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• FFMPEG PERFORMING VERY SLOW

  6 septembre 2016, par Gary Mathis

  I’m trying to setup a media processing server. I’ve done a lot of research for FFMPEG and wrote a command. The command is as follows.

  ffmpeg -y -i "bbb_sunflower_2160p_60fps_normal.mp4" -c:v libx264 \
  
  -threads 7 -profile:v main -preset ultrafast -vf scale=1920:-1 \
  
  "process/video/1080p.mp4" -c:v libx264 -threads 7 -profile:v main \
  
  -preset ultrafast -vf scale=1280:-1 "process/video/720p.mp4" -c:v \
  
  libx264 -threads 7 -profile:v main -preset ultrafast -vf \
  
  scale=854:-1 "process/video/480p.mp4" -vf fps=5/60 \
  
  process/image/thumb_%d.jpg

  This command works and runs perfectly, but it is dirt slow. My server, which is dedicated to just running ffmpeg has the following specs :

  12 core intel Xeon X5650 (Hyperthreading enabled)
  64 GB ECC DDR3 RAM
  250 GB SSD Drive
  
  But when I use this command, the server CPU load hangs around 250-300%, which I would like it to hang around 2,000% while processing the video. Currently when processing the video, the server is rendering around 17 frames per second. This would take a very long time to process a 10 minute video that’s 60fps.

• How to output a sequence of images in a loop with ffmpeg from rtsp stream

  6 juillet 2017, par The Doctor

  I am reading an RTSP stream from a surveillance camera and want to use ffmpeg to create a snapshot of the camera as jpeg. Principally it works to create a snapshot.jpg using the -update 1 option, but if it happens (what it does very often) that the client application reads the file while ffmpeg writes to it, the image is displayed only partially.

  Hence I want to use ffmpeg to capture more than 1 images in a kind of ring buffer, so I can access the image captured just before the current one and have also the last n images as short history.

  Though ffmpeg allows to create a series of jpgs, this seems infinite. Is it possible to tell ffmpeg to create images in a file pattern like this :

  pic1.jpg, pic2.jpg, pic3.jpg, pic4.jpg, pic5.jpg and after pic5.jpg to start over again using pic1.jpg etc. This way it could consume a stream continuously without filling up my drive. Unfortunately something like -update 5 seems not to work (ffmpeg simply exits).

  Principally I can also let it run infinitely and clean up all files older than n seconds, but that would introduce additional overhead and is IMHO not really clean programming compared to ffmpeg using this kind of ring buffer approach.

  Any help would be appreciated.

• C++ how to link ffmpeg with cmake on windows

  6 décembre 2016, par onurmhb

  I have downloaded ffmpeg dev files from ffmpeg.zeranoe.com and succesfully included the headers in my application. However, I am getting undefined errors when linking.

  undefined reference to `avformat_open_input(AVFormatContext**, char const*, AVInputFormat*, AVDictionary**)'

  I am using a FindFFMEG.cmake file to find ffmpeg library. From the cmake cache I see that it finds the library :

  FFMPEG_avcodec_LIBRARY:FILEPATH=C:/Users/User/Google Drive/workspace/C++/Project/Dependencies/ffmpeg/lib/libavcodec.dll.a
  
  ...

  This is how I am linking :

  find_package(FFMPEG REQUIRED)
  
  if (FFMPEG_FOUND)
  
      target_link_libraries(${PROJECT_NAME} ${FFMPEG_LIBRARIES})
  
      include_directories(${FFMPEG_INCLUDE_DIR})
  
  endif (FFMPEG_FOUND)

  I guess I am missing some files that should be included ?

  How can I link ffmpeg correcly in my c++ project with cmake ?

  Edit :
  I am using mingw64