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Invelos Forums->Posts by GSyren Page: 1 2 3 ...11  Previous   Next
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Quoting rdodolak:
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GSyren, ever consider the reverse, an EAN/UPC to ASIN converter?

Just to clarify, while I wrote AsinInfo, DJ Doena wrote ASIN to EAS/UPC Converter, and my program uses DJ's dll that handles the communication with Amazon's API. So my program just provides a slightly more advanced user interface.

Given that both our programs rely on Amazon's API, it seems unlikely that the API will provide better support than Amazon's own websites.
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Topic Replies: 55, Topic Views: 24712
Quoting mediadogg:
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Not sure how to interpret this. If you used some 1 channel discs, then you obviously could find them.  What did I miss?

Simple. I pulled some titles at random, and I made no note of which they were. At the time I wasn't actively looking for single channel mono, but at least one of them happened to have just that. I'm sure I could find some again, but I might have to go through quite a few to find one. And I will if you need it.
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Topic Replies: 47, Topic Views: 381
I was going to say that I do have several 1 channel discs, bur the problem would be to find them.
But now that AiAustria has provided an example maybe I don't have to?
If you need further examples, mediadogg, I can certainly take a look.
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Topic Replies: 47, Topic Views: 381
For what it's worth: All discs I looked at, whether 1 or 2 channels, were identified as AC3 by DVDPca. But that was only maybe half a dozen discs, so that could be just coincidence.

Barring a good way to display channel difference (l-r), it still seems to me that an educated guess is the best way to identify 2-channel mono. Not sure how well that would fare with voters/scanners though.
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Topic Replies: 47, Topic Views: 381
Quoting mediadogg:
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The "it" you are talking about is the amalgamation of the codec being used, and your receiver settings, including manual adjustments (e.g. "balance", or a "mono" switch, or down-mix settings and the list goes on).

That may well be so, but the bottom line is - is listening to the center speaker vs the left/right ones a reliable way to determine if it's mono or stereo. And my understanding is that it is not, if you're looking for a quick determination.
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Topic Replies: 47, Topic Views: 381
Okay, I read up a little bit about Dolby Prologic, and I think I understand it a bit better now. Maybe. Correct me if I'm wrong.

So, if I understand correctly, basically the more similar the two channels are, the more it will send that to the center speaker and correspondingly lower the volume on the left and right speaker. So a mono signlal would play pretty much only in the center speaker. Fine so far.

But - again if I understand correctly - if you have a stereo track where a passage has more or less the same sound in both channels, then this would also be played mainly in the center speaker. Is that right?

So that would more or less sound just like the mono track? And if so, it wouldn't be a very reliable test for mono vs. stereo unless you made sure that you listened to a passage where there was a stronger stereo effect?
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Topic Replies: 47, Topic Views: 381
Quoting AiAustria:
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Quoting GSyren:
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And wouldn't Dolby Prologic Decoding depend on the metadata to know if it is mono or stereo?

No, Dolby Prologic - as its predecessor Dolby Surround - is an upmixing from two (former analogous) channels to four chanels (usually Left, Center, Right, Rear). This works with any source material which has two channels.

But in this case it would downmix two mono channels to one center channel. That sounds iffy to me. How would it determine that it is mono without looking at the metadata?  Comparing the waveforms? What if there is suddenly a bit of noice on one channel? Would it switch to stereo (switching speakers) and then back to mono?

EDIT: See my next post for my better understanding of the issue.
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Topic Replies: 47, Topic Views: 381
Quoting mediadogg:
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what does it mean to (correctly) profile a DVD? To me, that means recording what the DVD metadata says.

Well, I don't agree with that. We should - if at all possible - document the data, not the description.

A difficult question to answer, perhaps, but does 2-channel mono ever have metadata that says mono?

The rules say
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Use the Audio specified on the DVD Cover unless you can verify there is a discrepancy between that and the actual Audio included on the disc.

Surely "actual Audio" is what's on the audio tracks, not what's in the metadata?

