Introduction

These 2 parts are just here to give you some clues about how to detect DVD VCD sourced and bootlegs mp3 sourced. I'm not a sound engineer, so i don't pretend to be totally right about what is following. I'm just arguing with the "bad" experiences i had in some trades with bootlegs i'm sure are mp3 sourced and DVDs i'm sure are VCD sourced, and i try to share with you my experience about these shitty conversions...

Part 1 : VCD detection guide

After having received some DVD VCD sourced, i do prefer informing people how to dectect this shitty DVD.

I really don’t see the point of having VCD on DVD..... The meaning of DVD is to have to best enabled quality .... with no loss of quality between the original source and the final result on DVD... But VCD are by definition lossy quality because real bad compression is used, the same way mp3 is a bad compression of original audio cd.....

There are 2 easy ways to dectect DVD VCD sourced :

1) The size of the DVD VCD sourced are about 1.2 Go to 1.5 Go (while real DVD size is about 3.5 Go to 4.5 Go)

2) If you read the DVD VCD sourced with PowerDVD, the video format is shown (MPEG-2 for real DVD and MPEG-1 for VCD sourced.)

Anyway, that's true that a S-VCD has a MPEG-2 encoding.... So this is a little comparaison between VCD / S-VCD and DVD format :

But you still have a doubt because your DVD has the good format (DVD standards), well ...., only your eyes can make the real difference !!!

Part 2: MP3 detection guide

I find these informations on a very good page. You can check at http://members.optushome.com.au/mattboland/mp3bug.htm

When a wave file is encoded to MP3, the higher frequencies are discarded to achieve a file size up to ~1/10th the size of the original. This smaller file size results in less time downloading. The different bit rates refer to the amount of data required per second. That is, 96 kilobits per second for a 61 second song is 5856000 bits, which is equal to 732000 bytes.

Now, there are many many different encoders out there, each claiming to 'sound' better, or encode quicker etc. Using a poor DAC, using a sound card that resamples, analog transfers et al can all effect the 'sound' of an audio file. This page will be used to compare the visual representation of these audio files.

The following graphs are pretty self explanatory. I've used the same song as my test file. It was encoded to 96kbps, 128kbps, 160kbps, 192kbps, 256kbps and 320kbps constant bit-rate mp3 files. Variable bit-rate mp3 files were also created at 10, 50 and 100 values (where 10 is the lowest quality setting and 100 is the highest). These were created using MP3/mp3Pro fraunhofer IIs encoder via CoolEdit Pro 2.
I also transferred the song to mini disc and recorded at SP and LP2 modes using a Sharp MD-MT99W with ATRAC 3 compression.

The following graphs are the visual representations of the resulting audio files.

96kbps     0.732MB

Notice sharp decline after 11KHz and not much after that

128kbps     0.976MB

Notice sharp decline after 16KHz and not much after that

160kbps     1.22MB

Notice sharp decline after 16KHz and not much after that

192kbps     1.464MB

Notice sharp decline after 16KHz and not much after that

256kbps     1.952MB

Notice sharp decline after 16KHz and not much after that

320kbps     2.440 MB

Notice sharp decline after 16KHz and not much after that

VBR10     0.724MB

Notice sharp decline after 13.5KHz and not much after that

VBR50     1.003MB

Notice sharp decline after 15KHz and not much after that

VBR100     1.676MB

Notice sharp decline after 16KHz and not much after that

MD

Notice sharpish decline after 16KHz yet not full cutoff

MDLP2

Notice bluntish decline after 15KHz yet not full cutoff as well as lower db from 20-15000Hz

Uncompressed wave file     10.750MB

Observing the frequency analysis of a song whilst playing, even an mp3, the values after the 'cutoff' may fluctuate, however these values are not a true representation of the file. In these images, I have chosen a specific point in the song where I can best determine the true file properties.

DVD

COMPILATIONS

OTHER BANDS

MAIDEN'S RELATED

NEW

INCOMING

WANTED