1.support one to many,only tested using one student

2.add macro to support using ffmpeg codec version 58,which need pcm format using AV_SAMPLE_FMT_FLTP when encoding aac

@@ -11,24 +11,36 @@ extern "C" {
 #define SRC_W 320
 #define SRC_H 240
 
-CAVTranscoder::CAVTranscoder():
+CAVTranscoder::CAVTranscoder(bool bOne2One):
 _start_time(INT64_MAX),
 _all_processed(true),
-_one2one(true),
 _nOutputWidth(320),
 _cur_out_v_ts(0),
 _cur_out_a_ts(0),
 _max_audio(1),
-_swsCtx(NULL)
+_swsCtx(NULL),
+_scaledFrame(NULL)
 {
+	_one2one = bOne2One;
 	if (_one2one) {
 		_nOutputHeight = 480;
 	}
 	else {
 		_nOutputHeight = 240;
-		_swsCtx = sws_getContext(SRC_W, SRC_H, PIX_FMT_YUV420P,
-			SCALED_W, SCALED_H, PIX_FMT_YUV420P, SWS_BILINEAR,
+		_swsCtx = sws_getContext(SRC_W, SRC_H, AV_PIX_FMT_YUV420P,
+			SCALED_W, SCALED_H, AV_PIX_FMT_YUV420P, SWS_BILINEAR,
 			NULL, NULL, NULL);
+		_scaledFrame = av_frame_alloc();
+		_scaledFrame->format = AV_PIX_FMT_YUV420P;
+		_scaledFrame->width = SCALED_W;
+		_scaledFrame->height = SCALED_H;
+		_scaledFrame->pts = 0;
+
+		int ret = av_frame_get_buffer(_scaledFrame, 32);
+		if (ret != 0)
+		{
+			printf("Error alloc frame buffer for scaling video frame");
+		}
 	}
 }
 
@@ -113,6 +125,10 @@ int CAVTranscoder::close()
 		sws_freeContext(_swsCtx);
 		_swsCtx = NULL;
 	}
+	if (_scaledFrame) {
+		av_frame_unref(_scaledFrame);
+		av_frame_free(&_scaledFrame);
+	}
 	flush_encoder(0);
 	flush_encoder(1);
 	av_write_trailer(_ofmt_ctx);
@@ -214,7 +230,7 @@ int CAVTranscoder::open_output_file(const char *filename)
 				enc_ctx->channel_layout = AV_CH_LAYOUT_MONO;
 				enc_ctx->channels = av_get_channel_layout_nb_channels(AV_CH_LAYOUT_MONO);
 				/* take first format from list of supported formats */
-				enc_ctx->sample_fmt = AV_SAMPLE_FMT_S16; //AV_SAMPLE_FMT_FLTP;
+				enc_ctx->sample_fmt = PCM_FORMAT_FOR_AAC_ENCODE; //AV_SAMPLE_FMT_FLTP;
 				enc_ctx->time_base.num = 1;
 				enc_ctx->time_base.den = enc_ctx->sample_rate;
 				enc_ctx->bit_rate = 64000;
@@ -264,7 +280,7 @@ int CAVTranscoder::open_output_file(const char *filename)
 		pDstFrame->nb_samples = 1024;
 		pDstFrame->channel_layout = AV_CH_LAYOUT_MONO;
 		pDstFrame->channels = av_get_channel_layout_nb_channels(AV_CH_LAYOUT_MONO);
-		pDstFrame->format = AV_SAMPLE_FMT_S16;
+		pDstFrame->format = PCM_FORMAT_FOR_AAC_ENCODE;
 		pDstFrame->sample_rate = 48000;
 
 		av_frame_get_buffer(pDstFrame, 0);
@@ -273,8 +289,13 @@ int CAVTranscoder::open_output_file(const char *filename)
 		for (; it != decoders_got_frame.end(); it++) {
 			AVFrame * pFrame = (*it)->_cur_a_frame;
 			if (pFrame) {
+#if LIBAVCODEC_VERSION_MAJOR < 58
 				int16_t * psrc = (int16_t *)pFrame->extended_data[0];
 				int16_t * pdst = (int16_t *)pDstFrame->extended_data[0];
+#else
+				float * psrc = (float *)pFrame->extended_data[0];
+				float * pdst = (float *)pDstFrame->extended_data[0];
+#endif
 				for (int i = 0; i < 1024; i++,pdst++,psrc++) {
 					*pdst += (*psrc/_max_audio);
 				}
@@ -310,40 +331,42 @@ int CAVTranscoder::open_output_file(const char *filename)
 		uint8_t *dstbuf = new uint8_t[nDstSize];
 		avpicture_fill((AVPicture*)pDstFrame, dstbuf, AV_PIX_FMT_YUV420P, _nOutputWidth, _nOutputHeight);
 
+		bool fill_pure_color = true;
 		if (idxTeacher != -1) {
 			//copy teacher frame to dest frame
 			CAVDecoder * pDecoder = decoders_got_frame[idxTeacher];
 			AVFrame * pFrame = pDecoder->_cur_v_frame;
 			if (pFrame) {
 				fillDestFrame(pDstFrame, pFrame, 0, 0);
+				fill_pure_color = false;
+				pDecoder->free_cur_v_frame();
 			}
-			else {//fill with pure color
+		}
+		if(fill_pure_color){//fill with pure color
 				memset(pDstFrame->data[0], 0, _nOutputWidth * _nOutputHeight);
 				memset(pDstFrame->data[1], 0x80, _nOutputWidth *_nOutputHeight / 4);
 				memset(pDstFrame->data[2], 0x80, _nOutputWidth * _nOutputHeight / 4);
 		}
 
