ffmpeg -headers "$(printf '%s\r\n%s\r\n%s\r\n%s\r\n%s' 'User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0' 'Accept-Encoding: gzip, deflate' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8' 'Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7' 'Accept-Language: en-us,en;q=0.5')" -cookies "GPS=1; PREF=f1=50000000&hl=en; VISITOR_INFO1_LIVE=YYVg5wZlZM4; YSC=nqFTzbjynHk; s_gl=1d69aac621b2f9c0a25dade722d6e24bcwIAAABVUw==;"  -i http://localhost:8000 -v trace


Splitting the commandline.
Reading option '-headers' ... matched as AVOption 'headers' with argument 'User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0
Accept-Encoding: gzip, deflate
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Accept-Language: en-us,en;q=0.5'.
Reading option '-cookies' ... matched as AVOption 'cookies' with argument 'GPS=1; PREF=f1=50000000&hl=en; VISITOR_INFO1_LIVE=YYVg5wZlZM4; YSC=nqFTzbjynHk; s_gl=1d69aac621b2f9c0a25dade722d6e24bcwIAAABVUw==\r\n'.
Reading option '-i' ... matched as input url with argument 'http://localhost:8000'.
Reading option '-v' ... matched as option 'v' (set logging level) with argument 'trace'.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option v (set logging level) with argument trace.
Successfully parsed a group of options.
Parsing a group of options: input url http://localhost:8000.
Successfully parsed a group of options.
Opening an input file: http://localhost:8000.
[NULL @ 0x561322cd99e0] Opening 'http://localhost:8000' for reading
[http @ 0x561322cda660] Setting default whitelist 'http,https,tls,rtp,tcp,udp,crypto,httpproxy'
[http @ 0x561322cda660] No trailing CRLF found in HTTP header.
[http @ 0x561322cda660] request: GET / HTTP/1.1
Range: bytes=0-
Connection: close
Host: localhost:8000
Icy-MetaData: 1
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0
Accept-Encoding: gzip, deflate
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Accept-Language: en-us,en;q=0.5


[http @ 0x561322cda660] header='HTTP/1.0 200 OK'
[http @ 0x561322cda660] http_code=200
[http @ 0x561322cda660] header='Server: BaseHTTP/0.6 Python/3.5.2'
[http @ 0x561322cda660] header='Date: Sat, 19 Jan 2019 22:44:35 GMT'
[http @ 0x561322cda660] header=''
[http @ 0x561322cda660] Stream ends prematurely at 13, should be 18446744073709551615
[AVIOContext @ 0x561322cdcfc0] Statistics: 13 bytes read, 0 seeks
http://localhost:8000: Input/output error