调用ffmpeg接口解码H264数据流，无法解码非关键帧

Question

调用ffmpeg的avcodec_decode_video2接口解码H264数据帧，为什么只能解码关键帧，非关键帧都解码不到呢，代码如下：
AVCodec *codec;
AVPacket packet;
AVFrame *pFrame;
AVCodecContext *pcodec;

av_init_packet(&packet);
av_register_all();
codec = avcodec_find_decoder(AV_CODEC_ID_H264);

if(!codec)
{
fprintf(stderr, "Codec not found\n");
return 0;
}

pcodec = avcodec_alloc_context3(codec);
if (!pcodec) {
fprintf(stderr, "Could not allocate audio codec context\n");
return 0;
}

pcodec->extradata =(uint8_t *)malloc(51);
pcodec->extradata_size = 51;
memcpy(pcodec->extradata, sps,43);
memcpy(pcodec->extradata+43, pps,8);

if(avcodec_open2(pcodec, codec,NULL) >= 0)
pFrame = avcodec_alloc_frame();// Allocate video frame
else return -1;

int got_picture;

packet.data = pBuffer;//这里填入一个指向完整H264数据帧的指针
packet.size = dwBufsize;//这个填入H264数据帧的大小

//printf("size of packet=%d\n",sizeof(packet));
printf("packet->size=%d\n",packet.size);

int DecodeRet=avcodec_decode_video2(pcodec, pFrame, &got_picture, &packet);
if (DecodeRet < 0) {
printf("Decode Error.\n");
return DecodeRet;
}

Answer 1

你这段代码八成在一个函数内，pFrame 需要一直保留，做成某个成员变量