Redirect from http to rtmp / another protocol

[Carl Eugen Hoyos]

​http://ffmpeg.org/pipermail/ffmpeg-user/2019-August/045227.html
A user provided a http url that redirects to rtmp. The rtmp stream is supported by FFmpeg, but the protocol change is not supported.

$ ffmpeg -loglevel trace -i http://http-to-rtsp-redirect-test.azurewebsites.net/api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow==
ffmpeg version N-94670-gb319feb05f Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9 (SUSE Linux)
  configuration: --enable-gpl --enable-gnutls --enable-libxml2 --enable-libx264 --enable-libx265 --enable-libvpx --enable-libaom
  libavutil      56. 33.100 / 56. 33.100
  libavcodec     58. 55.101 / 58. 55.101
  libavformat    58. 31.104 / 58. 31.104
  libavdevice    58.  9.100 / 58.  9.100
  libavfilter     7. 58.101 /  7. 58.101
  libswscale      5.  6.100 /  5.  6.100
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
Splitting the commandline.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'trace'.                                                     
Reading option '-i' ... matched as input url with argument 'http://http-to-rtsp-redirect-test.azurewebsites.net/api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow=='.                                                                                                                      
Finished splitting the commandline.                                                                                                                        
Parsing a group of options: global .
Applying option loglevel (set logging level) with argument trace.
Successfully parsed a group of options.
Parsing a group of options: input url http://http-to-rtsp-redirect-test.azurewebsites.net/api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow==.
Successfully parsed a group of options.
Opening an input file: http://http-to-rtsp-redirect-test.azurewebsites.net/api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow==.
[NULL @ 0x2796bc0] Opening 'http://http-to-rtsp-redirect-test.azurewebsites.net/api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow==' for reading
[http @ 0x2797680] Setting default whitelist 'http,https,tls,rtp,tcp,udp,crypto,httpproxy'
[tcp @ 0x27995c0] Original list of addresses:
[tcp @ 0x27995c0] Address 52.165.135.234 port 80
[tcp @ 0x27995c0] Interleaved list of addresses:
[tcp @ 0x27995c0] Address 52.165.135.234 port 80
[tcp @ 0x27995c0] Starting connection attempt to 52.165.135.234 port 80
[tcp @ 0x27995c0] Successfully connected to 52.165.135.234 port 80
[http @ 0x2797680] request: GET /api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow== HTTP/1.1
User-Agent: Lavf/58.31.104
Accept: */*
Range: bytes=0-
Connection: close
Host: http-to-rtsp-redirect-test.azurewebsites.net
Icy-MetaData: 1


[http @ 0x2797680] header='HTTP/1.1 302 Found'
[http @ 0x2797680] http_code=302
[http @ 0x2797680] header='Location: rtmp://ITSStreamingNO.dotd.la.gov:1935/public/hou-cam-006.streams'
[http @ 0x2797680] header='Request-Context: appId=cid-v1:b8ae84d1-8585-4d9f-9b3b-c4194a5cfa24'
[http @ 0x2797680] header='Date: Tue, 27 Aug 2019 20:40:02 GMT'
[http @ 0x2797680] header='Connection: close'
[http @ 0x2797680] header='Content-Length: 0'
[http @ 0x2797680] header=''
[tcp @ 0x2799c40] Original list of addresses:
[tcp @ 0x2799c40] Address 76.165.16.4 port 1935
[tcp @ 0x2799c40] Interleaved list of addresses:
[tcp @ 0x2799c40] Address 76.165.16.4 port 1935
[tcp @ 0x2799c40] Starting connection attempt to 76.165.16.4 port 1935
[tcp @ 0x2799c40] Successfully connected to 76.165.16.4 port 1935
[http @ 0x2797680] request: GET /public/hou-cam-006.streams HTTP/1.1
User-Agent: Lavf/58.31.104
Accept: */*
Range: bytes=0-
Connection: close
Host: ITSStreamingNO.dotd.la.gov:1935
Icy-MetaData: 1


[http @ 0x2797680] header='HTTP/1.1 200 OK'
[http @ 0x2797680] http_code=200
[http @ 0x2797680] header='Access-Control-Expose-Headers: Date, Server, Content-Type, Content-Length'
[http @ 0x2797680] header='Cache-Control: no-cache'
[http @ 0x2797680] header='Server: WowzaStreamingEngine/4.7.6'
[http @ 0x2797680] header='Access-Control-Allow-Origin: *'
[http @ 0x2797680] header='Access-Control-Allow-Credentials: true'
[http @ 0x2797680] header='Access-Control-Allow-Methods: OPTIONS, GET, POST, HEAD'
[http @ 0x2797680] header='Connection: Keep-Alive'
[http @ 0x2797680] header='Access-Control-Allow-Headers: Content-Type, User-Agent, If-Modified-Since, Cache-Control, Range'
[http @ 0x2797680] header='Date: Tue, 27 Aug 2019 20:43:01 GMT'
[http @ 0x2797680] header='Content-Type: text/html'
[http @ 0x2797680] header='Content-Length: 190'
[http @ 0x2797680] header=''
[AVIOContext @ 0x27a2080] Statistics: 190 bytes read, 0 seeks
http://http-to-rtsp-redirect-test.azurewebsites.net/api/HttpTrigger3?code=KsYPf7yjaMGPTaAWLpnJk98LcfF9XuhBVwZWsXNoNUdVjazxIJ3tow==: Invalid data found when processing input