标签：ffmpeg pkt avcodec mp4 ret yuv rgb av

视频编码
1.读取RGB文件转换为yuv
2.压缩为h264
3.封装为MP4

ffmpeg -i test.mp4 -pix_fmt bgra out.rgb

av_interleaved_write_frame

1.AVFormatContext *s
2.AVPacket *pkt
3.按照dts排序
4.av_write_frame (缓冲处理dts)

rgb_to_mp4.cpp

extern "C"
{
	#include <libavformat/avformat.h>
	#include <libswscale/swscale.h>
}
#include <iostream>
using namespace std;
int main()
{
	char infile[] = "out.rgb";
	char outfile[] = "rgb.mp4";
	//muxer,demuters
	av_register_all();
	avcodec_register_all();

	FILE *fp = fopen(infile,"rb");
	if(!fp)
	{
		cout<<infile<<"open file!"<<endl;
		return -1;
	}
	int width = 848;
	int height = 480;
	int fps = 25;
	//1. create codec
	AVCodec *codec = avcodec_find_encoder(AV_CODEC_ID_H264);
	if(!codec)
	{
		cout<<" avcodec_find_encoder AV_CODEC_ID_H264 failed!"<<endl;
		return -1;
	}
	AVCodecContext *c = avcodec_alloc_context3(codec);
	if(!c)
	{
		cout<<" avcodec_alloc_context3 failed!"<<endl;
		return -1;
	}
	//压缩比特率
	c->bit_rate = 400000000;

	c->width = width;
	c->height = height;
	c->time_base = {1,fps};
	c->framerate = {fps,1};
	//画面组大小
	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; 
	int ret = avcodec_open2(c,codec,NULL);
	if(ret < 0)
	{
		cout<<" avcodec_open2 failed"<<endl;
		return -1;
	}
	cout<<"avcodec_open2 success!"<<endl;

	//2 create out context
	AVFormatContext *oc = NULL;
	avformat_alloc_output_context2(&oc,0,0,outfile);

	//3 add video stream
	AVStream *st = avformat_new_stream(oc,NULL);
	//st->codec = c;
	st->id = 0;
	st->codecpar->codec_tag = 0;
	avcodec_parameters_from_context(st->codecpar,c);
	cout<<"==========================================="<<endl;
	av_dump_format(oc,0,outfile,1);
	cout<<"==========================================="<<endl;

	//4 rgb to yuv
	SwsContext *ctx = NULL;
	ctx = sws_getCachedContext(
		ctx,width,height,AV_PIX_FMT_RGBA,
        width,height,AV_PIX_FMT_YUV420P,
						 SWS_BICUBIC,
						 NULL,NULL,NULL);
	//输入的空间
	unsigned char *rgb = new unsigned char[width*height*4];
	
	//输出的空间
	AVFrame *yuv = av_frame_alloc();
	yuv->format = AV_PIX_FMT_YUV420P;
	yuv->height = height;
	yuv->width = width;
	ret = av_frame_get_buffer(yuv,32);
	if(ret < 0)
	{
		cout<<" av_frame_get_buffer failed!"<<endl;
		return -1;
	}

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

	int p = 0;
	for(;;)
	{
		int len = fread(rgb,1,width*height*4,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 * 4;
		int h = sws_scale(ctx,indata,inlinesize,0,height,
			yuv->data,yuv->linesize);
		if(h <= 0)
			break;

		//6 encode frame
		yuv->pts = p;
//		yuv->pict_type = AV_PICTURE_TYPE_I;
		p = p + 3600;
		ret = avcodec_send_frame(c,yuv);
		if(ret != 0)
		{
			continue;
		}
		AVPacket pkt;
		av_init_packet(&pkt);
		ret = avcodec_receive_packet(c,&pkt);
		if(ret != 0)
		{
			continue;
		}
		// av_write_frame(oc,&pkt);
		// av_packet_unref(&pkt);
		av_interleaved_write_frame(oc,&pkt);
		cout<<"<"<<pkt.size<<">";
	}

	//写入视频索引
	av_write_trailer(oc);
	//关闭视频输出io
	avio_close(oc->pb);
	//清理封装输出上下文
	avformat_free_context(oc);
	//关闭编码器
	avcodec_close(c);
	//清理编码器上下文
	avcodec_free_context(&c);
	//清理视频冲采样上下文
	sws_freeContext(ctx);
	cout<<"\n=======================end======================\n";

	return 0;
}

这里是引用

标签：ffmpeg,pkt,avcodec,mp4,ret,yuv,rgb,av
来源： https://blog.csdn.net/TM1695648164/article/details/121248400

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