Different narration volume after render

johnbl wrote on 11/7/2003, 4:42 PM
Im putting together a 25 minute slide show with background music and voice over narration on vv4d. When running on time line real time preview..I have great quality audio with the voice over. after rendering to MPEG2 and AC3 using DVDA and burning the DVD. ..the voice over narration volume is extremely low. I increased the volume on the audio envelope and rerendered..now on the newly created DVD I get fluctuations in the narration volume. IS this a AC3 compression problem?? should I just output the audio to MPEG2 or PCM. Im not tight on space on the DVD anyways. Thanks JOHN

Comments

MJhig wrote on 11/7/2003, 6:10 PM
I essentially turn off all the processes in the AC3 encoder and do all my audio editing and processing in Vegas (BTW it's not VV4).

I'm not at the PC with Vegas now so I have to work from memory. I render the video using the DVD-A template which as you know only encodes the video to MPEG-2.

Then render the audio. In the AC3 encoder, on the first page I set the threshold to -31 then on the last page turn off all the filters and set the compression to "None". This way I find the encoder does nothing to the audio I've mixed in Vegas.

MJ
johnbl wrote on 11/7/2003, 6:46 PM
The dialogue normalization you set at -31...what does that control??? voice dialogue??? Sounds like the various custom settings may be my problem. Anyone else with experience with these filters and compression settings??? spot?? Billy boy?? Jet?? JOHN
bgc wrote on 11/7/2003, 6:51 PM
johnbl -
your problem is the dialnorm setting.
dialnorm, as you guessed, is an ac-3 bitstream metadata element mean to convey to the decoder what the level of the dialog is from full scale digital. if the dialnorm value does not match the actual level of the dialog in the ac-3 stream the decoder will modify the gain of the audio to match the dialnorm setting.
Go here to read about dialnorm and the other parameters:

http://www.dolby.com/metadata/pa.st.0102.MDGuide.pdf

B.
johnbl wrote on 11/7/2003, 8:54 PM
B. Im most appreciative of your dolby link going over the parameters. Looks like I need the -31db setting on dialnorm as mentioned in the earlier post to keep the narration without change or render audio as MPEG2 or PCM. Thanks again for your kind help. JOhn