EasyDarwin云平台之EasyCMS中心管理服务接入ffmpeg实现264转图片快照功能

EasyDarwin一直坚持开源精神，所以我们着手把EasyDarwin中使用的非开源工具替换为开源项目。

我们将EasyCMS中使用的图片保存替换为FFmpeg。（这里说明Windows版）

首先到ffmpeg官网下载编译好的ffmpeg文件

下载页面：https://ffmpeg.zeranoe.com/builds/



Shared包含.dll文件，Dev包含.h和.lib文件

将.h/.lib/.dll引入EasyDarwin工程

.h放入EasyDarwin/Include/FFmpeg下

.lib放入EasyDarwin/Lib/FFmpeg/x86下

.dll放入EasyDarwin/Bin/FFmpeg/x86下

编写DecoderHelper类

DecoderHelper.h

#ifndef _DECODER_HELPER_
#define _DECODER_HELPER_

#define __STDC_CONSTANT_MACROS

extern "C"
{
#include <inttypes.h>
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavutil/avutil.h"
#include "libavutil/imgutils.h"
#include "libswresample/swresample.h"
#include "libswscale/swscale.h"
}

class DecoderHelper
{
public:
DecoderHelper();
~DecoderHelper();

int     SetVideoDecoderParam(int width, int height, int codec, int format);
int     DecodeVideo(char *inBuff, int inBuffSize, void *yuvBuff, int width, int height);

private:
void    releaseVideoDecoder();

private:
AVFormatContext*    _formatContext;
AVCodecContext*     _videoCodecContext;
AVFrame*            _videoFrame420;

struct SwsContext*  _swsContext;
uint8_t*            _buffYUV420;
AVPacket            _videoAVPacket;

uint8_t*            _buffYUV;
AVFrame*            _avframeYUV;

AVFrame*            _avframeSWS;

int                 _codec;
int                 _width;
int                 _height;
int                 _outputFormat;

};

#endif //_DECODER_HELPER_

DecoderHelper.cpp

#include "DecoderHelper.h"

DecoderHelper::DecoderHelper()
: _formatContext(NULL),
_videoCodecContext(NULL),
_videoFrame420(NULL),
_buffYUV420(NULL),
_buffYUV(NULL),
_avframeYUV(NULL),
_avframeSWS(NULL),
_swsContext(NULL),
_codec(0),
_width(0),
_height(0),
_outputFormat(0)
{
//Register all the codec
avcodec_register_all();
//Register all types of decoding
av_register_all();
}

DecoderHelper::~DecoderHelper()
{
releaseVideoDecoder();
}

int DecoderHelper::SetVideoDecoderParam(int width, int height, int codec, int format)
{
if (_width != width || _height != height || _codec != codec)
{
releaseVideoDecoder();
}

if (NULL != _videoCodecContext)
{
return -1;
}

AVCodec *avcodec = avcodec_find_decoder((AVCodecID)codec);
if (NULL == avcodec)
{
return -1;
}

_videoCodecContext = avcodec_alloc_context3(avcodec);
_videoCodecContext->pix_fmt = AV_PIX_FMT_YUV420P;
_videoCodecContext->width   = width;
_videoCodecContext->height  = height;

int ret = avcodec_open2(_videoCodecContext, avcodec, NULL);
if (ret < 0)
{
goto $fail;
}

int numBytes = avpicture_get_size(AV_PIX_FMT_YUV420P, width, height);
_buffYUV420 = (uint8_t *)av_malloc(numBytes * sizeof(uint8_t));
_videoFrame420 = av_frame_alloc();
if (avpicture_fill((AVPicture *)_videoFrame420, _buffYUV420, AV_PIX_FMT_YUV420P,
_width, _height) < 0)
{

}

av_init_packet(&_videoAVPacket);
_width = width;
_height = height;
_codec = codec;
_outputFormat = format;

return 0;

$fail:
{
return -1;
}

}

int DecoderHelper::DecodeVideo(char *inBuff, int inBuffSize, void *yuvBuff, int width, int height)
{
if (NULL == inBuff)         return -1;
if (1 > inBuffSize)         return -1;
if (NULL == yuvBuff)        return -1;
if (NULL == _videoCodecContext)     return -2;

_videoAVPacket.size = inBuffSize;
_videoAVPacket.data = (uint8_t*)inBuff;

int frameFinished = 0;
int nDecode = avcodec_decode_video2(_videoCodecContext, _videoFrame420, &frameFinished, &_videoAVPacket);//(uint8_t*)pInBuffer, inputSize);
if (nDecode < 0)    return -3;
if (!frameFinished) return -4;

if  (width != _width || height != _height)
{
if (NULL != _avframeYUV)
{
av_frame_free(&_avframeYUV);
_avframeYUV = NULL;
}

if (NULL != _swsContext)
{
sws_freeContext(_swsContext);
_swsContext = NULL;
}

_width = width;
_height = height;
}

if (NULL == _avframeYUV)
{
int numBytes = avpicture_get_size((AVPixelFormat)_outputFormat, width, height);
_avframeYUV = av_frame_alloc();
}
if (NULL == _avframeYUV)        return -5;

if (avpicture_fill((AVPicture *)_avframeYUV, (uint8_t*)yuvBuff, (AVPixelFormat)_outputFormat,
width, height) < 0)
{
return -1;
}

if (NULL == _swsContext)
{
_swsContext = sws_getCachedContext(_swsContext, _videoCodecContext->width, _videoCodecContext->height, (AVPixelFormat)AV_PIX_FMT_YUV420P,
width, height, (AVPixelFormat)_outputFormat, SWS_BICUBIC, NULL, NULL, NULL);
}
if (NULL == _swsContext)        return -1;

int ret = sws_scale(_swsContext, _videoFrame420->data, _videoFrame420->linesize, 0, _videoCodecContext->height,
_avframeYUV->data, _avframeYUV->linesize);

return 0;
}

void DecoderHelper::releaseVideoDecoder()
{
if (NULL != _videoFrame420)
{
av_frame_free(&_videoFrame420);
_videoFrame420 = NULL;
}
if (NULL != _buffYUV420)
{
av_free(_buffYUV420);
_buffYUV420 = NULL;
}
if (NULL != _avframeSWS)
{
av_frame_free(&_avframeSWS);
_avframeSWS = NULL;
}
if (NULL != _avframeYUV)
{
av_frame_free(&_avframeYUV);
_avframeYUV = NULL;
}
if (NULL != _buffYUV)
{
av_free(_buffYUV);
_buffYUV = NULL;
}

if (NULL != _swsContext)
{
sws_freeContext(_swsContext);
_swsContext = NULL;
}

if (NULL != _videoCodecContext)
{
avcodec_close(_videoCodecContext);
av_free(_videoCodecContext);
_videoCodecContext = NULL;
}
}

使用

DecoderHelper decoderHelper;
decoderHelper.SetVideoDecoderParam();
decoderHelper.DecodeVideo();

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