Popping static with Schizopolis using BeSweet

[colordog]

Howdy -

I've been trying to encode the audio portion of Schizopolis using GKnot (BeSweet 1.5b23). I had no trouble ripping the disc, and if I play the AC3 track through PowerDVD it sounds just fine.

However, once I encode it to VBR MP3, there are segments of the audio that have horrible 'bursts' of 'electronic popping'. This sometimes happens during scene transition, but also at times in the middle of a scene. The static reminds me of what happens when you get a normal CD player to play a data CD. Loud, bursty, digital squelch.

I went back and demux'ed the VOB again with DVD2AVI (1.77.3dg1.0.0RC2) to recreate the AC3 stream to make sure it wasn't damaged. Again, playing the AC3 didn't produce the popping. BeSweet's log shows 3 individual CRC errors near the end of the audio stream (where the static is worse), but no other errors.

Being a novice when it comes down to audio (I just click the buttons in GKnot usually, and no problems), I just clicking on a bunch of different options in lame and azid (using the BeSweet GUI (v0.6)). I tried low and highpass freq., using dialog normalization, lfe to lfe output, center downmix level, surround downmix level, decode f/r, control rear channel, etc. Played with normalzing gain. None of those prevented the popping in the resultant MP3 - in fact, the major difference I noticed was that it caused the filesize to grow.

I even tried just simply converting the AC3 to WAV, but the static popping was there in the exact same places. (I had hoped that AC3 -> WAV -> VBR MP3 may have helped).

I've never had trouble encoding an AC3 that didn't give tons and tons of CRC errors. I've never encountered anything like this!

Pasted below is one of the 30-some log files I've generated trying to produce a VBR MP3. Any speculation is very welcome.

BeSweet v1.5b23 by DSPguru.
--------------------------
Using azid.dll v1.8 (b825) by Midas (midas@egon.gyaloglo.hu).
Using lame_enc.dll v1.32 (8/8/2003), Engine 3.90 <http://www.mp3dev.org/>.

Logging start : 11/02/03 , 17:53:59.

C:\Program Files\Gordian Knot\BeSweet.exe -core( -input c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms.ac3 -output c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms.mp3 -logfilea C:\Program Files\Gordian Knot\BeSweet.log ) -azid( -s stereo -c normal -L -3db ) -lame( -m s --verbose --abr 128 )

[00:00:00:000] +------- BeSweet -----
[00:00:00:000] | Input : c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms.ac3
[00:00:00:000] | Output: c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms.mp3
[00:00:00:000] | Floating-Point Process: Yes
[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 1/0, Bitrate: 448kbps
[00:00:00:000] | Output Stereo mode: Stereo
[00:00:00:000] | Total Gain: 0.000dB, Compression: Normal
[00:00:00:000] | LFE levels: To LR -3.0dB, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: No
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- LAME -------
[00:00:00:000] | Bitrate method : ABR
[00:00:00:000] | Avarege Bitrate : 128
[00:00:00:000] | MP3 Min bitrate : 32
[00:00:00:000] | MP3 Max bitrate : 320
[00:00:00:000] | Channels Mode : Stereo
[00:00:00:000] | Error Protection: No
[00:00:00:000] +---------------------
[01:36:48.096] E7: CRC error
[01:36:49.248] E7: CRC error
[01:36:50.368] E7: CRC error
[01:37:07:648] Conversion Completed !
[01:37:07:648] Actual Avg. Bitrate : 117kbps
[00:06:53:000] <-- Transcoding Duration

[KpeX]

I don't see anything in your explanation that directly indicates what your problem is. However, I have a few suggestions to narrow down what might be going wrong.

1. Try playing the resulting MP3 in winamp instead of a dshow player such as windows media player, or vice versa, make sure first that this is not a playback problem.

2. If suggestion #1 shows that it is not a playback issue, try using Besweet v1.4 (stable) and see if the problem persists.

3. Try decoding to a .wav file from the original AC3 first, to see if your problem is coming from decoding the AC3 or encoding to MP3. If the .wav file plays okay, that should tell us something.

Good luck and let us know what you find.

[colordog]

@KpeX

Thanks for your reply. Concerning your suggestions:

1) I've actually been testing in WinAmp the whole time on each fresh encode.

2) That's a good idea, and I'll have to try that next.

