How to use FFmpeg - Dieptranivsr/DroneIVSR GitHub Wiki

What all the arguments mean ?

Command	Description
`ffmpeg -loglevel error`	logging level (quiet, error, warning).
`-f dshow`	build and run GStreamer pipelines from the command line
`-i video="USB Video Device":audio="Microphone (USB Audio Device)"`	find out what GStreamer elements you have available and their capabilities
`-vcodec libx264`	- video codec (libx264 for h264).
`-acodec aac`	audio codec (aac).
`-preset ultrafast`	encoding preset (ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo).
`-tune zerolatency`	tune zerolatency sends an I-Frame (complete pic) every frame so that users to not need to wait for intermetiate frames to complete.
`-thread_type slice`	slice-based threading tells all CPU threads work on the same frame, reducing latency a lot.
`-slices 1`	has to be 1 for vMix to decode the stream, don't know why.
`-intra-refresh 1`	intra-refresh has to be set to 1 because vMix expects a latency of 1 frame, I think.
`-r 30`	framerate.
`-g 60`	GOP (Group of Pictures), simply multiply your output frame rate * 2.
`-s 800x600`	scale my webcam's native picture is 1600x1200, so I scale it down.
`-aspect 4:3`	aspect ratio, my webcam is a Logitec 9000 which is 4:3.
`-acodec aac`	audio encode using AAC.
`-ar 44100`	audio sample rate 44.1 KHz.
`-b:v 2.5M`	desired bitrate for video 2.5 Mbps, can play with this.
`-minrate:v 900k`	min data rate video 900k, can play with this.
`-maxrate:v 2.5M`	min data rate video 2.5 Mbps, can play with this.
`-bufsize:v 5M`	buffer size for encoding, double max data rate seems to be a good starting point.
`-b:a 128K`	desired bitrate for audio 128 Kbps, can play with this.
`-pix_fmt yuv420p`	color space, has to be yuv420p for vMix to decode properly.
`-bufsize 5000k`	buffer size (double max data rate seems to be a good starting point)
`-f mpegts udp://192.168.0.123:35001?pkt_size=1316`	output format mpegts udp IP address, port, packet size - really important - The size of an MPEG-TS packet is 188 Bytes and 7 of them will fit into an Ethernet frame, 7*188=1316.