FFmpeg被声明为已否决的解决方案
参考雷神的最简单的打印Hello World的程序：
#include <stdio.h>
#include <string.h>
extern "C"
{
#include "libavformat/avformat.h"
#include "libavutil/dict.h"
};
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avcodec.lib")
int main()
{
AVFormatContext *pFormatCtx = NULL;
AVCodecContext *pCodecCtx = NULL;
AVCodec *pCodec;
AVDictionaryEntry *dict = NULL;
int iHour, iMinute, iSecond, iTotalSeconds;//HH:MM:SS
int videoIndex, audioIndex;
char *fileName = "bad.mp4";
//char *fileName = "Titanic.ts";
av_register_all();//注册所有组件
if (avformat_open_input(&pFormatCtx, fileName, NULL, NULL) != 0)//打开输入视频文件
{
printf("Couldn't open input stream.\n");
return -1;
}
if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
{
printf("Couldn't find stream information.\n");
return -1;
}
videoIndex = -1;
for (int i = 0; i < pFormatCtx->nb_streams/*视音频流的个数*/; i++)
{
if (pFormatCtx->streams[i]/*视音频流*/->codec->codec_type == AVMEDIA_TYPE_VIDEO)//查找音频
{
videoIndex = i;
break;
}
}
if (videoIndex == -1)
{
printf("Couldn't find a video stream.\n");
return -1;
}
pCodecCtx = pFormatCtx->streams[videoIndex]->codec; //指向AVCodecContext的指针
pCodec = avcodec_find_decoder(pCodecCtx->codec_id); //指向AVCodec的指针.查找解码器
if (pCodec == NULL)
{
printf("Codec not found.\n");
return -1;
}
//打开解码器
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
{
printf("Could not open codec.\n");
return -1;
}
audioIndex = -1;
for (int i = 0; i < pFormatCtx->nb_streams; i++)
{
if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)
{
audioIndex = i;
break;
}
}
if (audioIndex == -1)
{
printf("Couldn't find a audio stream.\n");
return -1;
}
//打印结构体信息
puts("AVFormatContext信息：");
puts("---------------------------------------------");
printf("文件名：%s\n", pFormatCtx->filename);
iTotalSeconds = (int)pFormatCtx->duration/*微秒*/ / 1000000;
iHour = iTotalSeconds / 3600;//小时
iMinute = iTotalSeconds % 3600 / 60;//分钟
iSecond = iTotalSeconds % 60;//秒
printf("持续时间：%02d:%02d:%02d\n", iHour, iMinute, iSecond);
printf("平均混合码率：%d kb/s\n", pFormatCtx->bit_rate / 1000);
printf("视音频个数：%d\n", pFormatCtx->nb_streams);
puts("---------------------------------------------");
puts("AVInputFormat信息:");
puts("---------------------------------------------");
printf("封装格式名称：%s\n", pFormatCtx->iformat->name);
printf("封装格式长名称：%s\n", pFormatCtx->iformat->long_name);
printf("封装格式扩展名：%s\n", pFormatCtx->iformat->extensions);
printf("封装格式ID：%d\n", pFormatCtx->iformat->raw_codec_id);
puts("---------------------------------------------");
puts("AVStream信息:");
puts("---------------------------------------------");
printf("视频流标识符：%d\n", pFormatCtx->streams[videoIndex]->index);
printf("音频流标识符：%d\n", pFormatCtx->streams[audioIndex]->index);
printf("视频流长度：%d微秒\n", pFormatCtx->streams[videoIndex]->duration);
printf("音频流长度：%d微秒\n", pFormatCtx->streams[audioIndex]->duration);
puts("---------------------------------------------");
puts("AVCodecContext信息:");
puts("---------------------------------------------");
printf("视频码率：%d kb/s\n", pCodecCtx->bit_rate / 1000);
printf("视频大小：%d * %d\n", pCodecCtx->width, pCodecCtx->height);
puts("---------------------------------------------");
puts("AVCodec信息:");
puts("---------------------------------------------");
printf("视频编码格式：%s\n", pCodec->name);
printf("视频编码详细格式：%s\n", pCodec->long_name);
puts("---------------------------------------------");
printf("视频时长：%d微秒\n", pFormatCtx->streams[videoIndex]->duration);
