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• Capturing Clear Stills from H264 Stream

  22 octobre 2013, par David Findlay

  I'm trying to capture still images from a H264 wireless IP camera using FFMPEG. I found a similar question here : How can I extract a good quality JPEG image from an H264 video file with ffmpeg ?

  ffmpeg -y -i rtsp://10.2.69.201:554/ch0_0.h264 -r 10 -f image2 /var/www/camera.jpg

  I've implemented it as shown in that example. You can see a sample of the image I'm getting here : http://storm.woodypointcomms.com.au/camera.jpg. Basically the issue is the bottom part of the image is always blocky. If the sky has more detail and clouds the whole bottom half of the image may be blocky or blurry.

  My camera has limited stream options. One of which is I-Frame interval, you can vary it between 25-100 kbps.

  Does anyone have some suggestions about how I can get a better image ?

• pthread : Avoid crashes/odd behavior caused by spurious wakeups

  18 octobre 2013, par Derek Buitenhuis

  pthread : Avoid crashes/odd behavior caused by spurious wakeups
  This is similar to 5152196b2b47d446d9a509b9bfb318daa26a1f2b.
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DBH] libavfilter/pthread.c

• Working way to make video from images in C#

  26 octobre 2013, par Jim Mischel

  Does anybody have a known reliable way to create a video from a series of image files ? Before you mod me down for not searching for the answer before posting the question, and before you fire off a simple message like "use FFMPEG," read the rest of this message.

  I'm trying to create a video, it doesn't matter too much what format as long as it's widely supported, from a series of images (.jpg, .bmp, etc.). My platform is Windows Server 2008, 64-bit. If I can make the video from within my C# program, that's great, but I'm not averse to writing a series of image files to a directory and then firing off an external program to make a video from those images.

  The only constraints are : it must work on my Windows Server 2008 system, and be scriptable. That is, no GUI programs that require operator intervention.

  I found a number of similar questions on StackOverflow, and have tried several of the solutions, all with varying degrees of frustration and none with anything like success.

  FFMPEG looks like a great program. Maybe it is, on Linux. The two Windows builds I downloaded are broken. Given this command line :

    ffmpeg -r 1 -f image2 -i jpeg\*.jpg video.avi

  One of the builds reads the images and then crashes due to data execution prevention. The other reads the first file and then spits out an error message that says "cannot find suitable codec for file jpeg/image2.jpg". Helpful, that. In any case, FFMPEG looks like a non-starter under Windows.

  One answer to a previous posting recommended Splicer . It looks like pretty good code. I compiled the samples and tried to run, but got some cryptic error message about a file not found. It looks like a COM class isn't registered. I suppose I need to install something (DirectShow, maybe, although I thought that was already installed ?). Depending on what's required, I might have a difficult time justifying its installation on a server. ("What ? Why do you need that on a server ?")

  Another answer suggested the AviFile library from Code Project. That looks simple enough : a wrapper around the Windows AviFile subsystem. Except that the AVI files the package creates appear to have all of the frames, but only the first frame shows when I play the AVI in Windows Media Player. Well, that and if you try to create a compressed video, the program throws an exception.

  So, I'm left wondering if there is a good, reliable way to do what I want : on a Windows system, create an AVI or other common video file format from a series of images, either through a .NET API or using an external program. Any help ?