AEO-Sound

(Automated Extractor of Optical Sound)

AEO-Sound
  • soundtrack: scans must be sufficiently wide to capture the full width of soundtrack area. Partial images of soundtrack may not always guarantee faithful reconstruction of audio signal (e.g., in the case of a single-sided variable area track, the highest or lowest amplitudes may get clipped).

  • scan overlap: a scan sequence must provide a contiguous coverage of the film as sound from missing portions of unknown length and location can not be recovered. Moreover, a moderate amount of overlap between consecutive scans (up to 25%) is welcomed since it improves the reliability of the algorithms used to match scans and to compensate shading due to uneven illumination.

  • image resolution: scans must possess resolution that is sufficient for reconstructing an audio signal with the full frequency range of the optical recorder used to create the soundtrack. This requirement is probably the least obvious of the three but is not less fundamental. It can be characterized quantitatively by a rigorous mathematical theory. According to the Shannon sampling theorem in order to completely recover a band limited analog signal, one must sample it at a rate equal to or higher than the Nyquist rate which equals twice the highest frequency present in that signal. With modern optical recorders having bandwidth from 20 Hz to 14 kHz, the smallest sampling rate that is guaranteed to capture all stored frequencies is 28 kHz. This translates into at least 28,000 samples per second of soundtrack, or 1167 samples per image frame assuming rate of 24 frames per second. Adding 25% of overscaning, a single scan would need to have height of at least 1460.

2012-2013 Borislav Karaivanov. All rights reserved.

FFmpeg

FFmpeg's installation is not a one-click matter. To save you some of the frustration we felt, we offer detailed instructions based on our experience. Should any of the links below become obsolete, start the journey at the official FFmpeg download site

http://ffmpeg.org/download.htm



Windows 7

To get FFmpeg binaries:

  • visit Zeranoe's web site;
  • download the latest 64-bit Static build for FFmpeg (check at the top of the right column; you are looking for a button with label of the form "Download FFmpeg git- ... 64-bit Static");
  • in your "Program Files" directory (most likely "C:\Program Files\") create a new directory called "FFmpeg";
  • uncompress the downloaded 7z package and move its entire content to the new "FFmpeg" directory you created (e.g., "C:\Program Files\FFmpeg\");

The next step is to include FFmpeg in your path. This can be done along the following lines:

  • press "Start"->"Control Panel"->"System and Security"->"System"->"Advanced system settings";
  • as a result, a new window called "System Properties" appears. Near its top, select the "Advanced" tab;
  • press the "Environment variables" button;
  • another window pops up. In its lower half, there is a list called "System variables". In that list, find the variable called "Path" (scroll down if necessary). Highlight it and press "Edit".
  • a small window pops up. There, place your cursor in the box called "Variable value" and use the right arrow to move all the way to the end;
  • when at the end, type: "; " (i.e. semicolon followed by a space), and then paste the full directory path to the bin directory of your FFmpeg installation. Expect result similar to:
    "; C:\Program Files\FFmpeg\bin\"
    (without the quotes);
  • once the path is added, keep clicking "Ok" on all windows until you close them all;

To check if FFmpeg is properly installed:

  • open an MS-DOS command prompt (press Start, type "command prompt" in the search box, and hit "Enter");
  • type "ffmpeg" (without the quotes) at the prompt, and hit "Enter";
  • getting information about FFmpeg indicates that it is properly installed. Otherwise, you would expect something in the spirit of "'ffmpeg' is not recognized ...";


Mac OS X

To get FFmpeg binaries:

  • visit tessus's web site;
  • download the latest 64-bit Static build for FFmpeg (you are looking for a link of the form "ffmpeg- ... .7z");
  • extract the content of the downloaded package. Currently it is a single file called "ffmpeg";
  • copy that "ffmpeg" file to the directory /usr/local/bin/;

The next step is to include FFmpeg in your path:

  • open a terminal and enter:

    sudo chown root:wheel /usr/local/bin/ffmpeg

    if prompted, enter your password;
  • enter:

    sudo chmod 755 /usr/local/bin/ffmpeg

    if prompted, enter your password;

To check if FFmpeg is properly installed:

  • open a terminal and enter "ffmpeg" (without the quotes);
  • getting information about FFmpeg indicates that it is properly installed. Otherwise, you would expect something in the spirit of "'ffmpeg' is not recognized ...";


Linux (Ubuntu)

To install FFmpeg:

  • open a terminal and enter:

    sudo add-apt-repository ppa:jon-severinsson/ffmpeg

    if prompted, enter your password;
  • enter:

    sudo apt-get update

    if prompted, enter your password;
  • ffmpeg should automatically install and update any time you run a general update;

To check if FFmpeg is properly installed:

  • open a terminal and enter "ffmpeg" (without the quotes);
  • getting information about FFmpeg indicates that it is properly installed. Otherwise, you would expect something in the spirit of "'ffmpeg' is not recognized ...";


2012-2013 Borislav Karaivanov. All rights reserved.