printf("音频时长：%d微秒\n", pFormatCtx->streams[audioIndex]->duration);
printf("音频采样率：%d\n", pFormatCtx->streams[audioIndex]->codec->sample_rate);
printf("音频信道数目：%d\n", pFormatCtx->streams[audioIndex]->codec->channels);
puts("AVFormatContext元数据：");
puts("---------------------------------------------");
while (dict = av_dict_get(pFormatCtx->metadata, "", dict, AV_DICT_IGNORE_SUFFIX))
{
printf("[%s] = %s\n", dict->key, dict->value);
}
puts("---------------------------------------------");
puts("AVStream视频元数据：");
puts("---------------------------------------------");
dict = NULL;
while (dict = av_dict_get(pFormatCtx->streams[videoIndex]->metadata, "", dict, AV_DICT_IGNORE_SUFFIX))
{
printf("[%s] = %s\n", dict->key, dict->value);
}
puts("---------------------------------------------");
puts("AVStream音频元数据：");
puts("---------------------------------------------");
dict = NULL;
while (dict = av_dict_get(pFormatCtx->streams[audioIndex]->metadata, "", dict, AV_DICT_IGNORE_SUFFIX))
{
printf("[%s] = %s\n", dict->key, dict->value);
}
puts("---------------------------------------------");
av_dump_format(pFormatCtx, -1, fileName, 0);
printf("\n\n编译信息：\n%s\n\n", avcodec_configuration());
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}
虽然足够的简单，但是还是报了”被声明为已否决”的error
在网上搜索到了解决方案：将VS的SDL检查关闭
这样error被降低为warning C4996
这样的解决方案是很冒险的。根据报错g:\coding\poet\ffmpegstudy\study.cpp(44): warning C4996: 'AVStream::codec': 被声明为已否决
我们定位到所在代码：
if (pFormatCtx->streams[i]/*视音频流*/->codec->codec_type == AVMEDIA_TYPE_VIDEO)//查找音频
{
videoIndex = i;
break;
}#if FF_API_LAVF_AVCTX
/**
* @deprecated use the codecpar struct instead
*/
attribute_deprecated
AVCodecContext *codec;
#endifAVStream的codec成员不再推荐使用，反而要求使用codecpar。
从而我们知道FFmpeg中所谓的“被声明为已否决”就是因为函数或者结构体属性被标示为attribute_deprecated，很有可能在未来的版本中就删除了。
所以我们最好的解决方案就是使用新的被推荐使用的函数、结构体等。
修改版（开启SDL检查也没有error与warning）：
#include <stdio.h>
#include <string.h>
extern "C"
{
#include "libavformat/avformat.h"
#include "libavutil/dict.h"
};
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avcodec.lib")
int main()
{
AVFormatContext *pFormatCtx = NULL;
AVCodecContext *pCodecCtx = NULL;
AVCodec *pCodec;
AVDictionaryEntry *dict = NULL;
int iHour, iMinute, iSecond, iTotalSeconds;//HH:MM:SS
int videoIndex, audioIndex;
char *fileName = "bad.mp4";
//char *fileName = "Titanic.ts";
av_register_all();//注册所有组件
if (avformat_open_input(&pFormatCtx, fileName, NULL, NULL) != 0)//打开输入视频文件
{
printf("Couldn't open input stream.\n");
return -1;
}
if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
{
printf("Couldn't find stream information.\n");
return -1;
}
videoIndex = -1;
for (int i = 0; i < pFormatCtx->nb_streams/*视音频流的个数*/; i++)
{
if (pFormatCtx->streams[i]/*视音频流*/->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)//查找音频
{
videoIndex = i;
break;
}
}
if (videoIndex == -1)
{
printf("Couldn't find a video stream.\n");
return -1;
}
/**
* 不赞成这样使用
* pCodecCtx = pFormatCtx->streams[videoIndex]->codec; //指向AVCodecContext的指针
*/
pCodecCtx = avcodec_alloc_context3(NULL);
if (pCodecCtx == NULL)
{
printf("Could not allocate AVCodecContext\n");
return -1;
}
avcodec_parameters_to_context(pCodecCtx, pFormatCtx->streams[videoIndex]->codecpar);
pCodec = avcodec_find_decoder(pCodecCtx->codec_id); //指向AVCodec的指针.查找解码器
if (pCodec == NULL)
{
printf("Codec not found.\n");
return -1;
}
//打开解码器
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
{
