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<blockquote data-quote="ngsm13" data-source="post: 1091738" data-attributes="member: 544830"><p><strong>How to view the Spectral Analysis of songs using Adobe Audition</strong></p><p></p><p>To view the spectral analysis of audio files in Adobe Audition, first ensure you are in Edit Waveform View by pressing the number 8 on your keyboard. Then, go to File &gt; Open and select the file you wish to test. Adobe Audition will open the audio file in the "Waveform View" by default each time, so you'll need to choose View &gt; Spectral View or press F9 to switch to Spectral View.</p><p></p><p>I've seen a lot of discussion here about how to spot transcodes. Many people have suggested using a spectral analysis from programs like Cool Edit / Adobe Audition / EAC and looking at the 'cut off' point. There is some disagreement about how effective this is, but those who recommend it suggest looking for cut-offs between 1600 Khz as the signature of a 128kbps mp3 source and 2100 Khz as the signature of Lossless.</p><p></p><p>One counter argument to this 'cut off' level method is that the same cut off which characterises lossy encodes may also be the result of a poor quality recording - a bootleg of a live show or a 'third world' vinyl master.</p><p></p><p>A number of spectral views have been posted and linked to, but nearly all of these have been analyses of entire tracks... which IMHO is NOT the most effective way to use spectral analysis to detect transcodes.</p><p></p><p>What I haven't seen anyone discuss is the 'blocky' appearance of the spectral analysis of lossy rips which is noticeable only when you zoom in close enough. IMHO this is a more reliable way to detect whether a file which purports to be lossless has in fact been transcoded from a lossy rip, and may even be a useful way to detect re-encodes from lower to higher bitrate mp3s (although this is much harder whatever method you use).</p><p></p><p>The image below illustrates what I mean. The track (from an album by Philip Glass) was ripped from CD to flac and a 1 second sample was saved to 320 kbps LAME mp3 and 128 kbps FhG mp3 and then in each case saved again to flac. The spectral analysis was done at full screen on a monitor with resolution of 1280 x 1024. Each of the three strips below is of the same 0.15 of a second.</p><p></p><p><strong>FLAC / 320 mp3 / 128 mp3 compared</strong></p><p></p><p><img src="http://img473.imageshack.us/img473/2159/flac320mp3128mp3compareum0.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>And here are bigger strips of the three spectral analyses. The zoom level is the same - bigger simply means that what is shown here is around 0.5 of a second - and NOT the whole track!</p><p></p><p><strong>FLAC</strong></p><p></p><p><img src="http://img473.imageshack.us/img473/6268/flacfn7.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><strong>320Kbps LAME mp3</strong></p><p></p><p><img src="http://img462.imageshack.us/img462/9240/320kbpslamemp3ok9.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><strong>128Kbps FhG mp3</strong></p><p></p><p><img src="http://img462.imageshack.us/img462/8555/128kbpsfhgmp3wu5.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><strong>Credits</strong></p><p></p><p>Adopted from the tutorial by <a href="http://what.cd/user.php?id=786" target="_blank">brigetd</a>: <a href="http://what.cd/forums.php?action=viewthread&amp;threadid=1200" target="_blank">forums.php?action=viewthread&amp;threadid=1200</a></p></blockquote><p></p>
[QUOTE="ngsm13, post: 1091738, member: 544830"] [B]How to view the Spectral Analysis of songs using Adobe Audition[/B] To view the spectral analysis of audio files in Adobe Audition, first ensure you are in Edit Waveform View by pressing the number 8 on your keyboard. Then, go to File > Open and select the file you wish to test. Adobe Audition will open the audio file in the "Waveform View" by default each time, so you'll need to choose View > Spectral View or press F9 to switch to Spectral View. I've seen a lot of discussion here about how to spot transcodes. Many people have suggested using a spectral analysis from programs like Cool Edit / Adobe Audition / EAC and looking at the 'cut off' point. There is some disagreement about how effective this is, but those who recommend it suggest looking for cut-offs between 1600 Khz as the signature of a 128kbps mp3 source and 2100 Khz as the signature of Lossless. One counter argument to this 'cut off' level method is that the same cut off which characterises lossy encodes may also be the result of a poor quality recording - a bootleg of a live show or a 'third world' vinyl master. A number of spectral views have been posted and linked to, but nearly all of these have been analyses of entire tracks... which IMHO is NOT the most effective way to use spectral analysis to detect transcodes. What I haven't seen anyone discuss is the 'blocky' appearance of the spectral analysis of lossy rips which is noticeable only when you zoom in close enough. IMHO this is a more reliable way to detect whether a file which purports to be lossless has in fact been transcoded from a lossy rip, and may even be a useful way to detect re-encodes from lower to higher bitrate mp3s (although this is much harder whatever method you use). The image below illustrates what I mean. The track (from an album by Philip Glass) was ripped from CD to flac and a 1 second sample was saved to 320 kbps LAME mp3 and 128 kbps FhG mp3 and then in each case saved again to flac. The spectral analysis was done at full screen on a monitor with resolution of 1280 x 1024. Each of the three strips below is of the same 0.15 of a second. [B]FLAC / 320 mp3 / 128 mp3 compared[/B] [IMG]http://img473.imageshack.us/img473/2159/flac320mp3128mp3compareum0.gif[/IMG] And here are bigger strips of the three spectral analyses. The zoom level is the same - bigger simply means that what is shown here is around 0.5 of a second - and NOT the whole track! [B]FLAC[/B] [IMG]http://img473.imageshack.us/img473/6268/flacfn7.gif[/IMG] [B]320Kbps LAME mp3[/B] [IMG]http://img462.imageshack.us/img462/9240/320kbpslamemp3ok9.gif[/IMG] [B]128Kbps FhG mp3[/B] [IMG]http://img462.imageshack.us/img462/8555/128kbpsfhgmp3wu5.gif[/IMG] [B]Credits[/B] Adopted from the tutorial by [URL="http://what.cd/user.php?id=786"]brigetd[/URL]: [URL="http://what.cd/forums.php?action=viewthread&threadid=1200"]forums.php?action=viewthread&threadid=1200[/URL] [/QUOTE]
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