[FFmpeg-trac] #7142(undetermined:new): Not stable fps in delivery rtmp stream

[FFmpeg]

#7142: Not stable fps in delivery rtmp stream
-------------------------------------+-------------------------------------
             Reporter:               |                    Owner:
  pavel.khilko                       |                   Status:  new
                 Type:  defect       |                Component:
             Priority:  normal       |  undetermined
              Version:  unspecified  |               Resolution:
             Keywords:  fps          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------

Comment (by pavel.khilko):

 ffmpeg version 3.4.2 Copyright (c) 2000-2018 the FFmpeg developers
   built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 20160609
   configuration: --prefix=/home/pavlo/.linuxbrew/Cellar/ffmpeg/3.4.2
 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-
 tables --enable-avresample --cc=gcc-5 --host-cflags= --host-ldflags=
 --disable-jack --enable-gpl --enable-ffplay --enable-frei0r --enable-
 libass --enable-libfdk-aac --enable-libmp3lame --enable-libopencore-amrnb
 --enable-libopencore-amrwb --enable-libopus --enable-librtmp --enable-
 libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-
 libx264 --enable-libx265 --enable-libxvid --disable-lzma --enable-
 libopenjpeg --disable-decoder=jpeg2000 --extra-
 cflags=-I/home/pavlo/.linuxbrew/Cellar/openjpeg/2.3.0/include/openjpeg-2.3
 --enable-nonfree
   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
 Hyper fast Audio and Video encoder
 usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options]
 outfile}...


 I get the stream from webcam with ffmpeg and publish it to nginx-rtmp:

 ffmpeg -f alsa -i default -f video4linux2 -i / dev / video0 -c: v libx264
 -c: a aac -f flv rtmp: // localhost / myapp / myStream

 After that, I get stream from nginx-rtmp to ffmpeg and transcode to the
 required format:

 ffmpeg -i rtmp: // localhost / myapp / myStream -s 1280x720 -aspect 16: 9
 \
 -c: a aac -b: a 64k -ac 2 -a 44100 -c: v libx264 -b: v 1500k -minate 1500k
 \
 -maxrate 1500k -bufsize 700k -profile: v main-level 4.0 -vf "fps = 30,
 format = yuv420p" \
 -x264opts "keyint = 60: min-keyint = 60: no-scenecut" -preset veryfast \
 -tune zerolatency -threads 0 -f flv rtmp: // localhost / myapp / myStream1

 Using the "video-quality-tools" module, I check the delivery time of the
 frames.
 If there is a problem with the incoming stream from the camera, ffmpeg
 does not save the set value in fps = 30 when delivering the tape

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7142#comment:2>
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