gstreamer播放教程二：字幕

参考：https://blog.youkuaiyun.com/sakulafly/article/list/2

https://gstreamer.freedesktop.org/documentation/tutorials/playback/subtitle-management.html

如何获取字幕、音轨、视频流个数，及其具体信息

如何切换字幕，切换音轨，切换视频流

如何外挂一个字幕

如何设置字幕的字体

下面结合播放教程一，实现了以上功能。

#include "pch.h"

//如何选择字幕
//如何添加字幕
//如何定制字幕的字体

#include<string.h>
#include<stdio.h>
#include <gst/gst.h>

typedef struct _CustomData{
	GstElement *playbin;

	gint n_video;
	gint n_audio;
	gint n_text;

	gint current_video;
	gint current_audio;
	gint current_text;

	GMainLoop *main_loop;
}CustomData;

typedef enum {
	GST_PLAY_FLAG_VIDEO = (1 << 0), //we want video output
	GST_PALY_FLAG_AUDIO = (1 << 1),
	GST_PALY_FLAG_TEXT = (1 << 2)
}GstPlayFlags;

static gboolean handle_message(GstBus *bus, GstMessage *msg, CustomData *data);
static gboolean handle_keyboard(GIOChannel *source, GIOCondition cond, CustomData *data);

int main(int argc, char *argv[]) {
	CustomData data;
	GstBus *bus;
	GstStateChangeReturn ret;
	gint flags;
	GIOChannel *io_stdin;

	gst_init(&argc, &argv);

	data.playbin = gst_element_factory_make("playbin", "playbin");
	if (!data.playbin) {
		g_printerr("could not create playbin\n");
		return -1;
	}
	g_object_set(data.playbin, "uri", "file:///C:/Users/lenovo/Desktop/testVideo/[PGS][Tintin-004][DTS-AC3][5PGS].mkv", NULL);
	//外挂字幕地址
	g_object_set(data.playbin, "suburi", "file:///C:/Users/lenovo/Desktop/testVideo/shenhua_waigua.srt", NULL);
	//设置字幕的字体
	g_object_set(data.playbin, "subtitle-font-desc", "Sans,18"