宽高比是指视频图像的宽度和高度之间的比率。
投影屏幕尺寸一般都按照对角线的大小来定义的。根据图像制式不同，屏幕的长宽比例也有几种格式：
传统影视的宽高比是 4：3，宽屏幕电影的宽高比是 1.85：1，高清晰度电视是 16：9，全景式格式电影是 2.35：1。
以下是VLC播放器中使用的宽高比，我们仿照这个宽高比例做一个界面。
使用libvlc_video_set_aspect_ratio设置视频宽高比。
首先做一个菜单：
//.h
QMenu *m_menu = nullptr;
QAction *m_default = nullptr;
QAction *m_16_9 = nullptr;
QAction *m_4_3 = nullptr;
QAction *m_1_1 = nullptr;
QAction *m_16_10 = nullptr;
QAction *m_2_21_1 = nullptr;
QAction *m_2_35_1= nullptr;
QAction *m_2_38_1 = nullptr;
QAction *m_5_4 = nullptr;
QActionGroup *m_group = nullptr;
//.cpp
m_menu = new QMenu(this);
m_default = m_menu->addAction("默认");
m_16_9 = m_menu->addAction("16:9");
m_4_3 = m_menu->addAction("4:3");
m_1_1 = m_menu->addAction("1:1");
m_16_10 = m_menu->addAction("16:10");
m_2_21_1 = m_menu->addAction("2.21:1");
m_2_35_1 = m_menu->addAction("2.35:1");
m_2_38_1 = m_menu->addAction("2.38:1");
m_5_4 = m_menu->addAction("5:4");
m_group = new QActionGroup(this);
m_group->addAction(m_default);
m_group->addAction(m_16_9);
m_group->addAction(m_4_3);
m_group->addAction(m_1_1);
m_group->addAction(m_16_10);
m_group->addAction(m_2_21_1);
m_group->addAction(m_2_35_1);
m_group->addAction(m_2_38_1);
m_group->addAction(m_5_4);
connect(m_group, &QActionGroup::triggered, this, &showWidget::slotActionTriggered);接受槽函数的响应事件：
void showWidget::slotActionTriggered(QAction *action)
{
if (!vlc_mediaPlayer)
return;
if (action == m_default)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer,m_defalutRate);
else if(action == m_16_9)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "16:9");
else if (action == m_4_3)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "4:3");
else if (action == m_1_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "1:1");
else if (action == m_16_10)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "16:10");
else if (action == m_2_21_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "221:100");
else if (action == m_2_35_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "235:100");
else if (action == m_2_38_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "238:100");
else if (action == m_5_4)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "5:4");
}设置鼠标右键弹出菜单：重写鼠标点击事件。
void showWidget::mousePressEvent(QMouseEvent *event)
{
switch (event->button())
{
case Qt::RightButton:
//this->服务器托管网setWindowState(Qt::WindowMinimized);
m_menu->exec(event->globalPos());
break;
default:
QWidget::mousePressEvent(event);
}
}完整代码：
#include "showWidget.h"
#include
#include
#pragma execution_character_set("utf-8")
showWidget::showWidget(QWidget *parent)
: QWidget(parent)
{
ui.setupUi(this);
this->setWindowTitle("视频播放器");
ui.cbxRate->setCurrentIndex(Rate1_0X);
m_lstRate addAction("默认");
m_16_9 = m_menu->addAction("16:9");
m_4_3 = m_menu->addAction("4:3");
m_1_1 = m_menu->addAction("1:1");
m_16_10 = m_menu->addAction("16:10");
m_2_21_1 = m_menu->addAction("2.21:1");
m_2_35_1 = m_menu->addAction("2.35:1");
m_2_38_1 = m_menu->addAction("2.38:1");
m_5_4 = m_menu->addAction("5:4");
m_group = new QActionGroup(this);
m_group->addAction(m_default);
m_group->addAction(m_16_9);
m_group->addAction(m_4_3);
m_group->addAction(m_1_1);
m_group->addAction(m_16_10);
m_group->addAction(m_2_21_1);
m_group->addAction(m_2_35_1);
m_group->addAction(m_2_38_1);
m_group->addAction(m_5_4);
connect(m_group, &QActionGroup::triggered, this, &showWidget::slotActionTriggered);
connect(ui.btnOpen, &QPushButton::clicked, this, &showWidget::slotOpenFile);
connect(ui.btnPlay, &QPushButton::clicked, this, &showWidget::slotPlay);
