[FFmpeg-user] Unable to get udp multicast stream

[Lucas da Vila]

Hi,

I'm trying to transcode from a mpeg transport stream to RTMP. I have a
ISDB-t tuner that generates a UDP mpeg ts stream over multicast but when I
ran this

ffmpeg -v 9 -loglevel 99 -re -i "udp://@239.255.0.1:56000" -c:v copy -c:a:0
libvo_aacenc -b:a: 64k -ar 44100 -f flv rtmp://localhost:1935/hls/channel

ffmpeg doesn't crash and just waits (kind of)

This is the output:
ffmpeg version N-74369-g55a07cf Copyright (c) 2000-2015 the FFmpeg
developers
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
  configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --enable-avresample
--disable-debug --enable-nonfree --enable-gpl --enable-version3
--enable-libopencore-amrnb --enable-libopencore-amrwb
--disable-decoder=amrnb --disable-decoder=amrwb --enable-libpulse
--enable-libdcadec --enable-libfreetype --enable-libx264 --enable-libx265
--enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus
--enable-libvpx --enable-libspeex --enable-libass --enable-avisynth
--enable-libsoxr --enable-libxvid --enable-libvo-aacenc --enable-libvidstab
  libavutil      54. 30.100 / 54. 30.100
  libavcodec     56. 57.100 / 56. 57.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 32.100 /  5. 32.100
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Splitting the commandline.
Reading option '-v' ... matched as option 'v' (set logging level) with
argument '9'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging
level) with argument '99'.
Reading option '-re' ... matched as option 're' (read input at native frame
rate) with argument '1'.
Reading option '-i' ... matched as input file with argument 'udp://@
239.255.0.1:56000'.
Reading option '-c:v' ... matched as option 'c' (codec name) with argument
'copy'.
Reading option '-pix_fmt' ... matched as option 'pix_fmt' (set pixel
format) with argument 'yuv420p'.
Reading option '-g' ... matched as AVOption 'g' with argument '25'.
Reading option '-c:a:0' ... matched as option 'c' (codec name) with
argument 'libvo_aacenc'.
Reading option '-b:a:' ... matched as option 'b' (video bitrate (please use
-b:v)) with argument '64k'.
Reading option '-ar' ... matched as option 'ar' (set audio sampling rate
(in Hz)) with argument '44100'.
Reading option '-f' ... matched as option 'f' (force format) with argument
'flv'.
Reading option 'rtmp://localhost:1935/hls/channel' ... matched as output
file.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option v (set logging level) with argument 9.
Successfully parsed a group of options.
Parsing a group of options: input file udp://@239.255.0.1:56000.
Applying option re (read input at native frame rate) with argument 1.
Successfully parsed a group of options.
Opening an input file: udp://@239.255.0.1:56000.
[udp @ 0x22e1e20] end receive buffer size reported is 131072

It works with video files and from multcast stream generated with ffmpeg or
going through a live transcoder, but not with the tuner output. I've
already tried to set the PID with no success.
Any ideas what's going on? It's too strange

Thanks in advance,
Lucas