Qt/C++音视频开发78-获取本地摄像头支持的分辨率/帧率/格式等信息/mjpeg/yuyv/h264
#include "ffmpegdevice.h"
#include "widgethead.h"
QString FFmpegDevice::logType = QString();
QString FFmpegDevice::logFlag = QString();
QStringList FFmpegDevice::logResult = QStringList();
void FFmpegDevice::logCallback(void *ptr, int level, const char *fmt, va_list vl)
{
static QMutex mutex;
QMutexLocker locker(&mutex);
char buf[1024];
vsprintf(buf, fmt, vl);
QString line = buf;
line = line.trimmed();
line.replace("\r", "");
line.replace("\n", "");
line.replace("\"", "");
//qDebug() << TIMEMS << line;
//根据不同的类型解析不同的结果
if (FFmpegDevice::logType == "list_devices") {
FFmpegDevice::log_list_devices(line);
} else if (FFmpegDevice::logType == "list_options") {
FFmpegDevice::log_list_options(line);
}
}
void FFmpegDevice::log_list_devices(const QString &line)
{
#if (FFMPEG_VERSION_MAJOR < 5)
//搞个标记记录接下来是什么结果
if (line.startsWith("DirectShow video devices")) {
FFmpegDevice::logFlag = "video";
} else if (line.startsWith("DirectShow audio devices")) {
FFmpegDevice::logFlag = "audio";
}
//过滤一些不需要的结果
if (line.startsWith("DirectShow") || line.startsWith("Alternative")) {
return;
}
QString result = QString("%1|%2").arg(FFmpegDevice::logFlag).arg(line);
if (!FFmpegDevice::logResult.contains(result)) {
FFmpegDevice::logResult << result;
}
#else
if (line.startsWith("(video") || line.startsWith("(audio")) {
QString type = line.mid(1, line.length());
QString result = QString("%1|%2").arg(type).arg(FFmpegDevice::logFlag);
if (!FFmpegDevice::logResult.contains(result)) {
FFmpegDevice::logResult << result;
}
} else {
FFmpegDevice::logFlag = line;
}
#endif
}
void FFmpegDevice::log_list_options(const QString &line)
{
//搞个标记记录接下来是什么结果
if (line.startsWith("vcodec=") || line.startsWith("pixel_format=")) {
FFmpegDevice::logFlag = line;
}
if (line.startsWith("min s=") && !FFmpegDevice::logFlag.isEmpty()) {
QString result = QString("%1 %2").arg(FFmpegDevice::logFlag).arg(line);
if (!FFmpegDevice::logResult.contains(result)) {
FFmpegDevice::logResult << result;
}
}
//音频设备参数
if (line.contains("ch=")) {
FFmpegDevice::logResult << line;
}
}
void FFmpegDevice::getInputDevices(bool video, QStringList &devices)
{
QStringList names;
//ffmpeg5以上版本可以直接通过函数获取
#if (FFMPEG_VERSION_MAJOR < 5)
QStringList infos = FFmpegDevice::getInputDevices(video ? Device_Video : Device_Audio);
foreach (QString info, infos) {
QString name = info.split("|").last();
if (video && info.startsWith("video")) {
names << name;
} else if (!video && info.startsWith("audio")) {
names << name;
}
}
#else
#ifdef ffmpegdevice
names << FFmpegDevice::getInputDevices(video);
#endif
#endif
//去重复加入到集合
//qDebug() << video << names;
foreach (QString name, names) {
if (!devices.contains(name)) {
devices << name;
}
}
}
//安装工具命令 sudo apt-get install v4l-utils
//获取所有设备 v4l2-ctl --list-devices
//获取所有格式 v4l2-ctl --list-formats -d /dev/video0
//获取所有参数 v4l2-ctl --list-formats-ext -d /dev/video0
//ffmpeg -f dshow -list_devices true -i dummy
QStringList FFmpegDevice::getInputDevices(const char *flag)
{
FFmpegHelper::initLib();
//启用日志回调接收输出信息
av_log_set_callback(FFmpegDevice::logCallback);
//设置相关参数以便记录对应结果
FFmpegDevice::logType = "list_devices";
FFmpegDevice::logFlag.clear();
FFmpegDevice::logResult.clear();
AVFormatContext *ctx = avformat_alloc_context();
AVInputFormatx *fmt = av_find_input_format(flag);
AVDictionary *opts = NULL;
