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• What is this "fixing the build scripts" for compiling x264 ?

  29 mai 2020, par Blake Senftner

  I am trying to compile an all static build of source-customized ffmpeg libraries with the additional codecs from VideoLAN, such as their x264 codec. I am ultimately building for use in Windows with Visual Studio 2015 C++, so I am comparing a few compiling guides for my instructions.

  



  In the guide linked below (I located via Google searches) shows how to compile x264 with the VS2015 toolchain in MSYS2 without any special steps :
https://gist.github.com/RangelReale/3e6392289d8ba1a52b6e70cdd7e10282

  



  While in this other guide, offered by the compiling guide pages from ffmpeg's web site, it includes steps for "fixing the build scripts" for x264 :
https://www.roxlu.com/2019/062/compiling-ffmpeg-with-x264-on-windows-10-using-msvc

  



  Problem being, when I "fix the build scripts" the configure script no longer finds a C compiler. Building with the first guide seems to work, but it was also written nearly 2 years ago, so perhaps the ffmpeg guide is doing some important fix ? I don't know.

  



  I am :

  



  

  1. Running a "VS2015 x64 Native Tools Command Prompt"

  


  2. launching a pacman loaded msys2 shell via "msys2_shell.cmd -mingw64 -use-full-path"

  


  3. git cloning http://git.videolan.org/git/x264.git

  


  



  and at this point the two compiling guides vary, the first guide just cd's into x264 and runs configure while the other guide does some curl download of a config.guess file and then some sed manipulation of ./configure. Considering these instructions are "endorsed" by the ffmpeg site, I am left wondering what that is doing and how critical is it that these "special" steps cause my x264 configure to fail.

  


• What is this "fixing the build scripts" for compiling x264 ?

  29 mai 2020, par Blake Senftner

  I am trying to compile an all static build of source-customized ffmpeg libraries with the additional codecs from VideoLAN, such as their x264 codec. I am ultimately building for use in Windows with Visual Studio 2015 C++, so I am comparing a few compiling guides for my instructions.

  



  In the guide linked below (I located via Google searches) shows how to compile x264 with the VS2015 toolchain in MSYS2 without any special steps :
https://gist.github.com/RangelReale/3e6392289d8ba1a52b6e70cdd7e10282

  



  While in this other guide, offered by the compiling guide pages from ffmpeg's web site, it includes steps for "fixing the build scripts" for x264 :
https://www.roxlu.com/2019/062/compiling-ffmpeg-with-x264-on-windows-10-using-msvc

  



  Problem being, when I "fix the build scripts" the configure script no longer finds a C compiler. Building with the first guide seems to work, but it was also written nearly 2 years ago, so perhaps the ffmpeg guide is doing some important fix ? I don't know.

  



  I am :

  



  

  1. Running a "VS2015 x64 Native Tools Command Prompt"

  


  2. launching a pacman loaded msys2 shell via "msys2_shell.cmd -mingw64 -use-full-path"

  


  3. git cloning http://git.videolan.org/git/x264.git

  


  



  and at this point the two compiling guides vary, the first guide just cd's into x264 and runs configure while the other guide does some curl download of a config.guess file and then some sed manipulation of ./configure. Considering these instructions are "endorsed" by the ffmpeg site, I am left wondering what that is doing and how critical is it that these "special" steps cause my x264 configure to fail.

  


• GoPro (MP4) video timestamp sync with precision of milliseconds

  3 février 2021, par Raphael Ottoni

  I need your help with a data sync problem... I m currently trying to sync my GoPro video with real world time (a.k.a my notebook). I manage to sync date and time of my notebook and my GoPro 3+ black perfectly. The problem is that when the GoPro save the files in disk it round up the milliseconds on the creation_time (the milliseconds is always 000000) . Thus, turning the perfect sync impossible. In attachment is a picture of the meta information (extracted by ffprobe) of the MP4 video.

  



  My question is : What I have to do, so the GoPro actually save the creation_time with precision of milliseconds ?

  



  Another small question : Looking at the attachment figure, we see the "timecode" which is a time synchronization data in the format of hours:minuts:seconds:frame. I was thinking that I could use the "frame" value to calculate the missing milliseconds value. If we take this attachment, as a example, we can see that the frame value is "36". Meaning that the millisecond that it started to record was the one associated with the 36th frame of the FPS (in this video : 60fps) value : Some thing like 1000/60 * 36 which is 600 milliseconds, thus the actual creation_time of this video would be : 2017-07-19T18:10:34.600

  



  Is this logic right ? it didn't work ! I don't know what else to do.

  



  P.S : I need this kind of time precision because I will sync the video frames with a external sensor data that is recorded at 11hz.

  



  Please Help

  



  

  



  update

  



  I forgot to mention, even if you check the original raw file information, inside the GoPro SSD card, using "stats" to read the creation time (see attachment) it still has the same timestamp without milliseconds.