FFmpeg进阶教程之给视频添加文字水印-编程学习网

前言

和图片水印一样，很多时候为了声明视频的原创性，我们会给视频添加文字水印进行版权保护。添加文字水印和添加图片水印的流程相似，但又略有不同，这里介绍一下如何通过FFmpeg给视频添加文字水印。添加文字水印的流程图如下图所示:

文字水印配置项

在讲文字水印之前先介绍一下文字水印支持的那些配置，方便大家的使用。

项目	介绍
使用格式	drawtext=fontfile=font_f:text=text1…(通过冒号分割配置项,通过=给配置项赋值)
fontfile	用于绘制文本的字体文件的正确路径，强制参数
text	要绘制的文本字符串，必须是UTF-8编码的字符序列
x,y	绘制的位置的起始坐标值
fontcolor	字体颜色名称或0xRRGGBB[AA]格式的颜色，默认为黑色
fontsize	要绘制的文本字体大小，默认值为16
tabsize	用于呈现选项卡的空间大小，默认值为4
line_h,lh	每个文本行的高度
main_h,h,H	输入的高度
main_w,w,W	输入的宽度

常用的配置项主要有这些，如果需要其他的配置可以参考官方文档介绍。

文字水印关键点

中文的支持

和QT一样，FFmpeg绘制文字水印也存在中文乱码的问题。在windows下解决中文乱码主要需要以下几点:

1.将源码文件修改为utf-8编码

2.将编译编码类型修改为utf-8编码对应的配置如下:

#pragma execution_character_set("utf-8")

同时我们还应该确保使用的字体支持中文。

字体路径问题

指定字体文件路径是强制参数，可以使用绝对路径和相对路径

//使用工程相对路径下的字体
fontfile=.//simsun.ttc
//使用D盘绝对路径下的字体,要对斜杠进行转义
fontfile=D\\\\:simun.ttc

定义滤镜实现

文字水印对应的绘制流程图如下图所示:

文字水印滤镜的实现如下:

int InitFilter(AVCodecContext * codecContext)
{
	char args[512];
	int ret = 0;
	//缓存输入和缓存输出
	const AVFilter *buffersrc = avfilter_get_by_name("buffer");
	const AVFilter *buffersink = avfilter_get_by_name("buffersink");

	//创建输入输出参数
	AVFilterInOut *outputs = avfilter_inout_alloc();
	AVFilterInOut *inputs = avfilter_inout_alloc();

	//滤镜的描述
	//使用simhei字体,绘制的字体大小为100,文本内容为"鬼灭之刃",绘制位置为(100,100)
	//绘制的字体颜色为白色
	string  filters_descr = "drawtext=fontfile=.//simsun.ttc:fontsize=100:text=鬼灭之刃:x=100:y=100:fontcolor=0xFFFFFF";
	enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV420P };

	//创建滤镜容器
	filter_graph = avfilter_graph_alloc();
	if (!outputs || !inputs || !filter_graph)
	{
		ret = AVERROR(ENOMEM);
		goto end;
	}

	//初始化数据帧的格式
	sprintf_s(args, sizeof(args),
		"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
		codecContext->width, codecContext->height, codecContext->pix_fmt,
		codecContext->time_base.num, codecContext->time_base.den,
		codecContext->sample_aspect_ratio.num, codecContext->sample_aspect_ratio.den);

	//输入数据缓存
	ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
		args, NULL, filter_graph);

	if (ret < 0) {
		goto end;
	}

	//输出数据缓存
	ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
		NULL, NULL, filter_graph);

	if (ret < 0)
	{
		av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");
		goto end;
	}

	//设置元素样式
	ret = av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,
		AV_PIX_FMT_YUV420P, AV_OPT_SEARCH_CHILDREN);
	if (ret < 0)
	{
		av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format\n");
		goto end;
	}

	//设置滤镜的端点
	outputs->name = av_strdup("in");
	outputs->filter_ctx = buffersrc_ctx;
	outputs->pad_idx = 0;
	outputs->next = NULL;

	inputs->name = av_strdup("out");
	inputs->filter_ctx = buffersink_ctx;
	inputs->pad_idx = 0;
	inputs->next = NULL;

	//初始化滤镜
	if ((ret = avfilter_graph_parse_ptr(filter_graph, filters_descr.c_str(),
		&inputs, &outputs, NULL)) < 0)
		goto end;

	//滤镜生效
	if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)
		goto end;
end:
	//释放对应的输入输出
	avfilter_inout_free(&inputs);
	avfilter_inout_free(&outputs);
	return ret;
}

