AC3 Encoding with Compressor 2

Question

AC3 Encoding with Compressor 2

Hi all --

Anyone know why Compressor 2 won't convert my MPG audio streams to AC3?

I demuxed an MPG-2 program stream to .m2v and .mpa elementary streams.

The .m2v plays fine -- the .mpa must first be converted to 48kHz AIFF before Compressor will convert it to AC3.

Wish I could skip that intermediate step -- anyone know how?

Thanks -- Jerry

Dual 1.25GHz G4 Mac OS X (10.3.9)

Posted on Feb 1, 2006 8:48 AM

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Answer 1

David S.

Level 7

20,636 points

Feb 1, 2006 9:14 AM in response to Jerome Silverman

If you're using MPEG Streamclip, you can demux to aiff.

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Answer 2

Stedman

Level 3

945 points

Feb 1, 2006 10:22 AM in response to Jerome Silverman

Because Compressor 2 is designed to encode full resolution PCM sound (ie .aiff) to Dolby Digital .ac3.

It does not have any transcoding features - which basically just involve de-compressing, and then re-compressing, the sound anyway. You can do this by hand, as suggested by David S.

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Answer 3

Hal MacLean

Level 6

14,833 points

Feb 1, 2006 10:26 AM in response to Jerome Silverman

As David suggests, a different demuxer will give you the .aiff directly, which you can then use. If your original content was already AC3 then a half decent demuxer should spit out the AC3 file and save you the hassle of re-encoding it.

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Answer 4

Feb 1, 2006 11:40 AM in response to Hal MacLean

Thanks everyone.

So here's a related question:

I've used MPEG Streamclip in the past --

When I do "Demux to M2V and AIFF" on a clip,

the AIFF comes out fine... but the M2V is a program stream, not elementary!

In other words, it's not a true demux, because the M2V still has an embedded audio stream!

Anyone know a fix for this, or can explain why this happens?

Thanks again for your support!

-- Jerry

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