码迷，mamicode.com
首页 > 其他好文 > 详细

最简单的基于FFmpeg的AVUtil例子 (AVLog, AVOption等)

时间：2015-07-18 17:06:41      阅读：158      评论：0      收藏：0      [点我收藏+]

标签：ffmpeg   avlog   avoption   avdictionary   parseutil   

本文的示例程序记录了FFmpeg的libavutil中几种工具函数的使用方法：
AVLog：日志输出
AVOption (AVClass)：选项设置
AVDictionary：键值对存储
ParseUtil：字符串解析

几个libavutil的工具


AVLog

AVLog是FFmpeg的日志输出工具。在FFmpeg中所有的日志输出不是通过printf()函数而是通过av_log()函数。av_log()会最终调用fprintf(stderr,…)函数将日志内容输出到命令行界面上。但是在一些非命令行程序（MFC程序，Android程序等）中，av_log()调用的fprintf(stderr,…)就无法将日志内容显示出来了。对于这种情况，FFmpeg提供了日志回调函数av_log_set_callback()。该函数可以指定一个自定义的日志输出函数，将日志输出到指定的位置。
下面的自定义函数custom_output()将日志输出到了“simplest_ffmpeg_log.txt”文本中。
void custom_output(void* ptr, int level, const char* fmt,va_list vl){
	FILE *fp = fopen("simplest_ffmpeg_log.txt","a+");   
	if(fp){   
		vfprintf(fp,fmt,vl);
		fflush(fp);
		fclose(fp);
	}   
}

在主函数中调用av_log_set_callback()设置一下该函数就可以了，如下所示。
int main(int argc, char* argv[])
{
	av_log_set_callback(custom_output);
	return 0;
}

此外，日志信息从重到轻分为Panic、Fatal、Error、Warning、Info、Verbose、Debug几个级别。下面的函数输出了几种不同级别的日志。
void test_log(){
	av_register_all();
	AVFormatContext *obj=NULL;
	obj=avformat_alloc_context();
	printf("====================================\n");
	av_log(obj,AV_LOG_PANIC,"Panic: Something went really wrong and we will crash now.\n");
	av_log(obj,AV_LOG_FATAL,"Fatal: Something went wrong and recovery is not possible.\n");
	av_log(obj,AV_LOG_ERROR,"Error: Something went wrong and cannot losslessly be recovered.\n");
	av_log(obj,AV_LOG_WARNING,"Warning: This may or may not lead to problems.\n");
	av_log(obj,AV_LOG_INFO,"Info: Standard information.\n");
	av_log(obj,AV_LOG_VERBOSE,"Verbose: Detailed information.\n");
	av_log(obj,AV_LOG_DEBUG,"Debug: Stuff which is only useful for libav* developers.\n");
	printf("====================================\n");
	avformat_free_context(obj);
}

PS：该部分源代码的解析可以参考文章《FFmpeg源代码简单分析：日志输出系统（av_log()等）》

AVOption (AVClass)

AVOption是FFmpeg的选项设置工具。与AVOption最相关的选项设置函数就是av_opt_set()了。AVOption的核心概念就是“根据字符串操作结构体的属性值”。例如下面代码中“#if”和“#else”之间代码的作用和“#else”和“#endif”之间代码的作用是一样的。
#if TEST_OPT
	av_opt_set(pCodecCtx,"b","400000",0);		//bitrate
	//Another method
	//av_opt_set_int(pCodecCtx,"b",400000,0);	//bitrate

	av_opt_set(pCodecCtx,"time_base","1/25",0);	//time_base
	av_opt_set(pCodecCtx,"bf","5",0);			//max b frame
	av_opt_set(pCodecCtx,"g","25",0);			//gop
	av_opt_set(pCodecCtx,"qmin","10",0);		//qmin/qmax
	av_opt_set(pCodecCtx,"qmax","51",0);
#else
	pCodecCtx->time_base.num = 1;  
	pCodecCtx->time_base.den = 25;  
	pCodecCtx->max_b_frames=5;
	pCodecCtx->bit_rate = 400000;  
	pCodecCtx->gop_size=25;
	pCodecCtx->qmin = 10;
	pCodecCtx->qmax = 51;
#endif