If the metadata says that an audio track is in English, but it is actually in French, would you document the metadata or the actual language? (Yes, I have seen that type of error)

The title that said mono on the cover but displayed 2-channel stereo was His Girl Friday (043396267091). I have uploaded the ifo files to our common Dropbox folder.
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Topic Replies: 47, Topic Views: 381
By the way, wouldn't a player like PowerDVD also use the metadata to display its audio information? Isn't that why we see so many profiles with 2-channel stereo where it ought to be mono; people enter what the player tells them?
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Topic Replies: 47, Topic Views: 381
By the way, I took a few titles that had been profiled as 2-channel stereo, but that I knew would be mono (and at least one actually said mono on the back cover), and I tested them with DVDPca. It reported them as 2-channel stereo. So if that info comes from the metadata, then the metadata is obviously not reliable.
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Topic Replies: 47, Topic Views: 381
Quoting mediadogg:
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Quoting GSyren:
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By the way, I just found out that VLC player actually can display waveforms. And I agree that it is impossible to say that ttwo waveforms are identical and therefore determine that it must be mono. But it is possible in many cases that waveforms are sufficiently different that you can tell with a fair degree of certainty that it is stereo.

Not sure how useful it is, though, since you would have to look for places where the tracks really are quite different.

You have got to be kidding! But if you really want to try using the waveforms, just wire a headphone plug to bridge across the L and R signal wires, ignoring the ground. Plug into the headphone jack of your amp, and you will hear the L-R content. If you hear silence, then both channels have the identical instantaneous content. This method should be electrically safe and offer no harm to you or your equipment, but to be super safe, you could add a small resistor 10 - 100 ohm in series.

The program Audacity can do just about anything with a waveform, including aligning the L and R channels horizontally next to each other. Very useful program for many purposes. I think you would enjoy it.


a) No I wasn't kidding. I ran a stereo title and at certain points I could clearly see a difference in the waveforms. But like I said, not sure how useful it would be.

b) Crossing the signal wires. Interesting, but I don't think I would be confident with that. Perhaps you have heard the old joke: How many programmers does it take to change a lightbulb? None, that's a hardware problem. That's me. I stay as far away from anything hardware related as I possibly can.

c) I have Audacity installed, I just don't know how to make it play DVD/BD audio.
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Topic Replies: 47, Topic Views: 381
Quoting mediadogg:
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I don't understand your point at all.

Well, maybe it would have been clearer if I had quoted the whole sentence:
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My point that you forgot: how about check what is on the actual DVD

Since I questioned the metadata's reliability, I obviously didn't forget about it. That's why your statement confused me.
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Topic Replies: 47, Topic Views: 381
Quoting T!M:
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Quoting GSyren:
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"How did Ken envision that we would tell 1-channel and 2-channel mono apart?"

I daresay he didn't envision that at all. I think he really didn't expect anything beyond entering what the cover says. It's just unfortunate that cover information is so often completely inaccurate.

Not to mention the fact that the cover quite often doesn't say anything at all about the audio.
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Topic Replies: 47, Topic Views: 381
Quoting iPatsa:
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Switch to Dolby Prologic Decoding. It will most certainly play 2-channel mono through the center speaker and 2-channel stereo through the left and right speakers.

I don't have a center speaker on my PC, nor any Dolby Prologic Decoding (as far as I know, anyway). And the rules surely can't assume that all users have a setup with a center speaker. And wouldn't Dolby Prologic Decoding depend on the metadata to know if it is mono or stereo? So if the metadata is unreliable, then the Dolby Prologic Decoding is unreliable as well, right?

Personally I do have a 5.1 setup in my living room, but that's not where I do my profiling.
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Topic Replies: 47, Topic Views: 381
Quoting iPatsa:
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A common problem with Swedish titles is that they seldom follow our general writing rules (nor do they have to).

True, but we should follow the rules of DVD Profiler for the purpose of contributing.
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Topic Replies: 8, Topic Views: 171
Oh, I forgot to mention that there is now an easter egg in ProfilerQuery. See if you can find it!

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Topic Replies: 208, Topic Views: 11549
By the way, I just found out that VLC player actually can display waveforms. And I agree that it is impossible to say that ttwo waveforms are identical and therefore determine that it must be mono. But it is possible in many cases that waveforms are sufficiently different that you can tell with a fair degree of certainty that it is stereo.

Not sure how useful it is, though, since you would have to look for places where the tracks really are quite different.
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Topic Replies: 47, Topic Views: 381
Quoting mediadogg:
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how about check what is on the actual DVD

Eh? You've got me confused now. I thought I covered metadata ("would the mastering engineer really care enough to create different metadata for mono and for stereo?"). Or are you talking about something else?
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Topic Replies: 47, Topic Views: 381
OK that makes sense. The reason for my confusion was that I felt that "Check capitalization of the title" could mean "Check how the title on the cover is capitalized", but I guess it means "Check that you follow the rules of capitalization".
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Topic Replies: 8, Topic Views: 171
Quoting mediadogg:
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as far as contributing, I can't imagine that Ken envisioned the community actually monitoring wave forms to make a contribution.

