GET

http://example.com:[port]//downloadarchivefile?cameraid =1&fromdatetime=2014-10-01T00:00:00&todatetime=2014-10-01T01:20:05

Example:

GET http://192.168.15.182:80/downloadarchivefile?cameraid =1&fromdatetime=2014-10-01T00:00:00&todatetime=2014-10-01T01:20:05

Response

HTTP/l.1 200 OK
Content-Type: application/octet-stream

Use ffmpeg to convert the downloaded resulting file.