How to get stdout from FFmpeg without format? - node.js

Question

I need to get stdout of rtsp stream without formatting. May someone know how to do it?
This is what I get if try to ffmpeg manually from command line:
root#cl-som-imx6ul-sid: ffmpeg -rtsp_transport tcp -i rtsp://admin:pass#10.168.9.141/Streaming/channels/1/ -vcodec cpoy -acodec copy -
ffmpeg version 3.2.5-1~bpo8+1 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 4.9.2 (Debian 4.9.2-10)
configuration: --prefix=/usr --extra-version='1~bpo8+1' --toolchain=hardened --libdir=/usr/lib/arm-linux-gnueabihf --incdir=/usr/include/arm-linux-gnueabihf --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --disable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 34.101 / 55. 34.101
libavcodec 57. 64.101 / 57. 64.101
libavformat 57. 56.101 / 57. 56.101
libavdevice 57. 1.100 / 57. 1.100
libavfilter 6. 65.100 / 6. 65.100
libavresample 3. 1. 0 / 3. 1. 0
libswscale 4. 2.100 / 4. 2.100
libswresample 2. 3.100 / 2. 3.100
libpostproc 54. 1.100 / 54. 1.100
Input #0, rtsp, from
'rtsp://admin:pass#10.168.9.141/Streaming/channels/1/':
Metadata:
title : Media Presentation
Duration: N/A, start: 0.240000, bitrate: N/A
Stream #0:0: Video: h264 (Main), yuv420p(progressive), 640x480, 25 fps, 25.08 tbr, 90k tbn, 50 tbc
[NULL # 0x5683bc30] Unable to find a suitable output format for 'pipe:'
pipe:: Invalid argument
NodeJS code sample
this.stream = child_process.spawn("ffmpeg", ["-rtsp_transport", "tcp", "-i", this.url, '-acodec', 'copy', '-vcodec', 'copy', '-'], {
detached: false
});
this.inputStreamStarted = true;
this.stream.stdout.on('data', function(data) {
return self.emit('mpeg1data', data);
});
this.stream.stderr.on('data', function(data) {
return self.emit('ffmpegError', data);
});

Answer 1

When outputting a pipe you are required to manually instruct ffmpeg what output format you want to use. You can do this with the -f option. Example:
ffmpeg -rtsp_transport tcp -i rtsp://admin:pass#10.168.9.141/Streaming/channels/1/ -c copy -f mpegts -
This does not perform any re-encoding because -c copy is being used.