Female In Distress !!!! mp2 encoding has lots of aliasing!

[sue denim]

Hi guys.
I've tried every piece of encoding software I know of and I STILL get a loud 'aliasing' whistle on all my .mp2 files!
My source file (usually a 44.1Khz .wav) is of superb quality.
Tried : tooLAME, TMPGenc (without tooLAME), XINGencoder, wav2mp - they all produce similar results.

If I play the encoded .mp2 file back on WinAmp or XING MPEG player, it sounds fine.
But on WindowsMedia Player it sounds nasty and also when I remultiplex with the video and replay on my VCD player.

Why do ALL these encoders do the same thing??!!??

I've got VCDs that I've ripped, demultiplexed, and recompressed and, low and behold, the 'aliasing' whistle appears!

I'm going out of my mind here - haven't a clue what to try next.

Any help you guys can offer would REALLY be appreciated.

Thanks in advance.

Sue xxx.

[pinoy2201]

what bitrate are you useing??????? and try SCMPx to convert your audio and the bitrate should be 224

[sue denim]

Well, I just downloaded SCMPx and encoded a 44.1kHz stereo .wav file.
Used 224 bit rate, layerII.
Guess what .... I got the same result!

Playback is fine on SCMPx player, WinAmp, XING MPEG player etc.
But on Windows Media Player it sounds really nasty - high pitched 'whistle', metallic mid-range .... YEUCK!
And if it sounds bad on WMP then it sounds bad on my DVD player!!

Now I could accept that both WMP and my DVD have got bad mp2 playback decoders - that would make sense - but I own commercial VCDs and ones ripped by other people and they sound fine!!

I really don't know what to do ..... I NEED to sort it out FAST though!

Sue xxx.

[poopyhead]

try normalizing in dvd2avi when u extract the .wav file

[sue denim]

Yeah, tried that already PH - sorry!
Actually normalised in CoolEditPro as well - same 'aliasing' noise.

If nobody else has any other suggestions then I'm resigned to thinking that my VCD/DVD player has a crappy mp2 playback decoder. Which REALLY sux!

Maybe I'll run the wav file through a compressor so it's really loud all the time and you hardly notice the whistling noise. That SUX too!!

Ah well - Thanks for trying anyhow guys!

Sue xxx.

[disturbed1]

Try CDex's built in mp2 encoder. http://prdownloads.sourceforge.net/cdexos/cdex_130.exe

I used tooLame a few times, and came to the same conclusion as you, it's sound quality is lame.

[Sefy]

sue denim, i've been going over what you said, are you encoding a MPEG2 file ? MP2 is usually for MPEG1 Audio Layer 2, which is the Audio Part of the MPEG, and that's what i'm gathering your problem is.

Also you keep mentioning that Windows Media Player is the only one that plays it bad, while everything else does it great, so the problem seems to be IN Media Player, not what you do.

Lastly, you mentioned you are playing back on a VCD Player ? if you are creating a MPEG2 Video file, how can you play it ?

[sue denim]

Hi Sefy!

No, my MPEG1 layerII audio encoding is the audio component of a MPEG1 video file.

OK - just to spell it out ..... i'm ripping a DVD to a VCD.
Everything's fine until I come to encode my stereo 44.1kHz WAV file to a MPEG layer II audiofile (@ 224kbits/sec as per VCD standard).

You're probably right in thinking that it's probably WMP that's at fault when playingback on my PC. But I have other VCD/MPEG1 files that other people have ripped and they all sound fine on WMP - that's the problem that I can't work out.
And although I can use a different player on my PC, my VCD player seems to exhibit the same playback problem as WMP!

I realise this seems like a bizarre problem but if you have any ideas that may help it would be much appreciated.

Thx,
Sue xxx

[sue denim]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR size=1 color=black></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-16 13:13:43, disturbed1 wrote:
Try CDex's built in mp2 encoder. http://prdownloads.sourceforge.net/cdexos/cdex_130.exe

I used tooLame a few times, and came to the same conclusion as you, it's sound quality is lame.


</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Thanks - will try this tonight - back to ya later ......

Sue xxx

[Sefy]

Hello Again Sue, one last curious thing, are you encoding each part on it's own ? which method are you using to convert from DVD to VCD ?

I've heard from several people (like Adam) that using DVD2AVI to produce the WAV at 44.1khz will result in a bit of a noisy file, and it's more recommanded to use Azid to convert the file from 48khz to 44.1khz.

