/*

ffmpeg视频编码 rgb转mp4

*/

#include <iostream>

extern "C"
{
	#include <libavformat/avformat.h>
	#include <libswscale/swscale.h>
}

using namespace std;

#pragma comment(lib,"avformat.lib")
#pragma comment(lib,"avcodec.lib")
#pragma comment(lib,"avutil.lib")
#pragma comment(lib,"swscale.lib")

#define CHANNEL 3   //3通道

int main()
{
	char infile[] = "D:/VideoTest/data24.rgb";
	char outfile[] = "D:/VideoTest/rgb.mp4";

	av_register_all();
	avcodec_register_all();

	FILE *fp = fopen(infile, "rb");

	if (!fp)
	{
		cout << infile << " open failed!" << endl;
		system("pause");
		return -1;
	}

	int width = 960;
	int height = 640;
	int fps = 25;

	//1 创建h264编码器
	AVCodec *codec = avcodec_find_encoder(AV_CODEC_ID_H264);
	if (!codec)
	{
		cout << " avcodec_find_encoder AV_CODEC_ID_H264 failed!" << endl;
		system("pause");
		return -1;
	}

   //编码器上下文
	AVCodecContext *c = avcodec_alloc_context3(codec);
	if (!c)
	{
		cout << " avcodec_alloc_context3  failed!" << endl;
		system("pause");
		return -1;
	}

	//压缩比特率
	c->bit_rate = 4000000;
	
	c->width = width;
	c->height = height;
	c->time_base = { 1, fps };
	c->framerate = { fps, 1 };
	
	//画面组大小，关键帧
	c->gop_size = 50;
	c->max_b_frames = 0;

	c->pix_fmt = AV_PIX_FMT_YUV420P;
	c->codec_id = AV_CODEC_ID_H264;
	c->thread_count = 4;
	
	//全局的编码信息
	c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;

    //打开编码器
	int ret = avcodec_open2(c, codec, NULL);
	if (ret < 0)
	{
		cout << " avcodec_open2  failed!" << endl;
		system("pause");
		return -1;
	}
	cout << "avcodec_open2 success!" << endl;

	//2 创建输出上下文
	AVFormatContext *oc = NULL;
	avformat_alloc_output_context2(&oc, 0, 0, outfile);

	//3 编码的视频流
	AVStream *st = avformat_new_stream(oc, NULL);

	st->id = 0;
	st->codecpar->codec_tag = 0;
	avcodec_parameters_from_context(st->codecpar, c);

	cout << "查看输出文件信息" << endl;
	av_dump_format(oc, 0, outfile, 1);
	
	//4 rgb to yuv
	SwsContext *ctx = NULL;
	ctx = sws_getCachedContext(ctx,
		width, height, AV_PIX_FMT_BGRA,
		width, height, AV_PIX_FMT_YUV420P,
		SWS_BICUBIC,
		NULL, NULL, NULL
		);

	// 输入空间
	unsigned char *rgb = new unsigned char[width * height * CHANNEL]; //抽取的rgb数据是3通道

	//rgb转换后的yuv视频帧
	AVFrame *yuv = av_frame_alloc();
	yuv->format = AV_PIX_FMT_YUV420P;
	yuv->width = width;
	yuv->height = height;
	ret = av_frame_get_buffer(yuv, CHANNEL * 8);

	if (ret < 0)
	{
		cout << " av_frame_get_buffer  failed!" << endl;
		system("pause");
		return -1;
	}

	//5 wirte mp4 head
	ret = avio_open(&oc->pb, outfile, AVIO_FLAG_WRITE);
	if (ret < 0)
	{
		cout << " avio_open  failed!" << endl;
		system("pause");
		return -1;
	}

	ret = avformat_write_header(oc, NULL);
	if (ret < 0)
	{
		cout << " avformat_write_header  failed!" << endl;
		system("pause");
		return -1;
	}

	int p = 0;

	for(;;)
	{
		int len = fread(rgb, 1, width * height * CHANNEL, fp);
		if (len <= 0)
		{
			break;
		}

		uint8_t *indata[AV_NUM_DATA_POINTERS] = { 0 };
		indata[0] = rgb;

		int inlinesize[AV_NUM_DATA_POINTERS] = { 0 };
		inlinesize[0] = width * CHANNEL;

		//把rgb数据indata转为yuv数据yuv
		int h = sws_scale(ctx, indata, inlinesize, 0, height, yuv->data, yuv->linesize);

		if (h <= 0)
			break;

		yuv->pts = p;
		p = p + 3600;  //3600 = 90000/25，st->time_base，时间基数的值是1/90000
		ret = avcodec_send_frame(c, yuv);  //把yuv进行编码
		if (ret != 0)
		{
			continue;
		}

		AVPacket pkt;   //packet是编码之后的数据
		av_init_packet(&pkt);
		ret = avcodec_receive_packet(c, &pkt);
		if (ret != 0)
			continue;

		av_interleaved_write_frame(oc, &pkt);

		cout << "pkt.size = " << pkt.size << endl;
	}
	
	//写入视频索引
	av_write_trailer(oc);

	avio_close(oc->pb);
	avformat_free_context(oc);
	avcodec_close(c);
	avcodec_free_context(&c);
	sws_freeContext(ctx);

	delete[] rgb;

	system("pause");
	return 0;
}

av_interleaved_write_frame函数的使用说明：

该函数在写入帧之后，不用再去释放packet的内存，如果用av_write_frame，则需要调用av_packet_unref把引用计数清零。

封装后的视频是黑白的，因为没有a通道。