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• Immidiately display first and latest frame of h264 stream which may sometimes pause

  22 septembre 2016, par jorp

  Steps to reproduce :

  1.Connect android device to linux PC via USB.
  

  2.Run command on pc :
  adb shell screenrecord --output-format=h264 - | ffplay -analyzeduration 1 -

  3.Screenrecord(an Android system tool) will start to capture Android screen, encode by MediaCodec, generate h264 stream, send stream data to ffplay via pipe.

  4.PC will pop up ffplay window, and start display Android screen graphs

  ---

  If adb command runs when Android screen graph keeps static (no pixel color changes), ffplay window won’t pop up, until I touch somewhere to make Android graph changes.

  Question 1 : how to make ffplay to immidiately display the first frame of video when Android screen keeps static and adb commmand runs ?

  I’m not talking about "latency", if Android graph keeps changing, the graphic latency is within 2 second. It’s fast enough.

  when Android graph is static, run command without ffplay :
  adb shell screenrecord --output-format=h264 -

  screenrecord will output H264 stream data immidiately then pause.(See picture below).
  stream data comes first

  Does the data contain all information of first frame graph ?
  If so, how to make ffplay to display it immidiately ?

  ---

  Question 2 : how to make ffplay to immidiately display the latest frame of video when Android screen suddenly become static ?

  When Android screen start casting and Android graph suddenly become static, H264 data stream transfer will pause, while PC graph is different with Android graph.

  For example, I make a popup menu on Android disappear, there has been a fadeoff animation, PC graph pauses and display a translucent popup menu.(See picture below)

  latest graph on pc

  The first and latest frames of stream doesn’t display in ffplay immidiately, they are "missing".
  when Android screen go on changing, the "missing" frames displays.
  So it seems like the latest frames are always in buffer.

  I’ve tried adding these params to ffplay :
  

  -noinfbuf
-fflags nobuffer
-max_delay 0
-sync ext
-preset ultrafast
-tune zerolatency

  
  They cannot solve the problems

  Modifing Android ROM or screenrecord source, making a pixel color changes every frame, may solve the problems(I guess), but it would enlarge data stream, it’s the last choise.
  Is there any solution by adding params of ffplay, or by modifing screenrecord or ffplay source code ?

  PS : mplayer also has the same problem :
  mplayer -demuxer h264es -

• High latency when reading latest frame from H264 stream with FFmpeg

  22 juin 2022, par massivemoisture

  I have an app in c# that receives a H264 video stream of Android device's screen from scrcpy-server (https://github.com/Genymobile/scrcpy).

  


  I want to continously get the latest image from the stream and send it to a web app for streaming.

  


  I created a Process for ffmpeg and gave it these arguments :

  


  -fflags -nobuffer -flags low_delay -probesize 32 -re -i pipe: -g 1 -f rawvideo -pix_fmt bgr24 -an -sn pipe:

  


  I have two threads. One thread to write to stdin of the FFmpeg process the bytes that I get from scrcpy-server. The other thread to read the stdout.

  


  But the image stream that I get has very high latency, especially if there is not much movement on the device's screen. And the latency just keeps mounting up, from a few seconds behind to a minute and more.

  


  How can I fix this issue ?

  


• Updated the Zip.php to reflect the latest version from PHPZip with changes for added compatibility to for instance the Mac OSX Archive Utility.

  10 mars 2012, par Asbjørn Grandt

  m Zip.php Updated the Zip.php to reflect the latest version from PHPZip with changes for added compatibility to for instance the Mac OSX Archive Utility.