项目工程源码

给视频文件添加文字水印的工程源码如下，欢迎参考，如有问题欢迎反馈。

#pragma execution_character_set("utf-8")
#include <string>
#include <iostream>
#include <thread>
#include <memory>
#include <iostream>
#include <fstream>

extern "C"
{
#include <libavcodec/avcodec.h>
#include <libavdevice/avdevice.h>
#include <libavfilter/avfilter.h>
#include <libavformat/avformat.h>
#include <libavformat/avio.h>
#include <libavutil/avutil.h>
#include <libswresample/swresample.h>
#include <libswscale/swscale.h>
#include <libavutil/frame.h>
#include <libavutil/imgutils.h>
#include <libavformat/avformat.h>
#include <libavutil/time.h>
#include <libavfilter/avfilter.h>
#include <libavfilter/buffersink.h>
#include <libavfilter/buffersrc.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>
#include <libavdevice/avdevice.h>
}

using namespace std;

//输入媒体文件的上下文
AVFormatContext * input_format_ctx = nullptr;

//输出媒体文件的上下文
AVFormatContext* output_format_ctx;

//输出视频编码器
AVCodecContext*	ouput_video_encode_ctx = NULL;

//音视频解码器
AVCodecContext *video_decode_ctx = NULL;
AVCodecContext *audio_decode_ctx = NULL;

//视频索引和音频索引
int video_stream_index = -1;
int audio_stream_index = -1;


//输出编码器
static AVCodec *  output_video_codec;

//滤镜容器和缓存
AVFilterGraph * filter_graph = nullptr;
AVFilterContext *buffersink_ctx = nullptr;;
AVFilterContext *buffersrc_ctx = nullptr;;
AVPacket packet;

//起始时间
static int64_t startTime;

int OpenOutput(char *fileName)
{
	//创建输出流,输出flv格式视频
	int ret = 0;
	ret = avformat_alloc_output_context2(&output_format_ctx, NULL, "flv", fileName);
	if (ret < 0)
	{
		return -1;
	}
	
	//打开输出流
	ret = avio_open(&output_format_ctx->pb, fileName, AVIO_FLAG_READ_WRITE);
	if (ret < 0)
	{
		return -2;
	}

	//创建输出流
	for (int index = 0; index < input_format_ctx->nb_streams; index++)
	{
		if (index == video_stream_index)
		{
			AVStream * stream = avformat_new_stream(output_format_ctx, output_video_codec);
			avcodec_parameters_from_context(stream->codecpar, ouput_video_encode_ctx);
			stream->codecpar->codec_tag = 0;
		}
		else if (index == audio_stream_index)
		{
			AVStream * stream = avformat_new_stream(output_format_ctx, NULL);
			stream->codecpar = input_format_ctx->streams[audio_stream_index]->codecpar;
			stream->codecpar->codec_tag = 0;
		}
	}
	//写文件头
	ret = avformat_write_header(output_format_ctx, nullptr);
	if (ret < 0)
	{
		return -3;
	}
	if (ret >= 0)
		cout << "open output stream successfully" << endl;
	return ret;
}

//初始化输出视频的编码器
int InitEncoderCodec(int iWidth, int iHeight)
{
	output_video_codec = avcodec_find_encoder(AV_CODEC_ID_H264);
	if (NULL == output_video_codec)
	{
		return  -1;
	}
	//指定编码器的参数
	ouput_video_encode_ctx = avcodec_alloc_context3(output_video_codec);
	ouput_video_encode_ctx->time_base = input_format_ctx->streams[video_stream_index]->time_base;
	ouput_video_encode_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
	ouput_video_encode_ctx->sample_fmt = AV_SAMPLE_FMT_S16;
	ouput_video_encode_ctx->width = iWidth;
	ouput_video_encode_ctx->height = iHeight;
	ouput_video_encode_ctx->bit_rate = input_format_ctx->streams[video_stream_index]->codecpar->bit_rate;
	ouput_video_encode_ctx->pix_fmt = (AVPixelFormat)*output_video_codec->pix_fmts;
	ouput_video_encode_ctx->profile = FF_PROFILE_H264_MAIN;
	ouput_video_encode_ctx->level = 41;
	ouput_video_encode_ctx->thread_count = 8;
	return 0;
}


int InitFilter(AVCodecContext * codecContext)
{
	char args[512];
	int ret = 0;
	//缓存输入和缓存输出
	const AVFilter *buffersrc = avfilter_get_by_name("buffer");
	const AVFilter *buffersink = avfilter_get_by_name("buffersink");

	//创建输入输出参数
	AVFilterInOut *outputs = avfilter_inout_alloc();
	AVFilterInOut *inputs = avfilter_inout_alloc();

	//滤镜的描述
	//使用simhei字体,绘制的字体大小为100,文本内容为"鬼灭之刃",绘制位置为(100,100)
	//绘制的字体颜色为白色
	string  filters_descr = "drawtext=fontfile=.//simsun.ttc:fontsize=100:text=鬼灭之刃:x=100:y=100:fontcolor=0xFFFFFF";
	enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV420P };

