The problem is in the encoding. If I play the VOB file directly from the hard drive (not the DVD) in, for example, Windows Media Player, I encounter the same problem.

I noticed that the sections with the fewest problems were encoded from MP3s, and the sections with the most frequent crackling came from the soundtracks of compiled videos, e.g., myvideo1.wmv.WAV and myvideo2.mxv.WAV, although each audio file played fine before being compiled and encoded into VOB format. So I exported the entire project as a single MP3 at 224 kbs, which played beautifully, then replaced all the audio files in the project with the single MP3. The situation improved, but there were still a lot of crackles, especially during noisier sections. My guess is that the VOB encoder is either automatically adjusting the volume upward into an unacceptable range or I am inadvertantly doing it somehow myself. Remember, though, that the exported WMV, MP4, MXV and MPG versions of the project have excellent audio.

I am going to reduce the volume of the project's soundtrack by 20db and re-burn the DVD, but suspect that the encoder will somehow override and "normalize" the audio volume. I'm not sure whether this makes a difference but the burn dialog does not let me change the MPEG layer 2 sample rate up or down from 44 MHz. I can change the bit rate to anything between 64 and 384, and have already tried 128 and 224. Not sure how the bi rate would influence crackling, but will try 384 this next time.

I will report back in 5 hours after the encoding is complete. Thank you for your help!

Hi,

OK, that helpfully focuses the issue.

I expect that some of my friends with greater audio technical skills than me will be along soon. Meanwhile it might help if you could create a very small project that exhibits the crackling/distortion. Then use File > Backup > Copy project and media into folder, zip it up and upload it so that we can try to reproduce it.

Also let us know your project and export settings. A mis-match there might be one possible cause.

--
Terry, East Grinstead, UK

Hi Terry,

My latest experiment seemed to have worked -- namely, setting the volume of the project files MUCH lower for encoding into VOB format than for exporting as WMV, MPG, MXV or MP4 files. The VOB encoder evidently has more sensitive ears than the other ones. The resulting fidelity is still not perfect (a couple errant crackles), but quieter audio files seem to be the key.

I am late for work but will upload later a snippet of my project file plus examples of the resulting VOB and WMV files. The VOB file will have obvious crackles, the WMV file will not.

Project settings were NTSC HDTV 1080i (1920x1280 29.97 fps), 32 tracks (13 used), and 48 kHz stereo sample rate.

WMV export settings were WMV 1280x720; 29.97 Frames/s; VBR Quality 75; 48000 Hz; Stereo; CBR 160 kBit/s. MP4 was 1280x720 ; 29.97 Frames/s; H.264 6000 kbit/s; 44100 Hz; Stereo;  AAC. MPG was 720x480; 29.97 Frames/s; Quality 10; Stereo 48,000. And  MXV was 1920x1080; 29.97 Frames/s; 48000 Hz; Stereo; PCM.

VOB encoding was DVD NTSC 6384 kBit/s; Quality 10; 720x480 29.97 fps; MPEG layer 2 audio 384 kBit/s 48 kHz stereo.

Thank you again for your kind assistance.

Pat Finegan in NYC

I am late for work but will upload later a snippet of my project file plus examples of the resulting VOB and WMV files

Pleased to hear you've made solid progress. Remember to use the feature I described for the upload.

--
Terry, East Grinstead, UK

Hi

You could experiment with "Rt click audio track > Normalize" this will set the clip to "maximum volume without digital distortion" ie -3db. The clicks may be some form of digital distortion.

Ss

Thank you, Scenestealer. I always perform a Select All >> Normalize when I compile projects. The problem is that the VOB encoder is for some reason dissatisfied with the normalized volume. The other encoders (WMV, MXV, MPG, MP4) handle it fine, but the VOB encoder requires considerably less volume to prevent distortion (crackling).

Hi

Do you have any codec packs, eg KLite,installed?

The fact that mpg files sound is OK is strange because the same codec should be used for creating the intermediate files before they are changed in to VOB's (all VOB files are MPEG streams, although the reverse is not necessarilly true). 

John

Hi John,

Here is a list of Audio Codecs on my system per Control Panel >> System Information >> Components >> Multimedia >> Audio Codecs:

iac25_32.ax        Intel audio software
imaadp32.acm  Microsoft IMA ADPCM Audio CODEC
l3codeca.acm    Fraunhofer IIS MPEG Layer-3 Codec
msadp32.acm   Microsoft ADPCM Audio CODEC
msaud32.acm   Microsoft Windows Media Audio
msg711.acm     Microsoft msg723.acm
msgsm32.acm Microsoft GSM 6.10 Audio CODEC
sl_anet.acm      Sipro Lab Telecom Audio Codec
tssoft32.acm     DSP Group TrueSpeech Audio Codec

These are the audio codecs listed when I play various exported versions of my project in Windows Media Player:

WMV   Windows Media Audio 9.2, 160 kbps, 48 kHz, stereo (A/V) 1-pass CBR
MP4    MainConcept AAC Decoder
MPG   Ligos MPEG Audio Decoder
MXV    Can't play in Windows Media Player. Don't know how to determine the codec
VOB    Codec not displayed in Windows Media Player. Don't know how to determine the codec

I also don't know how to match the first list of codecs to the second. This is all new to me. Sorry.

Pat

The video codecs on my system are:

iccvid.dll   Cinepak codec by Radius
ir32_32.dll  Intel codec
ir41_32.ax   Intel ir41_32.ax
ir50_32.dll  Intel Indeo video 5.10
iyuv_32.dll  Microsoft iyuv_32.dll
lvcodec2.dll Logitech ivcodec2.dll
mpg4c32.dll  Microsoft MPEG-4 video codec
msh261.drv   Microsoft msh261.drv
msh263.drv   Microsoft msh263.drv
msrle32.dll  Microsoft RLE codec
msvidc32.dll Microsoft Video 1
msyuv.dll    Microsoft msyuv.dll
tsbyuv.dll   Microsoft tsbyuv.dll
tsccvid.dll  TechSmith screen capture codec

The export file codec associations are:

WMV: Windows Media Video 9
MP4: MainConcept AVC/H.264 Video Decoder
MPG: Sonic CM(R) DS VideoDecoder 4.0
MXV: I don't know
VOB: I don't know

Hi Pat

Which version of Windows are you running?

The lists of installed codecs seems to be incredibly short for a standard installation of Windows XP/Vista or 7.

MXV's you will not be able to play in WMP - it is a Magix format.

John