转自：

void YV12ToAVFrame(BYTE * pData,int nLen,int nWidth,int nHeight,AVFrame * pFrame)

{

avcodec_get_frame_defaults(pFrame);

int size=avpicture_get_size(PIX_FMT_YUV420P,nWidth ,nHeight );

ASSERT(size==nLen);

avpicture_fill( (AVPicture*) pFrame,pData,PIX_FMT_YUV420P , nWidth ,nHeight );

BYTE * ptmp=pFrame->data [1];//U,V互换

pFrame->data [1]=pFrame->data [2];

pFrame->data [2]=ptmp;

}

void AVFrameToYV12(AVFrame * pFrame,int nWidth,int nHeight,BYTE * pData,int * npLen)

{

BYTE * ptmp=pFrame->data [1];//U,V互换

pFrame->data [1]=pFrame->data [2];

pFrame->data [2]=ptmp;

AVPicture pic;

int size=avpicture_get_size(PIX_FMT_YUV420P,nWidth ,nHeight );

if(*npLen<size)

  return;//缓冲区太小

avpicture_fill(&pic, pData, PIX_FMT_YUV420P,

    nWidth, nHeight);

*npLen=size;

img_copy(&pic,(AVPicture *)pFrame,PIX_FMT_YUV420P,nWidth,nHeight);

ptmp=pFrame->data [1];//恢复AVFrame

pFrame->data [1]=pFrame->data [2];

pFrame->data [2]=ptmp;

}