-
how to get ac3 sound for render?
I’m trying different ways to render my video for DVD.
If I use the free script from Vaast to render it creates an mpg2 and an ac3 for audio.
Because I want to control the vbr settings in my render, I can’t use the script so I’m rendering manually.
In the render settings, is there a big diff in sound quality between ac3 and the sound included in a file rendered with the mpg2 setting and the recommended 224 kbs bitrate?
cheers,
Gilles -
6 Replies
-
In the render settings, is there a big diff in sound quality between ac3 and the sound included in a file rendered with the mpg2 setting and the recommended 224 kbs bitrate?
Yes, because it will be rendered twice. NTSC DVD’s do not allow MPEG2 audio. The spec calls for PCM or AC3 so DVD Architect will re-encode your MPEG2 audio to AC3. This is why it’s better to do this from the original source.
Having said that, some people use tools that don’t adhere to the spec and place MPEG2 audio on an NTSC DVD and “most” DVD players will play the audio but if you want to be sure it will *always* play, you need to use PCM or AC3 and that’s best encoded from your source for highest quality.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks John! I’m learning so much here “on the Cow”. Thanks to people like you, Mike and all the others always willing to share their wealth of knowledge.
1. So, If get this right, to have my audio encoded once, for best quality I should go straight to AC3 if I’m to output my video to DVD?
2. I don’t see a setting for AC3 audio in the render for the NTSC template. so if I hear you correctly, this is normal and I must do a 2-pass and choose the AC3 from the list AFTER I render the mpg2? Do I tell the mpg2 render not to include audio then? if so, how?
3. Is an AC3 audio much larger in size than that of what’s encoded in an mpg2? Reason I ask is that i’ve had to compress this 140 minute training video like mad trying to fit it on one DVD.
Gilles
-
1. So, If get this right, to have my audio encoded once, for best quality I should go straight to AC3 if I’m to output my video to DVD?
Yes.
2. I don’t see a setting for AC3 audio in the render for the NTSC template. so if I hear you correctly, this is normal and I must do a 2-pass and choose the AC3 from the list AFTER I render the mpg2?
Yes. DVD’s don’t use the MPEG2 file directly anyway. It separates the video from the audio and rejoins them in the VOB format. So you are saving a step by supplying two streams to begin with.
Do I tell the mpg2 render not to include audio then? if so, how?
None of the “DVD Architect” MPEG2 render templates contain audio. This is on purpose. Just use one of the DVD Architect templates in Vegas. You could always turn off audio in any template you’d like by pressing the Custom button and going to the audio tab and unchecking the enable option. (but you don’t have to in this case)
3. Is an AC3 audio much larger in size than that of what’s encoded in an mpg2? Reason I ask is that i’ve had to compress this 140 minute training video like mad trying to fit it on one DVD.
Actually the AC3 might be the same size or smaller than MPEG2 audio. It shouldn’t make a big difference in the overall size.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks again John,
do the DVDA templates in vegas create the AC3 sound file?
-
do the DVDA templates in vegas create the AC3 sound file?
No, you must do that separately because you could also use a PCM wave file.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
perfect,
Thanks.
Reply to this Discussion! Login or Sign Up