ac3 question at DVinfo.net

Jonathan Grant · September 5th, 2006, 03:39 PM

I'm not that familiar with ac3. I know it allows you to do surround sound, but is there an advantage over 24bit wav when only doing stereo? The film I'm working on is stereo and not surround. Should I bother with trying export in ac3?

The audio has been cleaned up and edited in pro-tools, exported as a 24 bit wav file, then imported to sony vegas to match with the video. Would exporting it in ac3 format be any different than exporting it in 24bit wav?

Peter Jefferson · September 5th, 2006, 06:05 PM

I'm not that familiar with ac3. I know it allows you to do surround sound,
((surround sound wow factor is only one element)

but is there an advantage over 24bit wav when only doing stereo?

((if this si for DVD, then 24bit isnt an option...16bit@ 48khz is the DVD standard, whether it be wav or ac3 or dts ))

The film I'm working on is stereo and not surround. Should I bother with trying export in ac3?
((a 192kbps ac3 stereo file ill give you the full 20khz bandwidth of audio. much like a surround sound 5.1 encoded file at 448kbps. to the naked ear the differnce will not be noticable, however the end file you will have will be MUCH smaller than PCM wav, in turn allowing you to have a higher bitrate for your image))

The audio has been cleaned up and edited in pro-tools, exported as a 24 bit wav file, ((u sure about that?? How was it recorded? Scaling up and interplating the bitrate really makes no differece if the source material is recorded as 16bit... ))

then imported to sony vegas to match with the video. Would exporting it in ac3 format be any different than exporting it in 24bit wav?

((for DVD, yo udont have a choice. it MUST be 16bit... either pcm or ac3 or even mpg audio <which DVDArchitect doesnt support by the way>

good luck with it

Eric Darling · September 5th, 2006, 06:50 PM

AC3 format is compressed, whereas WAV isn't. So, you'll save a ton of room, and you'll also leave more total muxed bitrate percentage available for video - possibly leading to a better quality product. But perhaps the best side-effect of converting your sound tracks to AC3 format is that it will greatly improve the chances that your DVD will be more compatible with more DVD playing devices.

Make sure your settings are appropriate for DVD video - depending on what tools you're using for the encode, this can be more or less challenging.

Jonathan Grant · September 8th, 2006, 04:49 AM

Thanks guys. Is there a program out there that just converts wav files to ac3? I don't think the version of Vegas has an ac3 encoder.

Eric Darling · September 8th, 2006, 06:15 AM

http://www.dekorte.com/projects/shar...oundConverter/

Emre Safak · September 8th, 2006, 07:27 AM

Vegas does have an AC3 encoder; you just need to install DVD Architect. Go to Render As from the File menu. What are you making your DVDs with?

Jonathan Grant · September 11th, 2006, 06:02 PM

Is there a program for PC?

Emre Safak · September 11th, 2006, 06:47 PM

Vegas is a PC application. Do you mean free?

Jonathan Grant · September 12th, 2006, 01:29 PM

Sorry, no I meant stand-alone. I am doing the sound editing and don't have Vegas and all that.

Emre Safak · September 12th, 2006, 02:09 PM

Try this free, stand-alone encoder. While the guide is written for AC3 to AC3, you can use it for converting any common audio format to AC3.

Derek Prestegard · September 17th, 2006, 09:42 PM

yes yes yes! doom9! :)

There are some decent free AC3 encoders, but the payware is generally a lot better. Dolby charges too much for their IP licenses...

About your 24 bit master..

Make sure the sources were recorded in 24 bit. If they weren't, then re-export the project into a 16 bit wav. 24 bit is a waste of space in that case.

DVD standard supports PCM, MP2, AC3, and DTS. Some players won't play all of these formats, but they all HAVE to play AC3. So AC3 is always a safe route. It also has the advantage of dynamic range compression (assuming the decoder can make use of this metadata), and dialogue normalization. AC3 is awesome :) In general I would always reccommend it for the reasons other people have stated!

