[FFmpeg-trac] #1663(undetermined:new): Multiple named pipes don't work

[FFmpeg]

#1663: Multiple named pipes don't work
-------------------------------------+-------------------------------------
             Reporter:  burek        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug: When 1 ffmpeg is used to produce multiple outputs to
 named pipes and another ffmpeg is used to read those named pipes as
 inputs, everything just stucks and doesn't work.

 How to reproduce:

 * Run 2 shells.

 * Create 2 test named pipes (1 for audio and 1 for video):
 {{{
 mkfifo /tmp/aaa /tmp/vvv
 }}}

 * In first shell type the following, which would basically split the input
 to raw audio and raw video, sending the results to audio/video named
 pipes:
 {{{
 ffmpeg -y -i 1.flv -map 0:a -f u16le -acodec pcm_s16le -ac 2 -ar 44100
 /tmp/aaa -map 0:v -f yuv4mpegpipe -vcodec rawvideo /tmp/vvv
 }}}

 * In second shell type the following, which should join inputs and create
 the output:
 {{{
 ffmpeg -y -i /tmp/mcs_aaa -i /tmp/mcs_vvv out.avi
 }}}

 The result: It doesn't work.

 But, if you use 2 ffmpeg processes in the second shell instead, to
 separately grab the audio named pipe input and video named pipe input,
 then everything works as expected:
 {{{
 ffmpeg -y -i /tmp/mcs_aaa bla1.avi &
 ffmpeg -y -i /tmp/mcs_vvv bla2.avi
 }}}

 Conclusion: Something is implemented wrong in the ffmpeg's part that reads
 inputs in such a way that it prevents ffmpeg from reading both named pipes
 as inputs at the same time (second shell).

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1663>
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