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Author Topic: Lazy automatic audio analysis  (Read 1920 times)

gummbah

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Lazy automatic audio analysis
« on: May 07, 2008, 04:03:06 pm »

Sometimes automatic audio analysis is a bit 'lazy'.
It only calculates replay gain values, but it forgets to calculate BPM and intensity.
When I manually select and analyse them there is no problem.
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Alex B

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Re: Lazy automatic audio analysis
« Reply #1 on: May 08, 2008, 04:18:28 am »

That happens if imported MP3 files already contain ID3tags with Replay Gain and Peak values created by some other program. In this case MC uses the existing values and does not automatically start the analyzer.

The BPM and Intensity values are not used with Volume Leveling. They are useful only for displayed information, sorting and and searches.
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gummbah

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Re: Lazy automatic audio analysis
« Reply #2 on: May 08, 2008, 08:09:27 am »

That happens if imported MP3 files already contain ID3tags with Replay Gain and Peak values created by some other program. In this case MC uses the existing values and does not automatically start the analyzer.

The BPM and Intensity values are not used with Volume Leveling. They are useful only for displayed information, sorting and and searches.

My point is a bit different, i.e. for the files that are being automatically analysed BPM and intenstity are not always calculated.
But if I select these files after automatic analysis, these values are calculated.
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Alex B

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Re: Lazy automatic audio analysis
« Reply #3 on: May 08, 2008, 08:53:28 am »

How did you confirm that the automatic analyzer didn't skip those files?

Are the files not in MP3 format or have you verified that the files didn't already contain the mentioned ID3v2 tags (namely, TXXX REPLAY_GAIN_TRACK_GAIN and TXXX REPLAY_GAIN_TRACK_PEAK)?

By default, the analyzer is set to skip files that already have these two tags. When you run the analyzer manually you can untick the "skip option" for analyzing the BPM and Intensity values too.

When the analyzer is actually run all four values are always calculated and stored unless there really is a bug.
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gummbah

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Re: Lazy automatic audio analysis
« Reply #4 on: May 08, 2008, 11:05:40 am »

How did you confirm that the automatic analyzer didn't skip those files?

Are the files not in MP3 format or have you verified that the files didn't already contain the mentioned ID3v2 tags (namely, TXXX REPLAY_GAIN_TRACK_GAIN and TXXX REPLAY_GAIN_TRACK_PEAK)?

By default, the analyzer is set to skip files that already have these two tags. When you run the analyzer manually you can untick the "skip option" for analyzing the BPM and Intensity values too.

When the analyzer is actually run all four values are always calculated and stored unless there really is a bug.

There are two things here.

First, yes indeed I am sure automatic analysis on import starts analysing the files, because every I use foobar to calculate replay gain values for any album before adding it to my MC database. And each time MC starts its automatic analysis.

Second, for the files that get automatically analysed MC does not calculate BPM and intensity (it does in some cases strangely enough). I have to use manual analysis (unticking the skip option) to get BPM and intensity values.

All files are mp3.
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Alex B

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Re: Lazy automatic audio analysis
« Reply #5 on: May 08, 2008, 12:29:10 pm »

On import MC always "analyzes" the imported files by reading the file format and tag info.

It decides to not run the replay gain, intensity & BPM analyzer if the file already contains the track gain and peak tags. This happens only if the file format is MP3 and tag format is ID3v2.

Is this not what is happening on your PC?

Personally, I would rather run the analyzer manually as a separate task. Replay gain, intensity & BPM analysis is very slow because the files need to be decoded completely. I would like to have the files imported immediately and run the analyzer manually at some other convenient time. (Actually, I don't normally use Auto-importer at all, but that is OT in this thread.)
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gummbah

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Re: Lazy automatic audio analysis
« Reply #6 on: May 08, 2008, 01:08:10 pm »

Ok, I think part of the problem is that I have ID3v2 writer compatibility mode checked in Foobar.
I remember something that when having this checked replay gain values are not recognised.
Will try next time when I rip a cd.
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