[pinoy2201]

And other way is SSRC if you donr have the Ac3 file....SSRC is the best downsampleing tool there is and it is FREE!!!!!!!

[sue denim]

The one thing that REALLY gets to me about all this is that I'm a sound engineer by trade! So you'd think I'd be able to sort it out wouldn't ya??!!?!

Anywayz, let me assure you therefore that my WAV file is of a superb quality - used top-of-the range downsampler, Cedar deHiss etc etc.
So we can safely say that my source audio is ok!

Let me put it to you another way ........
I took a VCD with good audio playback in WMP and :
ripped the MPEG1 file out of the DAT file
de-multiplexed the audio out of the MPEG1 file.
converted the MPEG1 layerII audio to 44.1kHz WAV
re-compressed the WAV with tooLAME (back to MPEG1 layerII)
played the resulting MPEG layerII audiofile back on WMP ....
...... and ...... guess what? ......
THE ALIASING 'WHISTLE' NOISE HAD APPEARED!!!!!! ARRRRGGHHH!!

If any of you guys can sort this out then you're a damn sight better than me!!

Sue xxx.

[Sefy]

Sue, I know this is gonna sound stupid, but, why are you taking a VCD, demuplexing it, converting the MP2 Audio into a WAV, and then recompressing the WAV back to MP2 ??? why ???

Your source file may have been on ultra high quality, but what have you done to it ?? Demuplexing, converting to WAV then re-encoding to MP2 again ?? what for ?? any, and I mean ANY re encoding of a file will ALWAYS produce a lower quality result!

I don't know, maybe i'm understanding you diffrently then any other person here, but I can't figure out why you did all that!

[sue denim]

Hi Sefy.
That was just a test I ran to try to figure out what was causing the extra noise and at what part of the encoding process.

You see, by taking an mp2 file that I KNOW sounds fine in WinMediaPlayer, then re-compressing it, I end up with a mp2 file with THAT 'aliasing' whistle again.
OK, by recompressing an mp2 file the audio IS going to get worse in quality (ie. more grainy, metallic) - I accept that. But what I can't accept is that the process would introduce such a god awful HF noise!!

So what I end up with is this .......
It doesn't matter what MPEG layerII encoder I use,
it doesn't matter what quality my source audio is,
Windows Media Player and my VCD player both playback my encodings with the 'aliasing' noise.
Yet all my other VCDs that were done by other people playback WITHOUT the 'aliasing' noise.

Geezzzzz ...... talk about a paradox!

Sue xxx.

[Shabubu]

Ok, you've probably done a few of these already, but here are suggestions...

Update Media player

Use DVD2AVI t demux the audio, then downmix and the like with AZID, SSRC, Wavebooster and tooLame (all guides blah blah at doom9.org)

Try Denoising in Cooledit..

Try Joint Stereo (or true stereo)

Try a mono at 192

Post a clip of the problem audio and we'll test.

Sorry can't be more helpful, but I'm not a muso so I don't know I'll ask around my muso fiends

PS it's good to see female sound techs that make VCD's

[sue denim]

Hi Shabubu!
Thanks for the encouragement - I need it!!
Can't attach a clip on this forum and I haven't got your email address.
All you guys can get at my email so if you wanna hear my problem audio (like I KNOW you do!! then drop me a note and I'll send a short clip to ya.

Thx,
Sue xxx.

[Shabubu]

Check your e-mail.

[sue denim]

Everybody check your email.

A little feedback would be nice .......

Sue xxx.

[Shabubu]

Got the clip, played in winamp and media player.. even got the local sond tech to listen to it.

Unfortunately there is NO aliasing, of any kind, whatsoever...

Unfortunaetly it seems like your DVD players crap and your win media istallation is screwed. Sorry about this

All I can suggest id lowering bitrate, encoding in mono or forced stereo.

[pinoy2201]

i got the clip tooo and i didnt get a issss sound at all perfect played on WMP too same thing great audio

[Sefy]

i've just played back the file on my Windows Media Player, and i'm afraid I can't hear any problems in the file, and god knows my sound card isn't all that bad (a Live! 5.1), i'm thinking
maybe your sound card has some enhancment that might cause this, either that, or try checking which codec is being used by Windows Media Player to play MP2 files.

[disturbed1]

I heard the problem. It is high frequency aliasing. It sounds as if your sample rate converter might be using 32bit conversion instead of 64.

