ffmpeg: No trailing CRLF found in HTTP header

Question

I'm trying to use the -headers command in ffmpeg, but with the following command I'm getting a No trailing CRLF found in HTTP header error.

ffmpeg -headers "$(printf '\n%s\n%s\n%s\n%s\n%s\n%s\n\n' 'Cookie: GPS=1; PREF=f1=50000000&hl=en; VISITOR_INFO1_LIVE=YYVg5wZlZM4; YSC=nqFTzbjynHk; s_gl=1d69aac621b2f9c0a25dade722d6e24bcwIAAABVUw==' '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')" -i http://localhost:8000 -v trace

This is the ffmpeg -v output (Note I've also tried with \r\n, \\r\\n, \\n as well instead of just \n still get the same error (the double incase of printf escape)

ffmpeg -headers "$(printf '\n%s\n%s\n%s\n%s\n%s\n%s\n\n' 'Cookie: GPS=1; PREF=f1=50000000&hl=en; VISITOR_INFO1_LIVE=YYVg5wZlZM4; YSC=nqFTzbjynHk; s_gl=1d69aac621b2f9c0a25dade722d6e24bcwIAAABVUw==' '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')" -i http://localhost:8000 -v trace
ffmpeg version 3.4.4-0ubuntu0.18.04.1 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
  configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Splitting the commandline.
Reading option '-headers' ... matched as AVOption 'headers' with argument '
Cookie: GPS=1; PREF=f1=50000000&hl=en; VISITOR_INFO1_LIVE=YYVg5wZlZM4; YSC=nqFTzbjynHk; s_gl=1d69aac621b2f9c0a25dade722d6e24bcwIAAABVUw==
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 '-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 @ 0x556cf5231a60] Opening 'http://localhost:8000' for reading
[http @ 0x556cf5232780] Setting default whitelist 'http,https,tls,rtp,tcp,udp,crypto,httpproxy'
[http @ 0x556cf5232780] No trailing CRLF found in HTTP header.
[http @ 0x556cf5232780] request: GET / HTTP/1.1
User-Agent: Lavf/57.83.100
Accept: */*
Range: bytes=0-
Connection: close
Host: localhost:8000
Icy-MetaData: 1

Cookie: GPS=1; PREF=f1=50000000&hl=en; VISITOR_INFO1_LIVE=YYVg5wZlZM4; YSC=nqFTzbjynHk; s_gl=1d69aac621b2f9c0a25dade722d6e24bcwIAAABVUw==
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 @ 0x556cf5232780] header='HTTP/1.0 200 OK'
[http @ 0x556cf5232780] http_code=200

Solution

This comment is right:

It's a warning, not an error. ffmpeg appends the trailing CRLF on its own and proceeds.

My answer explains why the tool cannot "see" CRLF even if you use \r\n in printf. It's because of $(). POSIX specification says [emphasis mine]:

$(command)

[...]

The shell shall expand the command substitution by executing command in a subshell environment [...] and replacing the command substitution (the text of command plus the enclosing $() or backquotes) with the standard output of the command, removing sequences of one or more <newline> characters at the end of the substitution.

So there's no way to get a trailing \n from $().

---

You can ask your shell to add trailing newlines, although not all shells support this. In Bash instead of

foo "$(printf '\n%s\r\n' 'bar')"

use

foo "$(printf '\n%s' 'bar')"$'\r\n'

See How does the leading dollar sign affect single quotes in Bash?

Comments

[Gyan]

What's the issue? It's a warning, not an error. ffmpeg appends the trailing CRLF on its own and proceeds.