	//创建滤镜容器
	filter_graph = avfilter_graph_alloc();
	if (!outputs || !inputs || !filter_graph)
	{
		ret = AVERROR(ENOMEM);
		goto end;
	}

	//初始化数据帧的格式
	sprintf_s(args, sizeof(args),
		"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
		codecContext->width, codecContext->height, codecContext->pix_fmt,
		codecContext->time_base.num, codecContext->time_base.den,
		codecContext->sample_aspect_ratio.num, codecContext->sample_aspect_ratio.den);

	//输入数据缓存
	ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
		args, NULL, filter_graph);

	if (ret < 0) {
		goto end;
	}

	//输出数据缓存
	ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
		NULL, NULL, filter_graph);

	if (ret < 0)
	{
		av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");
		goto end;
	}

	//设置元素样式
	ret = av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,
		AV_PIX_FMT_YUV420P, AV_OPT_SEARCH_CHILDREN);
	if (ret < 0)
	{
		av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format\n");
		goto end;
	}

	//设置滤镜的端点
	outputs->name = av_strdup("in");
	outputs->filter_ctx = buffersrc_ctx;
	outputs->pad_idx = 0;
	outputs->next = NULL;

	inputs->name = av_strdup("out");
	inputs->filter_ctx = buffersink_ctx;
	inputs->pad_idx = 0;
	inputs->next = NULL;

	//初始化滤镜
	if ((ret = avfilter_graph_parse_ptr(filter_graph, filters_descr.c_str(),
		&inputs, &outputs, NULL)) < 0)
		goto end;

	//滤镜生效
	if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)
		goto end;
end:
	//释放对应的输入输出
	avfilter_inout_free(&inputs);
	avfilter_inout_free(&outputs);
	return ret;
}

//将加水印之后的图像帧输出到文件中
static int output_frame(AVFrame *frame, AVRational time_base)
{
	int code;
	AVPacket packet = { 0 };
	av_init_packet(&packet);

	int ret = avcodec_send_frame(ouput_video_encode_ctx, frame);
	if (ret < 0) 
	{
		printf("Error sending a frame for encoding\n");
		return -1;
	}
	while (ret >= 0)
	{
		ret = avcodec_receive_packet(ouput_video_encode_ctx, &packet);
		if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
		{
			return (ret == AVERROR(EAGAIN)) ? 0 : 1;
		}
		else if (ret < 0) {
			printf("Error during encoding\n");
			exit(1);
		}

		AVRational avTimeBaseQ = { 1, AV_TIME_BASE };
		int64_t ptsTime = av_rescale_q(frame->pts, input_format_ctx->streams[video_stream_index]->time_base, avTimeBaseQ);
		int64_t nowTime = av_gettime() - startTime;

		if ((ptsTime > nowTime))
		{
			int64_t sleepTime = ptsTime - nowTime;
			av_usleep((sleepTime));
		}
		else
		{
			printf("not sleeping\n");
		}

		packet.pts = av_rescale_q_rnd(packet.pts, time_base, output_format_ctx->streams[video_stream_index]->time_base, (AVRounding)(AV_ROUND_INF | AV_ROUND_PASS_MINMAX));
		packet.dts = av_rescale_q_rnd(packet.dts, time_base, output_format_ctx->streams[video_stream_index]->time_base, (AVRounding)(AV_ROUND_INF | AV_ROUND_PASS_MINMAX));
		packet.stream_index = video_stream_index;
		code = av_interleaved_write_frame(output_format_ctx, &packet);
		av_packet_unref(&packet);

		if (code < 0)
		{
			av_log(NULL, AV_LOG_ERROR, "[ERROR] Writing Live Stream Interleaved Frame");
		}

		if (ret < 0) {
			exit(1);
		}
		av_packet_unref(&packet);
	}
}


int main(int argc, char* argv[])
{
	if (argc != 3)
	{
		printf("usage:%1 input filepath %2 outputfilepath");
		return -1;
	}

	//输入文件地址、输出文件地址
	string fileInput = std::string(argv[1]);
	string fileOutput = std::string(argv[2]);

	//初始化各种配置
	avformat_network_init();
	av_log_set_level(AV_LOG_ERROR);

	//打开输入文件
	int ret = avformat_open_input(&input_format_ctx, fileInput.c_str(), NULL, NULL);
	if (ret < 0)
	{
		return  ret;
	}
	ret = avformat_find_stream_info(input_format_ctx, NULL);
	if (ret < 0)
	{
		return ret;
	}

	//查找音视频流的索引
	for (int index = 0; index < input_format_ctx->nb_streams; ++index)
	{
		if (index == AVMEDIA_TYPE_AUDIO)
		{
			audio_stream_index = index;
		}
		else if (index == AVMEDIA_TYPE_VIDEO)
		{
			video_stream_index = index;
		}
	}