同理，av_opt_get()可以将结构体的属性值以字符串的形式返回回来。例如下面这段代码就验证了av_opt_get()的作用：
		char *val_str=(char *)av_malloc(50);

		//preset: ultrafast, superfast, veryfast, faster, fast, 
		//medium, slow, slower, veryslow, placebo
		av_opt_set(pCodecCtx->priv_data,"preset","slow",0);
		//tune: film, animation, grain, stillimage, psnr, 
		//ssim, fastdecode, zerolatency
		av_opt_set(pCodecCtx->priv_data,"tune","zerolatency",0);
		//profile: baseline, main, high, high10, high422, high444
		av_opt_set(pCodecCtx->priv_data,"profile","main",0);

		//print
		av_opt_get(pCodecCtx->priv_data,"preset",0,(uint8_t **)&val_str);
		printf("preset val: %s\n",val_str);
		av_opt_get(pCodecCtx->priv_data,"tune",0,(uint8_t **)&val_str);
		printf("tune val: %s\n",val_str);
		av_opt_get(pCodecCtx->priv_data,"profile",0,(uint8_t **)&val_str);
		printf("profile val: %s\n",val_str);
		av_free(val_str);

可以通过av_opt_find()获取结构体中任意选项的AVOption结构体。写了一个简单的函数读取该结构体中一些字段的值。
void print_opt(const AVOption *opt_test){

	printf("====================================\n");
	printf("Option Information:\n");
	printf("[name]%s\n",opt_test->name);
	printf("[help]%s\n",opt_test->help);
	printf("[offset]%d\n",opt_test->offset);

	switch(opt_test->type){
	case AV_OPT_TYPE_INT:{
		printf("[type]int\n[default]%d\n",opt_test->default_val.i64);
		break;
						 }
	case AV_OPT_TYPE_INT64:{
		printf("[type]int64\n[default]%lld\n",opt_test->default_val.i64);
		break;
						   }
	case AV_OPT_TYPE_FLOAT:{
		printf("[type]float\n[default]%f\n",opt_test->default_val.dbl);
		break;
						   }
	case AV_OPT_TYPE_STRING:{
		printf("[type]string\n[default]%s\n",opt_test->default_val.str);
		break;
							}
	case AV_OPT_TYPE_RATIONAL:{
		printf("[type]rational\n[default]%d/%d\n",opt_test->default_val.q.num,opt_test->default_val.q.den);
		break;
							  }
	default:{
		printf("[type]others\n");
		break;
			}
	}

	printf("[max val]%f\n",opt_test->max);
	printf("[min val]%f\n",opt_test->min);

	if(opt_test->flags&AV_OPT_FLAG_ENCODING_PARAM){
		printf("Encoding param.\n");
	}
	if(opt_test->flags&AV_OPT_FLAG_DECODING_PARAM){
		printf("Decoding param.\n");
	}
	if(opt_test->flags&AV_OPT_FLAG_AUDIO_PARAM){
		printf("Audio param.\n");
	}
	if(opt_test->flags&AV_OPT_FLAG_VIDEO_PARAM){
		printf("Video param.\n");
	}
	if(opt_test->unit!=NULL)
		printf("Unit belong to:%s\n",opt_test->unit);

	printf("====================================\n");
}

使用下列代码调用上面的函数就可以打印出AVOption结构体每个字段的值。
	const AVOption *opt=NULL;
	opt=av_opt_find(pCodecCtx, "b", NULL, 0, 0);
	print_opt(opt);
	opt=av_opt_find(pCodecCtx, "g", NULL, 0, 0);
	print_opt(opt);
	opt=av_opt_find(pCodecCtx, "time_base", NULL, 0, 0);
	print_opt(opt);

下面代码可以打印出支持AVOption（即包含AVClass）的结构体的所有选项：
void list_obj_opt(void *obj){
	printf("Output some option info about object:\n");
	printf("Object name:%s\n",(*(AVClass **) obj)->class_name);
	printf("=====================================\n");
	printf("Video param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_VIDEO_PARAM,NULL);
	printf("Audio param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_AUDIO_PARAM,NULL);
	printf("Decoding param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_DECODING_PARAM,NULL);
	printf("Encoding param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_ENCODING_PARAM,NULL);
	printf("====================================\n");
}

