FFmpeg YUV420保存JPEG例子

说明 FFmpeg3.4版本

bool SaveYUV420ToJPEG(const std::string &strFileName, int nWidth, int nHeight, int linesize, uint8_t * Y, uint8_t * U, uint8_t * V)
{
AVFormatContext* pFormatCtx;
AVCodecContext* pCodecCtx;
AVCodec* pCodec;
AVFrame* pFrame;
AVPacket pkt;
int nRet = 0;

avformat_alloc_output_context2(&pFormatCtx, NULL, NULL, strFileName.c_str());

AVStream* pVideoAVStream = avformat_new_stream(pFormatCtx, 0);
if (NULL == pVideoAVStream) return false;

pCodecCtx = avcodec_alloc_context3(NULL);
if (NULL == pCodecCtx) return false;

avcodec_parameters_to_context(pCodecCtx, pVideoAVStream->codecpar);

pCodecCtx->codec_id = pFormatCtx->oformat->video_codec;
pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
pCodecCtx->pix_fmt = AV_PIX_FMT_YUVJ420P;
pCodecCtx->width = nWidth;
pCodecCtx->height = nHeight;
pCodecCtx->time_base.num = 1;
pCodecCtx->time_base.den = 25;

pCodec = avcodec_find_encoder(pCodecCtx->codec_id);
if (NULL == pCodec) return false;

if (avcodec_open2(pCodecCtx, pCodec,NULL) < 0)
{
return false;
}
pFrame = av_frame_alloc();

int nJpegQuality = 80;
pCodecCtx->qcompress = (float)nJpegQuality/100.f; // 0~1.0, default is 0.5
pCodecCtx->qmin = 2;
pCodecCtx->qmax = 31;
pCodecCtx->max_qdiff = 3;

avformat_write_header(pFormatCtx,NULL);
av_new_packet(&pkt, pCodecCtx->width * pCodecCtx->height * 3);
pFrame->data[0] = Y;
pFrame->data[1] = U;
pFrame->data[2] = V;
pFrame->linesize[0] = linesize;
pFrame->linesize[1] = linesize/2;
pFrame->linesize[2] = linesize/2;

nRet = avcodec_send_frame(pCodecCtx, pFrame);
if (avcodec_receive_packet(pCodecCtx, &pkt) != 0) return false;

pkt.stream_index = 0;
nRet = av_write_frame(pFormatCtx, &pkt);
av_packet_unref(&pkt);

av_write_trailer(pFormatCtx);
avcodec_close(pCodecCtx);
avcodec_free_context(&pCodecCtx);
av_frame_free(&pFrame);
avio_close(pFormatCtx->pb);
avformat_free_context(pFormatCtx);
return true;
}

调用例子

SaveYUV420ToJPEG("fengyuzaitu.jpg", pFrame->width, pFrame->height, pFrame->linesize[0], pFrame->data[0], pFrame->data[1], pFrame->data[2]);