linux平台上基于ffmpeg源码的视频格式转换器

绝地灬酷狼 2022-09-04 11:50 141阅读 0赞

linux平台上基于ffmpeg源码的视频格式转换器，比如MP4转FLV、MOV转FLV等

[完整工程代码（含makefile）][makefile]

#include <stdio.h> 
    #define __STDC_CONSTANT_MACROS
    #ifdef __cplusplus
    extern "C"
    { 
    #endif
    #include <libavformat/avformat.h>
    #include <libavutil/mathematics.h>
    #include <libavutil/time.h>
    #ifdef __cplusplus
    };
    #endif
     
    int main(int argc, char* argv[])
    { 
    	AVOutputFormat *ofmt = NULL;
    	//输入对应一个AVFormatContext，输出对应一个AVFormatContext
    	AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
    	AVPacket pkt;
    	const char *in_filename, *out_filename;
    	int ret, i;
    	int frame_index=0;
    	
    	if(argc < 2)
    	{ 
    		printf("请输入视频源路径！\n");
    		printf("sample: ./send /opt/720p.flv\n");
    		exit(0);
    	}
    	
    	in_filename  = argv[1];
    	out_filename = "uvc_enc_out.flv";//输出 URL（Output file URL）
     
    	av_register_all();
    
    	//输入（Input）
    	if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) 
    	{ 
    		printf( "Could not open input file.");
    		goto end;
    	}
    
    	if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) 
    	{ 
    		printf( "Failed to retrieve input stream information");
    		goto end;
    	}
     
    	av_dump_format(ifmt_ctx, 0, in_filename, 0);
     
    	//输出（Output）
    	avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", out_filename); //RTMP
     	//avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename); //RTMP
    	if (!ofmt_ctx) 
    	{ 
    		printf( "Could not create output context\n");
    		ret = AVERROR_UNKNOWN;
    		goto end;
    	}
    	
    	ofmt = ofmt_ctx->oformat;
    	for (i = 0; i < ifmt_ctx->nb_streams; i++) 
    	{ 
    		//根据输入流创建输出流（Create output AVStream according to input AVStream）
    		AVStream *in_stream = ifmt_ctx->streams[i];
    		AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);
    		if (!out_stream) 
    		{ 
    			printf( "Failed allocating output stream\n");
    			ret = AVERROR_UNKNOWN;
    			goto end;
    		}
    		//复制AVCodecContext的设置（Copy the settings of AVCodecContext）
    		ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
    		if (ret < 0) 
    		{ 
    			printf( "Failed to copy context from input to output stream codec context\n");
    			goto end;
    		}
    		out_stream->codec->codec_tag = 0;
    		if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
    			out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    	}
    
    	//Dump Format------------------
    	av_dump_format(ofmt_ctx, 0, out_filename, 1);
    	//打开输出URL（Open output URL）
    	if (!(ofmt->flags & AVFMT_NOFILE)) 
    	{ 
    		ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
    		if (ret < 0) { 
    			printf( "Could not open output URL '%s'", out_filename);
    			goto end;
    		}
    	}
    
    	//写文件头（Write file header）
    	ret = avformat_write_header(ofmt_ctx, NULL);
    	if (ret < 0) { 
    		printf( "Error occurred when opening output URL\n");
    		goto end;
    	}
    
    	while (1) 
    	{ 
    		AVStream *in_stream, *out_stream;
    		//获取一个AVPacket（Get an AVPacket）
    		ret = av_read_frame(ifmt_ctx, &pkt);
    		if (ret < 0)
    			break;
     
    		in_stream  = ifmt_ctx->streams[pkt.stream_index];
    		out_stream = ofmt_ctx->streams[pkt.stream_index];
    		/* copy packet */
    		//转换PTS/DTS（Convert PTS/DTS）
    		pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
    		pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
    		pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
    		pkt.pos = -1;
    		ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
     		if (ret < 0) 
    		{ 
    			printf( "Error muxing packet\n");
    			break;
    		}
    		printf("Write %8d frames to output file\n",frame_index);
    		av_free_packet(&pkt);
    		frame_index++;
    	}
    	//写文件尾（Write file trailer）
    	av_write_trailer(ofmt_ctx);
    end:
    	avformat_close_input(&ifmt_ctx);
    	/* close output */
    	if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
    		avio_close(ofmt_ctx->pb);
    	avformat_free_context(ofmt_ctx);
    	return 0;
    }

[makefile]: https://download.csdn.net/download/weixin_43793181/21059327?spm=1001.2014.3001.5501