebug()<<"ret: "<<ret;
if (ret <
0) {
av_strerror(ret, err2str, sizeof(err2str));
qDebug("avformat_open_input failed, ret:%d, err2str:%s", ret, err2str);
return ret;
}
ret = avformat_find_stream_info(ifmt_ctx, nullptr);
if (ret <
0) {
av_strerror(ret, err2str, sizeof(err2str));
qDebug("avformat_find_stream_info failed, ret:%d, err2str:%s", ret, err2str);
avformat_close_input(&ifmt_ctx);
return ret;
}
avformat_close_input(&ifmt_ctx);
qDebug() <<
"USB camera check OK!";
return ret;
}
void CameraThreadImpl::ReleaseQueue()
{
video_packet_queue_output->
release();
video_packet_queue->
release();
video_frame_queue->
release();
fmtConvert_queue_output->
release();
}
void CameraThreadImpl::setParamter(int resolution, int encodeformat, int containerformat)
{
if(resolution==0)
{
Resolution = "1920x1080";
}
else if(resolution==1)
{
Resolution = "1280x720";
}
else if(resolution==2)
{
Resolution = "640x480";
}
if(encodeformat==0)
{
EncodeFormat = "MJPEG";
}
else if(encodeformat==1)
{
EncodeFormat = "H264";
}
if(containerformat==0)
{
VideoContainerFormat = "avi";
}
else if(containerformat==1)
{
VideoContainerFormat = "mp4";
}
}
void CameraThreadImpl::handleVideoData()
{
qDebug()<<
"handleVideoData! ";
demux_thread->start_pts = 0;
save_thread->
Stop();
ReleaseQueue();
save_thread->
Init();
save_thread->
Start();
}
int CameraThreadImpl::OpenCamera()
{
int ret = 0;
/*************************************************************************************/
if(EncodeFormat == "MJPEG")
{
demux_thread = new DemuxThread(video_packet_queue, &url_);
demux_thread->
setResolution(Resolution);
ret = demux_thread->
Start();
if(ret<
0)
{
isCameraValid = false;
}
else
{
isCameraValid = true;
}
/**************************************************************************************/
decode_thread = new DecodeThread(video_packet_queue, video_packet_queue_output, &savePath_);
decode_thread->
setRemainingSpace(remainingSpace);
ret = decode_thread->
Init(demux_thread->
VideoCodecParameters());
ret = decode_thread->
Start();
}
if(EncodeFormat == "H264")
{
demux_thread = new DemuxThread(video_packet_queue, &url_);
demux_thread->
setResolution(Resolution);
ret = demux_thread->
Start();
if(ret<
0)
{
isCameraValid = false;
}
else
{
isCameraValid = true;
}
/**************************************************************************************/
decode_thread = new DecodeThread(video_packet_queue, video_frame_queue, &savePath_);
decode_thread->
setRemainingSpace(remainingSpace);
ret = decode_thread->
Init(demux_thread->
VideoCodecParameters());
ret = decode_thread->
Start();
}
/**************************************************************************************/
connect(decode_thread, &DecodeThread::frameReady, this, &CameraThreadImpl::sendPhoto);
connect(decode_thread, &DecodeThread::realTimeframeReady, this, &CameraThreadImpl::sendRealTimePhoto);
connect(decode_thread, &DecodeThread::frameReady, this, &CameraThreadImpl::CloseCamera);
connect(decode_thread, &DecodeThread::frameReady, this, &CameraThreadImpl::setisTakePhoto);
return ret;
}
int CameraThreadImpl::StartTakeVideo(QString name)
{
int ret = 0;
std::string savefilename = name.toStdString();
ReleaseQueue();
CloseCamera();
OpenCamera();
/**************************************************************************************/
if(isCameraValid)
{
if(EncodeFormat == "MJPEG")
{