connect(ui.btnPause, &QPushButton::clicked, this, &showWidget::slotPause);
connect(ui.btnStop, &QPushButton::clicked, this, &showWidget::slotStop);
connect(ui.hSliderVolumn, &QSlider::valueChanged, this, &showWidget::slotValueChanged);
connect(ui.cbxRate,SIGNAL(currentIndexChanged(int)), this, SLOT(slotCurrentIndexChanged(int)));
}
showWidget::~showWidget()服务器托管网
{
libvlc_release(vlc_base); //减少libvlc实例的引用计数，并销毁
}
void showWidget::mousePressEvent(QMouseEvent *event)
{
switch (event->button())
{
case Qt::RightButton:
//this->setWindowState(Qt::WindowMinimized);
m_menu->exec(event->globalPos());
break;
default:
QWidget::mousePressEvent(event);
}
}
void showWidget::slotOpenFile()
{
/*选择文件*/
QString filename = QFileDialog::getOpenFileName(this, "选择打开的文件", "D:/", tr("*.*"));
std::replace(filename.begin(), filename.end(), QChar('/'), QChar(''));
vlc_base = libvlc_new(0, NULL);
vlc_media = libvlc_media_new_path(vlc_base, filename.toUtf8().data());
if (!vlc_media) {
return;
}
// 创建libvlc实例和媒体播放器
vlc_mediaPlayer = libvlc_media_player_new_from_media(vlc_media);
if (!vlc_mediaPlayer) {
return;
}
// 等待元数据加载完成
libvlc_media_parse(vlc_media);
m_defalutRate = libvlc_video_get_aspect_ratio(vlc_mediaPlayer);
// 获取各种元数据
const char *title = libvlc_media_get_meta(vlc_media, libvlc_meta_Title);
const char *artist = libvlc_media_get_meta(vlc_media, libvlc_meta_Artist);
const char *album = libvlc_media_get_meta(vlc_media, libvlc_meta_Album);
const char *url = libvlc_media_get_meta(vlc_media, libvlc_meta_URL);
const char *date = libvlc_media_get_meta(vlc_media, libvlc_meta_Date);
const char *lang = libvlc_media_get_meta(vlc_media, libvlc_meta_Language);
int duration = libvlc_media_get_duration(vlc_media); // 获取时长（单位：毫秒）
qDebug("Title: %s", title ? title : "N/A");
qDebug("Artist: %s", artist ? artist : "N/A");
qDebug("Album: %s", album ? album : "N/A");
qDebug("Duration: %d ms", duration);
qDebug("url: %s", url ? url : "N/A");
qDebug("date: %s", date ? date : "N/A");
qDebug("lang: %s", lang ? lang : "N/A");
libvlc_media_track_t **tracks;
int track_count = libvlc_media_tracks_get(vlc_media,&tracks);
for (unsigned i = 0; i psz_description);
// 这里可以获取到每一个轨道的信息，比如轨道类型 track->i_type
// 可能是 libvlc_track_video, libvlc_track_audio 或者 libvlc_track_text (字幕)
if (track->i_type == libvlc_track_video) {
// 处理视频轨道信息
qDebug("width = %d",track->video->i_width);
qDebug("height = %d", track->video->i_height);
qDebug("rate_num = %d", track->video->i_frame_rate_num);
qDebug("rate_den = %d", track->video->i_frame_rate_den);
}
else if (track->i_type == libvlc_track_audio) {
// 处理音频轨道信息
qDebug("channels = %d", track->audio->i_channels);
qDebug("rate = %d", track->audio->i_rate);
}
else if (track->i_type == libvlc_track_text) {
// 处理字幕轨道信息
}
}
设置 logo 叠加
//libvlc_video_set_logo_int(vlc_mediaPlayer, libvlc_logo_enable, 1);
//libvlc_video_set_logo_string(vlc_mediaPlayer, libvlc_logo_file, "D:2.png");
libvlc_video_set_logo_int(vlc_mediaPlayer, libvlc_logo_position, libvlc_position_top_left);
//libvlc_video_set_logo_int(vlc_mediaPlayer, libvlc_logo_x, 100);
//libvlc_video_set_logo_int(vlc_mediaPlayer, libvlc_logo_y, 0);
//libvlc_video_set_logo_int(vlc_mediaPlayer, libvlc_logo_opacity, 255);
//libvlc_video_set_logo_int(vlc_mediaPlayer, libvlc_logo_repeat, 1);
创建并设置水印文本
//libvlc_video_set_marquee_int(vlc_mediaPlayer, libvlc_marquee_Enable, 1);
//libvlc_video_set_marquee_int(vlc_mediaPlayer, libvlc_marquee_Position, libvlc_position_center);
//libvlc_video_set_marquee_int(vlc_mediaPlayer, libvlc_marquee_Refresh, 2000);
