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• How do I edit the PKG_CONFIG_PATH environment variable on windows ?

  2 janvier 2024, par Project PowerPoint

  I'm trying to use pkg-config to combine files from ffmpeg into a library so I can use them as such in my program. However, I can't seem to figure out how to get pkg-config to look in another location.

  


  It's worth mentioning that I'm compiling this program into a node API addon for a node project, so I'm using pkg-config from NPM and CMake-js.

  


  Currently, pkg-config looks in C:/Strawberry/c/lib/pkgconfig

  


  I want it to look in C:/ffmpeg/lib/ as well.
I've tried looking for how to do this, but I can only find how to do it on linux.

  


  In the one stackoverflow question which is similar, the link provided is broken : link to question , broken link provided

  


  Otherwise, I find conflicting info saying pkg-config in windows doesn't consider PKG_CONFIG_PATH environment variable. I can't test this if I can't find out how to actually do it.

  


  I've also tried copying the ffmpeg folder inside C:/Strawberry/c/lib/pkgconfig so it can find it. Even then, it 'cant find libavcodec.pc' despite being located in that folder (albeit several folders deep).

  


  How do I change the environment variable for pkg-config ?

  


• HTML5 video (mp4) won't seek properly with Firefox 37/38/39 on Apache

  10 juin 2015, par degenerate

  Edit : Turns out this is actually a Firefox bug.

  Firefox will not seek properly past the loaded point in any mp4. It doesn’t matter what program encoded the file or where it came from ! I am hosting on Apache 2.2.29

  Obvious things you will probably ask me :

  • Yes I used -movflags faststart when encoding with ffmpeg
  • Yes AddType video/mp4 .mp4 is set correctly
  • This is a new problem without any changes to the server ; only the newer firefox (version 36, 37, 38+) has this issue.
  • Chrome works WONDERFULLY so this is a problem isolated to Firefox, and only started happening sometime in 2015 with one of the newer versions. Nothing was changed on the server.

  Firefox makes hundreds of requests after seeking to any point in the mp4. The closer to the end of the file, the more requests are made. Eventually after several minutes it will stop sending requests and finish playing ; I assume when this happens it has downloaded the entire mp4.

  Notice the byte-range request on chrome has a definitive size, yet all the requests one firefox are XXXXXX- with no ending byte...

  (FIREFOX = BAD, hundreds of requests — right click image to see full resolution)

  

  (CHROME = GOOD, one single request)

  

  Regarding keep-alives : I tried turning keepalive on and off. I get the same results in both browsers. Chrome is always able to seek, firefox is never able to seek.

• ffmpeg converting video to images while video file is being written

  20 décembre 2018, par user3398227

  Hopefully an easy question for an ffmpeg expert !

  I’m currently converting large (+6GB) mpeg video into an image sequence - which is working well using the below ffmpeg command :

  ffmpeg -i "input.mpeg" -vf - fps=fps=2 -f image2 -qscale 1 -s 1026x768
  "output%6d.jpg"

  however i have to wait for the file to finish being written to disk before i kick off ffmpeg - but this takes a good hour or so to finish writing, but what i’ve noticed is that ffmpeg can start reading the file while its being written to disk - the only snag here is it gets to the end of the file and stops before the file has finished being written...

  Question is, is there a way that ffmpeg can convert to an image sequence at the same pace the video is being written (and not exit out ?)... or know to wait for the next frame to be written from the source. (unfortunately the input doesn’t support streaming, I only get a network drive and file to work off.. ) I thought i read somewhere that ffmpeg can process at the video frame rate but cant seem to find this command for love or money in the doco !!

  Thanks !