H265解码一致性问题

使用FFmpeg库进行H265解码，并对解码输出进行比较验证

代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

extern "C" {
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
}

int main(int argc, char* argv[])
{
    AVFormatContext *pFormatCtx = NULL;
    int             videoStream;
    AVCodecContext  *pCodecCtx = NULL;
    AVCodec         *pCodec = NULL;
    AVFrame         *pFrame = NULL;
    AVFrame         *pFrameRGB = NULL;
    AVPacket        packet;
    int             frameFinished;
    int             numBytes;
    uint8_t         *buffer = NULL;
    struct SwsContext      *sws_ctx = NULL;
    int             width, height;

    if(argc < 3) {
        printf("Usage: %s <input file> <output file>\n", argv[0]);
        return -1;
    }

    // Open video file
    if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0)
        return -1; // Couldn't open file

    // Retrieve stream information
    if(avformat_find_stream_info(pFormatCtx, NULL)<0)
        return -1; // Couldn't find stream information

    // Dump information about file onto standard error
    av_dump_format(pFormatCtx, 0, argv[1], 0);

    // Find the first video stream
    videoStream=-1;
    for(int i=0; i<pFormatCtx->nb_streams; i++)
        if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {
            videoStream=i;
            break;
        }
    if(videoStream==-1)
        return -1; // Didn't find a video stream

    // Get a pointer to the codec context for the video stream
    pCodecCtx=pFormatCtx->streams[videoStream]->codec;

    // Find the decoder for the video stream
    pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
    if(pCodec==NULL) {
        fprintf(stderr, "Unsupported codec!\n");
        return -1; // Codec not