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• Is it possible to separate voices coming to a single channel at runtime (karaoke principle) ?

  10 décembre 2022, par PineapplePie

  I wonder if it is possible to filter separately two voices at runtime ? Let's say, you're listening to a song and there is a singer (voice A) and you're singing as well (voice B), like in karaoke. My only guess - is to filter out any noise by NoiseSuppressor API and then measure the sound intensity, and assume that the voice A will have 40db and voice B - 50db (which is definitely not the way to go bc songs are mostly not linear like that). Maybe there is a way with using pitches/frequency ? If yes, is there any tool which could help me ? Or algo ? I searched for this in the FFMPEG documentation and read some articles, but it seems like it's extremely hard - because I will have the only channel (an android device) that receives both sounds - your singing and singer's singing.

  


  So maybe somebody could guide me on the right path where to look or what I could use/read ?

  


• Merge several images to form a single image using C [on hold]

  6 mai 2016, par Muthu GM

  BufferedImage image1 = ImageIO.read(new File(path, "image1.png"));
  
  BufferedImage image2 = ImageIO.read(new File(path, "image2.png"));
  
  
  
  BufferedImage result = new BufferedImage(1020,780,BufferedImage.TYPE_INT_ARGB);
  
  Graphics g = result.getGraphics(); 
  
  
  
  g.drawImage(image1, 0, 0, null);
  
  g.drawImage(image2, 280, 540, null);
  
  
  
  ImageIO.write(result, "PNG", new File(path, "result.png"));

  I need the alternative way to merge image in C like the above java code.

• Using FFMPEG to add a single frame to end of MP4

  22 août 2017, par J. Scull

  I have written some image acquisition software and as I am acquiring these images I want to add the last image onto the end of a video file (a time-lapse of all images acquired so far). This will give a video view of all the images.

  However I am struggling with trying to add the single frame. I have generated the time-lapse fine. The way I am doing this is waiting until I have gathered 10 images, then I generate the time-lapse. The command I have used to generate the time-lapse I will be adding the frames to is :

  -framerate 40 -start_number N -i DSC_%05d.JPG -c:V libx264 -r 30 output.mp4

  I have tried a few different method, all almost working but none quite working as needed. Here is what I’ve tried, with what command and what the outputs are :

  Concat Demuxer to join JPG to MP4
  The text file with list of files to use for the concatenation looks as follows :

  file ’B00334_1.mp4’
  file ’test_image.jpg’
  duration 10

  The command I use to attempt to join the files is :

  ffmpeg -f concat -i concat.txt -c copy outputfile.mp4

  The output from this attempt is a non-corrupt video (score !) but it only shows the first video and does not show any signs of the new frame, especially not for the specified 10 seconds. (I don’t want it there for 10 seconds more like 0.1, however am using 10 seconds just so I can easily see when successful).

  Converting JPG to MP4 then Concat Demuxer
  So I thought ; Maybe it wants a second video instead of an image, so I’ll create a shor, frame-long video and append that onto the end of the time lapse.

  Command used to create MP4 from JPG :

  fmpeg -loop 1 -i test_image.jpg -r -t 5 test_video.mp4

  This generates the video fine, I get a 5 second long video showing the still image. This video does not load a thumbnail, I’m not sure if this means anything. Now the concat.txt file looks like this :

  file ’B00334_1.mp4’
  file ’text_video.mp4’

  Upon running the same command to call the text file shown in the first example I get the output of the first file (time-lapse) + the time of the concatenated video (success !?). However once you reach the point in the video at which it should be showing the image, it just shows the last frame of the timelapse and it glitches downwards for the 5 seconds of the second video. Basically not at all showing the second video and for however long the second video is the last frame will glitch out for that long.

  Converting both JPG and MP4 to .ts then concating back to MP4
  Command used to attempt to turn JPG to TS file :

  ffmpeg -y -i test_image.jpg -c copy -bsf:v h264_mp4toannexb -f mpegts medium1.ts

  This fails and returns the output :
  Codec 'mjpeg' (8) is not supported by the bitstream filter 'h264_mp4toannexb'. Supported codecs are: h264 (28).
  Changing the codec to the apparently supported h264 doesn’t affect the outcome either.

  Converting JPG to MP4 and then to .ts then concatenating
  Creating two TS files from the MP4s is fine, using the same command as before ffmpeg -y -i input.jpg -c copy -bsf:v h264_mp4toannexb -f mpegts output.ts. The newly made files also display as they should, the ts file created from the image just shows the image and the video shows the video. Now with these two new TS files I should be able to concatenate them together right ?

  I try to join these files with the concat protocol function of FFMPEG. Using this command :

  ffmpeg -y -i ’concat:medium1.ts|medium2.ts’ -c copy -bsf:a aac_adtstoasc output.mp4

  Now this joins the videos together ! The time is appended onto the end, and if you skip to the last few seconds you see the newly added image. However if you let the video play, as soon as it hits that second video the media-player crashes.

  Any help and or ideas are greatly appreciated, I can give more information as needed. Thanks for reading.

  Edit : Output log from Mulvya’s answer :

  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000255c0a0] Auto-inserting h264_mp4toannexb bitstream filter
  
  Input #0, concat, from 'concat.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 44807 kb/s
  
      Stream #0:0(und): Video: h264 (High 4:2:2) (avc1 / 0x31637661), yuvj422p(pc), 2896x1944, 44807 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Output #0, mp4, to 'merged.mp4':
  
    Metadata:
  
      encoder         : Lavf57.66.102
  
      Stream #0:0(und): Video: h264 (High 4:2:2) ([33][0][0][0] / 0x0021), yuvj422p(pc), 2896x1944, q=2-31, 44807 kb/s, 30 fps, 30 tbr, 15360 tbn, 15360 tbc
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0000000002564840] Auto-inserting h264_mp4toannexb 
  
  bitstream filter
  
  frame=   60 fps=0.0 q=-1.0 Lsize=    5564kB time=00:00:01.90 
  
  bitrate=23990.6kbits/s speed=30.6x
  
  video:5563kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.024155%