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View Full Version : Converting to AC3 with NeroVision Express. Many restriction apply.


mkanel
24th January 2004, 14:26
This is not an ideal audio conversion tool, of course that's not what it's designed to be. It's big advantage is that a lot of people already have Nero, if you don't own it it's a lot cheaper than a "proper" tool to convert audio to AC3. It probably won't appeal to very many users because of it's drawbacks: it will only make two channel AC3s at 192kbps, it's a little messy it makes an mpeg2 file that then needs to be demuxed, and it's slow because it makes a dummy mpeg2 file while converting the audio. You can make it go faster but it takes some more preparation.

Open NeroVision Express and select Make New Movie, not Make DVD. Add your .wav file (I think other formats are accepted) to Audio 1 in the timeline. Click export, make sure the template in the drop down box is DVD. Click configure, select the DVD-Video tab at the upper left. We now want to configure it for the lowest quality fastest rendering video we can since we only want the audio so select Quality setting: Super long play, Resolution: Fast encoding (1-pass), and Audio format: Dolby DIgital (AC-3) 2.0. Click OK, you can now change the output file path and name if you wish. Click export.

On my PIII 933mhz computer the conversion is slower than real time a 1 hour audio file will be processed in about 1.5 hours. When it's done just strip the audio out of the .mpg file, you can do this with TMPG's mpeg tools, virtualdubmod, or I'm sure there are other freeware tools available. You can also delete the mpg file but before you do make sure you don't want it for the procedure below. Congratulations you now have your AC3 file and you can stop reading right here.

If there's any value in the process but you would like to speed it up you can. What you need it an mpeg file that has the same parameters as the one that was produced by the above process. The mpeg must have audio otherwise for some reason you lose the speed savings and the audio must be nothing but silence because Nero doesn't replace the mpeg audio with the audio you add to the timeline but blends it together. Finding an mpeg of the right type is easy, it was produced with the first process. You can then use an audio editor (such as Nero's wave editor which you should already have) to produce a silent wav file or you can do it with NeroVision by putting the demuxed video file (TMPG calls it an .m2v file) in the Video Track on the timeline leaving Audio 1 and 2 empty. When you export the movie you'll now have blank audio and video. I don't think it matters if the blank movie has wav or ac3 audio.

For future conversions use the blank audio/video mpeg and the audio file that you want to convert. Make sure to select the same low quality video setting during export or it will spend a lot of time re-rendering the video. This conversion takes about 25 minutes for my 1 hour audio file. You want the blank video to exactly match the length of your audio. You can do this by adding the same blank video as many times as needed to the video track until it's longer than your audio file and then trimming the excess video in the preview window, it's not too hard once you figure out the editing controls.

If you don't own Nero you can give the trial program a shot but unless your desperate for this kind of AC3 you might want to wait before you buy it, Dolby seems to be showing up in a lot of these lower priced software packages with limited versions of AC3 production. Tmpg DVD Author now has a $30 plugin and allows you to select the bitrate and DVD-Lab sounds like they might have the same thing soon. Who knows, if Dolby licensing allows it maybe something a little more straight forward will turn up soon.

daphy
26th January 2004, 10:32
:confused:
strange

1. load the AC3 plugin from here (http://neroplugins.cd-rw.org/) and save it on the right place (see describtion on this site)
2. open your WAV with Nero WaveEditor
3. save as AC3
basta
result AC3 2.0

time: less the realtime

CYA Daphy

zettai
26th January 2004, 12:43
The ac3 plugin on that site is the ffmpeg one, which I belive isn't standards compliant hence its removal from besweet.

If that is the one I'm thinking of you shouldnt use it.

mkanel
26th January 2004, 15:52
Originally posted by daphy
:confused:


@daphy In other words why bother with all that dude? Good point.

Like zettai I also understood ffmpeg not to be standards compliant. I tried BeSweet when AC3 was still supported and found the volume to be very low. While looking into that I saw the reports on problems playing BeSweet's AC3s in some DVD players and quality problems. Since then I've just been using mp2 audio. I never tried the Nero plugin that you link to because I assumed it had the same problems.

To prove it I downloaded the above plugin and tried it with Nero's wave editor. It's a much simpler way of obtaing the audio file and I can select the bitrate. Of course it would still have the low volume issue. Oops, surprise, the volume is fine.

The quality seems fine but I don't have a descent audio system and my source material is not music but home video, kids passing gas and the like.

For me the big deal is compliancy, mp2 audio plays fine in my DVD player, the only reason to use AC3, at least in NTSC land is to be sure that future DVD players won't have a problem with the audio

I see that the Nero plugin DLL is newer than the one I used with BeSweet 8/6/2003 vs. 6/8/2002, is it possible that the author made some changes that allows for a compliant AC3?