Sur d’autres sites (4500)

• Play just audio (without launching a window)

  6 août 2017, par Paradise on E

  Is there a way to hide ffplay window on Windows ? I want to play audio files (some of them have video streem as well), but I don’t want a window to appear. Is there any way to hide window completelly ?

  I took a look at their documentationa and I didn’t find a way to do it. I also searched on the internet and didn’t find anything useful. Everyone are asking "Why in the world do you want to hide window..." and similar questions instead of actually posting an answer on how to do it.

  I believe ffplay doesn’t have native way to hide window. So, what are the most easiest alternative ? One of the alternatives would be to download ffplay source code, modify it and recompile it, but it is definitelly not an easy and quick way.

  Is there any way I can launch a process without showing window. It would be great if there is some way to achieve it when ffplay is launched from Node.js (becuase I am using Node.js’s module child_process to play audio files). So, how can I hide ffplay’s window ?

  My current code is following :

  var cp = require('child_process');
  
  var proc = cp.spawn('ffplay', [
  
    '-no_banner',
  
    '-loglevel', 'panic',
  
    playlist.splice(Math.random() * playlist.length | 0, 1)[0]
  
  ]);

  Question

  How to hide ffplay’s window ? If it is possible using ffplay native arguemnts (which I didn’t find in ther documentation) then what arguments to use ? If there is no native way, then is it possible to do it using Node.js’s module child_process ? If not, is there any other way I can hide ffplay’s window ? Again, I must note that some of files I play have video stream as well. So, is there any way to hide ffplay’s window ?

  Thanks in advance.

• avcodec/tiff : Restrict tag order based on specification

  20 août 2020, par Michael Niedermayer

  avcodec/tiff : Restrict tag order based on specification
  "The entries in an IFD must be sorted in ascending order by Tag. Note that this is
  
   not the order in which the fields are described in this document."
  This way various dimensions, sample and bit sizes cannot be changed at
  
  arbitrary times which reduces the potential for bugs.
  
  The tag reading code also on various places assumes that numerically previous
  
  tags have already been parsed, so this needs to be enforced one way or another.
  If this commit causes problems with real world files which are not easy to fix
  
  then some other form of checks are needed to ensure the various dependencies
  
  in the tag reading are not violated.
  Fixes : out of array access
  
  Fixes : 24825/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-6326925027704832
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/tiff.c

• Fast green screen video processing on android device

  17 mars 2015, par Si-N

  I have written an app in iOS that takes two video sources, one with moving character on a green screen and any other video. The program then uses the GPUImage framework to add a chroma key shader via OpenGL ES 2 and then merges each frame (so the bottom frame now shows where the green pixels are) and outputs to a new video file. This happens very quickly, faster than real time.

  I have now been tasked with porting the app to Android. I thought it would be fairly straightforward. After doing some research I think I am wrong. There is an Android port of GPUImage but it does not handle video at the moment. I have done some research and come up with a very basic idea.

  I was wondering if you think this approach is feasible :

  Convert one video file to match resolution and type of other video using ffmpeg or JavaCV wrappers.

  Read frame by frame of each video using ffmpeg as MediaMetadataRetriever is very slow and convert into some RGB format. Use shader to apply chroma key effect so both frames are merged.

  Use ffmpeg to output result to a new file.

  This sounds slow, but if it sounds feasible I will try it out. I am not at all sure about making sure the 2 video resolutions / bitrate etc match. One video will be fixed at 1280 * 720 and the other video source will come from the camera on the device so will be variable. Also I think ffmpeg means using NDK which is a whole world of pain I wanted to avoid.

  I have a headache thinking about it. Any advice would be greatly appreciated.