3) As I stated, I already tried that. Like I said, the .WAV has the exact same electronic popping.

Thanks for your suggestions......

[colordog]

Okay, so I downloaded the last stable release from DSPguru's site, and it actually took care of some of the hissing and static pops, but not all. Some are gone, some are exactly in the same place.

Would hearing a bite of the popping help out diagnosis?

One difference I noted is that with the beta release included in GKnot, it only scanned the first couple of minutes of the file to determine the gain; with the stable 1.4 release, it scanned the entire file.

And isn't there something strange of a gain of -123?

Here's the log.

BeSweet v1.4 by DSPguru.
--------------------------
Using azid.dll v1.8 (b825) by Midas (midas@egon.gyaloglo.hu).
Using lame_enc.dll v1.28 (4/6/2002), Engine 3.92 <http://www.mp3dev.org/>.

Logging start : 11/03/03 , 19:53:55.

C:\Documents and Settings\Colin.LABRAT\Desktop\audio\BeSweet.exe -core( -input c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms.ac3 -output c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms-New.mp3 -logfilea C:\Documents and Settings\Colin.LABRAT\Desktop\audio\BeSweet.log ) -azid( -n1 -s surround -c normal -L -3db --maximize ) -lame( --abr 128 ) -profile( ~~~~~ Default Profile ~~~~~ )

[00:00:00:000] +------- BeSweet -----
[00:00:00:000] | Input : c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms.ac3
[00:00:00:000] | Output: c:\vobs\schizopolis\VIDEO_TS\Schizopolis AC3 T01 1_0ch 448Kbps DELAY -159ms-New.mp3
[00:00:00:000] | Floating-Point Process: Yes
[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 1/0, Bitrate: 448kbps
[00:00:00:000] | Output Stereo mode: Dolby surround compatible
[00:00:00:000] | Total Gain: 0.000dB, Compression: Normal
[00:00:00:000] | LFE levels: To LR -3.0dB, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: Yes
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- LAME -------
[00:00:00:000] | Bitrate method : ABR
[00:00:00:000] | Avarege Bitrate : 128
[00:00:00:000] | MP3 Min bitrate : 32
[00:00:00:000] | MP3 Max bitrate : 320
[00:00:00:000] | Channels Mode : Joint Stereo
[00:00:00:000] | Error Protection: No
[00:00:00:000] +---------------------
[01:36:48.096] E7: CRC error
[01:36:49.248] E7: CRC error
[01:36:50.368] E7: CRC error
[01:37:07:584] Conversion Completed !
[01:37:07:584] Actual Avg. Bitrate : 81kbps
[00:08:21:000] <-- Transcoding Duration

[KpeX]

Honestly, I'm a little stumped. the 81 kbps bitrate is a little suspect. I'd recommend trying two more things: you could try transcoding the audio with headac3he instead of besweet, or you could try methodically eliminating options until you're transcoding with default options, i.e. try it without the gain, etc. hope this helps,

[colordog]

@KpeX

So, I downloaded HeadAC3he 0.23 from Dark Avenger's site, and the associated DLLs. When I encoded with that, I got a huge log list of downmix overflows.

For instance, a small sliver:
[01:36:27.152] W7: Downmix overflow (0: +70.4dB)
[01:36:27.157] W7: Downmix overflow (0: +70.4dB)
[01:36:27.162] W7: Downmix overflow (0: +70.1dB)
[01:36:27.168] W7: Downmix overflow (0: +65.0dB)
[01:36:27.173] W7: Downmix overflow (0: +66.3dB)
[01:36:27.178] W7: Downmix overflow (0: +66.3dB)
[01:36:27.184] W7: Downmix overflow (0: +66.3dB)
[01:36:27.189] W7: Downmix overflow (0: +66.3dB)
[01:36:27.194] W7: Downmix overflow (0: +66.5dB)
[01:36:27.200] W7: Downmix overflow (0: +63.2dB)
[01:36:27.205] W7: Downmix overflow (0: +59.9dB)
[01:36:27.210] W7: Downmix overflow (0: +59.9dB)
[01:36:27.216] W7: Downmix overflow (0: +59.9dB)
[01:36:27.221] W7: Downmix overflow (0: +59.9dB)
[01:36:27.226] W7: Downmix overflow (0: +54.9dB)
[01:36:27.232] W7: Downmix overflow (0: +62.2dB)
[01:36:27.237] W7: Downmix overflow (0: +64.4dB)
[01:36:27.242] W7: Downmix overflow (0: +64.4dB)
[01:36:27.248] W7: Downmix overflow (0: +64.4dB)
[01:36:27.253] W7: Downmix overflow (0: +64.4dB)
[01:36:27.258] W7: Downmix overflow (0: +64.4dB)
[01:36:27.264] W7: Downmix overflow (0: +64.4dB)
[01:36:27.269] W7: Downmix overflow (0: +64.9dB)
[01:36:27.274] W7: Downmix overflow (0: +66.4dB)
[01:36:27.280] W7: Downmix overflow (0: +65.7dB)
[01:36:27.285] W7: Downmix overflow (0: +65.7dB)
[01:36:27.290] W7: Downmix overflow (0: +65.7dB)
[01:36:27.296] W7: Downmix overflow (0: +65.7dB)
[01:36:27.301] W7: Downmix overflow (0: +65.7dB)