av_dict_set(&opts, "list_devices", "true", 0);
if (strcmp(flag, "vfwcap") == 0) {
avformat_open_input(&ctx, "list", fmt, NULL);
} else if (strcmp(flag, "dshow") == 0) {
avformat_open_input(&ctx, "dummy", fmt, &opts);
} else {
avformat_open_input(&ctx, "", fmt, &opts);
}
//释放资源
av_dict_free(&opts);
avformat_close_input(&ctx);
//重新设置日志回调以便恢复原样
av_log_set_callback(av_log_default_callback);
//取出日志结果
return FFmpegDevice::logResult;
}
QStringList FFmpegDevice::getDeviceOption(const QString &url)
{
const char *flag = (url.startsWith("video=") ? Device_Video : Device_Audio);
QString device = url;
#ifndef Q_OS_WIN
device.replace("video=", "");
device.replace("audio=", "");
#endif
return FFmpegDevice::getDeviceOption(flag, device);
}
//ffmpeg -f dshow -list_options true -i video="Webcam"
QStringList FFmpegDevice::getDeviceOption(const char *flag, const QString &device)
{
FFmpegHelper::initLib();
//启用日志回调接收输出信息
av_log_set_callback(FFmpegDevice::logCallback);
//设置相关参数以便记录对应结果
FFmpegDevice::logType = "list_options";
FFmpegDevice::logFlag.clear();
FFmpegDevice::logResult.clear();
AVFormatContext *ctx = avformat_alloc_context();
AVInputFormatx *fmt = av_find_input_format(flag);
AVDictionary *opts = NULL;
av_dict_set(&opts, "list_options", "true", 0);
avformat_open_input(&ctx, device.toUtf8().constData(), fmt, &opts);
//释放资源
av_dict_free(&opts);
avformat_close_input(&ctx);
//重新设置日志回调以便恢复原样
av_log_set_callback(av_log_default_callback);
//取出日志结果
return FFmpegDevice::logResult;
}
#ifdef ffmpegdevice
QStringList FFmpegDevice::getInputDevices(bool video)
{
FFmpegHelper::initLib();
//测试发现从ffmpeg5开始才能获取到值(以前的版本内部没有实现)
QStringList names;
AVDeviceInfoList *devices = NULL;
AVInputFormatx *fmt = NULL;
fmt = av_find_input_format(video ? Device_Video : Device_Audio);
if (fmt) {
if (avdevice_list_input_sources(fmt, NULL, NULL, &devices) >= 0) {
names = getDeviceNames(devices, video);
}
}
return names;
}
QStringList FFmpegDevice::getDeviceNames(bool input, bool video)
{
FFmpegHelper::initLib();
QStringList names;
AVDeviceInfoList *devices = NULL;
if (input) {
AVInputFormatx *fmt = NULL;
do {
names.clear();
fmt = (video ? av_input_video_device_next(fmt) : av_input_audio_device_next(fmt));
if (fmt) {
if (avdevice_list_input_sources(fmt, NULL, NULL, &devices) >= 0) {
names = getDeviceNames(devices, video);
}
//qDebug() << "input" << fmt->name << names;
}
} while (fmt);
} else {
AVOutputFormatx *fmt = NULL;
do {
names.clear();
fmt = (video ? av_output_video_device_next(fmt) : av_output_audio_device_next(fmt));
if (fmt) {
if (avdevice_list_output_sinks(fmt, NULL, NULL, &devices) >= 0) {
names = getDeviceNames(devices, video);
}
//qDebug() << "output" << fmt->name << names;
}
} while (fmt);
}
return names;
}
QStringList FFmpegDevice::getDeviceNames(AVDeviceInfoList *devices, bool video)
{
QStringList names;
int count = devices->nb_devices;
for (int i = 0; i < count; ++i) {
AVDeviceInfo *device = devices->devices[i];
#if (FFMPEG_VERSION_MAJOR > 4)
if (device->nb_media_types > 0) {
AVMediaType type = *device->media_types;
if ((video && type != AVMEDIA_TYPE_VIDEO) || (!video && type != AVMEDIA_TYPE_AUDIO)) {
continue;
}
}
#endif
//在win上设备名传描述符/linux是设备名
#ifdef Q_OS_WIN
names << device->device_description;
#else
names << device->device_name;
#endif
}
//释放设备列表
avdevice_free_list_devices(&devices);
return names;
}
#endif