最简单的基于FFmpeg的AVfilter的例子-修正版

代码是参考雷神的博客的代码，不过由于ffmpeg版本不同，记录使用中遇到的问题。

 

1.调用avfilter_get_by_name("ffbuffersink")时在新版本的ffmpeg要修改为avfilter_get_by_name("buffersink");否则返回指针为空，调用avfilter_graph_create_filter返回-12，在以前的版本则没有这个问题。

2.调用avfilter_graph_parse_ptr解析字幕水印时返回-22，ffmpeg报错No such filter: 'drawtext'，这是由于编译的时候没有开启FreeType字体引擎库，编译的时候./configure--enable-libfreetype。

 

3.调用avfilter_graph_parse_ptr解析参数时返回-2，drawtext=fontfile=arial.ttf:fontcolor=red:fontsize=30:text='Lei Xiaohua':x=50:y=50里面的arial.ttf是字体文件，要保证字体文件在程序可以找到的目录，冒号在里面是分隔符，路径中不能带冒号。

 

4.编译完ffmpeg后可能没有libpostproc.so这个库，编译的时候加入开启这个库的编译选项--enable-postproc。

 

5.代码

// test_avfilter.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"


/**
* 最简单的基于FFmpeg的AVFilter例子 - 纯净版
* Simplest FFmpeg AVfilter Example - Pure
*
* 雷霄骅 Lei Xiaohua
* [email protected]
* 中国传媒大学/数字电视技术
* Communication University of China / Digital TV Technology
* http://blog.csdn.net/leixiaohua1020
*
* 本程序使用FFmpeg的AVfilter实现了YUV像素数据的滤镜处理功能。
* 可以给YUV数据添加各种特效功能。
* 是最简单的FFmpeg的AVFilter方面的教程。
* 适合FFmpeg的初学者。
*
* This software uses FFmpeg's AVFilter to process YUV raw data.
* It can add many excellent effect to YUV data.
* It's the simplest example based on FFmpeg's AVFilter.
* Suitable for beginner of FFmpeg
*
*/
#include 

#define __STDC_CONSTANT_MACROS

#ifdef _WIN32
#define snprintf _snprintf
//Windows
extern "C"
{
#include "libavfilter/avfiltergraph.h"
#include "libavfilter/buffersink.h"
#include "libavfilter/buffersrc.h"
#include "libavutil/avutil.h"
#include "libavutil/imgutils.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include 
#include 
#include 
#include 
#include 
#ifdef __cplusplus
};
#endif
#endif


#pragma comment(lib,"avcodec.lib")
#pragma comment(lib,"avformat.lib")
#pragma comment(lib,"avutil.lib")
#pragma comment(lib,"avfilter.lib")
#pragma comment(lib,"swscale.lib")
#pragma comment(lib,"SDL2.lib")
#pragma comment(lib,"SDL2main.lib")

int main(int argc, char* argv[])
{
	getchar();

	int ret;
	AVFrame *frame_in;
	AVFrame *frame_out;
	unsigned char *frame_buffer_in;
	unsigned char *frame_buffer_out;

	AVFilterContext *buffersink_ctx;
	AVFilterContext *buffersrc_ctx;
	AVFilterGraph *filter_graph;
	static int video_stream_index = -1;

	//Input YUV
	FILE *fp_in = fopen("trans.yuv", "rb+");
	if (fp_in == NULL) {
		printf("Error open input file.\n");
		return -1;
	}
	int in_width = 1588;
	int in_height = 900;

	//Output YUV
	FILE *fp_out = fopen("output.yuv", "wb+");
	if (fp_out == NULL) {
		printf("Error open output file.\n");
		return -1;
	}

