More > JRiver Media Center 19 for Windows
NEW: Improved audio analysis and volume leveling (R128)
mojave:
What is the difference between Peak Level (R128) and Peak Level (Sample)?
6233638:
--- Quote from: mojave on August 21, 2013, 09:54:26 am ---What is the difference between Peak Level (R128) and Peak Level (Sample)?
--- End quote ---
Peak Level (sample) measures the peak level encoded inside the file. The maximum this can be with a lossless file, is 0dB. Lossy files may have samples that are above 0dB, as they use floating point values.
Peak Level (R128) upsamples the audio before measurement, and then measures the peak level. This is known as True Peak Level, and is measured in dBTP.
This is done because when you convert a digital signal to an analog waveform, it's possible to have signal levels that go above 0dB. Particularly with modern music releases, tracks are often adjusted so that the peak sample level is encoded at -0.1dB.
Most DACs do not seem to have headroom built into them to account for this, because any headroom you leave is effectively "throwing away" SNR, so you have the possibility of clipping/distortion on playback. The only DAC I am aware of that has headroom built in and advertises this fact, is Benchmark's DAC2 models. (that doesn't mean it's the only DAC with headroom though)
This clipping is known as an inter-sample peak. The Peak Level (R128) measurement is not going to be 100% accurate (speed of analysis is a factor, and different DACs may produce different results) so there's an additional 1dB headroom to account for this variance.
Here's an example that I pulled off Google Images which illustrates the problem:
In this image, you can see that none of the samples (the squares) exceed 0dB - but the analog waveform those samples represent exceeds 0dB. This would result in clipping/distortion when played through most DACs.
mojave:
Thanks, 6233638, for the explanation.
contium:
Here is an article along the same lines:
http://www.indexcom.com/tech/0dBFS+/
Denti:
I'm still using MC17, but am thinking of upgrading when MC19 is available. But a lot of the technical talk is over my head.
1) Is this feature something I can turn on and off? I like to list to albums a lot, and I don't want it affecting volume between tracks
2) Does this feature negatively impact sound quality in any way? I use FLAC and try to get the most out of these files. I don't want something interfering or changing this.
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