Question

我尝试使用ffmpeg捕获Windows屏幕。一切正常，但avcodec_receive_packet返回错误AVERROR（EAGAIN）我无法理解为什么会发生这种情况。有人可以提供建议吗？

SwsContext* convertContext = sws_getContext(c->width, c->height, AV_PIX_FMT_BGRA, c->width, c->height, c->pix_fmt, SWS_FAST_BILINEAR, NULL, NULL, NULL);

for (int i = 0; i < fps*seconds; i++)
{
fflush(stdout);

/* make sure the frame data is writable */
ret = av_frame_make_writable(frame);
if (ret < 0)
  exit(1);

gdi->MakeScreenshoot();

OutFrame->pts = i;

int ret = av_image_fill_arrays(GDIFrame->data, GDIFrame->linesize, gdi->m_bufferGDIBits, AV_PIX_FMT_BGRA, c->width, c->height, 1);
ret = av_image_fill_arrays(OutFrame->data, OutFrame->linesize, outbuffer, c->pix_fmt, c->width, c->height, 1);

GDIFrame->data[0] += GDIFrame->linesize[0] * (c->height - 1);                                                      // flipping frame
GDIFrame->linesize[0] *= -1;

int hslice = sws_scale(convertContext, GDIFrame->data, GDIFrame->linesize, 0, c->height,OutFrame->data, OutFrame->linesize);

/* encode the image */
encode(c, OutFrame, pkt, f);
}

static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt, FILE *outfile)
{
 int ret = -1;

 /* send the frame to the encoder */
 /*if (frame)
 printf("Send frame %3"PRId64"\n", frame->pts);*/

 ret = avcodec_send_frame(enc_ctx, frame);
 if (ret < 0)
 {
   fprintf(stderr, "Error sending a frame for encoding\n");
   exit(1);
 }

 while (ret >= 0)
 {
   ret = avcodec_receive_packet(enc_ctx, pkt);
   if (ret == AVERROR_EOF)
     return;
   if (ret == AVERROR(EAGAIN))
     return;
   else
  if (ret < 0)
  {
    fprintf(stderr, "Error during encoding\n");
    exit(1);
  }

  //printf("Write packet %3"PRId64" (size=%5d)\n", pkt->pts, pkt->size);
  fwrite(pkt->data, 1, pkt->size, outfile);
  av_packet_unref(pkt);
  }
}

如果我评论

if (ret == AVERROR_EOF)
  return;
if (ret == AVERROR(EAGAIN))
  return;
else
  if (ret < 0)
  {
    fprintf(stderr, "Error during encoding\n");
    exit(1);
  }

在编码功能 - 一切都很好，文件将被写入并且是正确的，但我想解决问题。

Answer 1

晚点参加聚会。我也尝试使用encode_video.c

当编码器尚未准备好完整的数据包时，似乎avcodec_receive_packet（）将返回这些“错误” ...下一次调用avcodec_send_frame（）可能会导致完整的数据包。

所以继续吧。使用NULL帧对avcodec_send_frame（）的最终调用将刷新最终数据包。

avcodec_receive_packet出错（gdi screenshot + ffmpeg）

1 个答案: