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• pip installation failure of pyAV with exit status 1181

  11 février 2020, par Kesar Murthy

  I am having trouble installing PyAV through pip. First it required me to download Microsoft Visual C++ Build Tools

  building 'av.buffer' extension
  error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual C++ Build Tools": https://visualstudio.microsoft.com/downloads/
  

  and when I did install this, I get the following error

  LINK : fatal error LNK1181: cannot open input file 'avcodec.lib'
      error: command 'C:\\Users\\Kesar\\AppData\\Local\\Programs\\Common\\Microsoft\\Visual C++ for Python\\9.0\\VC\\Bin\\amd64\\link.exe' failed with exit status 1181
  

  I even tried to build PyAV from source, but the same problem persists. How do I solve this?

• FFmpeg + Dshow + filter_complex How do I identify the input ?

  11 février 2020, par John Doe

  I have a command which will draw a waveform over a background image using the input audio from [1:a] however when I try to feed my microphone as the input the waveform no longer works. No error messages, the waveform simply doesn't get drawn. What am I missing? I basically wish to create a waveform for audio picked up via my microphone. Here's what I have so far:

  ffmpeg -re -framerate 10 -loop 1 -i background.jpg -f dshow -i audio="Microphone (Realtek High Defini" -filter_complex "[1:a]showwaves=mode=cline:s=170x54:r=10:scale=sqrt:colors=0x222222,colorkey=0x000000:0.01:0.1,format=yuva420p[v];[0][v]overlay=555:416,scale=1280:720[outv]" -map "[outv]" -map 1:a -c:v libx264 -c:a aac -tune stillimage -pix_fmt yuv420p -shortest -maxrate 3000k -bufsize 4000k -r 10 -g 20 -f flv rtmp://a.rtmp.youtube.com/live2/XXXX-XXXX-XXXX-XXXX
  

  UPDATE: I also tried piping the data but no luck:

  ffmpeg -y -re -f dshow -i audio="Microphone (Realtek High Defini" -f mp3 - | ffmpeg -y -framerate 10 -loop 1 -i background.jpg -i - -filter_complex "[1:a]showwaves=mode=cline:s=170x54:r=10:scale=sqrt:colors=0x222222,colorkey=0x000000:0.01:0.1,format=yuva420p[v];[0][v]overlay=555:416,scale=1280:720[outv]" -map "[outv]" -map 1:a -c:v libx264 -c:a aac -tune stillimage -pix_fmt yuv420p -shortest -maxrate 3000k -bufsize 4000k -r 10 -g 20 test.mp4
  

• ffmpeg. Artifacts after cut and concat of the same video file

  10 février 2020, par user3841429

  I cut the video using the following commands:

  ffmpeg -i 'example.mp4' -ss 0 -t 640.509 -c copy -y o1.mp4
  ffmpeg -i 'example.mp4' -ss 645.342 -t 424.195 -c copy -y o2.mp4
  ffmpeg -i 'example.mp4' -ss 1074.37 -t 463.202 -c copy -y o3.mp4
  ffmpeg -i 'example.mp4' -ss 1542.405 -t 295.6 -c copy -y o4.mp4
  ffmpeg -i 'example.mp4' -ss 1842.838 -t 368.54 -c copy -y o5.mp4
  ffmpeg -i 'example.mp4' -ss 2216.211 -c copy -y o6.mp4
  

  After that I concat them with:

  ffmpeg -auto_convert 1 -f concat -i concat.txt -c copy -y result.mp4
  

  my concat.txt file:

  file o1.mp4
  file o2.mp4
  file o3.mp4
  file o4.mp4
  file o5.mp4
  file o6.mp4
  

  The issue is: I'm getting a short artifacts in the beginning of each fragment in the result.mp4 file.

  During the concat I get the following:

  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb8db801400] Auto-inserting h264_mp4toannexb bitstream filter177x    
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb8db801400] Auto-inserting h264_mp4toannexb bitstream filter188x    
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb8e0000600] Auto-inserting h264_mp4toannexb bitstream filter188x    
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb8db801400] Auto-inserting h264_mp4toannexb bitstream filter189x    
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb8db801400] Auto-inserting h264_mp4toannexb bitstream filter186x 
  

• H264 ByteStream to Image Files

  10 février 2020, par Tzah Mazuz

  first time here so be gentle.

  I've been working for a few weeks on a given H.264 byte stream:

  General notes:

  1. The Byte Stream is not from a file, it is being fed live to me from an external source.
  2. The Byte Stream is encoded with Android's Media Codec.
  3. When writing the stream into a file with a .H264 extension, VLC is able to play it properly.

  What I'm trying to achieve? One of the following:

  1. Converting the frames of the H264 stream to a saveable picture file (png/jpeg etc')

  2. Converting the H264 raw bytes into a MP4 stream that can be played as source by a browser.

  I tried already using JavaCV (FFmpegFrameGrabber) without any success, my main problem is that i have no idea how to parse the byte stream or what each "packet" means

  So, I've attached a text file with some of the packets I'm getting from the stream H264 Packets

• ffmpeg : Set "year" metadata equal to first 4 characters of another metadata variable (flac)

  10 février 2020, par Hello

  The flac files I am dealing with has an attributed named "Date released", whose value is in the format "YYYY-MM-DD".

  Is it possible for me to take the "YYYY" from this and set the year variable equal to it?

  
      ffmpeg -i input.flac -metadata year=??? -codec copy output.flac
  
  

  ---

  Bonus question, is it possible to do this in place without creating a new file? Or would I have to create a new file and then delete the old one?