	//打开视频解码器
	const AVCodec* codec = avcodec_find_decoder(input_format_ctx->streams[video_stream_index]->codecpar->codec_id);
	if (!codec)
	{
		return -1;
	}
	video_decode_ctx = avcodec_alloc_context3(codec);
	if (!video_decode_ctx)
	{
		fprintf(stderr, "Could not allocate video codec context\n");
		return -2;
	}
	avcodec_parameters_to_context(video_decode_ctx, input_format_ctx->streams[video_stream_index]->codecpar);
	if (codec->capabilities & AV_CODEC_CAP_TRUNCATED)
		video_decode_ctx->flags |= AV_CODEC_FLAG_TRUNCATED;

	ret = avcodec_open2(video_decode_ctx, codec, NULL);
	if (ret < 0)
	{
		av_free(video_decode_ctx);
		return -3;
	}

	//初始化视频编码器
	ret = InitEncoderCodec(video_decode_ctx->width, video_decode_ctx->height);
	if (ret < 0)
	{
		return 0;
	}

	//初始化滤镜
	ret = InitFilter(ouput_video_encode_ctx);

	//打开编码器
	ret = avcodec_open2(ouput_video_encode_ctx, output_video_codec, NULL);
	if (ret < 0)
	{
		return  ret;
	}

	//初始化输出
	if (OpenOutput((char *)fileOutput.c_str()) < 0)
	{
		cout << "Open file Output failed!" << endl;
		this_thread::sleep_for(chrono::seconds(10));
		return 0;
	}

	AVFrame* pSrcFrame = av_frame_alloc();
	AVFrame*  filterFrame = av_frame_alloc();

	av_init_packet(&packet);
	startTime = av_gettime();

	while (true)
	{
		int ret = av_read_frame(input_format_ctx, &packet);
		if (ret < 0)
		{
			break;
		}
		//视频帧通过滤镜处理之后编码输出
		if (packet.stream_index == video_stream_index)
		{
			int ret = avcodec_send_packet(video_decode_ctx, &packet);
			if (ret < 0)
			{
				break;
			}
			while (ret >= 0) 
			{
				ret = avcodec_receive_frame(video_decode_ctx, pSrcFrame);
				if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
				{
					break;
				}
				else if (ret < 0)
				{
					goto End;
				}
				pSrcFrame->pts = pSrcFrame->best_effort_timestamp;

				//添加到滤镜中
				if (av_buffersrc_add_frame_flags(buffersrc_ctx, pSrcFrame, AV_BUFFERSRC_FLAG_KEEP_REF) < 0)
				{
					break;
				}
				while (1)
				{
					//获取滤镜输出
					int ret = av_buffersink_get_frame(buffersink_ctx, filterFrame);
					if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
					{
						break;
					}
					else if (ret < 0)
					{
						goto End;
					}
					//编码之后输出
					output_frame(filterFrame, buffersink_ctx->inputs[0]->time_base);
					av_frame_unref(filterFrame);
				}
				av_frame_unref(pSrcFrame);
			}
				
		}
		else if (packet.stream_index == audio_stream_index)
		{
			packet.pts = av_rescale_q_rnd(packet.pts, input_format_ctx->streams[audio_stream_index]->time_base, output_format_ctx->streams[audio_stream_index]->time_base, (AVRounding)(AV_ROUND_INF | AV_ROUND_PASS_MINMAX));
			packet.dts = av_rescale_q_rnd(packet.dts, input_format_ctx->streams[audio_stream_index]->time_base, output_format_ctx->streams[audio_stream_index]->time_base, (AVRounding)(AV_ROUND_INF | AV_ROUND_PASS_MINMAX));
			packet.stream_index = audio_stream_index;
			av_interleaved_write_frame(output_format_ctx, &packet);
		}
		av_packet_unref(&packet);
	}
	av_write_trailer(output_format_ctx);

End:
    //结束的时候清理资源
	avfilter_graph_free(&filter_graph);
	if (input_format_ctx != NULL)
	{
		avformat_close_input(&input_format_ctx);
	}
	avcodec_free_context(&video_decode_ctx);
	avcodec_free_context(&ouput_video_encode_ctx);
	return 0;
}

使用效果

没有添加水印之前的视频截图如下:

添加水印之后的效果图如下图所示:

总结

到此这篇关于FFmpeg进阶教程之给视频添加文字水印的文章就介绍到这了,更多相关FFmpeg视频加文字水印内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！

文章详情

FFmpeg进阶教程之给视频添加文字水印

目录

前言

文字水印配置项

文字水印关键点

定义滤镜实现

项目工程源码

使用效果

总结

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FFmpeg进阶教程之给视频添加文字水印