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• Accessing web content with ffmpeg on android

  9 janvier 2017, par Pure_eyes

  I’m using ffmpeg inside my xamarin.android project,by accessing a statically build version for the corresponding architecture of the device.
  I’m using https://www.johnvansickle.com/ffmpeg/, static builds which support https protocol.
  I’m calling ffmpeg by starting a new process and passing the arguments.Here is a pseudo code for the operation :

  arguments = {'-i',inputFileName,...}
  
  run('./ffmpeg',arguments,redirectOutput = true,...)
  
       .OnOutput(s) => log(s)

  Now,I want to access a file in the web, directly with ffmpeg, since from my testing it is more efficient in term of bandwidth, and speed.

  The problem i’m facing is that because i’m using a static build of ffmpeg, we need to statically link gclib, which results loss of dns resolution as stated in the readme :

  A limitation of statically linking glibc is the loss of DNS resolution. Installing
  nscd through your package manager will fix this or you can use
  "ffmpeg -i http://<ip address="address" here="here">/"</ip> instead of "ffmpeg -i http://example.com/"

  But the content that i’m trying to get provides strictly only through HTTPS,so there is no way to access it via the ip.
  But on Linux systems i had no problem accessing the content(With the same command as for android), thanks to nscd, which isn’t present in android.

  • Is there anyway to use android’s dns resolution ?
  • Or compile ffmpeg
    differently, as stated in this
    question ?Maybe using android
    NDK would default this ?Would ffmpeg even work then ?
  • Or somehow pipe the content, to
    ffmpeg’s stdin, and tell it to input from pipe (Would it still be
    more efficient, than downloading and saving the file, then running
    ffmpeg ) ?

  All suggestions are welcomed !

  EDIT

  As for SushiHangover advice, i was able to implement it via piping,i came up with two ways :

  Process ffmpegProcess = new Process();
  
  ffmpegProcess.StartInfo.FileName = "ffmpeg";
  
  ffmpegProcess.StartInfo.Arguments = ....
  
  ffmpegProcess.StartInfo.UseShellExecute = false;
  
  ffmpegProcess.StartInfo.RedirectStandardInput = true;
  
  ffmpegProcess.Start();
  
  
  
  //Way 1
  
  var data = await GetBytesAsync();
  
  await ffmpegProcess.StandardInput.BaseStream.WriteAsync(b, 0,b.Length);
  
  
  
  // Way 2
  
  await (await GetStreamAsync()).CopyToAsync(ffmpegProcess.StandardInput.BaseStream);

  Which both work, but they aren’t efficient in term of bandwidth as ffmpeg itself, i tested the network traffic with NetBalancer.

  Way 1 (Fresh Data - First time running program) : 401 KB Upload/ 19.7 MB Download
  Way 1 (Second time running program) : 334.3 KB Upload/ 17.7 MB Download
  Way 2 (Second time running program) : 370 KB Upload/ 16.6 MB Download
  Through FFmpeg Only (Fresh Data - First time running program) : 142.4 KB Upload / 5.3 MB Download
  Through FFmpeg Only (Second time running program) : 67.5 KB Upload / 3.7 MB Download

  Who can i overcome the gap ? I speculate that ffmpeg only reads the headers, and able to download only the needed audio stream based on my arguments, rather than the whole video as my snippets do.

• PHP extension writing

  19 octobre 2013, par Mikko Koppanen — Imagick

  I’ve written quite a few PHP extensions over the past years and thought that I could share some of the experience with larger community. PHP internals can be a bit scary at times and in the past I’ve scoured through a lot of extensions to find practical examples of things such as how to return objects from internal functions/methods, how to handle different types of parameters, class properties etc.

  To document some of the experiences I started a project called extsample, in which I plan to add practical examples related to extension writing. There won’t be extensive written documentation outside the code, but hopefully the code itself contains enough nuggets of information to be useful. As the README says, if you need a specific example or clarification on something just open an issue in Github.

  The project is still very fresh but hopefully soon it will contain more examples. Pull requests are also welcome if you have code that you want to share with others.

• FFMPEG Output video quality is getting very low [duplicate]

  7 mars 2018, par Enhance Labs

  This question already has an answer here :

  • ffmpeg - how to apply filters without losing quality
    
    1 answer
    

  i am newer to this FFMPEG. I succesffully create a function where i can merge PNG and Video. But the final output quality is very low and PNG frame is pixelating.

  I tried this :

  ffmpeg.exe -y -i input.file -i water.mark -filter_complex "[1][0]scale2ref[i][m];[m][i] overlay[v]" -map "[v]" -map 0:a? -ac 2 output.file

  What should i do get original PNG frame quality over video.

  Thanks