-Derek Prestegard

September 5th, 2006, 03:39 PM	#1
Jonathan Grant Regular Crew Join Date: Jun 2006 Location: norman, OK Posts: 111	ac3 question I'm not that familiar with ac3. I know it allows you to do surround sound, but is there an advantage over 24bit wav when only doing stereo? The film I'm working on is stereo and not surround. Should I bother with trying export in ac3? The audio has been cleaned up and edited in pro-tools, exported as a 24 bit wav file, then imported to sony vegas to match with the video. Would exporting it in ac3 format be any different than exporting it in 24bit wav?

September 5th, 2006, 06:05 PM	#2
Peter Jefferson Inner Circle Join Date: Apr 2003 Location: Aus Posts: 3,884	I'm not that familiar with ac3. I know it allows you to do surround sound, ((surround sound wow factor is only one element) but is there an advantage over 24bit wav when only doing stereo? ((if this si for DVD, then 24bit isnt an option...16bit@ 48khz is the DVD standard, whether it be wav or ac3 or dts )) The film I'm working on is stereo and not surround. Should I bother with trying export in ac3? ((a 192kbps ac3 stereo file ill give you the full 20khz bandwidth of audio. much like a surround sound 5.1 encoded file at 448kbps. to the naked ear the differnce will not be noticable, however the end file you will have will be MUCH smaller than PCM wav, in turn allowing you to have a higher bitrate for your image)) The audio has been cleaned up and edited in pro-tools, exported as a 24 bit wav file, ((u sure about that?? How was it recorded? Scaling up and interplating the bitrate really makes no differece if the source material is recorded as 16bit... )) then imported to sony vegas to match with the video. Would exporting it in ac3 format be any different than exporting it in 24bit wav? ((for DVD, yo udont have a choice. it MUST be 16bit... either pcm or ac3 or even mpg audio <which DVDArchitect doesnt support by the way> good luck with it

September 5th, 2006, 06:50 PM	#3
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	AC3 format is compressed, whereas WAV isn't. So, you'll save a ton of room, and you'll also leave more total muxed bitrate percentage available for video - possibly leading to a better quality product. But perhaps the best side-effect of converting your sound tracks to AC3 format is that it will greatly improve the chances that your DVD will be more compatible with more DVD playing devices. Make sure your settings are appropriate for DVD video - depending on what tools you're using for the encode, this can be more or less challenging.

September 8th, 2006, 04:49 AM	#4
Jonathan Grant Regular Crew Join Date: Jun 2006 Location: norman, OK Posts: 111	Thanks guys. Is there a program out there that just converts wav files to ac3? I don't think the version of Vegas has an ac3 encoder.

September 8th, 2006, 06:15 AM	#5
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	http://www.dekorte.com/projects/shar...oundConverter/

September 8th, 2006, 07:27 AM	#6
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	Vegas does have an AC3 encoder; you just need to install DVD Architect. Go to Render As from the File menu. What are you making your DVDs with?

September 11th, 2006, 06:02 PM	#7
Jonathan Grant Regular Crew Join Date: Jun 2006 Location: norman, OK Posts: 111	Is there a program for PC?

September 11th, 2006, 06:47 PM	#8
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	Vegas is a PC application. Do you mean free?

September 12th, 2006, 01:29 PM	#9
Jonathan Grant Regular Crew Join Date: Jun 2006 Location: norman, OK Posts: 111	Sorry, no I meant stand-alone. I am doing the sound editing and don't have Vegas and all that.

September 12th, 2006, 02:09 PM	#10
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	Try this free, stand-alone encoder. While the guide is written for AC3 to AC3, you can use it for converting any common audio format to AC3.

September 17th, 2006, 09:42 PM	#11
Derek Prestegard Regular Crew Join Date: Sep 2006 Location: Santa Cruz, California Posts: 30	yes yes yes! doom9! :) There are some decent free AC3 encoders, but the payware is generally a lot better. Dolby charges too much for their IP licenses... About your 24 bit master.. Make sure the sources were recorded in 24 bit. If they weren't, then re-export the project into a 16 bit wav. 24 bit is a waste of space in that case. DVD standard supports PCM, MP2, AC3, and DTS. Some players won't play all of these formats, but they all HAVE to play AC3. So AC3 is always a safe route. It also has the advantage of dynamic range compression (assuming the decoder can make use of this metadata), and dialogue normalization. AC3 is awesome :) In general I would always reccommend it for the reasons other people have stated! -Derek Prestegard