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Author Topic: GroupSummary on "True Peak Level"  (Read 632 times)

DieterKoessl

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GroupSummary on "True Peak Level"
« on: February 07, 2021, 04:26:13 am »

Hello,

I made a view which summarizes some acoustic values on a per album bases. The expression displayed in the summary column, for instance, includes

GroupSummary(Bitrate, 1)
GroupSummary(Volume Level /(R128/), 1)

which work as intended and compute the respective average values of the album. I also tried to add the average "true peak level", but failed. The expression

GroupSummary(Peak Level /(R128/), 1)

outputs only "[Varies]" for all instances. I tried to outsmart Media Center by defining a calculated library field TPL = Number([Peak Level /(R128/)], 0). This expressions works and retrieves the maximum TPL of a track as a simple signed number. Summarizing TPL as in

GroupSummary(TPL, 1)

still fails and results in "[Varies]". What is it that I am missing?

The curious things is, that GroupSummary works when defining TPL as a simple constant (say 42), but again fails when using it as a direct alias to a field (say [Bitrate]) which otherwise works.

Thanks
Dieter
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zybex

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Re: GroupSummary on "True Peak Level"
« Reply #1 on: February 07, 2021, 05:17:41 am »

That's because [Volume Level (R128)] is defined as a Decimal field (numeric), while [Peak Level (R128)] is a String field, so math functions cannot be used on it. Not sure if that's an oversight, of it it needs to be String so that it can also hold non-numeric values for some special cases.

Any Calculated field is, unfortunately, also of String type, so it can't be used with GroupSummary either (I tried using "&DataType[Decimal]" but it didn't work).

So you would need to create a Decimal type field, copy all values from Peak Level to it with "=[Peak Level (R128)]", and then you can use GroupSummary on this new field.
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DieterKoessl

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Re: GroupSummary on "True Peak Level"
« Reply #2 on: February 07, 2021, 06:35:52 am »

Thanks for your help. It worked... well, for the most part...

To be more specific, manually assigning =[Peak Level (R128)] to a decimal field in the tag editor works for approximately 0,85% of my files (ca. 122000 out of 145000). For the rest, nothing gets assigned. This even happens for files which are part of one and the same album (c.f. picture).

To you have any idea what might by amiss? Analyzing the files a second time does not change a thing.

Thanks
Dieter
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EnglishTiger

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Re: GroupSummary on "True Peak Level"
« Reply #3 on: February 07, 2021, 06:38:31 am »

Another problem could be that [Peak Level (R128)] can contain multiple values:-

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zybex

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Re: GroupSummary on "True Peak Level"
« Reply #4 on: February 07, 2021, 07:00:23 am »

Zero values are not shown on Decimal fields (+0.0 or -0.0 = 0). They should still count towards the GroupSummary.
Regarding the different left/right values... I think the first value is the Peak level of both channels, which is usually the value you'll want.
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DieterKoessl

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Re: GroupSummary on "True Peak Level"
« Reply #5 on: February 07, 2021, 10:19:13 am »

Thanks again. I had another look at my view and now it works. Using "FormatNumber([TPL], 1)" and "FormatNumber(GroupSummary(TPL, 1), 1)" did the trick. This formats the "empty" decimal into a proper Zero ("0,0").

By the way, I know that there are three values: maximum, left and right channel. Currently I am only interested in the maximum, which gets returned when simply assigning "Peak Level (R128)" to a decimal field.

My intention was to create a list of all the albums I own, which are or have been victims of the "loudness war". I do own a few where the "mastering" is atrocious. The most prominent example is "All Directions" by The Temptations "remastered" and published by "Culture Factory" in 2014. The TPL during the song "Papa Was a Rolling Stone" actually never falls below Zero and the maximum peak is at an unbelievable +4.8 dbTP! Needless to say, listing to that CD isn't fun at all.
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