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• unsynchronized graph when h264 stream pause

  24 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 -

• 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 -

• Write a function to run through a series of commands, zsh

  8 septembre 2016, par Ali Samii

  I am trying to write a function to run through a series of commands, but I have no idea where to start.

  This is the series of commands I want to run.

  find ./ -name '*.mp4' -exec bash -c 'ffmpeg -i "$0" -vcodec libx264 -vf scale=854:480 -cpu-used 5 -threads 8 "${0%%.mp4}-copy.mp4"' {} \;
  
  touch -r video.mp4 video-copy.mp4
  
  rm -rf video.mp4
  
  mv video-copy.mp4 video.mp4
  
  find ./ -name '*.mp4' -exec bash -c 'qt-faststart "$0" "${0%%.mp4}-fs.mp4"' {} \;
  
  touch -r video.mp4 video-fs.mp4
  
  rm -rf video.mp4
  
  mv video-fs.mp4 video.mp4
  
  find ./ -name '*.mp4' -exec bash -c 'ffmpeg -i "$0" -vcodec libvpx -acodec libvorbis -vf scale=-1:480 -cpu-used 5 -threads 8 "${0%%.mp4}.webm"' {} \;
  
  touch -r video.mp4 video.webm
  
  find ./ -name '*.mp4' -exec bash -c 'ffmpeg -i "$0" -ss 00:00:10 -vframes 1 -r 1 -vf scale=-1:480 -f image2 "${0%%.mp4}.jpg"' {} \;
  
  touch -r video.mp4 video.jpg
  
  mv video.jpg thumbnail.jpg

  Can someone help me please.