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• Drop packets instead of causing DTS error

  26 August 2020, by ottpeter

  I have 2 ffmpeg instances which are going through a buffer that is written in C.

  


  One of the ffmpeg instance is creating an FLV output and sending it to a TCP socket, which is connected to the C program. The C is filling up an array, then sends the packets to the other ffmpeg instance.

  


  The point is that the first ffmpeg instance can loose connection, and can be restarted.

  


  The other ffmpeg instance looks something like this:

  


  ffmpeg \
    -re \
    -fflags +igndts \
    -fflags flush_packets \
    -fflags discardcorrupt \
    -r 25 \ \
    -i $INPUT_VIDEO_STREAM \
    -safe 0 \
    -i music.txt \
    -fflags +genpts \
    -c:a mp3 \
    -b:a 320k \
    -c:v copy \
    -frame_drop_threshold 1.0
    -preset ultrafast \
    -f flv  rtmp://live.twitch.tv/app/live_KEY \
    -async 1 \
    -vsync 2


  


  The problem is, if I stop the other ffmpeg instance and restart it, I will get "Packet lost" error, and after, I will get a bunch of Non-monotonous DTS in output stream errors.

  


  


  [flv @ 0x55acf23632a0] Packet mismatch -1135911011 34757 9695626ate=1560.2kbits/s speed= 1x

  


  


  


  ...
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19080; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19120; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19160; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19200; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19240; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19280; changing to 62560. This may result in incorrect timestamps in the output file.
[flv @ 0x55acf23d0ec0] Non-monotonous DTS in output stream 0:0; previous: 62560, current: 19320; changing to 62560. This may result in incorrect timestamps in the output file.
...

  


  


  What I would like to happen is to continue playing the mp3 and drop the bad video packages, the video clip can be cut and the new clip can start playing. Even that would be OK if video is behaving strange for some seconds, but stream need to be continuous.

  


  Things I already tried:

  


  

  • several async / vsync options (vsync 1, vsync 2, vsync drop)

  


  • "-fflags +igndts", removing this option, adding it to the output instead

  


  • -fflags +genpts

  


  • to set probesize to 32

  


  • fflags discardcorrupt

  


  


  I also started to write a setpts filter, but couldn't figure out the syntax

  


  How can I stream the mp3 list that way that the video timestamps are not continuous, packet loss will happen sometimes?

  


• OpenCV 3.0.0 make error with FFMPEG

  14 October 2017, by Ujjwal Aryan

  I have been using OpenCV for a while. However I have recently changed my system to a cluster where I do not have any admin permission. The problem is like this :

  In my home folder, I installed FFMPEG (latest stable version available on ffmpeg site). I installed it in $HOME, and so in $HOME/lib there are the library files installed. For more information I compiled FFMPEG with following options :

  ./configure --prefix=$HOME --enable-shared --enable-pic

  I then downloaded the latest stable version of OpenCV 3.0.0 and configured it using ccmake. When I try to make -j8, it gives me the following error.

   Scanning dependencies of target opencv_videoio
  
  [ 63%] [ 63%] [ 63%] [ 63%] [ 63%] [ 63%] Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_mjpeg_decoder.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_images.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_v4l.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_mjpeg_encoder.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o
  
  In file included from /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg.cpp:45:0:
  
  /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg_impl.hpp:1546:71: error: use of enum 'AVCodecID' without previous declaration
  
  /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg_impl.hpp:1556:83: error: use of enum 'AVCodecID' without previous declaration
  
  make[2]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o] Error 1
  
  make[2]: *** Waiting for unfinished jobs....

  However without ffmpeg support it works fine. However I need ffmpeg support due to the nature of my work.

  In trying to resolve the problem, I tried installing OpenCV 2.4.11 but it also gave this error. The latest GIT version does not give me this error but rather an error a part of which goes like this

  Linking CXX shared library ../../lib/libopencv_highgui.so /usr/bin/ld: /home/matheus/ffmpeg_build/lib/../lib/libavcodec.a(avpacket.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used

  I have pasted the above error from another unresolved question online and so the folder names are different but the relocation error is exactly the same.

  In trying to resolve the problem I searched and found the following link http://answers.opencv.org/question/12597/build-problems-for-opencv-241-with-ubuntu-1204-lts/

  However, one of the answers over there mentioned changing some lines in cap_ffmpeg_impl.hpp file. I tried doing that but either i am not able to do it correctly or something else is going wrong and it is not working. Exact line numbers and exact changes are not mentioned and so I am having difficulty changing things and being sure.

  I am using Fedora 19 (Schrodinger Cat) as the operating system I hope the details of my question are clear and I hope that the community would oblige me with a good response.

  Regards
  Ujjwal

• OpenCV 3.0.0 make error with FFMPEG

  24 March 2016, by Ujjwal Aryan

  I have been using OpenCV for a while. However I have recently changed my system to a cluster where I do not have any admin permission. The problem is like this :

  In my home folder, I installed FFMPEG (latest stable version available on ffmpeg site). I installed it in $HOME, and so in $HOME/lib there are the library files installed. For more information I compiled FFMPEG with following options :

  ./configure --prefix=$HOME --enable-shared --enable-pic

  I then downloaded the latest stable version of OpenCV 3.0.0 and configured it using ccmake. When I try to make -j8, it gives me the following error.

   Scanning dependencies of target opencv_videoio
  
  [ 63%] [ 63%] [ 63%] [ 63%] [ 63%] [ 63%] Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_mjpeg_decoder.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_images.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_v4l.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_mjpeg_encoder.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o
  
  In file included from /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg.cpp:45:0:
  
  /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg_impl.hpp:1546:71: error: use of enum 'AVCodecID' without previous declaration
  
  /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg_impl.hpp:1556:83: error: use of enum 'AVCodecID' without previous declaration
  
  make[2]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o] Error 1
  
  make[2]: *** Waiting for unfinished jobs....

  However without ffmpeg support it works fine. However I need ffmpeg support due to the nature of my work.

  In trying to resolve the problem, I tried installing OpenCV 2.4.11 but it also gave this error. The latest GIT version does not give me this error but rather an error a part of which goes like this

  Linking CXX shared library ../../lib/libopencv_highgui.so /usr/bin/ld: /home/matheus/ffmpeg_build/lib/../lib/libavcodec.a(avpacket.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used

  I have pasted the above error from another unresolved question online and so the folder names are different but the relocation error is exactly the same.

  In trying to resolve the problem I searched and found the following link http://answers.opencv.org/question/12597/build-problems-for-opencv-241-with-ubuntu-1204-lts/

  However, one of the answers over there mentioned changing some lines in cap_ffmpeg_impl.hpp file. I tried doing that but either i am not able to do it correctly or something else is going wrong and it is not working. Exact line numbers and exact changes are not mentioned and so I am having difficulty changing things and being sure.

  I am using Fedora 19 (Schrodinger Cat) as the operating system I hope the details of my question are clear and I hope that the community would oblige me with a good response.

  Regards
  Ujjwal