下面代码调用上面的函数就可以打印出AVFormatContext中的所有选项。
void test_opt(){
	av_register_all();
	AVFormatContext *obj=NULL;
	obj=avformat_alloc_context();
	list_obj_opt(obj);
	avformat_free_context(obj);
}

PS：该部分源代码的解析可以参考文章《FFmpeg源代码简单分析：结构体成员管理系统-AVClass》、《FFmpeg源代码简单分析：结构体成员管理系统-AVOption》。

AVDictionary

AVDictionary是FFmpeg的键值对存储工具，FFmpeg经常使用AVDictionary设置/读取内部参数。下面这段代码记录了AVDictionary的使用方法。
void test_avdictionary(){

	AVDictionary *d = NULL;
	AVDictionaryEntry *t = NULL;

	av_dict_set(&d, "name", "lei xiaohua", 0);
	av_dict_set(&d, "email", "leixiaohua1020@126.com", 0);
	av_dict_set(&d, "school", "cuc", 0);
	av_dict_set(&d, "gender", "man", 0);
	av_dict_set(&d, "website", "http://blog.csdn.net/leixiaohua1020", 0);
	//av_strdup()
	char *k = av_strdup("location");
	char *v = av_strdup("Beijing-China");
	av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
	printf("====================================\n");
	int dict_cnt= av_dict_count(d);
	printf("dict_count:%d\n",dict_cnt);
	printf("dict_element:\n");
	while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
		printf("key:%10s  |  value:%s\n",t->key,t->value);
	}

	t = av_dict_get(d, "email", t, AV_DICT_IGNORE_SUFFIX);
	printf("email is %s\n",t->value);
	printf("====================================\n");
	av_dict_free(&d);
}

ParseUtil

ParseUtil是FFmpeg的字符串解析工具。它的分辨率解析函数av_parse_video_size()可以从形如“1920x1080”的字符串中解析出图像宽为1920，高为1080；它的帧率函数av_parse_video_rate()可以解析出帧率信息；它的时间解析函数则可以从形如“00:01:01”的字符串解析出时间的毫秒数。下面这段代码记录了ParseUtil的使用方法。
void test_parseutil(){
	char input_str[100]={0};
	printf("========= Parse Video Size =========\n");
	int output_w=0;
	int output_h=0;
	strcpy(input_str,"1920x1080");
	av_parse_video_size(&output_w,&output_h,input_str);
	printf("w:%4d | h:%4d\n",output_w,output_h);
	strcpy(input_str,"vga");
	//strcpy(input_str,"hd1080");
	//strcpy(input_str,"ntsc");
	av_parse_video_size(&output_w,&output_h,input_str);
	printf("w:%4d | h:%4d\n",output_w,output_h);
	printf("========= Parse Frame Rate =========\n");
	AVRational output_rational={0,0};
	strcpy(input_str,"15/1");
	av_parse_video_rate(&output_rational,input_str);
	printf("framerate:%d/%d\n",output_rational.num,output_rational.den);
	strcpy(input_str,"pal");
	av_parse_video_rate(&output_rational,input_str);
	printf("framerate:%d/%d\n",output_rational.num,output_rational.den);
	printf("=========== Parse Time =============\n");
	int64_t output_timeval;
	strcpy(input_str,"00:01:01");
	av_parse_time(&output_timeval,input_str,1);
	printf("microseconds:%lld\n",output_timeval);
	printf("====================================\n");
}


源代码


/**
 * 最简单的FFmpeg的AVUtil示例
 * Simplest FFmpeg AVUtil
 *
 * 雷霄骅 Lei Xiaohua
 * leixiaohua1020@126.com
 * 中国传媒大学/数字电视技术
 * Communication University of China / Digital TV Technology
 * http://blog.csdn.net/leixiaohua1020
 *
 * 本程序是FFmpeg中的libavutil的示例，目前包含：
 * AVLog
 * AVOption (AVClass)
 * AVDictionary
 * ParseUtil
 *
 * This software is the example about FFmpeg‘s libavutil.
 * It contains:
 * AVLog
 * AVOption (AVClass)
 * AVDictionary
 * ParseUtil 
 *
 */

