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Topic: 6 channel FLAC (Read 10606 times) previous topic - next topic

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  • HTS
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6 channel FLAC
How do I rip the 6 channel audio from video DVDs into 6 channel FLAC? I tried to convert the AC3 into WAV then into FLAC, but it turned into 2 channels.

  • j7n
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6 channel FLAC
Reply #1
Why would you want to convert lossy AC-3 to FLAC? Anyway AC-3 files can be decoded fine using Foobar2000, either by downmixing on-the-fly or not.

  • HTS
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6 channel FLAC
Reply #2
Why would you want to convert lossy AC-3 to FLAC? Anyway AC-3 files can be decoded fine using Foobar2000, either by downmixing on-the-fly or not.

Oh, so AC3 is not just another type of WAV? Like it's actually something like mp3?

That explains it, because I re extracted them, and found out that 95 minutes of sound is only 302 megabytes for 6 channels.

So is AC3 a compression it self? So the video DVD's audio is worse than CD audio in terms of per channel quality?

Is the 2 channel PCM also lossy or not lossy?

Thanks.

6 channel FLAC
Reply #3
Oh, so AC3 is not just another type of WAV? Like it's actually something like mp3?

That’s correct; AC3 is a lossy, compressed format much like MP3.

The stereo PCM track should be both lossless and uncompressed (like WAV). You’ll see a (size) benefit if you compress that with FLAC.
  • Last Edit: 20 June, 2008, 09:41:00 PM by MuncherOfSpleens

  • HTS
  • [*][*][*][*]
6 channel FLAC
Reply #4

Oh, so AC3 is not just another type of WAV? Like it's actually something like mp3?

That’s correct; AC3 is a lossy, compressed format much like MP3.

The stereo PCM track should be both lossless and uncompressed (like WAV). You’ll see a (size) benefit if you compress that with FLAC.

So did they just try to save space by using AC3 and not a lossless 6 channel audio?

Is AC3 better than stereo PCM even if it's lossless? I think it is because mine is at like 448 kbps, that is higher than the highest mp3 at 320k which is already considered transparent.

Do all video DVDs use AC3 or some lossy codec for 5.1?

Is DVD-Audio 448kbps too? I thought that DVD audio and SACDs are supposed to be higher fidelity than redbook CDs? Isn't it even worse then because it has lower bitrate than the audio CDs?
  • Last Edit: 20 June, 2008, 10:12:53 PM by HTS

  • j7n
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6 channel FLAC
Reply #5
Yes, AC-3 is used to save space and perhaps to enable sending surround data over existing stereo links (S/PDIF). Whether surround or stereo is better depends on the given programme. Cheap homemade DVDs might be upmixed to surround making the data fake and "not better".

I don't think surround in lossless format can be stored on a standard video DVD. Digital versatile discs don't have enough space for that, and also the audio alone would come close to max allowed transfer rate. (Video DVDs can't spin at 16x due to noise.) The bitrate of a typical surround file compressed with FLAC/wavpack/MLP will be around 8 MBit/s.

Audio DVDs use Meridian Lossless Packing exclusively, which is lossless as long as the bitrate stays under legal limit for DVD.

  • HTS
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6 channel FLAC
Reply #6
Audio DVDs use Meridian Lossless Packing exclusively, which is lossless as long as the bitrate stays under legal limit for DVD.

Shouldn't it always be greater than the limit? Because if the limit if 448 kbps, then 5.1 channels of even at redbook CD quality should be at very high bit rate right? Because FLAC files often leaves the Audio CDs at 500 Megabytes. And that's stereo, so wouldn't 5.1 FLACs have high bitrate? Or is the MLP more efficient?

So what happens when MLP exceeds the maximum allowed bit rate? Then the signal gets lossy? Then how do we know if an audio DVD is really better than a redbook CD which is guaranteed at 1411 kbps uncompressed?
Like 5.1 channel lossy or stereo lossless?

And how does SACD do it?

Thanks.

  • j7n
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6 channel FLAC
Reply #7
The bitrate limit for DVD is near 10 MBit/s.

SACD has been discussed to death already. Basically they've modified the DVD so badly, so that it couldn't be pirated (without expensive gear). And even then copies are not technically lossless.

  • HTS
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6 channel FLAC
Reply #8
The bitrate limit for DVD is near 10 MBit/s.

How much is it for the CD?

And so Audio DVDs have all of the disc to audio? I thought it reserved the video section empty?

  • j7n
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6 channel FLAC
Reply #9
Audio CD always runs at single speed and does not allow any logical structure variations. Audio gets all the space, shared equally between both channels.

I don't know if its obligatory to put real or at least dummy video_ts structure on every audio DVD. Actual albums I've seen always had two copies of the data, one as audio standard VOBs, and one video standard.

  • HTS
  • [*][*][*][*]
6 channel FLAC
Reply #10
Audio CD always runs at single speed and does not allow any logical structure variations. Audio gets all the space, shared equally between both channels.

I don't know if its obligatory to put real or at least dummy video_ts structure on every audio DVD. Actual albums I've seen always had two copies of the data, one as audio standard VOBs, and one video standard.

So basically audio DVDs should always be better than Audio CDs right? Like by the technical matters discussed here, for the same album, and assuming that they are equally well mastered ofcourse.