BGane
1st June 2003, 21:10
FYI - This post isn't a question - its just an observation - but I am interested in comments from others that may have experienced a similar issue. Here is the homework that I have done so far:
(Also - I have done a search, but I didn't see anything that precisely mentions this issue - at least not recently)
I have been using dvd2svcd for approx one year now. While the video encoding is great (I use TMPGEenc), I have been noticing a problem with the audio recently. Perhaps it was always there, but just didn't come to my attention.
In several of the MPEG1s that I have made, there is a high-pitched squeal that runs throughout the file. I used a graphic equalizer to attempt to notch it, and found that it is in the range of 12-14khz. Fairly high frequency, but still audible, even for old ears. It is most noticeable, of course, during quiet sections, and MOST annoying, now that I know it is present.
In order to isolate the problem, I tried analyzing one of the noisy sections, using Cool Edit Pro. Cool Edit, of course, decompresses the file into a WAV, and then allows you to perform various analyses or edits. I ran a frequency spectrum analysis, and, interestingly, found NO artifacts in the high frequency range. In fact - playing back the file in Cool Edit - there was NO noise. So then - where was the noise coming from? It must be from the decoding stage.
Using Microsoft GraphEdit, I was able to replace the standard Microsoft MPEG Audio Decoder (which is actually licensed from Mediamatics) with ones from Moonlight Elecard (Odio Dekoda); from Ligos (Ligos MPEG Audio Decoder); from Cyberlink - makers of PowerDVD (Cyberlink Audio Decoder); and from Intervideo - makers of WinDVD (IVI Audio Decoder).
For MPEG1 audio (which is different of course from the AC3 stream), both the Cyberlink and Intervideo decoders were as noisy as the original Microsoft decoder. But when I used Odio Dekoda or Ligos, the tracks were as clean as could be. No artifacts. No squeal.
So - my presumption here is that there must be a bug in the standard Microsoft DirectShow audio decoder filter. Either that, or at least there must be certain encodings that cannot be as "nicely" handled by the decoder.
Have any of you observed this problem? Listen carefully, at higher volume, during a quiet section of your movie? Is there a high pitched noise present in the background?
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For reference, I construct my files using DVD2SVCD 1.1.3 Build 2, with all of the standard tools that come with DVD2SVCD. My video encoder is TMPGEnc 2.512. My machine is an Intel P4, Windows XP, Audigy2, Matrox G450, 512MB RDRAM, 400GB disk. DirectX is 9.0a.
Settings for DVD2SVCD are 2200 kpbs, CQ 100, Audio 224kbps, joint stereo. Source is a DVD of music videos where the only audio track available is LPCM 2 channel stereo.
(Also - I have done a search, but I didn't see anything that precisely mentions this issue - at least not recently)
I have been using dvd2svcd for approx one year now. While the video encoding is great (I use TMPGEenc), I have been noticing a problem with the audio recently. Perhaps it was always there, but just didn't come to my attention.
In several of the MPEG1s that I have made, there is a high-pitched squeal that runs throughout the file. I used a graphic equalizer to attempt to notch it, and found that it is in the range of 12-14khz. Fairly high frequency, but still audible, even for old ears. It is most noticeable, of course, during quiet sections, and MOST annoying, now that I know it is present.
In order to isolate the problem, I tried analyzing one of the noisy sections, using Cool Edit Pro. Cool Edit, of course, decompresses the file into a WAV, and then allows you to perform various analyses or edits. I ran a frequency spectrum analysis, and, interestingly, found NO artifacts in the high frequency range. In fact - playing back the file in Cool Edit - there was NO noise. So then - where was the noise coming from? It must be from the decoding stage.
Using Microsoft GraphEdit, I was able to replace the standard Microsoft MPEG Audio Decoder (which is actually licensed from Mediamatics) with ones from Moonlight Elecard (Odio Dekoda); from Ligos (Ligos MPEG Audio Decoder); from Cyberlink - makers of PowerDVD (Cyberlink Audio Decoder); and from Intervideo - makers of WinDVD (IVI Audio Decoder).
For MPEG1 audio (which is different of course from the AC3 stream), both the Cyberlink and Intervideo decoders were as noisy as the original Microsoft decoder. But when I used Odio Dekoda or Ligos, the tracks were as clean as could be. No artifacts. No squeal.
So - my presumption here is that there must be a bug in the standard Microsoft DirectShow audio decoder filter. Either that, or at least there must be certain encodings that cannot be as "nicely" handled by the decoder.
Have any of you observed this problem? Listen carefully, at higher volume, during a quiet section of your movie? Is there a high pitched noise present in the background?
----------
For reference, I construct my files using DVD2SVCD 1.1.3 Build 2, with all of the standard tools that come with DVD2SVCD. My video encoder is TMPGEnc 2.512. My machine is an Intel P4, Windows XP, Audigy2, Matrox G450, 512MB RDRAM, 400GB disk. DirectX is 9.0a.
Settings for DVD2SVCD are 2200 kpbs, CQ 100, Audio 224kbps, joint stereo. Source is a DVD of music videos where the only audio track available is LPCM 2 channel stereo.