Audio Format Options...

[Tolwyn]

When using Ahead Nero's Vision Express, my audio was auto-encoded as an AC3 stream.

TMPGEnc enocoder needs an addutional AC3 filter to encode into AC3 audio.

Now... I've been (I guess) encoding into MP2 audio.

Questions...
What's the difference?
Why the difference?
What benefits are AC3 over MP2?

I DID look for a guide, and must be looking in the wrong spot.
Is there some treatsie that I can look at explaining these two formats?

I'm familiar, quite a lot actually, with MP3.
I can even mix to Dolby 5 Surround (can't find an encoder that likes it, though) using Adobe Audition 1.5.

Sorry. My brain just must not be working today.

PS:
IS there an encoder I can use that will handle Dolby 5.x Surround WAVE files as generated/mixed by Adobe Audition?

Thanks.

David

[daamon]

Hi Tolwyn,

Q1: What's the difference between MP2 and AC3?

Well, apart from the obvious - they use different compression codecs - quality vs filesize is (I believe) quite similar. However, AC3 can go to higher bitrates (as per spec) because, I think (please check), of the fact that it can hold 5.1 whereas MP2 (here's what I'm not sure on) can't.

Q2 & Q3 - Covered above, to a degree.

One of the main benefits of AC3 over MP2 is that it is globally acceptable in DVDs - AC3 is in spec for both NTSC and PAL DVDs. Whereas MP2 is only in spec for PAL, but is likely (though no guaranteed) to play on NTSC machines.

Q4: IS there an encoder I can use that will handle Dolby 5.x Surround WAVE files as generated/mixed by Adobe Audition?

Sonic Foundry Soft Encode - But is no longer available and was pricey when it was around.

Then there's Surcode. There's probably others, but 5.1 AC3 encoding isn't my thing...

Both of the above found doing a preliminary search through "Tools" -> Audio Encoders (don't type in AC3 as the search criteria).

[Tolwyn]

Ok. I did find a guide on Doom9 as well.
Looks like per standard, CBR AC3 is the way to go... and I'll need some encoding tools (Surcode or the encoder I can buy for TMPGEnc) to get my audio encoded as AC3.

Course.... I'm not entirely sure how to insert/mux a 5.1 surround WAV - AC3 into my MPEG stream. Hmmm.

Surcode I'm checking out now. Thanks!

[Tolwyn]

Holy horsecrap, Batman! $2K for that?

[reboot]

ffmpeggui will convert to ac3. Not sure if that's exactly what you want though.

[Tolwyn]

Yup! I have that one too.
I'm just trying to wrap my noodle around this stuff.

It'll click eventually. Everything has thus far (except aspect ratios... I'm still confused on canvas size vs. aspect ratios)...

[daamon]

ffmpeggui will convert to ac3. Not sure if that's exactly what you want though.

True. But it only does 2.0 channel stereo, not the 5.1 stuff.

[jimmalenko]

ffmpeggui will convert to ac3. Not sure if that's exactly what you want though.

True. But it only does 2.0 channel stereo, not the 5.1 stuff.

... and daamon would know ...

[daamon]

... and daamon would know ...

Also, ffmpeggui can only do one file at a time... Now if only there was a well tested, feature-rich multi-file audio batch converter GUI out there...

[jimmalenko]

... and daamon would know ...

Also, ffmpeggui can only do one file at a time... Now if only there was a well tested, feature-rich multi-file audio batch converter GUI out there...

[daamon]

Yes, exactly....

[Nilfennasion]

If MP2 is what I think it is (the MPEG Multichannel format), then it most certainly can be encoded in 5.1, but why would you want to?

Digital receivers that can decode Dolby 5.1: 100%

Digital receivers that can decode MPEG Multichannel 5.1: Few, if any.

This makes AC3 a fairly obvious choice.

[daamon]

If MP2 is what I think it is (the MPEG Multichannel format), then it most certainly can be encoded in 5.1, but why would you want to?

Cheers for clearing that up - I wasn't sure. Now I know...

And this:

Digital receivers that can decode Dolby 5.1: 100%

Digital receivers that can decode MPEG Multichannel 5.1: Few, if any.

This makes AC3 a fairly obvious choice.

...is a good point. I guess that's why I've never come across 5.1 MP2.

[Nilfennasion]

It makes sense when you consider what happened with MPEG Multichannel. Basically, the guys behind MPEG rallied to get it added to the DVD specification, and the DVD consortium saw it as a chance to make DVDs in America and Europe more incompatible with each other. What they didn't anticipate was that very few manufacturers would add support for MPEG to their receivers, which basically meant that as time went on, fewer and fewer discs came out that had MPEG soundtracks. I have a couple of them myself, and I have never found hardware that can play the soundtracks back in their native format (although all but one of them also has Dolby 5.1 anyway, so it is a moot point).

[adam]

.Mp2 is a file extension that can apply to either mpeg1 audio layer II or Mpeg2 multichannel audio. Per spec, all PAL compliant hardware must play mpeg1 audio layer II audio on a DVD. Most NTSC hardware will play it as well, but there is no guarantee.

There are plenty of dvd players and receivers that support multichannel mpeg2 audio, primarily in Europe and Asia. Mpeg2 audio actually supports up to 7.1 channels and the quality is on par with Dolby Digital, but the format never caught on and there are not many commercial sources out there.