save_thread = new SaveThread(video_packet_queue_output, demux_thread->inputStream, &savefilename);
save_thread->
setRemainingSpace(remainingSpace);
save_thread->
setVideoContainerFormat(VideoContainerFormat);
ret = save_thread->
Init();
ReleaseQueue();
demux_thread->start_pts = 0;
decode_thread->isSaveFile = true;
ret = save_thread->
Start();
}
if(EncodeFormat == "H264")
{
/************************************************************************/
fmtConvert_thread = new FormatConvertThread(video_frame_queue, fmtConvert_queue_output);
/*********************************************************************/
encode_thread = new EncodeThread(fmtConvert_queue_output, video_packet_queue_output, demux_thread->inputStream);
encode_thread->
setBitrate(Bitrate);
encode_thread->isFIlter = isFilterOn;
encode_thread->EncodeFormat = "H264";
ret = encode_thread->
Init();
ret = fmtConvert_thread->
Start();
ret = encode_thread->
Start();
save_thread = new SaveThread(video_packet_queue_output, demux_thread->inputStream, &savefilename, encode_thread->encoderContext);
save_thread->
setRemainingSpace(remainingSpace);
save_thread->
setVideoContainerFormat(VideoContainerFormat);
ret = save_thread->
Init();
ReleaseQueue();
demux_thread->start_pts = 0;
decode_thread->isSaveFile = true;
ret = save_thread->
Start();
}
timer->
start();
}
else
{
qDebug()<<
"Camera is not Valid! Cannot video!";
}
return ret;
}
int CameraThreadImpl::StopTakeVideo()
{
if(isCameraValid)
{
if(save_thread!=nullptr)
{
save_thread->
Stop();
save_thread = nullptr;
decode_thread->isSaveFile = false;
if (fmtConvert_thread) fmtConvert_thread->
Stop();
if (encode_thread) encode_thread->
Stop();
ReleaseQueue();
timer->
stop();
qDebug()<<
"StopTakeVideo!";
}
else
{
qDebug()<<
"No save_thread!";
}
}
else
{
qDebug()<<
"Camera is not Valid! Cannot video!";
}
return 0;
}
int CameraThreadImpl::CloseCamera()
{
StopTakeVideo();
if(isCameraValid)
{
decode_thread->
Stop();
demux_thread->
Stop();
isCameraValid = false;
}
ReleaseQueue();
//清空缓冲队列里的东西，每次关闭相机的时候，必须要有！
return 0;
}
void CameraThreadImpl::setisTakePhoto()
{
isTakePhoto = false;
}
int CameraThreadImpl::TakePhoto(QString name)
{
qDebug()<<
"isTakePhoto: "<<isTakePhoto;
if(!isTakePhoto)
{
qDebug()<<
"In TakePhoto!!!!!! ";
isTakePhoto = true;
CloseCamera();
int ret = 0;
demux_thread = new DemuxThread(video_packet_queue, &url_);
demux_thread->
setResolution("2592x1944");
ret = demux_thread->
Start();
if(ret<
0)
{
isCameraValid = false;
}
else
{
isCameraValid = true;
}
/**************************************************************************************/
decode_thread = new DecodeThread(video_packet_queue, video_packet_queue_output, &savePath_);
decode_thread->
setRemainingSpace(remainingSpace);
ret = decode_thread->
Init(demux_thread->
VideoCodecParameters());
ret = decode_thread->
Start();
connect(decode_thread, &DecodeThread::frameReady, this, &CameraThreadImpl::sendPhoto);
connect(decode_thread, &DecodeThread::frameReady, this, &CameraThreadImpl::CloseCamera);
connect(decode_thread, &DecodeThread::frameReady, this, &CameraThreadImpl::setisTakePhoto);
if (decode_thread)
{
decode_thread->
takePhoto(name);
}
else
{
return -1;
}
return ret;
}
else
{
return 0;
}
}
int CameraThreadImpl::DeletPhoto()
{
decode_thread->
DeletPhoto();
return 0;
}4 资源下载
本案例中涉及到的所有代码请到此处下载 https://download.csdn.net/download/wang_chao118/91923444。
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