Recherche avancée

Sur d’autres sites (13017)

• How to compile FFmpeg with bash on Windows 10 ?

  10 août 2017, par user2980183

  In the Creators Update (1703), the Windows 10 bash linux (WSL) can run native windows tools. So, under Windows 10, you can now compile FFmpeg with Visual Studio and the required linux utilities, natively, without having to install MinGW or other interop crap software.

  Here is how I tried to compile FFmpeg (using MSVC 2017 toolchain) :

  • I started the bash shell from "Developer Command Prompt for VS 2017" to set PATH variable to find the MSVC compiler/linker.

  • I installed the "make" tool with the following command : "sudo apt-get install make".

  • To call Windows program from the bash shell, I have to type the command with its .exe extension. So, I must adapt the "configure" and "compat/windows/makedef" files to add ".exe" at the end of "cl", "link" (no confusion possible with the /usr/bin/link), "dumpbin" and "lib" executables :

  configure

  cl_major_ver=$(cl 2>&1 | sed -n 's/.*Version \([[:digit:]]\{1,\}\)\..*/\1/p')
  
      if [ -z "$cl_major_ver" ] || [ $cl_major_ver -ge 18 ]; then
  
          cc_default="cl.exe"
  
      else
  
          cc_default="c99wrap cl"
  
      fi
  
      ld_default="link.exe"
  
      nm_default="dumpbin.exe -symbols"
  
      ar_default="lib.exe"

  compat/windows/makedef

  lib.exe -out:${libname} $@ >/dev/null
  
  
  
  arch=$(dumpbin.exe -headers ${libname} |
  
     tr '\t' ' ' |
  
     grep '^ \+.\+machine \+(.\+)' |
  
     head -1 |
  
     sed -e 's/^ \{1,\}.\{1,\} \{1,\}machine \{1,\}(\(...\)).*/\1/')
  
  
  
  dump=$(dumpbin.exe -linkermember:1 ${libname})

  I hope the FFmpeg build tool chain will be adapted in the future to support natively compiling on bash on Windows...

  • If you want to set an absolute path for YASM in the "configure", you have to use the following pattern /mnt/[letter_partition]/path/yasm.exe.

  ./configure --toolchain=msvc --yasmexe='/mnt/e/Home/Important/Development/Toolkit/Tools/yasm-1.3.0-win32.exe' [all other settings you need]

  • The make command should generate the lib as expected.

  • I tried to type make install but I get the following error :
    No rule to make the target "libavutil\x86\x86util.asm", needed for "libavutil/x86/cpuid.o".

  I don’t know what is wrong...

  As you can see, building FFmpeg on bash under Windows is not very developer friendly yet. Compiling FFmpeg in Windows should be as easy as Linux. Do you know if there is an easier way to proceed ? Do you know if this compilation scenario will be officially supported in next versions of FFmpeg (I don’t find any roadmap) ?

  Thanks.

• NodeJS spawn ffmpeg thumb %t in filename

  7 septembre 2017, par asafg

  I’m creating screenshots at 15 fps with this NodeJS code :

  var spawn   = require('child_process').spawn;
  
  var args    = ['-ss', '00:00:07.86', '-i', 'filename.mp4', '-vf', 'fps=15', '/out%d.png'];
  
  var ffmpeg  = spawn('ffmpeg', args);

  This works fine, but I want the time stamp of each screenshot in the filename.

  from FFMPEG docs :

  %t is expanded to a timestamp

  But putting ... ,'/out%t.png'] fails and prints :

  grep stderr: [image2 @ 0x7f828c802c00] Could not get frame filename 
  
  number 2 from pattern '/Users/***/projects/out%t.png' (either set updatefirst or use a pattern like %03d within the filename pattern)
  
  av_interleaved_write_frame(): Invalid argument
  
  ...
  
  grep stderr: Conversion failed!
  
  
  
  child process exited with code 1

  So that doesn’t look like the way to go.

  How do i get the timestamp for each screenshot ?

  Thanks

• FFMPEG- filtered video coming rotated

  31 août 2017, par Alok Kumar Verma

  After a lot of struggle I finally did what I want, i.e., save filters using ffmpeg now for now I’m using the Vintage filter command line from FFMPEG in order to add Vintage Filter to it. But there is a certain problem, and the problem is that The output is coming 90 degree clockwise rotated which is not what I wanted.

  I’ve used this command from FFMPEG documentation, and the vintage filter application is working fine.

  String complexCommand[] = {"-y", "-i", stringBuilder.toString(), "-strict", "experimental", "-vf", "curves=vintage",
  
              "-s", "640x480", "-r", "30", "-aspect", "4:3", "-ab",
  
              "48000","-ac", "2", "-ar", "22050", "-b:a", "2097k", "-vcodec", "mpeg4", savingPath};

  I’ve read about how to do the rotation from this link : Video Rotation using FFMPEG

  Now what I’ve tried is rotating the video 90 degree counterclockwise which transpose=2 after -vf from the documentation.

  1.This is what I’ve done :

  String complexCommand[] = {"-y", "-i", stringBuilder.toString(), "-strict", "experimental", "-vf", "transpose=2", "curves=vintage",
  
              "-s", "640x480", "-r", "30", "-aspect", "4:3", "-ab",
  
              "48000","-ac", "2", "-ar", "22050", "-b:a", "2097k", "-vcodec", "mpeg4", savingPath};

  But I got this problem in my logcat, i.e.,

  [NULL @ 0xaaab0c00] Unable to find a suitable output format for 'curves=vintage' curves=vintage: Invalid argument

  2. I’ve also done this in order to get the desired result :

  String complexCommand[] = {"-y", "-i", stringBuilder.toString(), "-strict", "experimental", "-vf", "transpose=2",
  
          "-s", "640x480", "-r", "30", "-aspect", "4:3", "-ab",
  
          "48000","-ac", "2", "-ar", "22050", "-b:a", "2097k", "-vcodec", "mpeg4", savingPath};

  Now from above the result is fine, without any filter.

  3. I’ve tried this also which was my last attempt to do that :

  String complexCommand[] = {"-y", "-i", stringBuilder.toString(), "-strict", "experimental", "-vf", "curves=vintage", "-vf", "transpose=2",
  
          "-s", "640x480", "-r", "30", "-aspect", "4:3", "-ab",
  
          "48000","-ac", "2", "-ar", "22050", "-b:a", "2097k", "-vcodec", "mpeg4", savingPath};

  Here is what I have changed : "-vf", "curves=vintage", "-vf","transpose=2"

  But the result was same as in the second, only the rotated video, no fiters applied to the video.

  I’m in need of the result as I’ve reached close to my destination but the problem is there and I need the result as the filtered video with the rotated form and that has to be implemented in the string only.

  I think there is some issue with the string before -vf as the video is getting rotated before -vf and when I apply transpose then the correct result comes. Any suggestion would be appreciated.

  EDITS

  I’ve tried using this too, the && in between the command in order to get the result but I’m getting this error in my logcat :

  E/MediaMetadataRetrieverJNI: getFrameAtTime: videoFrame is a NULL pointer

  What I’ve done is :

  String complexCommand[] = {"-y", "-i", stringBuilder.toString(), "-strict", "experimental", "-vf", "curves=vintage",
  
              "&&", "-vf", "transpose=2", "-s", "720x720", "-r", "30", "-aspect", "4:3", "-ab",
  
              "48000","-ac", "2", "-ar", "22050", "-b:v", "2097k", "-vcodec", "mpeg4", savingPath};