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• Having trouble building FFmpeg using GNU make, Makefile:182 : /tests/Makefile : No such file or directory

  24 mai 2022, par Daedalus

  I'm having trouble building FFmpeg as a library to use in a project in vscode C++. I have no experience working with C/C++ libraries and would greatly appreciate any help. I've installed chocolatey and GNU make (GNU Make 4.3) with that, and the source code for FFmpeg. I cannot run make, as it tells me to do in the INSTALL.md file of the source code. I've been using command prompt to run the commands. Here are my errors :

  


  C:\ffmpeg>PowerShell ./configure

C:\ffmpeg>make
Makefile:182: /tests/Makefile: No such file or directory
make: *** No rule to make target '/tests/Makefile'.  Stop.

C:\ffmpeg>make install
Makefile:182: /tests/Makefile: No such file or directory
make: *** No rule to make target '/tests/Makefile'.  Stop.


  


  I've installed FFmpeg from github, and I can't find a working prebuilt library. I've tried different variations of the commands, with PowerShell and directories, but nothing has worked. This is INSTALL.md :

  


  


  Installing FFmpeg

  


  


  1. Type ./configure to create the configuration. A list of configure options is printed by running configure --help.

     


     configure can be launched from a directory different from the FFmpeg sources to build the objects out of tree. To do this, use an
absolute path when launching configure, e.g.
/ffmpegdir/ffmpeg/configure.

     


  


  2. Then type make to build FFmpeg. GNU Make 3.81 or later is required.

     


  


  3. Type make install to install all binaries and libraries you built.

     


  


  


  NOTICE

  


  

  • Non system dependencies (e.g. libx264, libvpx) are disabled by default.

  


  


  


  Any help would be greatly appreciated. Thanks in advance.

  


• Using a Web-based installer to retrieve (not distribute) 3rd party GPL or non-free software

  25 août 2013, par user1493918

  I am developing a software product which is able to communicate over a command line interface with GPL-covered software (specifically, my software can feed commands to FFMpeg). I understand that a crucial aspect of the GPL license is whether or not you distribute GPL-covered applications. My goal is to allow my users to have a seamless experience installing both my software and 3rd party GPL software. But I am trying to do this without my software actually including the the 3rd party (GPL-covered) software. To do this I am considering Web-based installers. I could use a Web-based installer to allow the end-user the option to retrieve a GPL-covered or non-free software app from a totally different server, independent of my own and outside my control. The user would be the one to install the software simply by making a decision (i.e. pressing "Next" in my installer). If they chose to do so, then my software's Web-based installer would retrieve the 3rd-party software, decompress and install it, then move on to installing my own application. In this way, my installer doesn't ship any GPL-covered or non-free software, and yet from the user's perspective all they had to do is click Next... Next... Next... Done !

  I have read about the GPL allowing you to distribute GPL-covered apps as part of an "aggregate..."
  http://www.gnu.org/licenses/gpl-faq.html#MereAggregation

  ...but this scenario isn't that. It's allowing the user to retrieve applications or libraries at his own discretion, using his own bandwidth, downloading from a server that has nothing to do with me.

  I can't seem to find information anywhere about the GPL-related licensing implications of using a Web-based installer. My goal is simply to give the end user every high-quality transcoding option possible within FFMpeg without stepping on anybody's toes legally.

  Possible ? If so then I'm hoping someone might be able to point me to a software installer program that would facilitate this. Thank you in advance for any replies.

• Improve ffmpeg scene detection in particular scenario

  17 septembre 2021, par Nobody-Knows-I-am-a-Dog

  I have 50 hours of video where a speaker is in the lower right corner of the video and the by far larger part of the video consists of slides in the center. The speaker moves a bit, the slides transition into the video. I need to detect the time codes of the slide transitions. +- 1 second precision is fine. I am playing around with select filters in ffmpeg such as ffmpeg -i lecture.mp4  -filter:v "select='gt(scene,0.1)',showinfo"   -f null - but I have remaining problems where some help or hint would be highly appreciated.

  


  Problem 1 : Speaker movement occasionally triggers false positives. If there is some possibility to restrict frame comparison to a certain (spatial, cropped) area of the scene then I could focus on the slide area and this would greatly help.

  


  Problem 2 : Speed of slide transition is slow so I occasionally miss a transition since the change from frame(n) to frame(n+1) is too small. It would be great if I could compare, for example, frame(n) to frame(n+10) for threshold detection. ffmpeg scene detection : check only every nth frame ? does not help here, because it only checks every n-th frame but still compares a frame with its immediate neighbor.

  


  Of course, both problems can be solved by producing a cropped version with reduced framerate. However, I am looking for a solution where I can do this in a single pass with some complex filter expression ... and this is exactly the place where my own experience with ffmpeg fails me and where I would appreciate some help.

  


  Problem 3 : Occasionally a single slide transition triggers several times in a row throughout the transition. I have no idea how to solve this in ffmpeg.