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• Android : How to record the mobile screen without using USB cable ?

  21 juin 2012, par Rajesh

  I want to build an application which would record my screen activities and would store them in a video file.

  1) I need to take the screenshots of my screen movements at periodic intervals and store them on the SD card.

  2) How can I create the video from the images which are already available on my SD card. I have tried with the FFMPEG. But I have encountered a few problems I don't know how to solve. The truth is I don't know the program to convert them.

  3 ) Is it possible to show the picture in my camera ?? That means if a user opens the camera from my app, it should show the pictures which are available on the SD card. If so, please advice me.

  EDIT : I have made a sample which can capable of taking 7 screen shots per second.

  Thanks,
  Rajesh .

• FFMPEG UDP MPEG2TS to Cable TV Channel - Video & Audio Problems

  30 janvier 2019, par user2884023

  Channel Feed Distored Picture

  $ ffmpeg
  
  -re
  
  -i playlist1.txt
  
  -b:v 15000k 
  
  -bufsize 15000k
  
  -maxrate 16000k
  
  -f mpegts "udp://XXX.XXX.X.XXX:XXXX"

  I have mpeg2.ts files encoded to CBR15mbs.
  The files are set to different frame rates. Although initial testing was just playing 1 file.
  They are currently 1080p I think without declaring the frame rate, they are defaulting to 30fps.
  From the server locally via Port2 (that we are using to send our feed), everything plays fine via FFPLAY.
  The final out put local CATV is pixelated and distorted, the video is missing data playing slowly and the audio is choppy / distorted.
  I even tried just a 192kps .mp2 and it played distorted on the CATV channel.
  They set me up with a cable modem. 2 ports, 1 WAN, 1 a dedicated port to feed their head end and I have a fiber synchronous 20/20 connection.

  I am guessing its a packet issue, perhaps on our end with our FFMPEG setup ? And maybe FFPLAY isn’t as sensitive to the actual distro process.

  Perhaps the secret lies here, but there isn’t much info about them, even scouring the net.

  ?pkt_size=188&buffer_size=65535

  For example what is this one :

  broadcast=1|0

  Explicitly allow or disallow UDP broadcasting.

  I apologize if data is missing, please ask questions. I didn’t want to write a novel.

  I am hoping some can provide the correct code so my signal is corrected. I assume the problem is on our end, and not the CATV end. At least I can try some solutions on our end first. I can make real-time FFMPEG changes to the server, and see the channel results instantly so that helps.

  Finally, the fact it wouldn’t even play a .mp2 audio file cleanly on the channel, does make me wonder, is there a problem on their end, or is it a config on our end, and we just need the correct answer ?

• Why does ffplay read both video and keyboard input from stdin ?

  27 janvier 2016, par cxrodgers

  I’m trying to compress a video feed from a webcam while simultaneously displaying it, using ffmpeg and ffplay. I do actually have this working, but I want to disable the ffplay window from interpreting keyboard presses.

  It took me a while to figure this out but here’s what I’m using :

  ffmpeg -f video4linux2 -i /dev/video0 -vcodec mpeg4 -f rawvideo - \
  
    | tee output.mkv \
  
    | ffplay -fflags nobuffer -

  (Actually I am doing all of this from a Python script using the subprocess module. Here I have represented it as a straightforward terminal command because the result is the same.)

  So this actually works and does everything I want. The only thing is that if the ffplay window is active, it interprets keypresses (like "F" for fullscreen). Instead I want it to completely ignore all keypresses.

  My questions :

  1. How is this even possible ? I thought I was redirecting video input to stdin, and then telling ffplay to read video from stdin. How can keypresses be multiplexed on the same pipe ?
  2. How can I disable this behavior ? I tried "-nostdin" but it doesn’t work with my version.

  # ffplay -nostdin output.mkv

  ffplay version N-77455-g4707497 Copyright
  (c) 2003-2015 the FFmpeg developers built with gcc 4.8 (Ubuntu
  4.8.4-2ubuntu1 14.04)

  ...

  Failed to set value ’output.mkv’ for option ’nostdin’ : Option not
  found