[FFmpeg-trac] #3347(undetermined:new): Amounts of UDP traffic below some limit are not transmitted with aviocat

[FFmpeg]

#3347: Amounts of UDP traffic below some limit are not transmitted with aviocat
-------------------------------------+-------------------------------------
             Reporter:  Krieger      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 Amounts of UDP traffic below some limit are not transmitted with aviocat.
 Haven't determined yet whether that's just aviocat, or UDP protocol
 implementation failure.
 The problem must be on receiving side (because traffic is seen in sniffer,
 and because GStreamer udpsrc catches it).
 Transmitting and reading continuous media stream by same UDP address works
 (both unicast and multicast).

 ffmpeg version N-60111-g094516a

 How to reproduce:
 {{{
 ./tools/aviocat "udp://127.0.0.1:1234" /dev/stdout &  sleep 1; yes | head
 -n 10000 | ./tools/aviocat /dev/stdin "udp://127.0.0.1:1234?pkt_size=2";
 fg
 }}}
 {{{
 ./tools/aviocat "udp://225.1.1.1:1234?localaddr=127.0.0.1" /dev/stdout &
 sleep 1; yes | head -n 10000 | ./tools/aviocat /dev/stdin
 "udp://225.1.1.1:1234?localaddr=127.0.0.1&pkt_size=2"; fg
 }}}
 There you get no "y" lines output in terminal. Setting fifo_size=0 and/or
 buffer_size=0 on receiving side does not help.

 Although if you increase number of transmitted packets, then you get
 output:
 {{{
 ./tools/aviocat "udp://127.0.0.1:1234" /dev/stdout &  sleep 1; yes | head
 -n 100000 | ./tools/aviocat /dev/stdin "udp://127.0.0.1:1234?pkt_size=2";
 fg
 }}}

 GStreamer socket reading interface gives output even with one byte
 transmitted:
 {{{
 gst-launch-1.0 udpsrc uri=udp://127.0.0.1:1234  ! fdsink fd://1 &  sleep
 1; echo -n "y" | ./tools/aviocat /dev/stdin udp://127.0.0.1:1234; fg
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/3347>
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