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• Started Programming Young

  6 septembre 2011, par Multimedia Mike — Programming

  I have some of the strangest memories of my struggles to jump into computer programming.

  Back To BASIC
  I remember doing some Logo programming on Apple II computers at school in 5th grade (1987 timeframe). But that was mostly driving turtle graphics. Then I remember doing some TRS-80 BASIC in 7th grade, circa 1989. Emboldened by what very little I had learned in perhaps the week or 2 we took in a science class to do this, I tried a little GW-BASIC on my family’s “IBM-PC compatible” computer (they were still called that back then). I still remember what my first program consisted of. Even back then I was interested in manipulating graphics and color on a computer screen. Thus :

  10 color 1
  20 print "This is color 1"
  30 color 2
  40 print "This is color 2"
  ...
  

  And so on through 15 colors. Hey, it did the job– it demonstrated the 15 different colors you could set in text mode.

  What’s FOR For ?
  That 7th grade computer unit in science class wasn’t very thick on computer science details. I recall working with a lab partner to transcribe code listings into a computer (and also saving my work to a storage cassette). We also developed form processing programs that would print instructions to input text followed by an “INPUT I$” statement to obtain the user’s output.

  I remember there was some situation where we needed a brief delay between input and printing. The teacher told us to use a construct of the form :

  10 FOR I = 1 TO 20000
  20 NEXT I
  

  We had to calibrate the number based on our empirical assessment of how long it lasted but I recall that the number couldn’t be much higher than about 32000, for reasons that would become clearer much later.

  Imagine my confusion when I would read and try to comprehend BASIC program code I would find in magazines. I would of course see that FOR..NEXT construct all over the place but obviously not in the context of introducing deliberate execution delays. Indeed, my understanding of one of the fundamental building blocks of computer programming — iteration — was completely skewed because of this early lesson.

  Refactoring
  Somewhere along the line, I figured out that the FOR..NEXT could be used to do the same thing a bunch of times, possibly with different values. A few years after I had written that color program, I found it again and realized that I could write it as :

  10 for I = 1 to 15
  20 color I
  30 print I
  40 next I
  

  It still took me a few more years to sort out the meaning of WHILE..WEND, though.

• FFMPEG How to join the audio of one song into the instrumental of another song

  28 mai 2020, par Patrice Andala

  The Problem :

  



  So I am creating an android app where people can upload music and I want people to be able to take the vocals of one song and the instrumental from another song and merge them to create a different song, and I think the android FFMPEG library is the best way to accomplish this.

  



  What I've been able to do :

  



  1.) I have been able to get the instrumental from a song using this command : -i audio1.mp3 -af pan='stereo|c0=c0|c1=-1*c1' -ac 1 output.mp3But the job isn't so good, since I can still hear some audio in the background and not all the audio is removed.

  



  2)I've been able to join two audio files using the command -y -i audio1.mp3 -i audio2.mp3 -filter_complex '[0:0][1:0] amix=inputs=2:duration=longest' -c:a libmp3lame output.mp3

  



  What I need

  



  1) I need to be able to strip just the vocals of a song. Is there an FFMPEG command to do this ?

  



  2)I need a better command to get me the instrumental of the song, since the one I'm using is not goood enough.

  



  3) I need a command that will help me determine the starting point of a song in an instrumental, so that I know where to place the new vocals when I finally merge them.

  



  4) How to get the bpm of an audio file with ffmpeg, since I know songs mix well when their bmp is almost similar

  



  Any help in any of these areas is greatly appreciated.

  


• Make a video file with the song cover for each song in a folder [closed]

  19 novembre 2024, par Nathan Kaufmann

  I have a folder full of wav audio files, and I would want, using ffmpeg in a batch file, to output as many video files as there is songs, with a still image of the cover, with the highest possible audio quality as permitted by ffmpeg. Additionally I would want the metadata (title, artist, album and year) to be copied to the corresponding video file.

  


  For now I have the command :
ffmpeg -f lavfi -i color=c=black:s=640x480 -i song.wav -c:v libx264 -tune stillimage -pix_fmt yuv420p -shortest -c:a aac -ar 96000 -b:a -metadata title="My title" 1000000000k output.mp4

  


  But it only makes a black video with the song, with the highest quality sound I could set, and it changes the title but I couldn't find how to change it to the song's title. Also for now I don't know how to automate it for a whole folder.