[FFmpeg-trac] #8705(avformat:new): content_type option is not working with tee output

[FFmpeg]

#8705: content_type option is not working with tee output
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             Reporter:  animtim   |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avformat  |                  Version:  unspecified
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 Summary of the bug:

 When using ffmpeg to send a webm video stream to an icecast server, it
 needs the option -content_type video/webm . It works fine for a single
 output, but when using a tee output (to both send the stream to the server
 and save to disk for example), the -content_type option is lost and
 default value (audio/mpeg) is used instead, so the stream on the icecast
 server is not readable.

 I could workaround the issue locally by editing libavformat/icecast.c to
 replace the default value to video/webm and rebuild ffmpeg, but of course
 this is not a solution for most users...

 Also, I tried to pass the option to the corresponding tee output but it
 was not recognized/not working.

 So I guess it is a bug to fix... Or maybe I missed something?


 How to reproduce:

 -install an icecast server, with a mountpoint for video.webm, and of
 course adapt the source, password and url in the command below:

 {{{
 ffmpeg -video_size 1920x1080 -thread_queue_size 512 -framerate 30 -f
 x11grab -i :0.0+0,0 \
   -thread_queue_size 512 -f pulse -ac 2 -i default \
   -f webm -cluster_size_limit 2M -cluster_time_limit 5100 -content_type
 video/webm \
   -vf scale=640:-1 \
   -acodec libvorbis -aq 4 \
   -vcodec libvpx -b:v 1000K -crf 40 -g 150 -deadline good -threads 2 \
   -f tee -map 0:v -map 1:a
 "icecast://source:password@example.domain:8000/video.webm|savedVideo.webm"

 ffmpeg version 4.1.5 Copyright (c) 2000-2020 the FFmpeg developers
   built with gcc 8.4.0 (Mageia 8.4.0-1.mga7)
 }}}

 Note: tested with several distribution packages (Debian stable and sid,
 Manjaro), issue is the same.

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Ticket URL: <https://trac.ffmpeg.org/ticket/8705>
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