Try another sample rate converter. Some people like SSRC, AZID, I've used wavefs44(same routines as DVD2AVI), Cool Edit Pro (with pre/post filter level 650), or vssrc.


VSSRC comes with a 32bit and 64bit converter http://www.vlsi.fi/other/VS_SRC/

<font size=-1>[ This Message was edited by: disturbed1 on 2001-12-17 13:53:10 ]</font>

[Shabubu]

What soundcard are you 2 using, I'm live! player 1024...

[disturbed1]

On 2001-12-17 14:15:33, Shabubu wrote:
What soundcard are you 2 using, I'm live! player 1024...

I heard the aliasing on both my comp and my home system.

My home system is a Kenwood Dolby Pro Logic Reviever, with 5 Yamaha (NS-AP150 for center/surround and 2 NS-A838)speakers and a sub (YST-SW300)

The computer's is a SB PCI (not live or anything) and Cambridge Soundworks FPS1500

<font size=-1>[ This Message was edited by: disturbed1 on 2001-12-17 14:31:27 ]</font>

[sue denim]

Hey you guys are the best!!

AT LAST - somebody else hears it - I'M NOT GOING CRAZY!!!!

er ....... sorry about that ..... don't know what happened there ..... anyhow ..... :

My soundcard is a SB Live! Value (you know, the cheap one!)
And I don't usually do ANY samplerate conversion before I give the WAV file to tooLAME/wav2mp/XING etc etc.
During all the many tests that I have run over the last few weeks on this problem, I'm sure I HAVE done srconversion from 48-44.1 in CoolEdit but I can't remember what settings I used.
Will try your advice ASAP.

Hey disturbed ...... if it's not too much hassle, could you quickly run through what YOU do when you rip a DVD?
You don't have to tell me everything, but a few notes on the audio rip part would be very VERY handy!!

Speak to y'all soon.

Sue xxx.

[sue denim]

oh i forgot, my WMP has Windows MPEG1 decode codec v2.0

[Sefy]

I'm presuming you installed the latest WMP 7.1 (crap program, but comes with all latest codecs ) well atleast someone here has heard the problem for himself, Oh that reminds me, are yu using the latest Sound Card drivers for your SBLive ?

[disturbed1]

I usually do DVD rips to SVCD and use the 48khz audio file, but most Divx I convert to VCD.

Any time you down sample aliasing will occur. The type depends on your sample rate converter. The hack and slash method gives poor high frequencies, a type of ringing harshness (common with 32bit routines). Other sample rate converters use a slight low pass filter, that keeps the higher frequencies from coming through. 48khz has a higher frequency bandwidth than 44khz, so the filter isn't noticed.

I personally use Cool Edit Pro. They recommend 100-400 for good quality, the max is 999. It takes a while. The time to quality ratio isn't that good above 650.
If that doesn't give good results, you can EQ.

I always use CDex's internal mp2 encoder.

Although I have been playing with VSSRC for 44khz (CD audio) to 48khz (DVD audio) with decent results.

[sue denim]

Hi again!
Yeah I am using WMP 7.1 but it still has the same MPEG1 codec as 6!
I haven't updated my SB drivers but that's really not the problem - I want a VCD that sounds good on my VCD Player.
Win Media Player is only a good for 'testing', so I don't waste blank CDRs!

Thanks disturbed .... I did a test :

Got a 48kHz WAV from DVD2AVI

SR Converted it with CoolEditPro on 999 (highest quality) down to 44.1kHz

Played back 44.1 WAV in WinMediaPlayer - Sounds good.

Encoded 44.1kHz WAV to MPEG1 layerII @ 224kb/sec using CDex internal encoder

Played resulting file back in WMP7.1 - Sounds terrible!! ARRRGHHHH!!!!!!

Have you NEVER had this problem Disturbed?

It doesn't seem to be the source WAV file that's at fault.
Haven't tried VSSRC yet, but will do so if you think it'll help.

Sue xxx.

[poopyhead]

hrm...just a suggestion, don't know if this applies here. but i've had a similar problem with deep impact. at first, i thought it was the cd-r getting old and wearing down. apparently, it's the actual sound source from the dvd that's making the crackling during high-pitched sounds. i generally extract the first track with dvd2avi if it's in english, whether or not it's the highest bitrate or not. well, track 1 of deep impact was like 192 kbps, and it had the crackling noise. track 2 of deep impact was like 448 kbps, and the crackling noise is gone.

perhaps, the source is the problem for you too.