Reverse proxy for streaming live video

[fedel]

I am having trouble streaming HTTP tunneled video through nginx reverse
proxy. My frontend server is running nginx 0.7.67 and a backend server
sources a live video feed (RTSP wrapped in HTTP, mime
application/x-rtsp-tunneled).

This is the video tag in the webpage:
[code]


[/code]
The quicktime browser plugin requests redirect.mov from the streaming
server. Then the streaming server and the browser plugin use an HTTP
tunnel for wrapping the actual RTSP stream (.../path/stream).

I can access the video stream fine  using any web browser if I get it
directly from the backend. However, behind nginx reverse proxy, the
stream won't play. Here's my nginx configuration:
[code]
server {
    listen 80;
    server_name frontend;
    location / {
        proxy_pass http://backend;
        proxy_redirect off;
        proxy_buffering off;
        proxy_set_header Host $host;
    }
}
[/code]
Nginx starts loading http://backend/path/stream when the client requests
http://frontend/path/stream. However, it stops shortly thereafter. 

The quicktime user agent sends a POST request for the stream URL with
content-length set to 32767. This request only comes with 280 or so
bytes of body data. I guess the UA claims a huge content-length just to
keep the pipe open. Now, nginx waits on the client connection for the
remaining 32500 bytes, i.e. it does not forward the first 280 bytes to
the backend streaming server which would have responded and triggered
more data from the client but since the client won't receive a response
to its first 280 bytes of "in-band" request the quicktime user agent
times out and shuts down the connection. End of stream...

Is it possible to "magically" configure nginx to transparently forward
request data and response data immediately when they arrive?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,122149,122149#msg-122149