rtmpdump: add page (#3551)

pages/common/rtmpdump.md

@@ -0,0 +1,20 @@
+# rtmpdump
+
+> A tool to dump media content streamed over the RTMP protocol.
+> More information: <http://rtmpdump.mplayerhq.hu/>.
+
+- Download a file:
+
+`rtmpdump --rtmp {{rtmp://example.com/path/to/video}} -o {{file.ext}}`
+
+- Download a file from a Flash player:
+
+`rtmpdump --rtmp {{rtmp://example.com/path/to/video}} --swfVfy {{http://example.com/player}} --flashVer "{{LNX 10,0,32,18}}" -o {{file.ext}}`
+
+- Specify connection parameters if they are not detected correctly:
+
+`rtmpdump --rtmp {{rtmp://example.com/path/to/video}} --app {{app_name}} --playpath {{path/to/video}} -o {{file.ext}}`
+
+- Download a file from a server that requires a referrer:
+
+`rtmpdump --rtmp {{rtmp://example.com/path/to/video}} --pageUrl {{http://example.com/webpage}} -o {{file.ext}}`