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• Black overlay appears when merging a transparent video to another video

  13 juin 2012, par RakeshS

  This is what I have done so far :

  Command to create a transparent PNG image :

  convert -size 640x480 -background transparent -fill blue \
  
  -gravity South label:ROCK image1-0.png

  Command to create a transparent video :

  ffmpeg -loop 1 -f image2 -i image1-0.png -r 20 -vframes 100 \
  
  -vcodec png -pix_fmt bgra mov-1.mov

  (as per this post) - I expect this video to be a transparent video.

  Command to overlay a video with another :

  ffmpeg -i final-video.mov -sameq -ar 44100 \
  
  -vf "movie=mov-1.mov [logo];[in][logo] overlay=0:0 [out]" \
  
  -strict experimental final-video.mov

  Above commands works perfect and I have not faced any problem, but I don't get what I expect which is kinda watermarking effect, I want mov-1.mov to be transparent with final-video.mov.

  Questions :

  1. Is there any way to verify if the generated video is transparent ? other than merging ?
  2. Not sure why the above mov-1.mov is not transparent when it is merged with final-video.mov, any info to solve this problem would be great.

  Please help.

• 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.

• compression android video trimmer ffmpeg Exoplayer2 [closed]

  6 mars 2024, par andrew cummins

  I'm trying to compress the video trimmed android video

  


  I have some android code from github that I've been working on. The code is a video trimmer in enter image description hereAndroid. However I'm trying to compress the video after the video is trimmed. Here's the source code

  


  https://github.com/a914-gowtham/android-video-trimmer

  


  I was able to modify the timeline that's generated with a set duration minimum similar to a whatsapp status, with a set max at 10 sec and max 90 seconds

  


  // TrimType.MIN_MAX_DURATION TrimVideo.activity(videoUri) .setTrimType(TrimType.MIN_MAX_DURATION) .setMinToMax(10, 90)  //seconds .start(this,startForResult);

  


  Now all is is working fine but I'm trying to compress the file after the video is trimmed and add an overlay.

  


  Any ideas would be helpful