10.13例子改成屏幕，报错

[yundmb]

` 
int flush_encoder(AVFormatContext fmtCtx, AVCodecContext codecCtx, int vStreamIndex) {
 int ret = 0;
 AVPacket enc_pkt = av_packet_alloc();
 enc_pkt->data = NULL;
 enc_pkt->size = 0;

 if (!(codecCtx->codec->capabilities & AV_CODEC_CAP_DELAY))
 return 0;

 printf("Flushing stream #%u encoder\n", vStreamIndex);
 if (avcodec_send_frame(codecCtx, 0) >= 0) {
 while (avcodec_receive_packet(codecCtx, enc_pkt) >= 0) {
 printf("success encoder 1 frame.\n");

 // parpare packet for muxing
 enc_pkt->stream_index = vStreamIndex;
 av_packet_rescale_ts(enc_pkt, codecCtx->time_base,
 fmtCtx->streams[vStreamIndex]->time_base);
 ret = av_interleaved_write_frame(fmtCtx, enc_pkt);
 if (ret < 0) {
 break;
 }
 }
 }

 av_packet_unref(enc_pkt);

 return ret;
}

int main() {
 int ret = 0;
 avdevice_register_all();

 AVFormatContext inFmtCtx = avformat_alloc_context();
 AVCodecContext inCodecCtx = NULL;
 const AVCodec inCodec = NULL;
 AVPacket inPkt = av_packet_alloc();
 AVFrame srcFrame = av_frame_alloc();
 AVFrame yuvFrame = av_frame_alloc();

 //打开输出文件，并填充fmtCtx数据
 AVFormatContext outFmtCtx = avformat_alloc_context();
 const AVOutputFormat outFmt = NULL;
 AVCodecContext outCodecCtx = NULL;
 const AVCodec outCodec = NULL;
 AVStream outVStream = NULL;

 AVPacket outPkt = av_packet_alloc();

 struct SwsContext img_ctx = NULL;

 int inVideoStreamIndex = -1;

 do {
 /////////////解码器部分//////////////////////
 //打开摄像头
#ifdef _WIN32
 const AVInputFormat inFmt = av_find_input_format("gdigrab");
 if (avformat_open_input(&inFmtCtx, "desktop", inFmt, NULL) < 0) {
 printf("Cannot open camera.\n");
 break;
 }
#elif linux
 AVInputFormat inFmt = av_find_input_format("v4l2");
 if(avformat_open_input(&inFmtCtx,"/dev/video0",inFmt,NULL)<0){
 printf("Cannot open camera.\n");
 break;
 }
#endif

 if (avformat_find_stream_info(inFmtCtx, NULL) < 0) {
 printf("Cannot find any stream in file.\n");
 break;
 }

 for (uint32_t i = 0; i < inFmtCtx->nb_streams; i++) {
 if (inFmtCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
 inVideoStreamIndex = i;
 break;
 }
 }
 if (inVideoStreamIndex == -1) {
 printf("Cannot find video stream in file.\n");
 break;
 }

 AVCodecParameters inVideoCodecPara = inFmtCtx->streams[inVideoStreamIndex]->codecpar;
 if (!(inCodec = avcodec_find_decoder(inVideoCodecPara->codec_id))) {
 printf("Cannot find valid video decoder.\n");
 break;
 }
 if (!(inCodecCtx = avcodec_alloc_context3(inCodec))) {
 printf("Cannot alloc valid decode codec context.\n");
 break;
 }
 if (avcodec_parameters_to_context(inCodecCtx, inVideoCodecPara) < 0) {
 printf("Cannot initialize parameters.\n");
 break;
 }

 if (avcodec_open2(inCodecCtx, inCodec, NULL) < 0) {
 printf("Cannot open codec.\n");
 break;
 }

 img_ctx = sws_getContext(inCodecCtx->width,
 inCodecCtx->height,
 inCodecCtx->pix_fmt,
 inCodecCtx->width,
 inCodecCtx->height,
 AV_PIX_FMT_YUV420P,
 SWS_BICUBIC,
 NULL, NULL, NULL);

 int numBytes = av_image_get_buffer_size(AV_PIX_FMT_YUV420P,
 inCodecCtx->width,
 inCodecCtx->height, 1);
 uint8_t out_buffer = (unsigned char ) av_malloc(numBytes sizeof(unsigned char));

 ret = av_image_fill_arrays(yuvFrame->data,
 yuvFrame->linesize,
 out_buffer,
 AV_PIX_FMT_YUV420P,
 inCodecCtx->width,
 inCodecCtx->height,
 1);
 if (ret < 0) {
 printf("Fill arrays failed.\n");
 break;
 }
 //////////////解码器部分结束/////////////////////

 //////////////编码器部分开始/////////////////////
 const char outFile = "camera.mp4";

 if (avformat_alloc_output_context2(&outFmtCtx, NULL, "mp4", outFile) < 0) {
 printf("Cannot alloc output file context.\n");
 break;
 }
 outFmt = outFmtCtx->oformat;

 //打开输出文件
 if (avio_open(&outFmtCtx->pb, outFile, AVIO_FLAG_READ_WRITE) < 0) {
 printf("output file open failed.\n");
 break;
 }

 //创建h264视频流，并设置参数
 outVStream = avformat_new_stream(outFmtCtx, outCodec);
 if (outVStream == NULL) {
 printf("create new video stream fialed.\n");
 break;
 }
 outVStream->time_base.den = 60;
 outVStream->time_base.num = 1;