#include <stdio.h>

#define __STDC_CONSTANT_MACROS

#ifdef _WIN32
//Windows
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/avutil.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavutil/opt.h>
#include <libavutil/parseutils.h>
#include <libavutil/avutil.h>
#ifdef __cplusplus
};
#endif
#endif


#define TEST_OPT	1
#define TEST_LOG	1
#define TEST_DIC	0


void list_obj_opt(void *obj){
	printf("Output some option info about object:\n");
	printf("Object name:%s\n",(*(AVClass **) obj)->class_name);
	printf("=====================================\n");
	printf("Video param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_VIDEO_PARAM,NULL);
	printf("Audio param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_AUDIO_PARAM,NULL);
	printf("Decoding param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_DECODING_PARAM,NULL);
	printf("Encoding param:\n");
	av_opt_show2(obj,stderr,AV_OPT_FLAG_ENCODING_PARAM,NULL);
	printf("====================================\n");
}

void test_opt(){
	av_register_all();
	AVFormatContext *obj=NULL;
	obj=avformat_alloc_context();
	list_obj_opt(obj);
	avformat_free_context(obj);
}


void test_log(){
	av_register_all();
	AVFormatContext *obj=NULL;
	obj=avformat_alloc_context();
	printf("====================================\n");
	av_log(obj,AV_LOG_PANIC,"Panic: Something went really wrong and we will crash now.\n");
	av_log(obj,AV_LOG_FATAL,"Fatal: Something went wrong and recovery is not possible.\n");
	av_log(obj,AV_LOG_ERROR,"Error: Something went wrong and cannot losslessly be recovered.\n");
	av_log(obj,AV_LOG_WARNING,"Warning: This may or may not lead to problems.\n");
	av_log(obj,AV_LOG_INFO,"Info: Standard information.\n");
	av_log(obj,AV_LOG_VERBOSE,"Verbose: Detailed information.\n");
	av_log(obj,AV_LOG_DEBUG,"Debug: Stuff which is only useful for libav* developers.\n");
	printf("====================================\n");
	avformat_free_context(obj);
}

void print_opt(const AVOption *opt_test){

	printf("====================================\n");
	printf("Option Information:\n");
	printf("[name]%s\n",opt_test->name);
	printf("[help]%s\n",opt_test->help);
	printf("[offset]%d\n",opt_test->offset);

	switch(opt_test->type){
	case AV_OPT_TYPE_INT:{
		printf("[type]int\n[default]%d\n",opt_test->default_val.i64);
		break;
						 }
	case AV_OPT_TYPE_INT64:{
		printf("[type]int64\n[default]%lld\n",opt_test->default_val.i64);
		break;
						   }
	case AV_OPT_TYPE_FLOAT:{
		printf("[type]float\n[default]%f\n",opt_test->default_val.dbl);
		break;
						   }
	case AV_OPT_TYPE_STRING:{
		printf("[type]string\n[default]%s\n",opt_test->default_val.str);
		break;
							}
	case AV_OPT_TYPE_RATIONAL:{
		printf("[type]rational\n[default]%d/%d\n",opt_test->default_val.q.num,opt_test->default_val.q.den);
		break;
							  }
	default:{
		printf("[type]others\n");
		break;
			}
	}

	printf("[max val]%f\n",opt_test->max);
	printf("[min val]%f\n",opt_test->min);

	if(opt_test->flags&AV_OPT_FLAG_ENCODING_PARAM){
		printf("Encoding param.\n");
	}
	if(opt_test->flags&AV_OPT_FLAG_DECODING_PARAM){
		printf("Decoding param.\n");
	}
	if(opt_test->flags&AV_OPT_FLAG_AUDIO_PARAM){
		printf("Audio param.\n");
	}
	if(opt_test->flags&AV_OPT_FLAG_VIDEO_PARAM){
		printf("Video param.\n");
	}
	if(opt_test->unit!=NULL)
		printf("Unit belong to:%s\n",opt_test->unit);