+		int imageIdx = 0;
 		for (int i = 0; i < decoders_got_frame.size(); i++){
 			if (i != idxTeacher) {
 				//scale eacher frame
-
-					//copy each frame to the dest frame
-
-				}
+				CAVDecoder * pDecoder = decoders_got_frame[i];
+				AVFrame * pFrame = pDecoder->_cur_v_frame;
+				if (!pFrame) {
+					continue;
 				}
+				int h = sws_scale(_swsCtx, pFrame->data, pFrame->linesize, 0, pFrame->height,
+					_scaledFrame->data, _scaledFrame->linesize);
+				if (h <= 0){
+					printf("scale output 0?");
 				}
-		else {
-			memset(pDstFrame->data[0], 0, _nOutputWidth * _nOutputHeight);
-			memset(pDstFrame->data[1], 0x80, _nOutputWidth *_nOutputHeight / 4);
-			memset(pDstFrame->data[2], 0x80, _nOutputWidth * _nOutputHeight / 4);
-
-				for (int i = 0; i < decoders_got_frame.size(); i++){
-					if (i != idxTeacher) {
-						//scale eacher frame
 				
 				//copy each frame to the dest frame
-
-					}
+				fillDestFrame(pDstFrame, _scaledFrame, SRC_W - SCALED_H - ((imageIdx % 4) * SCALED_H), SRC_H - SCALED_H - (SCALED_H + 8)*imageIdx / 4, (SCALED_W - SCALED_H) / 2, 0, SCALED_H, SCALED_H);
+				pDecoder->free_cur_v_frame();
+				imageIdx++;
 			}
 		}
 
@@ -381,6 +404,19 @@ int CAVTranscoder::open_output_file(const char *filename)
 		return 0;
 	}
 
+	int CAVTranscoder::fillDestFrame(AVFrame * pDstFrame, AVFrame * pSrcFrame, int x, int y, int srcx, int srcy, int w, int h)
+	{
+		for (int i = 0; i < h; i++)	{
+			memcpy(pDstFrame->data[0] + (y + i)*pDstFrame->linesize[0] + x, pSrcFrame->data[0] + (i+srcy) * pSrcFrame->linesize[0] + srcx, pSrcFrame->linesize[0] > 0 ? w : -w);
+		}
+
+		for (int i = 0; i < h / 2; i++){
+			memcpy(pDstFrame->data[1] + (y / 2 + i)*pDstFrame->linesize[1] + x / 2, pSrcFrame->data[1] + (i + srcy/2) * pSrcFrame->linesize[1], pSrcFrame->linesize[1] > 0 ? w/2 : -w/2);
+			memcpy(pDstFrame->data[2] + (y / 2 + i)*pDstFrame->linesize[2] + x / 2, pSrcFrame->data[2] + (i + srcy/2) * pSrcFrame->linesize[2], pSrcFrame->linesize[2] > 0 ? w/2 : -w/2);
+		}
+		return 0;
+	}
+
 	int CAVTranscoder::mix_and_output_one2one_vframe(vector<CAVDecoder *> & decoders_got_frame)
 	{
 		//prepare one2one base frame

@@ -5,7 +5,7 @@
 class CAVTranscoder
 {
 public:
-	CAVTranscoder();
+	CAVTranscoder(bool bOne2One);
 	virtual ~CAVTranscoder();
 
 	int add(media_info & info);
@@ -35,12 +35,14 @@ private:
 	int mix_and_output_one2many_vframe(vector<CAVDecoder *> & decoders_got_frame);
 
 	int fillDestFrame(AVFrame * pDstFrame, AVFrame * pSrcFrame, int x, int y);
+	int fillDestFrame(AVFrame * pDstFrame, AVFrame * pSrcFrame, int destx, int desty, int srcx,int srcy,int w,int h);
 	int encode_write_frame(AVFrame *filt_frame, unsigned int stream_index, int *got_frame);
 	int flush_encoder(unsigned int stream_index);
 
 	void * _a_frame_pool;
 	int _max_audio;
 	struct SwsContext * _swsCtx;
+	AVFrame * _scaledFrame;
 public:
 	void set_max_audio(int max_audio);
 };

@@ -123,7 +123,7 @@ int CAudioDecoder::init_filter(FilteringContext* fctx, AVCodecContext *dec_ctx,
 			av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer sink\n");
 			goto end;
 		}
-		enum AVSampleFormat sample_fmt = AV_SAMPLE_FMT_S16;
+		enum AVSampleFormat sample_fmt = PCM_FORMAT_FOR_AAC_ENCODE;
 		ret = av_opt_set_bin(buffersink_ctx, "sample_fmts",
 			(uint8_t*)&sample_fmt, sizeof(sample_fmt),
 			AV_OPT_SEARCH_CHILDREN);

 #pragma  once
-
+#define  __STDC_LIMIT_MACROS
 #include <string>
 #include <vector>
 #include <stdint.h>
@@ -79,3 +79,9 @@ typedef struct FilteringContext {
 
 #define AFRAME_DURATION_MS 21.333333
 #define VFRAME_DURATION_MS 50
+
+#if LIBAVCODEC_VERSION_MAJOR < 58
+#define PCM_FORMAT_FOR_AAC_ENCODE  AV_SAMPLE_FMT_S16
+#else
+#define PCM_FORMAT_FOR_AAC_ENCODE  AV_SAMPLE_FMT_FLTP
+#endif

@@ -954,7 +954,7 @@ int process_av_files()
 	av_register_all();
 	avfilter_register_all();
 
-	CAVTranscoder videoTranscoder;
+	CAVTranscoder videoTranscoder(max_audio==2);
 	videoTranscoder.set_max_audio(max_audio);
 
 	int64_t cur_time = 0;