Newest 'ffmpeg' Questions - Stack Overflow

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• Writing to a custom output with FFmpeg

  3 septembre 2015, par Joe Allen

  So I have been reading about using AVIO struct to be able to load from a custom source. Here are the posts I have been reading:

  How can libavformat be used without using other libav libraries?

  Reading a file located in memory with libavformat

  But in each of these posts talk about loading data from a different source. What about if you want to write your converted data to a std::string for instance? How would you go about it. Ideally, I want to avoid as much file I/O as possible.

• ffmpeg capture single window screen freezes with only mouse working

  2 septembre 2015, par Saad Abdullah

  Scenario and Problem: I have two machines with windows 8.1 installed. On one computer, every thing works fine with video recording by using gdigrab to capture a window by title. But on the other pc, the desktop recording works fine, but when it comes to capture single window by title, the video freezes with only mouse working. (to be exact, if i play webcam or images in the window being captured, it records the content too, but when some video is played it starts showing black screen or freezed at first frame.

  Commandline: here is the commandline args

  ffmpeg -f gdigrab -framerate 30 -i title="Video - VLC media player" germ.flv
  

  What can be the issue on the other pc?

• ffmpeg - Record Server Desktop Without Connection

  2 septembre 2015, par Chris.

  I set up an application which uses ffmpeg to record a desktop on an Amazon AWS EC2 instance having Windows Server 2012 R2 installed. It records the desktop and puts the result into a file.

  This works as long as a Remote Desktop or TeamViewer connection is active for that particular Amazon AWS EC2 instance. As soon as I close the Remote Desktop and TeamViewer connection the recording stops and continues as soon as I reconnect.

  I assume that it's because the GPU doesn't deliver frames without a display in use.

  How can I make sure that frames are constantly being rendered so that I can record them?

• What is the variable "a" in ffmpeg ?

  2 septembre 2015, par coco

  In using the scale filter with ffmpeg, I see many examples similar to this:

  ffmpeg -i input.mov -vf scale="'if(gt(a,4/3),320,-2)':'if(gt(a,4/3),-2,240)'" output.mov
  

  What does the variable a signify?

• How to get and use FFMPEG in a Objective-C OS X app

  2 septembre 2015, par Coiman

  I have an application where I need to use FFMPEG for something (video from AVCaptureSession encoded to MPEG(1)).

  So far I have been looking for ways to build and use FFMPEG in my project but I have not found a way for OS X. All of the wrappers I have found so far are for iOS instead of OS X.

  I need a solution that works on OS X and I would prefer if you explained how to use it a bit (build instructions, getting it into the Xcode project, code samples).

  Thanks in advance for your help. :)