	printf("====================================\n");
}

int flush_encoder(AVFormatContext *fmt_ctx,unsigned int stream_index)
{
	int ret;
	int got_frame;
	AVPacket enc_pkt;
	if (!(fmt_ctx->streams[stream_index]->codec->codec->capabilities &
		CODEC_CAP_DELAY))
		return 0;
	while (1) {
		printf("Flushing stream #%u encoder\n", stream_index);
		enc_pkt.data = NULL;
		enc_pkt.size = 0;
		av_init_packet(&enc_pkt);
		ret = avcodec_encode_video2 (fmt_ctx->streams[stream_index]->codec, &enc_pkt,
			NULL, &got_frame);
		av_frame_free(NULL);
		if (ret < 0)
			break;
		if (!got_frame){
			ret=0;
			break;
		}
		printf("Succeed to encode 1 frame!\n");
		/* mux encoded frame */
		ret = av_write_frame(fmt_ctx, &enc_pkt);
		if (ret < 0)
			break;
	}
	return ret;
}

int encoder(){
	AVFormatContext* pFormatCtx;
	AVStream* video_st;
	AVCodecContext* pCodecCtx;
	AVCodec* pCodec;

	uint8_t* picture_buf;
	AVFrame* picture;
	int size;
	int ret;
	AVPacket pkt;
	int y_size;

	FILE *in_file = fopen("ds_480x272.yuv", "rb");	//Input YUV data
	int in_w=480,in_h=272;                          //Input width and height
	//Frames to encode
	int framenum=100;
	const char* out_file = "ds.h264";	            //Output Filepath
	//const char* out_file = "ds.ts";
	//const char* out_file = "ds.hevc";
	char temp_str[250]={0};

	av_register_all();
	
	avformat_alloc_output_context2(&pFormatCtx, NULL, NULL, out_file);

	if (avio_open(&pFormatCtx->pb,out_file, AVIO_FLAG_READ_WRITE) < 0){
		printf("Failed to open output file!\n");
		return -1;
	}

	pCodec = avcodec_find_encoder(pFormatCtx->oformat->video_codec);
	if (!pCodec) {
		fprintf(stderr, "Codec not found.\n");
		return -1;
	}
	video_st = avformat_new_stream(pFormatCtx, pCodec);
	video_st->time_base.num = 1; 
	video_st->time_base.den = 25;  

	if (video_st==NULL){
		return -1;
	}
	//Param that must set
	pCodecCtx = video_st->codec;
	pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
	pCodecCtx->pix_fmt = PIX_FMT_YUV420P;
	pCodecCtx->width = in_w;  
	pCodecCtx->height = in_h;

#if TEST_OPT
	av_opt_set(pCodecCtx,"b","400000",0);		//bitrate
	//Another method
	//av_opt_set_int(pCodecCtx,"b",400000,0);	//bitrate

	av_opt_set(pCodecCtx,"time_base","1/25",0);	//time_base
	av_opt_set(pCodecCtx,"bf","5",0);			//max b frame
	av_opt_set(pCodecCtx,"g","25",0);			//gop
	av_opt_set(pCodecCtx,"qmin","10",0);		//qmin/qmax
	av_opt_set(pCodecCtx,"qmax","51",0);
#else
	pCodecCtx->time_base.num = 1;  
	pCodecCtx->time_base.den = 25;  
	pCodecCtx->max_b_frames=5;
	pCodecCtx->bit_rate = 400000;  
	pCodecCtx->gop_size=25;
	pCodecCtx->qmin = 10;
	pCodecCtx->qmax = 51;
#endif

#if TEST_OPT
	//list_obj_opt(pFormatCtx);
	//list_obj_opt(pCodecCtx);
	const AVOption *opt=NULL;
	opt=av_opt_find(pCodecCtx, "b", NULL, 0, 0);
	print_opt(opt);
	opt=av_opt_find(pCodecCtx, "g", NULL, 0, 0);
	print_opt(opt);
	opt=av_opt_find(pCodecCtx, "time_base", NULL, 0, 0);
	print_opt(opt);
	//Get Option
	//Get String
	int64_t *val_str=(int64_t *)av_malloc(1*sizeof(int64_t));
	av_opt_get(pCodecCtx,"b",0,(uint8_t **)&val_str);
	printf("get bitrate(str):%s\n",val_str);
	av_free(val_str);
	//Get int
	int64_t val_int=0;
	av_opt_get_int(pCodecCtx,"b",0,&val_int);
	printf("get bitrate(int):%lld\n",val_int);
#endif

	AVDictionary *param = 0;