 //编码参数相关
 AVCodecParameters outCodecPara = outFmtCtx->streams[outVStream->index]->codecpar;
 outCodecPara->codec_type = AVMEDIA_TYPE_VIDEO;
 outCodecPara->codec_id = outFmt->video_codec;
 outCodecPara->width = 1920;
 outCodecPara->height = 1080;
 outCodecPara->bit_rate = 110000;

 //查找编码器
 outCodec = avcodec_find_encoder(outFmt->video_codec);
 if (outCodec == NULL) {
 printf("Cannot find any encoder.\n");
 break;
 }

 //设置编码器内容
 outCodecCtx = avcodec_alloc_context3(outCodec);
 avcodec_parameters_to_context(outCodecCtx, outCodecPara);
 if (outCodecCtx == NULL) {
 printf("Cannot alloc output codec content.\n");
 break;
 }
 outCodecCtx->codec_id = outFmt->video_codec;
 outCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
 outCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
 outCodecCtx->width = inCodecCtx->width;
 outCodecCtx->height = inCodecCtx->height;
 outCodecCtx->time_base.num = 1;
 outCodecCtx->time_base.den = 60;
 outCodecCtx->bit_rate = 110000;
 outCodecCtx->gop_size = 10;

 if (outCodecCtx->codec_id == AV_CODEC_ID_H264) {
 outCodecCtx->qmin = 10;
 outCodecCtx->qmax = 51;
 outCodecCtx->qcompress = (float) 0.6;
 } else if (outCodecCtx->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
 outCodecCtx->max_b_frames = 2;
 } else if (outCodecCtx->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
 outCodecCtx->mb_decision = 2;
 }

 //打开编码器
 if (avcodec_open2(outCodecCtx, outCodec, NULL) < 0) {
 printf("Open encoder failed.\n");
 break;
 }
 ///////////////编码器部分结束////////////////////

 ///////////////编解码部分//////////////////////
 yuvFrame->format = outCodecCtx->pix_fmt;
 yuvFrame->width = outCodecCtx->width;
 yuvFrame->height = outCodecCtx->height;

 ret = avformat_write_header(outFmtCtx, NULL);

 int count = 0;
 while (av_read_frame(inFmtCtx, inPkt) >= 0 && count < 50) {
 if (inPkt->stream_index == inVideoStreamIndex) {
 if (avcodec_send_packet(inCodecCtx, inPkt) >= 0) {
 while ((ret = avcodec_receive_frame(inCodecCtx, srcFrame)) >= 0) {
 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
 return -1;
 else if (ret < 0) {
 fprintf(stderr, "Error during decoding\n");
 exit(1);
 }
 sws_scale(img_ctx,
 (const uint8_t const ) srcFrame->data,
 srcFrame->linesize,
 0, inCodecCtx->height,
 yuvFrame->data, yuvFrame->linesize);

 yuvFrame->pts = srcFrame->pts;
 //encode
 if (avcodec_send_frame(outCodecCtx, yuvFrame) >= 0) {
 if (avcodec_receive_packet(outCodecCtx, outPkt) >= 0) {
 printf("encode %d frame.\n", count);
 ++count;
 outPkt->stream_index = outVStream->index;
 av_packet_rescale_ts(outPkt, outCodecCtx->time_base,
 outVStream->time_base);
 outPkt->pos = -1;
 av_interleaved_write_frame(outFmtCtx, outPkt);
 av_packet_unref(outPkt);
 }
 }
#ifdef _WIN32
 Sleep(24);//延时24毫秒
#elif linux
 usleep(1000*24);
#endif
 }
 }
 av_packet_unref(inPkt);
 fflush(stdout);
 }
 }

 ret = flush_encoder(outFmtCtx, outCodecCtx, outVStream->index);
 if (ret < 0) {
 printf("flushing encoder failed.\n");
 break;
 }

 av_write_trailer(outFmtCtx);
 ////////////////编解码部分结束////////////////
 } while (0);

 ///////////内存释放部分/////////////////////////
 av_packet_free(&inPkt);
 avcodec_free_context(&inCodecCtx);
 avcodec_close(inCodecCtx);
 avformat_close_input(&inFmtCtx);
 av_frame_free(&srcFrame);
 av_frame_free(&yuvFrame);

 av_packet_free(&outPkt);
 avcodec_free_context(&outCodecCtx);
 avcodec_close(outCodecCtx);
 avformat_close_input(&outFmtCtx);

 return 0;
}

` [gdigrab @ 00000200744161c0] Capturing whole desktop as 1920x1080x32 at (0,0) [gdigrab @ 00000200744161c0] Stream #0: not enough frames to estimate rate; consider increasing probesize [mpeg4 @ 0000020077990140] time_incr 28484223107072 too large [mpeg4 @ 0000020077990140] time_incr 28484223108885 too large [mpeg4 @ 0000020077990140] time_incr 28484223109141 too large [mpeg4 @ 0000020077990140] time_incr 28484223109138 too large [mpeg4 @ 0000020077990140] time_incr 28484223109359 too large [mpeg4 @ 0000020077990140] time_incr 28484223108843 too large [mpeg4 @ 0000020077990140] time_incr 28484223109364 too large [mpeg4 @ 0000020077990140] time_incr 28484223109107 too large [mpeg4 @ 0000020077990140] time_incr 28484223108890 too large [mpeg4 @ 0000020077990140] time_incr 28484223108883 too large