Friday, October 31, 2014

Remastering an audio track from multimedia file using Open Source tools

I finished the multimedia file manipulation tutorial. In this case I show the audience how to effectively and at one's best attempt remaster a neglected audio track from a multimedia file found at coursera's website. Any other unheeded multimedia file bearing a lacking audio track may be used, but the filters would have to be applied with slightly different parameters. Notice it does not make any miracles, it simply improves a low quality recorded voice track.

We use the famous Open Source audio software Audacity to apply Noise Removal, Compress Dynamics, Equalization, Zero Cross, Silence and other filters. After the voice track is improved, we set a series of parameters for FFmpeg:


ffmpeg.exe -i path/video_filename -i path/audio_filename -map 0:0 -map 1:0 -vcodec copy -acodec libmp3lame -b:a 128k -ac 2 output_filename.mp4 It will show series of statistics from the processing being computed in regards to the frames, quality, time, size, etc. Once it finishes the processing, the output file will be ready to be played by default on the bin directory of FFmpeg.

Sunday, June 8, 2014

Ethernet issues

Extending the RAM memory from 3 GB(3 slots with 1 GB of RAM slots) to 4GB of RAM, by adding a compatible RAM module to the remaining slot(1GB of DIMM 6400 RAM, at 800 Mhz) turned out to disable the Ethernet card. So I tried resinstalling the ethernet driver, the BIOS and motherboard device drivers to no avail.

Ultimately I installed a new PCI Ethernet card and the networks started working. Thankfully I had an Ethernet card stored in a warehouse, otherwise I would be left spending for a new Ethernet card or not possessing network connection at all.

Friday, March 28, 2014

Gabriel's idiocy.






















Despitemy seemingly intact ego, sometimes I LOOK at myself  with self loathe, feeling guilty that such simple operations like radicalization of a fraction would fly over my head. I blame it on sleep deprivation, which is diminishing over time.

Reviewing some trigonometry, I stumbled upon this exercise on the excellent Free and Open Khan academy website.



 

                ___


Of course BC  is equal to 5 since tan is 1 and the other side(opposite to the angle) is 5.

However, it is not clear how

 5
___
√50


  1
____
  ___
√2


But the answer is: radicalization, i.e. multiplying the unit-length denominator by the monomial(term). In other words square root of 50 divided by square root of 50 multiplied by 5 divided by square root of 50.

Here are the steps:


0,70710678118654752440084436210485

 5
___
√50




Radicalization:

5·√50
____
50

Simplification:

 √50
 ____
  10

Factorization:

    ____
  √5· 10
  ______
    10
   
Square factorization:

     __    ___
   √5  · √10
   ___________
        10

Reverse radicalization:
       
    ___
   √5
   _____
    ___
   √10

Factorization

     ___
   √5
   _____
     ___
   √2·5

Square factorization:

     ___
   √5
   _____
     _      _
   √2 · √5

Finally:




   1
   ____
    ___
   √2

Which radicalized equates to: