//?H264_yuv.cpp?:?定義控制臺應(yīng)用程序的入口點(diǎn)。
//

#include?“stdafx.h“
#include?
#include?
#include?
#include??


#ifdef?__cplusplus?
extern?“C“
{?
#endif?
#include?“l(fā)ibavutil/imgutils.h“?
#include?“l(fā)ibavutil/opt.h“?
#include?“l(fā)ibavcodec/avcodec.h“?
#include?“l(fā)ibavutil/mathematics.h“?
#include?“l(fā)ibavutil/samplefmt.h“???
#ifdef?__cplusplus?
#pragma?comment（lib?“avcodec.lib“）
#pragma?comment（lib?“avutil.lib“）
}?
#endif???
#define?INBUF_SIZE?（4096）?
static?void?pgm_save（unsigned?char?*buf?int?wrap?int?xsize?int?ysize?FILE?*f）?
{?????
	int?i;??
	//buf?+=?64;?????
	//fprintf（f“P5\n%d?%d\n%d\n“xsizeysize255）;?????
	for（i=0;i		fwrite（buf?+?i?*?wrap1xsizef）;
}?
static?int?_find_head（unsigned?char?*buffer?int?len）?
{??
	int?i;??int?j;?????
	for?（i=512;i	{???
		if?（buffer[i]?==?0?&&?buffer[i+1]?==?0?&&?buffer[i+2]?==?0?&&?buffer[i+3]?==?1）????
			break;??
	}??
	if?（i?==?len）???
		return?0;??
	if?（i?==?512）???
		return?0;??
	return?i;?
}?
#define?FILE_READING_BUFFER?（1*1024*1024）?
static?void?build_avpkt（AVPacket?*avpkt?FILE?*fp）?
{?
	#if?0??
	int?len;??
	static?unsigned?char?buffer[INBUF_SIZE];?
	len?=?fread（buffer?1?INBUF_SIZE?fp）;?
	avpkt->data?=?buffer;??
	avpkt->size?=?len;?
	#else??
	static?unsigned?char?buffer[1*1024*1024];??
	static?int?readptr?=?0;??
	static?int?writeptr?=?0;??
	int?lentoread;????
	int?nexthead;????
	if?（writeptr?-?readptr?	{???
		memmove（buffer?&buffer[readptr]?writeptr?-?readptr）;???
		writeptr?-=?readptr;???
		readptr?=?0;???
		toread?=?FILE_READING_BUFFER?-?writeptr;???
		len?=?fread（&buffer[writeptr]?1?toread?fp）;???
		writeptr?+=?len;??
	}????
	nexthead?=?_find_head（&buffer[readptr]?writeptr-readptr）;??
	if?（nexthead?==?0）??
	{???
		printf（“failed?find?next?head...\n“）;???
		nexthead?=?writeptr?-?readptr;??
	}????
	avpkt->size?=?nexthead;??
	avpkt->data?=?&buffer[readptr];??
	readptr?+=?nexthead;?
#endif?
}?
static?void?video_decode_example（const?char?*outfilename?const?char?*filename）?
{?????
	AVCodec?*codec;?????
	AVCodecContext?*c=?NULL;?????
	int?frame?got_picture?len;?????
	FILE?*f?*fout;?????
	AVframe?*picture;?????
	uint8_t?inbuf[INBUF_SIZE?+?FF_INPUT_BUFFER_PADDING_SIZE];?????
	char?buf[1024];?????
	AVPacket?avpkt;??
	//AVDictionary?*opts;??

	av_init_packet（&avpkt）;??//使用默認(rèn)值初始化avpacket?

	/*?set?end?of?buffer?to?0?（this?ensures?that?no?overreading?happens?for?damaged?mpeg?streams）?*/????
	memset（inbuf?+?INBUF_SIZE?0?FF_INPUT_BUFFER_PADDING_SIZE）;???

	printf（“Video?decoding\n“）;??
	//opts?=?NULL;??
	????
	/*?find?the?H264?video?decoder?*/????
	codec?=?avcodec_find_decoder（CODEC_ID_H264）;?????//查找對應(yīng)解碼器
	if?（!codec）?{?????????
		fprintf（stderr?“codec?not?found\n“）;?????????
		exit（1）;?????
	}?

	c?=?avcodec_alloc_context3（codec）;?????//分配編碼解碼器上下文
	if?（!c）?{
		fprintf（stderr?“Could?not?allocate?video?codec?c