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• How to rename the .wav file which is going to download using the below program ?

  29 avril 2020, par Y V Sravan Kumar Reddy

  from __future__ import unicode_literals
import youtube_dl

ydl_opts = {
    'format': 'bestaudio/best',
    'postprocessors': [{
        'key': 'FFmpegExtractAudio',
        'preferredcodec': 'wav',
        'preferredquality': '192'
    }],
    'postprocessor_args': [
        '-ar', '16000'
    ],
    'prefer_ffmpeg': True,
    'keepvideo': True
}

with youtube_dl.YoutubeDL(ydl_opts) as ydl:
    ydl.download(['https://www.youtube.com/watch?v=JpjEwIceVIo'])


  



  ---

  



  Output :

  



  [youtube] JpjEwIceVIo: Downloading webpage
[download] Speech on Importance of Education in English for Higher Secondary students by Smile Please World-JpjEwIceVIo.webm has already been downloaded
[download] 100% of 1.69MiB
[ffmpeg] Destination: Speech on Importance of Education in English for Higher Secondary students by Smile Please World-JpjEwIceVIo.wav


  



  ---

  



  I want to change the filename to audio1.wav instead of Speech on Importance of Education in English for Higher Secondary students by Smile Please World-JpjEwIceVIo.wav. Please help me with this problem.

  


• Using lcov With FFmpeg/Libav

  21 novembre 2011, par Multimedia Mike — Programming, code coverage, ffmpeg, lcov, libav

  Last year, I delved into code coverage tools and their usage with FFmpeg. I learned about using GNU gcov, which is powerful but pretty raw about the details it provides to you. I wrote a script to help interpret its output and later found another script called gcovr to do the same, only much better.

  I later found another tool called lcov which is absolutely amazing for understanding code coverage of your software. I’ve been meaning to use it to further FATE test coverage for the multimedia projects.

  
  
  Click for larger image
  

  Basic Instructions
  Install the lcov tool, of course. In Ubuntu, 'apt-get install lcov' will do the trick.

  Build the project with code coverage support, i.e.,

  ./configure —enable-gpl —samples=/path/to/fate/samples \
   —extra-cflags="-fprofile-arcs -ftest-coverage" \
   —extra-ldflags="-fprofile-arcs -ftest-coverage"
  make
  

  Clear the coverage data :

  lcov —directory . —zerocounters
  

  Run the software (in this case, the FATE test suite) :

  make fate
  

  Let lcov work its magic :

  lcov —directory . —capture —output-file coverage.info
  mkdir html-output
  genhtml -o html-output coverage.info
  

  At this point, you can aim your web browser at html-output/index.html to learn everything you could possibly want to know about code coverage of the test suite. You can sort various columns in order to see which modules have the least code coverage. You can drill into individual source files and see highlighted markup demonstrating which lines have been executed.

  As you can see from the screenshot above, FFmpeg / Libav are not anywhere close to full coverage. But lcov provides an exquisite roadmap.

• How to calculate bit-rate for ffmpeg ?

  2 juin 2015, par rs41

  I want to convert one video to 4 formats( webm low/high, mp4 low/high)

  When I execute last mp4 high conversion for small files, which looks like this (line-breaks added for readability) :

  ffmpeg -i Weird9.3gp -codec:v libx264 -b:v 10k -maxrate 1000k -bufsize 2000k 
  
         -movflags +faststart -vprofile high -preset slow -vf 'scale=trunc(iw/2)*2:720' 
  
         -threads 0 -codec:a aac -strict -2 -b:a 128k -ac 2 -f mp4 -threads 0 
  
         -y /Users/guest/high/movie.mp4

  It shows something like this

  Error while opening encoder for output stream #0:1 - maybe incorrect parameters
  such as bit_rate, rate, width or height

  If I change "-b:a 128k" to "-b:a 32k" everything is ok.

  How do I calculate the bit-rate properly ? Does it depends on source video file size ?