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DVD-A Mastering
Reply #25
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I debated adding this to one of the existing DVD-A threads, but they're getting a little congested.

With DVD-A now rippable, let's use this thread to analyze DVD-A mastering and, if possible, how that mastering compares to the CD version of the album.  The primary difference will hopefully be that DVD-As are unaffected (or less affected) by the loudness race.

Here's a look at "Deadwing" by Porcupine Tree.

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Is there a WAVstat analysis available of these two pieces of music?

See [a href="http://www.huennebeck-online.de/musik/stat/]http://www.huennebeck-online.de/musik/stat/[/url]

Easiest way is to count the level distribution and send the result to me.

unsigned short  Distr [65536] ;
signed short Samples [...] ;
long SampleCount = fread ( Samples, sizeof(*Samples), sizeof (Samples)/sizeof(*Samples), fpi ) ;
for ( i = 0; i < SampleCount; i++ )
    Distr [ Samples + 0x8000 ] ++ ;
fwrite ( Distr, 1, sizeof Distr, fpo ) ;
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The explanation page there is only available in German and that's a bit hard for Cyaneyes I think. I could do it, but Cyaneyes didn't make samples available and I recommend him not to do this.
Near to the bottom right corner of the German page are links "Windows" (or "Linux", if you have that) which lead to the English download pages for the binaries/executables.
As far as I understand it, interpret the plot like this:
clipped/compressed: The plot line hits the bottom horizontal axis at more than -4,7 (or the top horizontal axis at less than +4,7)
unclipressed: other
What is this "sigma" ?
I know that I know nothing. But how can I then know that ?

DVD-A Mastering
Reply #26
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er..wouldn't the *mixes* be different too?  I'd be very surprised if a 6-channel remix , downmixed to 2-channel, sounded the same as the original 2-channel mix.

To test this, one can compress the downmix until it matches the stereo master's loudness and ABX the samples. no longer ABXable => "compression is audible" proven. I expect that they'll still be ABXable, though.
By the way, in this post I reported an ABX test proving that 3 dB compression can be audible.
I know that I know nothing. But how can I then know that ?

  • krabapple
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DVD-A Mastering
Reply #27
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er..wouldn't the *mixes* be different too?  I'd be very surprised if a 6-channel remix , downmixed to 2-channel, sounded the same as the original 2-channel mix.

To test this, one can compress the downmix until it matches the stereo master's loudness and ABX the samples. no longer ABXable => "compression is audible" proven. I expect that they'll still be ABXable, though.
By the way, in this post I reported an ABX test proving that 3 dB compression can be audible.
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No, it's not a matter of the *compression* being audible -- in my experience even the most faithful 2-channel remix will still have notable differences from the original stereo mix.  Things like certain instrumental parts or sound effect missing or at a different volume in the remix, or different reverb/EQ compared to the original.  An example would be 'South Side of the Sky' or 'America' from the Yes 'Fragile' DVD -- parts of the surround mix are completely different from the original mix, and folding it down to 2-channel would not mask those differences.  Similarly, the 'Brain Salad Surgery' DVD-A uses alternate vocal takes in certain parts, contains a piano chord here or there that wasn't on the original, etc.  Not to mention that instrumental placement in the left or right channel is not necessarily going to match the original mix.  These are gross differences, not subtle .  So again, it seems HIGHLY unlikely to me that a fold-down of a new 5.1 mix would fail an ABX ttest against the original stereo mix, even if they both had the same amount of dynamic range compression.
I don't think an ABX of fold-down vs. original stereo mix would tell you anything necessarily about the compression differences, there's too many other possible differences to account for.
  • Last Edit: 10 October, 2005, 04:37:34 AM by krabapple

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DVD-A Mastering
Reply #28
yes, the multichannel capabilities of DVD-A is 1 nice feature,
though it doesn't help much to show, wether hi-res format is audible superior to CD or not.
Could these comparisons be carried out with the special hi-res stereo content of DVD-A/Sacd vs. the CD version ?
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  • MugFunky
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DVD-A Mastering
Reply #29
hmm.  considering the different mixes and whatnot, objective comparison is not that easily done.

of course, when talking about music, what matters is how it sounds.  put a squish next to an un-squished song, both gained to a reference level, and the un-squished one is going to sound better.

i'm not surprised that 3dB of compression is ABX'able, but i wonder how that compression was done - compressors can produce a huge variety of effects, and when set to behave like a limiter they'll flatten transients like hi-hats and snares in a very audible way.  "upward compression" could provide a more transparent way to get an extra 3dB out of a recording - that is mixing a heavily compressed, low level version with the uncompressed original.  this effectively brings the volume up "from the bottom" rather than reducing peaks and applying a global gain.

DVD-A Mastering
Reply #30
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i'm not surprised that 3dB of compression is ABX'able, but i wonder how that compression was done - compressors can produce a huge variety of effects, and when set to behave like a limiter they'll flatten transients like hi-hats and snares in a very audible way.

On various test with Cool edit I realized that it's often possible to reach the same average loudness with less compression and clipping artefacts than in the CD's masters.
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"upward compression" could provide a more transparent way to get an extra 3dB out of a recording - that is mixing a heavily compressed, low level version with the uncompressed original.  this effectively brings the volume up "from the bottom" rather than reducing peaks and applying a global gain.
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But also doesn't provide much headroom for amplifying up. When I tested this I found it not that effective. Or what precisely do you mean ?
I know that I know nothing. But how can I then know that ?

  • krabapple
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DVD-A Mastering
Reply #31
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yes, the multichannel capabilities of DVD-A is 1 nice feature,
though it doesn't help much to show, wether hi-res format is audible superior to CD or not.
Could these comparisons be carried out with the special hi-res stereo content of DVD-A/Sacd vs. the CD version ?
[a href="index.php?act=findpost&pid=333471"][{POST_SNAPBACK}][/a]



Yes, that would make more sense.  Though of course you might still just be comparing mastering choices, not formats -- even when you're comparing two layers of the same disc.

DVD-A Mastering
Reply #32
Has anyone else downmixed this album.. and it just sounds wrong?
Now I'm no expert of audio jargon, but it sounds as if the the drums are sucking the volume away from all other sounds in the song, which is very annoying to listen to as the sounds cuts in and out.
I've downmixed many albums and this is the 1st one that does this, I've also tried using a couple of different ways and still get the same result.

  • krabapple
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DVD-A Mastering
Reply #33
Has anyone else downmixed this album.. and it just sounds wrong?


Which album?


DVD-A Mastering
Reply #34
Porcupine Tree - Deadwing