printf("Could not open codec.\n");
return -1;
}
audioIndex = -1;
for (int i = 0; i < pFormatCtx->nb_streams; i++)
{
if (pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
{
audioIndex = i;
break;
}
}
if (audioIndex == -1)
{
printf("Couldn't find a audio stream.\n");
return -1;
}
//打印结构体信息
puts("AVFormatContext信息：");
puts("---------------------------------------------");
printf("文件名：%s\n", pFormatCtx->filename);
iTotalSeconds = (int)pFormatCtx->duration/*微秒*/ / 1000000;
iHour = iTotalSeconds / 3600;//小时
iMinute = iTotalSeconds % 3600 / 60;//分钟
iSecond = iTotalSeconds % 60;//秒
printf("持续时间：%02d:%02d:%02d\n", iHour, iMinute, iSecond);
printf("平均混合码率：%d kb/s\n", pFormatCtx->bit_rate / 1000);
printf("视音频个数：%d\n", pFormatCtx->nb_streams);
puts("---------------------------------------------");
puts("AVInputFormat信息:");
puts("---------------------------------------------");
printf("封装格式名称：%s\n", pFormatCtx->iformat->name);
printf("封装格式长名称：%s\n", pFormatCtx->iformat->long_name);
printf("封装格式扩展名：%s\n", pFormatCtx->iformat->extensions);
printf("封装格式ID：%d\n", pFormatCtx->iformat->raw_codec_id);
puts("---------------------------------------------");
puts("AVStream信息:");
puts("---------------------------------------------");
printf("视频流标识符：%d\n", pFormatCtx->streams[videoIndex]->index);
printf("音频流标识符：%d\n", pFormatCtx->streams[audioIndex]->index);
printf("视频流长度：%d微秒\n", pFormatCtx->streams[videoIndex]->duration);
printf("音频流长度：%d微秒\n", pFormatCtx->streams[audioIndex]->duration);
puts("---------------------------------------------");
puts("AVCodecContext信息:");
puts("---------------------------------------------");
printf("视频码率：%d kb/s\n", pCodecCtx->bit_rate / 1000);
printf("视频大小：%d * %d\n", pCodecCtx->width, pCodecCtx->height);
puts("---------------------------------------------");
puts("AVCodec信息:");
puts("---------------------------------------------");
printf("视频编码格式：%s\n", pCodec->name);
printf("视频编码详细格式：%s\n", pCodec->long_name);
puts("---------------------------------------------");
printf("视频时长：%d微秒\n", pFormatCtx->streams[videoIndex]->duration);
printf("音频时长：%d微秒\n", pFormatCtx->streams[audioIndex]->duration);
printf("音频采样率：%d\n", pFormatCtx->streams[audioIndex]->codecpar->sample_rate);
printf("音频信道数目：%d\n", pFormatCtx->streams[audioIndex]->codecpar->channels);
puts("AVFormatContext元数据：");
puts("---------------------------------------------");
while (dict = av_dict_get(pFormatCtx->metadata, "", dict, AV_DICT_IGNORE_SUFFIX))
{
printf("[%s] = %s\n", dict->key, dict->value);
}
puts("---------------------------------------------");
puts("AVStream视频元数据：");
puts("---------------------------------------------");
dict = NULL;
while (dict = av_dict_get(pFormatCtx->streams[videoIndex]->metadata, "", dict, AV_DICT_IGNORE_SUFFIX))
{
printf("[%s] = %s\n", dict->key, dict->value);
}
puts("---------------------------------------------");
puts("AVStream音频元数据：");
puts("---------------------------------------------");
dict = NULL;
while (dict = av_dict_get(pFormatCtx->streams[audioIndex]->metadata, "", dict, AV_DICT_IGNORE_SUFFIX))
{
printf("[%s] = %s\n", dict->key, dict->value);
}
puts("---------------------------------------------");
av_dump_format(pFormatCtx, -1, fileName, 0);
printf("\n\n编译信息：\n%s\n\n", avcodec_configuration());
avcodec_free_context(&pCodecCtx);
//avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}
参考自：ffplay.c
Keep it simple!
