FFmpeg에서 avcodec_encode_video 압축되지 않는문제

void saveCapturedImage(FILE *fp, XImage *pImage)
{
	AppContext *pApp = getAppContext();
	int outSize, i;
 
	//To validate captured image
	//saveXImageToBitmap(pImage);	
 
	if(pApp->state & DV_START)
	{
		av_register_all();
 
		//Determine AVOutputFormat
		pFileOutputFormat = guess_format("avi",NULL,NULL);
		if(!pFileOutputFormat)
		{
			DavidMessageBox("Error to guess format");
			exit(1);
		}
 
		pOutputFile = av_alloc_format_context();
		if(!pOutputFile)
		{
			DavidMessageBox("Error allocating memory for format context");
			exit(1);
		}
 
		pOutputFile->oformat = pFileOutputFormat;
		if(pOutputFile->oformat->priv_data_size > 0)
		{
			pOutputFile->priv_data = av_mallocz(pOutputFile->oformat->priv_data_size);			
		}
 
		pOutputFile->preload = (int)(0.5 * AV_TIME_BASE);
		pOutputFile->max_delay = (int)(0.7 * AV_TIME_BASE);
 
		//Add the video stream and initilize the codecs
		//Prepare video stream
		pOutputStream = addVideoStream(pOutputFile, pImage, PIX_FMT_RGB24, CODEC_ID_MPEG4);
 
		if(av_set_parameters(pOutputFile, NULL) < 0)
		{
			DavidMessageBox("Invalid encoding parameters");
			exit(0);
		}	
 
		//Open the codec we will use
		if(avcodec_open(pOutputStream->codec, pCodec) < 0)
		{
			fprintf(stderr, "Could not open video codec\n");
			exit(1);
		}
 
		//We should implement the code for audio capturing here
 
		/*
		 * Prepare image buffer and frame that will hold captured data
		 */
		//Input Frame(Picture)		
		pInputFrame = avcodec_alloc_frame();
 
		//We should implement the code to process image which has 8 bit palette following
		avpicture_fill((AVPicture *)pInputFrame, (uint8_t *)pImage->data,
					   PIX_FMT_RGB32, pImage->width, pImage->height);
 
		//Output Frame(Picture)
		pOutputFrame = avcodec_alloc_frame();
 
		outputImageSize = avpicture_get_size(pOutputStream->codec->pix_fmt,
											 pOutputStream->codec->width, pOutputStream->codec->height);
		pOutputPicBuffer = av_malloc(outputImageSize);
		if(!pOutputPicBuffer)
		{
			fprintf(stderr, "Couldn't allocate buffer for output picture buffer\n");
			exit(1);
		}
		avpicture_fill((AVPicture *)pOutputFrame, pOutputPicBuffer, 
						pOutputStream->codec->pix_fmt, pOutputStream->codec->width,
	  					pOutputStream->codec->height);
 
		/*
		 * Prepare output buffer for encoded frames
		 */
		if((outputImageSize + 200) < FF_MIN_BUFFER_SIZE)
		{
			outputEncodedFrameBufferSize = FF_MIN_BUFFER_SIZE;
		}
		else
		{
			outputEncodedFrameBufferSize = outputImageSize + 200;
		}
		pOutputEncodedFrameBuffer = malloc(outputEncodedFrameBufferSize);
		if(!pOutputEncodedFrameBuffer)
		{
			fprintf(stderr, "Couldn't allocate buffer for encoded frame buffer\n");
			exit(1);
		}
 
		//Image resampling
		if(!pImgResampleCtx)
		{
			pImgResampleCtx = sws_getContext(pImage->width, pImage->height, PIX_FMT_RGB32,
											 pOutputStream->codec->width,
											 pOutputStream->codec->height,
											 pOutputStream->codec->pix_fmt, 1, NULL, NULL, NULL);
		}
 
		sprintf(pOutputFile->filename, "temp_movie.mpeg");
 
		if(url_fopen(&pOutputFile->pb, pOutputFile->filename, URL_WRONLY) < 0)
		{
			DavidMessageBox("Couldn't open url_fopen");
		}
 
		if(av_write_header(pOutputFile) < 0)
		{
			DavidMessageBox("Couldn't write header for output file");
		}
	}
 
	/*
	 * Convert input picture to pixel format the encoder expects
	 */
	//Image resampling and conversion
 
	if(sws_scale(pImgResampleCtx, pInputFrame->data, pInputFrame->linesize, 0,
		  		 pImage->height, pOutputFrame->data, pOutputFrame->linesize) < 0)
	{
		fprintf(stderr, "Error converting or resampling frame\n");
		exit(1);
	}
 
	/*
	 * Encode the image to capture
	 */
	outSize = avcodec_encode_video(pOutputStream->codec, pOutputEncodedFrameBuffer, 
									outputEncodedFrameBufferSize, pOutputFrame);
	if(outSize < 0)
	{
		fprintf(stderr, "Error encoding frame: codec %p, encodedbuffer %p\n", pOutputStream->codec,
				pOutputEncodedFrameBuffer);
		exit(1);
	}
 
	/*
	 * Write output frame to file
	 */
	if(outSize > 0)
	{
		writeVideoOut(pOutputFile, pOutputStream, pOutputEncodedFrameBuffer, 
					  outputEncodedFrameBufferSize);
	}
}