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• Tailing last frame of a growing video file

  9 janvier 2012, par ebayindir

  On windows, I have a dynamically created uncompressed avi video file which grows overtime. The application which generates the video file can only write to a physical file. I can start/stop generation of video file and delete the old video file easily.

  I would like to analyze the changing last frame of the growing video file to make some decision depending on the content of the current/latest image in real time. If I can achieve more than 10fps it should be enough.
  I would like to get uncompressed images whenever a new frame available in the video file.

  As a file format I think png could be the best options in that case but I am open to alternatives.
  I wonder if such a thing is possible with ffmpeg or with a similar tool.

  I prefer to analyze the image and make decisions by using a perl+Imager module.
  Tha analyisis requirements are not complicated. Basically I just need to find existence of a few small images in certain locations inside the last frame.
  I would also appreciate if you can suggest an efficient way to get this information in to my application from ffmpeg.
  For example piping directly to my code or reading from saved png files.

  I know perl already has an ffmpeg interface module but as far as I understand that module can't provide the functionality I need.

• Video encoding libraries for iOS

  7 novembre 2011, par peetonn

  I really stucked with that problem, because I haven't seen enough information in the internet regarding video encoding in iOS, however we can observe plenty of apps that deal with the problem of video streaming successfully (skype, qik, justin.tv, etc.)
  I'm going to develop an application, that should send video frames obtained from camera and encoded in h.263 (h.264 or MPEG-4 it is under decision) to a web-server. For this, I need some video encoding library. Obviously, ffmpeg can deal with that task, but it is under LGPL license, which could probably lead to some problems in submitting the app in the AppStore. On the other hand, there are some applications, which are seemed to use ffmpeg library, but only Timelapser clearly states this fact in app description. Does this mean, that other apps are not using ffmpeg or just hiding this information ?

  Please, share your thoughts and experience in this topic. I'm open for dicsussion.

• video captured from iphone gets rotated when converted to .mp4 using ffmpeg

  10 avril 2017, par aqs

  When I try to upload videos captured from my iPhone in my app, the server performs a conversion from .mov to .mp4 so that it can be played in other platforms. However the problem is that when I shoot the video (in portrait orientation) and it is converted (using ffmpeg) and then played back from the server, it appears to be rotated. Any idea ?