	//H.264
	if(pCodecCtx->codec_id == AV_CODEC_ID_H264) {
		char *val_str=(char *)av_malloc(50);
		//List it
		//list_obj_opt(pCodecCtx->priv_data);

		//preset: ultrafast, superfast, veryfast, faster, fast, 
		//medium, slow, slower, veryslow, placebo
		av_opt_set(pCodecCtx->priv_data,"preset","slow",0);
		//tune: film, animation, grain, stillimage, psnr, 
		//ssim, fastdecode, zerolatency
		av_opt_set(pCodecCtx->priv_data,"tune","zerolatency",0);
		//profile: baseline, main, high, high10, high422, high444
		av_opt_set(pCodecCtx->priv_data,"profile","main",0);

		//print
		av_opt_get(pCodecCtx->priv_data,"preset",0,(uint8_t **)&val_str);
		printf("preset val: %s\n",val_str);
		av_opt_get(pCodecCtx->priv_data,"tune",0,(uint8_t **)&val_str);
		printf("tune val: %s\n",val_str);
		av_opt_get(pCodecCtx->priv_data,"profile",0,(uint8_t **)&val_str);
		printf("profile val: %s\n",val_str);
		av_free(val_str);

#if TEST_DIC
		av_dict_set(?m, "preset", "slow", 0);  
		av_dict_set(?m, "tune", "zerolatency", 0);  
		//av_dict_set(?m, "profile", "main", 0);  
#endif
	}
	//H.265
	if(pCodecCtx->codec_id == AV_CODEC_ID_H265){
		//list_obj_opt(pCodecCtx->priv_data);

		//preset: ultrafast, superfast, veryfast, faster, fast, 
		//medium, slow, slower, veryslow, placebo
		av_opt_set(pCodecCtx->priv_data, "preset", "ultrafast", 0);
		//tune: psnr, ssim, zerolatency, fastdecode
		av_opt_set(pCodecCtx->priv_data, "tune", "zero-latency", 0);
		//profile: main, main10, mainstillpicture
		av_opt_set(pCodecCtx->priv_data,"profile","main",0);
	}

	if (avcodec_open2(pCodecCtx, pCodec,?m) < 0){
		printf("Failed to open encoder!\n");
		return -1;
	}

	picture = avcodec_alloc_frame();
	size = avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
	picture_buf = (uint8_t *)av_malloc(size);
	avpicture_fill((AVPicture *)picture, picture_buf, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);

	//Write File Header
	avformat_write_header(pFormatCtx,NULL);

	y_size = pCodecCtx->width * pCodecCtx->height;
	av_new_packet(&pkt,y_size*3);

	for (int i=0; i<framenum; i++){
		//Read YUV
		if (fread(picture_buf, 1, y_size*3/2, in_file) < 0){
			printf("Failed to read YUV data!\n");
			return -1;
		}else if(feof(in_file)){
			break;
		}
		picture->data[0] = picture_buf;              // Y
		picture->data[1] = picture_buf+ y_size;      // U 
		picture->data[2] = picture_buf+ y_size*5/4;  // V
		//PTS
		picture->pts=i;
		int got_picture=0;
		//Encode
		ret = avcodec_encode_video2(pCodecCtx, &pkt,picture, &got_picture);
		if(ret < 0){
			printf("Failed to encode!\n");
			return -1;
		}
		if (got_picture==1){
			//printf("Succeed to encode 1 frame!\n");
			pkt.stream_index = video_st->index;
			ret = av_write_frame(pFormatCtx, &pkt);
			av_free_packet(&pkt);
		}
	}
	//Flush Encoder
	ret = flush_encoder(pFormatCtx,0);
	if (ret < 0) {
		printf("Flushing encoder failed\n");
		return -1;
	}

	//Write file trailer
	av_write_trailer(pFormatCtx);