//libvlc_video_set_marquee_int(vlc_mediaPlayer, libvlc_marquee_Size, 24);
//libvlc_video_set_marquee_string(vlc_mediaPlayer, libvlc_marquee_Text, "这里是水印文本");
libvlc_video_set_marquee_int(w->vlc_mediaPlayer, libvlc_marquee_Timeout, 5000);
//libvlc_video_set_marquee_int(vlc_mediaPlayer, libvlc_marquee_Opacity, 255); // 不透明
//获取事件管理器
libvlc_event_manager_t *em = libvlc_media_player_event_manager(vlc_mediaPlayer);
// 注册事件监听器
libvlc_event_attach(em, libvlc_MediaPlayerTimeChanged, vlcEvents, this);
libvlc_event_attach(em, libvlc_MediaPlayerEndReached, vlcEvents, this);
libvlc_event_attach(em, libvlc_MediaPlayerStopped, vlcEvents, this);
libvlc_event_attach(em, libvlc_MediaPlayerPlaying, vlcEvents, this);
libvlc_event_attach(em, libvlc_MediaPlayerPaused, vlcEvents, this);
libvlc_media_player_set_hwnd(vlc_mediaPlayer, (void *)ui.widgetShow->winId());
QTimer::singleShot(1000, this, &showWidget::slotPlay);
}
void showWidget::slotPlay()
{
if (vlc_mediaPlayer)
libvlc_media_player_play(vlc_mediaPlayer);
}
void showWidget::slotPause()
{
if (vlc_mediaPlayer)
libvlc_media_player_pause(vlc_mediaPlayer);
}
void showWidget::slotStop()
{
if (vlc_mediaPlayer)
libvlc_media_player_stop(vlc_mediaPlayer);
}
void showWidget::slotValueChanged(int value)
{
if (vlc_mediaPlayer)
libvlc_audio_set_volume(vlc_mediaPlayer, value);
}
void showWidget::slotCurrentIndexChanged(int index)
{
if (vlc_mediaPlayer)
libvlc_media_player_set_rate(vlc_mediaPlayer, m_lstRate[index]);
}
void showWidget::slotActionTriggered(QAction *action)
{
if (!vlc_mediaPlayer)
return;
if (action == m_default)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer,m_defalutRate);
else if(action == m_16_9)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "16:9");
else if (action == m_4_3)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "4:3");
else if (action == m_1_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "1:1");
else if (action == m_16_10)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "16:10");
else if (action == m_2_21_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "221:100");
else if (action == m_2_35_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "235:100");
else if (action == m_2_38_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "238:100");
else if (action == m_5_4)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "5:4");
}
//事件回调
void showWidget::vlcEvents(const libvlc_event_t *ev, void *param)
{
showWidget *w = (showWidget*)param;
//处理不同的事件
switch (ev->type) {
case libvlc_MediaPlayerTimeChanged:
{
//qDebug() vlc_mediaPlayer);
libvlc_time_t lenSec = len / 1000;
libvlc_time_t totalLen = libvlc_media_player_get_length(w->vlc_mediaPlayer);
libvlc_time_t totalLenSec = totalLen / 1000;
int thh, tmm, tss;
thh = lenSec / 3600;
tmm = (lenSec % 3600) / 60;
tss = (lenSec % 60);
QTime time(thh, tmm, tss);
w->ui.lbCurTime->setText(time.toString("hh:mm:ss"));
thh = totalLenSec / 3600;
tmm = (totalLenSec % 3600) / 60;
tss = (totalLenSec % 60);
QTime TotalTime(thh, tmm, tss);
w->ui.lbTotalTime->setText(TotalTime.toString("hh:mm:ss"));
double pos = (double)lenSec / totalLenSec * 100;
w->ui.horizontalSlider->setValue(pos);
}
break;
case libvlc_MediaPlayerEndReached:
qDebug() 更多参考：
libVLC 事件机制-CSDN博客
libVLC windows开发环境搭建-CSDN博客
https://sunnnnnn666.blog.csdn.net/article/details/136854500
libVLC 元数据-CSDN博客
libVLC 添加图片和文本水印-CSDN博客
服务器托管，北京服务器托管，服务器租用 http://www.fwqtg.net
原文链接：R语言生物群落（生态）数据统计分析与绘图教程 前沿 R 语言作的开源、自由、免费等特点使其广泛应用于生物群落数据统计分析。生物群落数据多样而复杂，涉及众多统计分析方法。 第一R基础及数据准备 一：R和Rstudio简介及入门和作图基础 1）R及Rst…