Etc.

I was wondering if you thought that it could be related to the problem in this thread (http://forum.doom9.org/showthread.php?s=&threadid=26952&highlight=downmix+overflow)
I noticed that the version of Azid on DA's site is 1.8, but I'm not sure about the version included with GKnot, although that DLL does have a file creation date of Feb 2002, which I think corresponds to the version 1.8 release of Azid.

The problem listed here seems identical to mine, with garbledness and especially during scene changes. Do you think it might be the same thing?

[KpeX]

This is quite possible. To determine whether azid is causing the problem, I recommend you try to decode the AC3 to a .wav with Graphedit using AC3Filter (http://ac3filter.sourceforge.net), which I assume you have installed.

Render the file in graphedit, then remove the audio renderer (waveout or directsound), and add a 'wave dest' filter, then a 'file writer' filter. (Edit - make sure AC3Filter is set to 2-channel mode (stereo)) Play the graph and you should be able to decode the .wav this way. See if this works to eliminate the audio problem.

[colordog]

Actually, what I did instead (just because it was easier for me), was to instruct DVD2AVI to decode the AC3 to a WAV instead of just muxing it.

This new WAV file didn't have the popping or garbles, and so I used BeSweet to encode it to a VBR MP3 which resulted in a 'perfect' MP3!!! Also, the three CRC errors that appeared near the end of the encoding were gone, as well as the buffer overflows.

I'm so happy I finally got it to work - I had tried encoding it over 60 times!

Doesn't this further suggest a bug in Azid though?

[KpeX]

Yeah I should have thought of that ;) you're right it is a much simpler solution.

This definitely suggests a problem with azid, but as you'll notice in that thread you linked to earlier, azid is closed source and midas is tough to reach. This problem doesn't occur often so there's not much you can do other than decode with alternate methods.

Everyone say it with me now...'Behold the power of the search button.' :D

[colordog]

Yeah... I saw that in the thread... that's really too bad, especially considering that someone else found this bug over a year ago! But like you said, this error hardly ever happens. This is the first I've seen it, and I've used BeSweet (i.e. Azid) constantly for the last couple years.

Thanks for you help - I wouldn't have found the thread that talked about the bug if I hadn't used HeadAC3he and saw all the downmix overflows. (Not sure why I didn't see them in the log from BeSweet).

[tim222tim]

I've been following this thread as I too have been having the same problem with Schizopolis, using DVD2SVCD. I happy to see you've resolved the problem. Unfortunately, I do not understand now to implement the solution (DVD2AVI to decode the AC3 to a WAV, BeSweet to, BeSweet to encode to an MP3).

Can anyone help me? I'm only familiar with DVD2SVCDs dialogs, but am willing to learn if pointed in the right direction.

Thanks.

-- Tim

[KpeX]

Welcome to the forum tim222tim -

Get DVD2AVI from the Doom9 download page. Open up your .vob files with DVD2AVI (open one and the rest should auto-load), then click audio, and choose the track you want, set dolby digital to decode, and click file, save project. For reference on other options see the DVD2AVI faq. Regards,

[tim222tim]

Thanks, Kpex! WIth your help I was able to get it done. That's all I needed.

-- Tim