	//const char *filter_descr = "lutyuv='u=128:v=128'";
	//const char *filter_descr = "boxblur";
	//const char *filter_descr = "hflip";
	//const char *filter_descr = "hue='h=60:s=-3'";
	//const char *filter_descr = "crop=2/3*in_w:2/3*in_h";
	//const char *filter_descr = "drawbox=x=100:y=100:w=100:h=100:[email protected]";
	const char *filter_descr = "drawtext=fontfile=arial.ttf:fontcolor=red:fontsize=30:text='Lei Xiaohua':x=50:y=50";

	avfilter_register_all();

	char args[512];
	AVFilter *buffersrc = avfilter_get_by_name("buffer");
	AVFilter *buffersink = avfilter_get_by_name("buffersink");
	AVFilterInOut *outputs = avfilter_inout_alloc();
	AVFilterInOut *inputs = avfilter_inout_alloc();
	enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE };
	AVBufferSinkParams *buffersink_params;

	filter_graph = avfilter_graph_alloc();

	/* buffer video source: the decoded frames from the decoder will be inserted here. */
	snprintf(args, sizeof(args),
		"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
		in_width, in_height, AV_PIX_FMT_YUV420P,
		1, 25, 1, 1);

	ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
		args, NULL, filter_graph);
	if (ret < 0) {
		printf("Cannot create buffer source\n");
		return ret;
	}

	/* buffer video sink: to terminate the filter chain. */
	buffersink_params = av_buffersink_params_alloc();
	buffersink_params->pixel_fmts = pix_fmts;
	ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
		NULL, buffersink_params, filter_graph);
	av_free(buffersink_params);
	if (ret < 0) {
		printf("Cannot create buffer sink\n");
		return ret;
	}

	/* Endpoints for the filter graph. */
	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;

	if ((ret = avfilter_graph_parse_ptr(filter_graph, filter_descr,
		&inputs, &outputs, NULL)) < 0)
		return ret;

	if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)
		return ret;

	frame_in = av_frame_alloc();
	frame_buffer_in = (unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, in_width, in_height, 1));
	av_image_fill_arrays(frame_in->data, frame_in->linesize, frame_buffer_in,
		AV_PIX_FMT_YUV420P, in_width, in_height, 1);

	frame_out = av_frame_alloc();
	frame_buffer_out = (unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, in_width, in_height, 1));
	av_image_fill_arrays(frame_out->data, frame_out->linesize, frame_buffer_out,
		AV_PIX_FMT_YUV420P, in_width, in_height, 1);

	frame_in->width = in_width;
	frame_in->height = in_height;
	frame_in->format = AV_PIX_FMT_YUV420P;

	while (1) {

		if (fread(frame_buffer_in, 1, in_width*in_height * 3 / 2, fp_in) != in_width*in_height * 3 / 2) {
			break;
		}
		//input Y,U,V
		frame_in->data[0] = frame_buffer_in;
		frame_in->data[1] = frame_buffer_in + in_width*in_height;
		frame_in->data[2] = frame_buffer_in + in_width*in_height * 5 / 4;

		if (av_buffersrc_add_frame(buffersrc_ctx, frame_in) < 0) {
			printf("Error while add frame.\n");
			break;
		}

		/* pull filtered pictures from the filtergraph */
		ret = av_buffersink_get_frame(buffersink_ctx, frame_out);
		if (ret < 0)
			break;

		//output Y,U,V
		if (frame_out->format == AV_PIX_FMT_YUV420P) {
			for (int i = 0; iheight; i++) {
				fwrite(frame_out->data[0] + frame_out->linesize[0] * i, 1, frame_out->width, fp_out);
			}
			for (int i = 0; iheight / 2; i++) {
				fwrite(frame_out->data[1] + frame_out->linesize[1] * i, 1, frame_out->width / 2, fp_out);
			}
			for (int i = 0; iheight / 2; i++) {
				fwrite(frame_out->data[2] + frame_out->linesize[2] * i, 1, frame_out->width / 2, fp_out);
			}
		}
		printf("Process 1 frame!\n");
		av_frame_unref(frame_out);
	}

	fclose(fp_in);
	fclose(fp_out);

	av_frame_free(&frame_in);
	av_frame_free(&frame_out);
	avfilter_graph_free(&filter_graph);

	return 0;
}

 

5.效果图

 

6.参考资料

http://blog.csdn.net/leixiaohua1020/article/details/50618190