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• Streaming live video from ios

  12 février 2014, par John

  I have a need to stream video from the iPhone/iPad camera to a server. It looks like this will need to be done with AVCaptureSession but I don't know how to best architect this.

  I found this post :

  streaming video FROM an iPhone

  But it doesn't handle the "live" part, latency needs to be 2 or 3 seconds at most. Devices can be constrained to 4 or 4S capability if needed, and there is no requirement for HD, VGA is probably what we'll end up with. I assume any solution would use ffmpeg, I haven't found any more appropriate library.

  How is this best accomplished ?

• libswscale/swscale.h : No such file or directory

  23 octobre 2019, par Aman

  When installing Sumo-0.30.0 on Ubuntu 16.04, make resulted in the following error :

  make[4]: Entering directory '/home/<path>/sumo-0.30.0/src/gui'
  
  g++ -DHAVE_CONFIG_H -I. -I../../src  -I/home/<path>/sumo-0.30.0/./src  -I/usr/include/ffmpeg -I/usr/local/include -I/usr/include/fox-1.6 -I/usr/include/gdal  -I/usr/local/include -I/usr/include   -msse2 -mfpmath=sse -O2 -DNDEBUG  -MT GUIViewTraffic.o -MD -MP -MF .deps/GUIViewTraffic.Tpo -c -o GUIViewTraffic.o GUIViewTraffic.cpp
  
  In file included from GUIViewTraffic.cpp:36:0:
  
  ../../src/utils/gui/div/GUIVideoEncoder.h:58:32: fatal error: libswscale/swscale.h: No such file or directory
  
  compilation terminated.
  
  Makefile:449: recipe for target 'GUIViewTraffic.o' failed
  
  </path></path>

  Having installed all the prerequisite libraries as mentioned in Installing/Linux Build Libraries and verifying my ffmpeg version is the latest one, I proceeded with ./configure command from installation guide which was successful. The last lines of ./configure result shows that ffmpeg is enabled.

      Optional features summary
  
  -------------------------
  
  Enabled: TRACI PROJ GDAL GUI ffmpeg
  
  Disabled: Debug Profiling Coverage PIC UnitTests Python OSG

  I could neither locate libswscale directory nor swscale.h even after going through similar post here.

  According to another post here, someone mentions that on Ubuntu the problem is that ffmpeg package does not install swscale.h.

  How do I fix this ?

• How to "stream" images to ffmpeg to construct a video in .NET 6

  13 septembre 2021, par alkasel

  I'm using FFMPEG command line tool to create a video. As of now I retrive images from memory, but I'd like to avoid writing them to memory in first place and feed FFMPEG directly from memory.

  


  I tried accord-framework.net and it works very well, but now I've switched to .NET 6 and it is not supported (the functionality I used is based on AForge.Video.FFMPEG, an archived project not supporting recent frameworks).

  


  Now as I understand it is possible to have FFMPEG to work on streams instead of images saved on disk. In this post there is a very nice example of doing it in Python.

  


  However I don't know how to do this on .NET 6 using System.Diagnostics.Process : From this post I undestand that I could have FFMPEG take images from standard input using the syntax

  


  -i -


  


  The problem is that I cannot write on standard input before the System.IO.Process (cmd.exe ... \C ffmpeg.exe .... ) has started (I get System.InvalidOperationException : "StandardIn has not been redirected"). However, as soon as such process start, since it find standard input empty, it ends immediately, so I cannot make it in time to fill standard input.

  


  My code looks like this :

  


          MemoryStream memStream = new MemoryStream();

        // Data acquisition
        [...]
        bitmap.Save(memStream, System.Drawing.Imaging.ImageFormat.Bmp);
        [...]

        string ffmpegArgument = "/C ffmpeg.exe -y -i - -c:v libx264 -crf 12 -pix_fmt yuv420p -c:a libvo_aacenc -b:a 128k [...];

        Process cmd = new Process();
        cmd.StartInfo.FileName = "cmd.exe";
        cmd.StartInfo.Arguments = ffmpegArgument;
        cmd.StartInfo.UseShellExecute = false;
        cmd.StartInfo.RedirectStandardInput = true;
        cmd.Start();
        cmd.StandardInput.Write(memStream);


  


  Thanks to everyone who will answer.