ffmpeg 发rtp流的问题

Chuang_Shang_Deng_NI 2015-11-02 10:33:42

我从网络接受rtp数据然后再发出去.原先是直接转发，vlc没法播放（通过rtsp）。。
后来考虑用ffmpeg，先探测输入流，用av_read_frame读取AVPacket,然后通过av_write_frame发出去。。







//输入相关的

AVInputFormat *inputFormat = nullptr;

AVFormatContext *inputFormatContext = nullptr;

AVIOContext *inputIoContext;

AVCodecContext *inputCodecContext;



AVCodec *codec;





//输入相关的

AVFormatContext* outputFormatContext;

AVOutputFormat* outputFormat;

AVStream* outputStream;

AVCodecContext* outCodecContext;







//探测输入码流 (略)



//构造输出

outputFormatContext = avformat_alloc_context();

outputFormatContext->oformat = av_guess_format("rtp", nullptr, nullptr);

#if 0

sprintf_s(outputFormatContext->filename, sizeof(outputFormatContext->filename), "rtp://%s:%d", "10.78.4.111", 12121);

#else

sprintf_s(outputFormatContext->filename, sizeof(outputFormatContext->filename), "rtp://%s:%d", "127.0.0.1", 12121);

#endif

avio_open(&outputFormatContext->pb, outputFormatContext->filename, AVIO_FLAG_WRITE);



outputStream = avformat_new_stream(outputFormatContext, codec);



outCodecContext = outputStream->codec;



avcodec_get_context_defaults3(outCodecContext, codec);

outCodecContext->codec_id = inputCodecContext->codec_id;

outCodecContext->width = inputCodecContext->width;

outCodecContext->height = inputCodecContext->height;

outCodecContext->time_base.den = inputCodecContext->time_base.den;

outCodecContext->pix_fmt = inputCodecContext->pix_fmt;



if (outputFormatContext->oformat->flags & AVFMT_GLOBALHEADER)

	outCodecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;



//av_opt_set(outCodecContext->priv_data, "preset", "ultrafast", 0);

//av_opt_set(outCodecContext->priv_data, "tune", "stillimage,fastdecode,zerolatency", 0);

//av_opt_set(outCodecContext->priv_data, "x264opts", "crf=26:vbv-maxrate=728:vbv-bufsize=364:keyint=25", 0);



//复制outCodecContext->extradata  据说里面包含了sps pps的东西

outCodecContext->extradata = (unsigned char*)av_malloc(inputCodecContext->extradata_size);

memcpy(outCodecContext->extradata, inputCodecContext->extradata, inputCodecContext->extradata_size);

outCodecContext->extradata_size = inputCodecContext->extradata_size;

avcodec_open2(outCodecContext, codec, nullptr);

avformat_write_header(outputFormatContext, nullptr);



char sdp[2048];

av_sdp_create(&outputFormatContext, 1, sdp, sizeof(sdp));



//发数据

	for (;;)

	{

		if (av_read_frame(inputFormatContext, &pkt) >= 0)

		{

			if (pkt.stream_index == videoindex)

			{

				

				//static int b = 0;

				//printf("读到数据 %d\n",b++);



				av_write_frame(outputFormatContext, &pkt);

				//fwrite(pkt.data, pkt.size, 1, a);

				//fflush(a);

			}

		}

		else

		{

			break;

		}

	}

生成的 sdp为
v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 127.0.0.1
t=0 0
a=tool:libavformat 56.40.101
m=video 12121 RTP/AVP 96
b=AS:200
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z0KAKJpmA8ARPy4C3AQEBQAAAwPoAADDUOhgAe4gAAX14LvLjQwAPcQAAL68F3lwoA==,aM44gA==; profile-level-id=428028
保存到文件，然后拖到vlc，接着发流，vlc一点反应没有
我看抓包除了rtp头之外，后面的数据直接就是7c01、7c41、7c81之类的（应该是a分片吧）

我还要做啥vlc才能播？

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