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[jkauff]

Having recently run a ton of movies through Analyze Audio, I'm wondering why analyzing some movies takes 30 seconds or less, while others need as long as two hours to complete.

My guesses include length of movie (not the case, as it turns out); audio codec used; 2 channel versus 5.1 or 7.1 format; and CPU capabilities.

Maybe the developer responsible for Analyze Audio could tell us more about what it's doing exactly?

[JimH]

May have been analyzed.  May not be possible.

[mattkhan]

I have never seen anything take anything like 2hrs

Was that a common event?

[wer]

I have see things like this happen if the hard disk is failing.  Read errors provoke retries, which slow things down dramatically.

Find a movie that you think took 2hrs to analyze, and copy it to a new file, preferably on a different drive.   See if the copy process is slow, and when the copy is done, try analyzing the copied file.

Analyze audio reads the entire file. Processing time, if everything in the system is functioning normally, is a function of file length and disk transfer speed.  A 2hr DVD rip will analyze much faster than a 2hr Bluray rip because the file is much smaller.

[jkauff]

I have never seen anything take anything like 2hrs

Was that a common event?

Yes. I did them in batches of 15-20, set to process 6 files at a time (my CPU is 4 cores/8 threads). In every batch, there were one or two movies that took 1-2 hours to process. All Blu-rays. MC27 is installed on a Samsung NVMe SSD, and the movies are on USB 3.0 external drives.

[wer]

For starters don't do that. Your CPU can efficiently process between 4 and 8 files simultaneously. Your USB hard drive can not, assuming it is a magnetic drive.  Your drive is spending too much time seeking doing it the way you are doing it.

I think you will find your total processing time goes down if you process files 1 at a time when reading from magnetic drives. The batch can be as many files long as you want, but 1-at-a-time sequential processing will give you better performance.

Analyze Audio for movies is i/o bound on magnetic drives with your CPU.

Multiple files at once increases throughput with small files, like audio, but with large files, like movies, it decreases throughput when magnetic drives are used.  If your USB drive is an SSD that might be different.

[jkauff]

I did some experimenting last night. With SD material, using 6 processors works just fine. With HD movies, using even two processors slows things to a crawl. Doing one HD movie at a time takes about 4.5 minutes, so even though that's a lot of extra labor it seems to work the best.

I assume that analyzing two or more high bitrate movies simultaneously overloads the USB 3.0 interface, and in that state in takes 1-2 hours to complete the analysis.

[wer]

Doing one HD movie at a time takes about 4.5 minutes, so even though that's a lot of extra labor it seems to work the best.

I assume that analyzing two or more high bitrate movies simultaneously overloads the USB 3.0 interface, and in that state in takes 1-2 hours to complete the analysis.

It's no extra labor at all. Select them all, do analyze audio, and just set the analyze audio dialog to 1 at a time. You can do a single hundred-movie batch, not 100 one-movie batches. I said that before.

The circumstances also occur when using internal magnetic drives over SATA interfaces. It has to do with the physicalities of how magnetic disks read data.

Glad you're sorted out now.