Track & Album Gain (Conversion) Very Slow on macOS

[sal9k]

I use dBpoweramp on both Windows and Mac (v17.7), and have noticed that adding ReplayGain to FLAC's is very slow on macOS Monterey (12.4) versus on Windows (Win 10 Pro 21H2). I'm seeing ~20x ReplayGain encoding on macOS (2019 Macbook Pro 15" w/ 2.3 GHz 8-Core Intel Core i9, 16GB RAM), versus ~500x on a much older Dell Precision 5510 (circa 2016). What gives? FLAC's reside on the computers' SSD while encoding, btw, so this isn't an external drive access bottleneck.

[PeterP]

Re: Track & Album Gain (Conversion) Very Slow on macOS

Thanks for your feedback.

I've tried recreating the problem and everything looks normal to me, 800x realtime scanning of FLAC on my 2013 macbook pro with 4-core i7.

What exact settings do you use? Gain Calculation set to EBU R128 or ReplayGain?
Do you by chance have any DSP Effects enabled with ReplayGain scanning?
What are the specifications of the FLAC files: channel count, sample rate?


What about:
- Running the same FLAC files thru Test Conversion?
- Decoding the FLAC files to WAV then performing ReplayGain scan of the resulting WAV?
This should answer which part is to blame for the slowdown, decoding or ReplayGain math.

[sal9k]

Re: Track & Album Gain (Conversion) Very Slow on macOS

Strangely, I went to try the conversion again, so I could describe the exact setup I was using, and lo and behold, I cannot reproduce the mac-specific slow-down. I was doing ReplayGain, "Track & Album Gain", with the default Advanced Options, and no additional DSP Effects, on FLAC 24b/[48,96]k, and 16b/44k files. Today, everything is speedy as normal, and my newer 2019 Macbook Pro encodes at the expected >500x (typically 800x-1000x) now. I don't know what has changed, other than I'm re-encoding the same files again. I tried deleting the replay gain tags, and re-converting, but the slowd-down does not occur. I apologize for the false alert, as I can't duplicate the issue.

[PeterP]

Re: Track & Album Gain (Conversion) Very Slow on macOS

Thanks for the details.

The problem could be somehow related to writing of tags - FLAC storing tags before audio content, so in some cases a full file rewrite is needed, which would not be needed anymore on consecutive updates.
However, on an internal SSD, the delay is really unnoticeable, it could get worse only on slow external or network storage which isn't the case here.