	//Clean
	if (video_st){
		avcodec_close(video_st->codec);
		av_free(picture);
		av_free(picture_buf);
	}
	avio_close(pFormatCtx->pb);
	avformat_free_context(pFormatCtx);

	fclose(in_file);
	return 0;
}

void custom_output(void* ptr, int level, const char* fmt,va_list vl){
	FILE *fp = fopen("simplest_ffmpeg_log.txt","a+");   
	if(fp){   
		vfprintf(fp,fmt,vl);
		fflush(fp);
		fclose(fp);
	}   
}

void test_parseutil(){
	char input_str[100]={0};
	printf("========= Parse Video Size =========\n");
	int output_w=0;
	int output_h=0;
	strcpy(input_str,"1920x1080");
	av_parse_video_size(&output_w,&output_h,input_str);
	printf("w:%4d | h:%4d\n",output_w,output_h);
	strcpy(input_str,"vga");
	//strcpy(input_str,"hd1080");
	//strcpy(input_str,"ntsc");
	av_parse_video_size(&output_w,&output_h,input_str);
	printf("w:%4d | h:%4d\n",output_w,output_h);
	printf("========= Parse Frame Rate =========\n");
	AVRational output_rational={0,0};
	strcpy(input_str,"15/1");
	av_parse_video_rate(&output_rational,input_str);
	printf("framerate:%d/%d\n",output_rational.num,output_rational.den);
	strcpy(input_str,"pal");
	av_parse_video_rate(&output_rational,input_str);
	printf("framerate:%d/%d\n",output_rational.num,output_rational.den);
	printf("=========== Parse Time =============\n");
	int64_t output_timeval;
	strcpy(input_str,"00:01:01");
	av_parse_time(&output_timeval,input_str,1);
	printf("microseconds:%lld\n",output_timeval);
	printf("====================================\n");
}

void test_avdictionary(){

	AVDictionary *d = NULL;
	AVDictionaryEntry *t = NULL;

	av_dict_set(&d, "name", "lei xiaohua", 0);
	av_dict_set(&d, "email", "leixiaohua1020@126.com", 0);
	av_dict_set(&d, "school", "cuc", 0);
	av_dict_set(&d, "gender", "man", 0);
	av_dict_set(&d, "website", "http://blog.csdn.net/leixiaohua1020", 0);
	//av_strdup()
	char *k = av_strdup("location");
	char *v = av_strdup("Beijing-China");
	av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
	printf("====================================\n");
	int dict_cnt= av_dict_count(d);
	printf("dict_count:%d\n",dict_cnt);
	printf("dict_element:\n");
	while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
		printf("key:%10s  |  value:%s\n",t->key,t->value);
	}

	t = av_dict_get(d, "email", t, AV_DICT_IGNORE_SUFFIX);
	printf("email is %s\n",t->value);
	printf("====================================\n");
	av_dict_free(&d);
}

int main(int argc, char* argv[])
{
	int loglevel=av_log_get_level();
	av_log_set_level(AV_LOG_DEBUG);
	//av_log_set_flags(AV_LOG_PRINT_LEVEL);
	//av_log_set_callback(custom_output);
	test_log();

	test_avdictionary();
	test_parseutil();

	//test_opt();

	encoder();

	return 0;
}


运行结果

不同级别的AVLog日志输出后的结果：
 技术分享
结构体中所有AVOption信息输出后的结果：
 技术分享
AVDictionary示例输出的结果：
 技术分享
ParseUtil示例输出的结果：
 技术分享
编码的时候设置回调函数后输出到文本中的日志：
 技术分享

下载


Simplest FFmpeg AVUtil

项目主页
SourceForge：https://sourceforge.net/projects/simplestffmpegavutil/
Github：https://github.com/leixiaohua1020/simplest_ffmpeg_avutil
开源中国：http://git.oschina.net/leixiaohua1020/simplest_ffmpeg_avutil

本程序是FFmpeg中的libavutil的示例，目前包含：
AVLog
AVOption (AVClass)
AVDictionary
ParseUtil



版权声明：本文为博主原创文章，未经博主允许不得转载。

最简单的基于FFmpeg的AVUtil例子 (AVLog, AVOption等)

标签：ffmpeg   avlog   avoption   avdictionary   parseutil   

原文地址：http://blog.csdn.net/leixiaohua1020/article/details/46890739
踩
(0)
赞
(0)
   
举报
评论 一句话评论（0）
登录后才能评论！
分享档案
更多>
2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)
周排行
mamicode.com排行更多图片
更多
友情链接
兰亭集智   国之画   百度统计   站长统计   阿里云   chrome插件   新版天听网
关于我们 - 联系我们 - 留言反馈
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码！