Bash Script Needed!

[CraigWatson]

Hi Guys,
I'm looking for someone that can cobble together a Bash script to automate extracting and splicing some audio files for me. I have a folder full of multi-part RAR'd video as follows:

Video1 --> CD1 --> *.rar
Video1 --> CD2 --> *.rar

Inside the RAR is an AVI file, and I need to splice the two files together to create a full-length video.

Rough algorithm is as follows:
1) Extract CD1
2) Extract CD2
3) Splice
4) Move spliced video to new folder

There's 23 video folders, so I'd need a script to loop through each of these folders and do the above in each. I have ffmpeg and mencoder installed.

I'm fairly good with scripting, but I'm not too keen on ruining about 35GB of video!

Cheers,
Craig

[errorxp]

One problem with joining two videos together is that after the point where it's joined video and audio may go out of sync - this is due to the fact that sometimes the audio track is shorter than the video track. The solution is to delay the audio track of the second file by the amount that the audio and video track differ in the first file. I remember having done this in Virtualdub a long time ago. You'd have to join the video and audio track separately, then mux them together. Anyway good luck if you manage to make all this work within a single script.

[jpollard]

My suggestion, (I'm not familar with handling video data this way)
If you want to test what you are doing, make a copy of one of your directories
to test in. Then use the "script" utility to record what you are doing.

Perform the steps you want - and let the script utility log file record what
you do. Then you can use the log file to extract only the commands that
do the work you want (removing the test verifications...)

The end result is a script that works with only one directory.

You can now use the script 35 times... or create another script that
will set the working directory to each of the real directories and then
invoke the other script.

[CraigWatson]

Just to update people, I managed to write a script to do what I wanted, but in PHP rather than Bash (string manipulation in Bash isn't my strong point!):

PHP Code:

<?php

// Path to files
$path = "/tmp/Video";

// Open the directory
$dir = opendir($path);

$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$starttime = $mtime; 

    // Loop through directory
    while (false !== ($file = readdir($dir))) {
    
        // Ignore dot-files
        if (($file == ".") || ($file == "..") || ($file == "Final")) { continue;}
    
        // Extract name and year
        preg_match("/007(.*)\.(\d\d\d\d)/", $file, $matches);
        $name = trim(str_replace("."," ",$matches[1]));
        $year = $matches[2];

        // Unrar CD1
        echo "Extracting $name CD 1\n";
        exec("unrar e -inul -y \"$path/$file/CD1/*.rar\" \"$path/$file/\"");
        
        // Unrar CD2
        echo "Extracting $name CD 2\n";
        exec("unrar e -inul -y \"$path/$file/CD2/*.rar\" \"$path/$file/\"");
        
        // Create Final Dir
        echo "Creating \"$year - $name\" Directory\n";
        mkdir("$path/Final/$year - $name");
        
        // Merge
        $merge_path = "$path/$file/";
        echo "Merging $name ...\n";
        echo "\tUsing cat\n";
        exec("cd \"$merge_path\" && cat *.avi > \"$path/Final/$year - $name/$name-tmp.avi\"");
        echo "\tUsing mencoder\n";
        exec("mencoder -forceidx -oac copy -ovc copy \"$path/Final/$year - $name/$name-tmp.avi\" -o \"$path/Final/$year - $name/$name.avi\"");
        
        // Cleanup
        echo "Cleaning up $name\n";
        exec("rm -Rf \"$path/$file\"");
        exec("rm -f \"$path/Final/$year - $name/$name-tmp.avi\"");
        echo "---------------------------\n";
    }
    
   $mtime = microtime();
   $mtime = explode(" ",$mtime);
   $mtime = $mtime[1] + $mtime[0];
   $endtime = $mtime;
   $totaltime = ($endtime - $starttime);
   $totaltime = round($totaltime,1);
   echo "Execution time: ".$totaltime." seconds\n";
   echo "---------------------------\n";
    
echo "\n";

?>

The basic algorithm is:

1) Do string manipulation to get nice clean data (mine was formatted with dots instead of spaces and with the year of the film hidden within the folder name)
2) Unrar each CD using unrar
3) Merge the CDs using cat
4) Fix the AVI headers and sync audio by using mencoder with the -forceidx flag

The manipulation in step 1 is optional, but it allows me to save the files in a nice, neat format (I'm pedantic when it comes to my movie collection!).

Any questions, by all means ask