SDL2.09 and MFC vs2010 when the window RESIZE int the Onsize the progrma is stoped at sdl_rendeclearr

MFC creat the dialog and use sdl_createwindowform to set the mfc picturel control,
and use the message WM_SIZE to resize the window.
there is a problem when the window dialg resize by the mouse the decoder thread is stoped at function sdl_renderclear; the code is below here.
int simplest_ffmpeg_player1(LPVOID lpParam)
{
MyVideoDlg1 *dlg=(MyVideoDlg1 *)lpParam;
AVFrame *pFrame;
AVPacket *packet;
int ret, got_picture;
int screen_w,screen_h;
AVFrame *frameold;
double oldpts=0;
num1 = 0;
dlg->video1_continue=0;
int first = 1;
int64_t seek_target = 0;
int thread_back = 0;

SDL_Renderer* sdlRenderer;
SDL_Texture* sdlTexture;
AVFrame *frameout = NULL;

uint8_t *out_buffer;
struct SwsContext *img_convert_ctx;
AVFrame	*pFrameYUV;
pFrameYUV=av_frame_alloc();
out_buffer=(uint8_t *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx1->width, pCodecCtx1->height, 1));
av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx1->width, pCodecCtx1->height, 1);

img_convert_ctx = sws_getContext(pCodecCtx1->width, pCodecCtx1->height, pCodecCtx1->pix_fmt, 
	pCodecCtx1->width, pCodecCtx1->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);

frameout = av_frame_alloc();
pFrame=av_frame_alloc();
frameold = av_frame_alloc();

screen_h = pCodecCtx1->height;
screen_w = pCodecCtx1->width;

screen1 = SDL_CreateWindowFrom(dlg->GetDlgItem(IDC_PICTURE1)->GetSafeHwnd());

if(!screen1) {  
	TRACE("SDL: could not create window - exiting\n");
	return -1;
}
sdlRenderer = SDL_CreateRenderer(screen1, -1, 0);  
sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING,screen_w, screen_h);
packet=(AVPacket *)av_malloc(sizeof(AVPacket));


thread_ontime1 = 1;
thread_exit1 = 0;
thread_seek1 = 0;
thread_over1 = 0;
while(thread_exit1 == 0)
{
	if(thread_ontime1 == 1)
	{

		if(av_read_frame(pFormatCtx1, packet)>=0)
		{
			if(packet->stream_index==videoindex1)
			{
				ret = avcodec_send_packet(pCodecCtx1, packet);
				if (ret != 0)
				{
					TRACE("%s/n","error");
					return 0;
				}
				got_picture = avcodec_receive_frame(pCodecCtx1, pFrame);
				if(got_picture==0)
				{
					//TRACE("packet->pts = %f\n",(packet->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base));
					//TRACE("11 pFrame->pts = %f\n",(pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base));
					if (thread_over1 == 1)
					{
						//TRACE("packet->pts = %f\n",(pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base));
						int time_now = (pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base);
						//TRACE("time_now = %f\n",time_now);
						if (time_now == TIME_START_BASE)
						{
							num1=1;
							TRACE("a1 %d\n",num1);
							sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx1->height, pFrameYUV->data, pFrameYUV->linesize);
							//Rotate1(pFrame, &frameout);
							thread_over1 = 0;
							SDL_UpdateTexture(sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0]);
							SDL_RenderClear(sdlRenderer);
							SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
							SDL_RenderPresent(sdlRenderer);
							thread_ontime1 = 0;
							av_packet_unref(packet);
							thread_back = 0;
						}
						continue;
					}


					if (thread_back == 1)
					{
						if ((oldpts - (pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base) <= 0.04)&&(oldpts - (pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base) >= 0))
						{
							num1--;
							TRACE("b1 %d\n",num1);
							sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx1->height, pFrameYUV->data, pFrameYUV->linesize);
							oldpts = (pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base);
							//Rotate1(pFrame, &frameout);
							thread_ontime1 = 0;
							SDL_UpdateTexture(sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0]);
							SDL_RenderClear(sdlRenderer);
							SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
							SDL_RenderPresent(sdlRenderer);
							av_packet_unref(packet);
							thread_back = 0;

							continue;
						}
						else
							continue;
					}

					if (packet->pts >= seek_target)
					{
						num1++;
						TRACE("c1 %d\n",num1);
						oldpts = (pFrame->pts)*av_q2d(pFormatCtx1->streams[videoindex1]->time_base);
						if (first == 1)   //第一次解析到第一帧时刷新到屏幕
						{
							first = 0;
							TIME_START_BASE = (int)(packet->pts*av_q2d(pFormatCtx1->streams[videoindex1]->time_base));
							TRACE("TIME_START_BASE %d\n",TIME_START_BASE);
							thread_ontime1 = 0;
							sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx1->height, pFrameYUV->data, pFrameYUV->linesize);
							//Rotate1(pFrame, &frameout);
							SDL_UpdateTexture( sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0]);
							SDL_RenderClear( sdlRenderer );
							SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, NULL);
							SDL_RenderPresent(sdlRenderer );
							av_packet_unref(packet);
							continue;
						}


						thread_ontime1 = 0;
						sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx1->height, pFrameYUV->data, pFrameYUV->linesize);
						//Rotate1(pFrame, &frameout);
						SDL_UpdateTexture( sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0]);
						SDL_RenderClear( sdlRenderer ); 
						SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, NULL);
						SDL_RenderPresent(sdlRenderer );

						if (dlg->video1_continue == 1)
						{
							av_packet_unref(packet);
							TRACE("11111\n");
							dlg->video1_continue = 0;
							thread_ontime1 = 1;
							continue;
						}
					} 
					else
					{
						av_packet_unref(packet);
						//TRACE("1111111111111\n");
						continue;
					}
				}
			}
		av_packet_unref(packet);
		}
		else
		{

			break;
		}
	}
	Sleep(10);
}

dlg->GetDlgItem(IDC_PICTURE1)->ShowWindow(SW_SHOWNORMAL);
av_frame_free(&frameold);
av_frame_free(&frameout);
av_frame_free(&pFrame);
TRACE("simplest_ffmpeg_player1 exit\n");
return 0;

}

this is the ONsi函数

void MyVideoDlg1::OnSize(UINT nType, int cx, int cy)
{
CDialogEx::OnSize(nType, cx, cy);
// TODO: 在此处添加消息处理程序代码
int xcount = 0;
int ycount = 0;
int xycount = 0;

//xcount = cx / 3;
//ycount = cy / 4;


//xycount = (xcount - ycount) ? ycount : xcount; 

// TRACE(“cx = %d, cy = %d\n”, cx, cy);
if (IsAccess_control_position == 1)
{
//GetDlgItem(IDC_PICTURE1)->MoveWindow(Picture1Rect.left+(cx - xycount3)/2 ,Picture1Rect.top,
//xycount
3 , xycount4);
GetDlgItem(IDC_PICTURE1)->MoveWindow(Picture1Rect.left ,Picture1Rect.top,
cx , cy);
//TRACE(“cx = %d, cy = %d\n”,xycount
3, xycount*4);
Invalidate(TRUE);
}
else
{
Picture1Width = cx;
Picture1Height = cy;
}

}

The program stops at SDL_renderclear when I drag the window with the mouse to resize the windows