You're right. This whole thing actually started by me wondering how Ken envisoned that we would tell 1-channel mono from 2-channel mono.
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By the way, just to be clear, the "encoding" I am talking about is the encoding of descriptive information (metadata) in the IFO files on the DVD, not the audio stream encoding.

Ah, thanks! Now the penny dropped!

So that kind of shifts the focus a bit. Why is the overwhelming majority of old mono titles mastered as 2-channel mono? I can only assume that it is because the media company figured that most customers would prefer to have a wider sound image, coming from both main speakers rather than from the center speaker (if any). But if that was their intention, would the mastering engineer really care enough to create different metadata for mono and for stereo, if the audio was supposed to be presented the same way anyway, i.e. through the left and right speakers? Sounds like it would be just as unreliable as the back cover info.

So that seems to put as back at square one, doesn't it? We just have to make an educated guess. If the back cover says "mono", then it probably is. But that's about as far as I would trust the cover info. If it's an older movie and it days "stereo", I would be a bit suspicious and I would dig a bit. If it just says something like "Dolby 2-channel", or if there is no mention of the sound encoding, then I suppose I would go with an educated guess.

A relatively safe guess would be that fullscreen b&w movies from before 1960 would be mono unless there is info that says it was re-mixed. Color or widescreen would indicate a bigger budget which might mean more expensive audio, i.e. stereo (or better). Why 1960? No special reason, I just picked a year. It just seemed like stereo would become more popular after that.

Checking with IMDb is of course an option. If it says mono, and there is no indication of a remix, then I would assume that it is probably mono. That said, I know that Disney has remixed many of it's old cartoon features for DVD release.

So that brings me full circle back to "How did Ken envision that we would tell 1-channel and 2-channel mono apart?"
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Topic Replies: 47, Topic Views: 381
I used the same title that Ken used as an example, so that is not an actual example, but I do have Swedish titles that are mis-capitalized that way.

So we should use the correct capitalization, even if the cover title doesn't? E.g. ”Tout va bien"?
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Topic Replies: 8, Topic Views: 171
Quoting mediadogg:
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Ah, I almost forgot: the real issue is: what do the rules require that you submit? I think it is (2) - what is encoded on the DVD.

Surely, the encoding doesn't differentiate between 2-channel mono and 2-channel stereo? It's the content that differs, not the encoding.

(1) What is actually on the DVD audio tracks must be the right answer, as I see it. And yes, perhaps one would need software to compare the tracks to really determine what is what.
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Topic Replies: 47, Topic Views: 381
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Check capitalization of the title.

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Use capitalization rules common to the language of the title. “Tout va bien” is correctly capitalized. “Tout Va Bien” is not.

These two rules seem to potentially contradict each other. Or maybe I'm misreading them.
If the title on the cover should actually happen to be "Tout Va Bien", should that capitalization be kept or not?
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Topic Replies: 8, Topic Views: 171
The problem isn't differentiating between 1-channel and 2-channel.
The problem is differentiating between 2-channel mono and 2-channel stereo.
2-channel mono will play through the left and right speakers, just like 2-channel stereo.
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Topic Replies: 47, Topic Views: 381
The rules say:
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Select Mono for both 1-channel and 2-channel mono.

Well, that is sometimes easier said than done. Even listening with headphones, it can be difficult to be sure that a 2-channel track is actually mono. And cover info is notoriously unreliable.

Checking IMDb can be a help. If they say that the original sound was mono, and there is no mention on the DVD/BD that it has been remixed, then the likelyhood that it is actually mono is very high. But IMDb is not always reliable, and looking up everý title is a bit time consuming.

What would be helpful, though, would be to be able to display the waveforms for both tracks and compare them. If they are constantly the same, then it is mono.

Does anyone know of any software (preferably freeware) that can monitor the audio waveforms while the DVD/BD is playing? Ripping isn't practical; takes too long. Thorough profile auditing is time consuming enough. 
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Topic Replies: 47, Topic Views: 381
Invelos Forums->Posts by GSyren Page: 1 2 3 ...11  Previous   Next