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• Internecine Legal Threats

  1er juin 2011, par Multimedia Mike — Legal/Ethical

  FFmpeg and associated open source multimedia projects such as xine, MPlayer, and VLC have long had a rebel mystique about them ; a bunch of hackers playing fast and loose with IP law in order to give the world the free multimedia experience it deserved. We figured out the algorithms using any tools available, including the feared technique of binary reverse engineering. When I gave a presentation about FFmpeg at Linuxtag in 2007, I created this image illustrating said mystique :

  
  
  

  It garnered laughs. But I made the point that we multimedia hackers just press on, doing our thing while ignoring legal threats. The policy has historically worked out famously for us– to date, I seem to be the only person on the receiving end of a sort-of legal threat from the outside world.

  Who would have thought that the most credible legal threat to an open source multimedia project would emanate from a fork of that very project ? Because that’s exactly what has transpired :

  
  
  Click for full threat
  

  So it came to pass that Michael Niedermayer — the leader of the FFmpeg project — received a bona fide legal nastygram from Mans Rullgard, a representative of the FFmpeg-forked Libav project. The subject of dispute is a scorched-earth matter involving the somewhat iconic FFmpeg zigzag logo :

  Original 2D logo		enhanced 3D logo

  To think of all those years we spent worrying about legal threats from organizations outside the community. I’m reminded of that time-honored horror trope/urban legend staple : Get out ! The legal threats are coming from inside the house !

  I’m interested to see how this all plays out, particularly regarding jurisdiction, as we have a U.K. resident engaging an Italian lawyer outfit to deliver a legal threat to an Austrian citizen regarding an image hosted on a server in Hungary. I suspect I know why that law firm was chosen, but it’s still a curious jurisdictional setup.

  People often used to ask me if we multimedia hackers would get sued to death for doing what we do. My response was always, “There’s only one way to know for sure,” by which I meant that we would just have to engage in said shady activities and determine empirically if lawsuits resulted. So I’m a strong advocate for experimentation to push the limits. Kudos to Michael and Mans for volunteering to push the legal limits.

• Building FFMPEG for Visual Studio development

  28 juillet 2016, par gboy

  I’m trying to use ffmpeg in Visual Studio 2013 C++ software (ultimately as part of an OpenCV project) - but right now I’m just trying to get basic FFMPEG functionality. In general, when building in Visual Studio, I build 64—bit software with Multi-threaded DLL runtime libraries. I have built ffmpeg using the general instructions for ’Native Windows compilation using ... MinGW-w64’ at http://ffmpeg.org/platform.html#Windows (I provide a more detailed set of steps I followed below...).

  After building the ffmpeg software on my system, I tried to create a simple ’hello world’ project in Visual Studio 2013. Specifically, I tried to implement the initial tutorial file presented at http://dranger.com/ffmpeg/tutorial01.html. Upon building the project, I get the error :

  c :\msys64\usr\local\ffmpeg\libavutil\common.h(45) : fatal error C1083 : Cannot
  open include file : ’libavutil/avconfig.h’ : No such file or directory

  The following are the detailed steps I took to build ffmpeg and create my basic Visual Studio project :

  ============ Building ffmpeg ===============

  1. Downloaded and intalled msys2-x86_64-20160205.exe from http://msys2.github.io
  2. Ran update-core to update the Msys2 install
  3. Ran pacman -Suu (twice) to complete the update (following the instructions about updating shortcuts, etc.)
  4. Then I quit out of the MSys2 shell and opened the MinGW-w64 Win64 Shell. In this new shell :
  5. Installed the following packages using pacman -S The list of packages I installed is : make, pkg-config, diffutils, mingw-w64-x86_64-yasm, mingw-w64-x86_64-gcc, mingw-w64-x86_64-SDL, git
  6. Then I cd’d into cd /usr/local
  7. Ran git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
  8. I wanted to build the ffmpeg library ’out-of-tree’ of this MSys64 folder. So, in the regular file system of my Windows machine I created a folder at C :\ffmpeg
  9. Back in the Win64 Shell, I cd’d to this new folder : cd /c/ffmpeg
  10. Then ran /usr/loca/ffmpeg/configure --enable-shared
  11. Then make -r
  12. And, finally make install

  Now, if I had to guess, my ’flaw’ was in the options I used when calling the ’configure’ script of ffmpeg. Do I need to use particular options so that I can take the ffmpeg libraries built here and use them as dynamic (DLL) libraries in Visual Studio ?

  ========== Configuring my Visual Studio Project ============

  Here’s how I created a simple hello world project in Visual Studio to see if ffmpeg is working.

  1. I created a new Visual C++ ’Empty Project’ in Visual Studio 2013

  2. I then configured the project properties as follows :

     a. In C/C++ => General => Additional Include Directories, I put

     C :\msys64\usr\local\ffmpeg

     b. In Linker=>General => Additional Library Directories, I pointed to each of the built library folders (basically I pointed at all of the libraries that were built to ensure I was not inadvertently missing the critical one). The list is as follows :

     • C :\ffmpeg\libavcodec
     • C :\ffmpeg\libavdevice
     • C :\ffmpeg\libavfilter
     • C :\ffmpeg\libavformat
     • C :\ffmpeg\libavutil
     • C :\ffmpeg\libswresample
     • C :\ffmpeg\libswscale
     • C :\ffmpeg

     c. In Linker=> Input => Additional Dependencies, I pointed to the particular libraries (again - I pointed to all of the ones present). The list is :

     • avcodec.lib
     • avdevice.lib
     • avfilter.lib
     • avformat.lib
     • avutil.lib
     • swresample.lib
     • swscale.lib

  3. I then created a new source file called ’tut01.c’ and copied/pasted the code from http://dranger.com/ffmpeg/tutorial01.c

  4. Then hit F7 and got the error specified above about not finding avconfig.h

  The above is my best guess as to the steps I need to follow to get this working in Windows (btw, it’s Windows 10, 64-bit) & Microsoft Visual Studio 2013. What should I change to get this basic program to build and run ?

• How to restrict fetching hls segment files on pause in Safari (MacOS and iOS)

  24 juillet 2021, par Charan Kumar

  We generate hls files with segment size of 3 seconds. We use hlsjs for non Safari browsers and Safari has native hls support.

  


  In hlsjs world we were able to restrict how much ahead we should be in terms of buffer using maxMaxBufferLength, where as we are unable to find similar solution for Safari. In Safari, after loading video m3u8, even if I pause after a second, in the network tab I can see that all the segments are being fetched which I would like to restrict.

  


  I'll not be able to share our examples due to company polices. But, a public example file by hls.js is attached below :

  


  https://test-streams.mux.dev/x36xhzz/url_6/193039199_mp4_h264_aac_hq_7.m3u8 try opening this url in Safari, and try pausing the video, you'll see that it continues to download. Where as if you open same one using https://hls-js.netlify.app/demo/ with maxMaxBufferLength : 5 it won't happen.

  


  Is there an option at ffmpeg to make it controlled buffer or some solution that we should do for Safari by listening to events ?

  


  Found the same question here -> https://developer.apple.com/forums/thread/121074