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V6 AC-3 Dynamic Range Compression Question
I needed to render audio (and video but my question concerns the audio) in Vegas 6 to AC-3 because I wanted to later put it on a DVD. The original avi audio was really bad to begin with so in Vegas 6, wanting to equalize the sound, I used the volume envelope tool. When I finally rendered it, the AC-3 file’s volume was much lower than I expected and was originally. I then searched the forum for problems similar to mine and I discovered that the Default settings for rendering AC-3 stereo changes the original audio. I also found a way to fix this on this forum and this is where my question comes in.
I have read that for unaltered audio the “Dialog normalization” option should be set to -31dB -27dB and the “Dynamic Range Compression Line mode profile” option should be set to “None” instead of “Film: Standard”. What about the “Dynamic Range Compression RF Mode Profile” option? Should that be set to “None” too? Is this all I have to change to make the audio unaltered?
Thanks for any help,
Michael M.
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8 Replies
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When rendering to AC3 format, the volume will be automatically reduced. If you wish to prevent this from happening, make the following setting changes:
Change the dialog normalization to -31
On the PreProcessing tab, change both the Line mode profile and RF mode profile to NONE.
Edward Troxel
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Edward,
Do you know if DVDA3 drops the volume when rendering from AVI? If so, how would one avoid this, and do you know why this is done?Regards,
Jerry -
I believe you will have to render from Vegas to prevent this from happening.
Edward Troxel
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Thank you very much for the quick response and the clarification.
I have one more quick question:
[jeditdv] “When rendering to AC3 format, the volume will be automatically reduced.”
Is the reduction of the volume constant throughout the entire track? When it reduces the volume, does it reduce the volume in such a way that the result is similar to moving the track volume next to the time line down or is it more complex than this? I hope my wording isn’t too confusing.
I am asking this becuase I am wondering whether I can just render the avi audio to AC3 without equalizing the volume manually. I’m not sure which would give a better result but I can compare later.
Thanks again for the help,
Michael M.
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Take a quick read here:
https://www.sonymediasoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=340571
Edward Troxel
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Thanks, that cleared things up for me.
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Don’t forget also that you only have to use ac3 if you’re “pushed for space” on the DVD.
You can set the audio in DVDA to be PCM wav and avoid these compression issues.
Peter Wright
Perth, Western Oz
http://www.allroundvision.com.au -
I would suggest you use AC3 all the time. AC3 is very good and it’s very difficult to detect the difference between it and PCM. In addition, PCM takes up about 8 TIMES the space of a typical stereo AC3 track. For 2 hours of video (a typical amount to try to fit on a standard DVD) PCM would need almost 1.4 GB of the 4.7 GB total. AC3 would take up 176MB. I’d rather have those extra 1.2 GB allocated to the video.
As always, YMMV.
Good luck.
Dennis
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