Recherche avancée

Sur d’autres sites (7203)

• Ffmpeg : Scale+crop video then overlay image ?

  8 juillet 2019, par skitzo

  This is my first SO question. Help me help you help me : does this question need any clarification ?

  Goal : A script that makes Instagram-ready videos with audio, and a logo overlay. The script takes in an audio and video source and combines them. Important : the logo should have a consistent position and size for each video. This probably means that all output videos should have the same width x height.

  Any alternate approaches are welcome !

  The ffmpeg command I’m calling from python is below. I try to scale the video to 720 :-2 (so auto-height), then crop a 500x500 square from the center. The choices of 720 and 500 are arbitrary ; better approaches are welcome.

  ffmpeg -i video.mp4 -i logo.png -i audio.mp3 -filter_complex "[0:v]scale=720:-2,crop=500:500[bg];[bg][1:v] overlay=(W-w)/2:(H-h)/2" -pix_fmt yuv420p -map 0:v -map 2:a -shortest + output.mp4

  This script errors on some videos.

  [Parsed_crop_1 @ 0x7fcf96401f00] Invalid too big or non positive size for width '500' or height '500'
  
  [Parsed_crop_1 @ 0x7fcf96401f00] Failed to configure input pad on Parsed_crop_1

  I’m new to ffmpeg so please guide me to correct usage of filter_complex. Thank you !

• How is better to use ffmpeg with the ASP.NET Core, on Linux ?

  26 mars, par user8245660

  I've got the project (ASP.NET Core, on Linux) where are the several tasks, which relate to the video converting and extracting frames from the video file.

  



  I thought about the two possible options :

  



  

  1. using ffmpeg console utility

  


  2. using P/Invoke with the libavcodec library and others, which ffmpeg uses

  


  



  The second option is miles harder and may be very impractical, because it reminds me developing the new wrapper/library, instead of using the ready products.

  



  I've done googling, but there aren't well-done projects for the C#/ASP.NET Core on Linux platform. There are some good for C++ and Python, but NOT for the C# on Linux/.NET Core.

  



  I decided to look at the first option, which I suppose would be more easier and practical. But, there are some weak places, which can produce many problems. We understand (I suppose), that using the 1st option, the end-developer shall use the process forking. So, there could be possible problems with the process idle and other possible issues...

  



  I'm asking about your practice, because it's my first experience on Linux platform with the video converting/sampling using C#. I've used the Expression Encoder .NET library on Windows platform, but it's other story and it makes no sense, right now.

  



  May be, there are other options, which I can't see right at the moment. I dislike the 1st option because of possible unhandled exceptions, because ffmpeg with such role becomes the black box for the ASP.NET Core backend.

  


• Is there somewhere that I can get pre-compiled libraries for reading mp4 files (MinGW32, Windows, C++)

  25 juin 2023, par Gorlash

  I would like to find a simple library that I can link to a console-mode C++ utility, to display info about mp4 files (play length, width, height, maybe bit-rate)... I don't need to write or convert data, just read and display it.

  


  The library should come with the standard SDK components :
.lib, .dll, .h, examples.c or examples.cpp, api docs
I build with MinGW 32-bit, not with Visual C++.

  


  I am developing a console media-listing utility to display interesting data about various audio/video media files. It works for almost all formats that I could wish to examine, but mp4 has ended up being a real headache !! mp3 was challenging enough, but I was able eventually to find a short example program in C that would decode the various formats, and over a couple of years I weeded out a couple of bugs with that... but mp4 puts mp3 to shame !! There don't seem to be any single-source-file utilities that will handle parsing mp4 files successfully, so I'm falling back on looking for a library that will handle this for me, with a simple API...

  


  I've looked at a number of common libraries for this purpose (ffmpeg, libvlc, opencv, Bento4, some others) but none of them come as pre-compiled libraries, ready for use, and none of them are trivial to build, especially with MinGW...