話不多說命令如下：

ffmpeg -f dshow -i video="Logitech QuickCam Easy/Cool" -vcodec libx264 -preset:v ultrafast -tune:v zerolatency -f rtp rtp://127.0.0.1:6666>sd.sdp

用此命令可以產生264的rtp流， video="Logitech QuickCam Easy/Cool" 為攝像頭的名字，-vcodec libx264表示採用264編碼器，-preset:v ultrafast -tune:v zerolatency表示實時編碼，>sd.sdp表示產生sdp，此sdp的作用是提供給接收rtp流的資訊，接收rtp流的一方讀取這個檔案就可以接受流顯示。

但是因為此命令產生的h264流是用yuv444編碼的，所以接收方要想儲存h264流的話，得在傳送方的命令加一個引數：

-pixfmt YUV420P

至於有人問怎麼知道攝像頭的名字，用這個命令就好了：

ffmpeg -list_devices true -f dshow -i dummy

基本這樣就大功告成了~

from: http://www.aichengxu.com/other/1438151.htm

Streaming a simple RTP audio stream from FFmpeg ¶

FFmpeg can stream a single stream using the 

For example the following command will generate a signal, and will stream it to the port 1234 on localhost:

ffmpeg -re -f lavfi -i aevalsrc="sin(400*2*PI*t)" -ar 8000 -f mulaw -f rtp rtp://127.0.0.1:1234

To play the stream with ffplay (which has some caveats, see above), run the command:

ffplay rtp://127.0.0.1:1234

Note that rtp by default uses UDP, which, for large streams, can cause packet loss. See the "point to point" section in this document for hints if this ever happens to you.

from:https://trac.ffmpeg.org/wiki/StreamingGuide