Is there's any hardware / software that can measure modulation or loudness of web streams? Yes I realize there's no legal requirement for doing so, this is just something I'm curious about.
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Web Stream Modulation Monitoring
- Thread starter Robert Bass
- Start date
Did you look at the Inovonics 610 network monitor? It has meters but I don't know it they correspond to dbfs or something else:
http://www.inovonicsbroadcast.com/model/610
http://www.inovonicsbroadcast.com/model/610
Assuming that you don't clip your audio in the processor (who would want to do that to a nice web stream, anyway?) you can set 'modulation' by simply raising the audio level on the codec until you see waveform clipping, then back it off a bit to give some headroom. I just look carefully for the characteristic digital flattopping on the decoded web stream on an analog oscilloscope, on a waveform display on an audio editor, or an audio spectrum analyzer like the excellent freeware, Visual Analyzer:
http://www.sillanumsoft.org/download.htm
Digital clipping at the codec sounds bad and probably leads to the aac or mp3 codec wasting precious bits trying to encode a bunch of extra clipped garbage, mixed in there with the desired audio.
http://www.sillanumsoft.org/download.htm
Digital clipping at the codec sounds bad and probably leads to the aac or mp3 codec wasting precious bits trying to encode a bunch of extra clipped garbage, mixed in there with the desired audio.
Hiya Bill,
Yes the 610 Internet Radio Monitor does indeed display metering on the front panel in dbfs, so if you want to maintain peaks around -12dB (as LA_Guy states) then you can simply match peaks to the front panel meters.
At this time Inovonics is not aware of any international standard for streaming levels but if anyone here has info on it we'd sure be interested to know. Discovering inconsistent levels across different streams is one of the first things the 610 will allow you to see.
Lukas Hurwitz
Inovonics
831 458 0552
Yes the 610 Internet Radio Monitor does indeed display metering on the front panel in dbfs, so if you want to maintain peaks around -12dB (as LA_Guy states) then you can simply match peaks to the front panel meters.
At this time Inovonics is not aware of any international standard for streaming levels but if anyone here has info on it we'd sure be interested to know. Discovering inconsistent levels across different streams is one of the first things the 610 will allow you to see.
Lukas Hurwitz
Inovonics
831 458 0552
@Lukas: Thanks for the added info on the 610. I too am unaware of any international standard for streaming audio levels but it looks like the 610 would be the perfect tool to compare one stream to another.
I'm not aware of any countries that have any jurisdiction to regulate streaming audio *loudness*, but I see no reason why ITU-R B.S.1770-3 wouldn't be a great standard for streaming as well.
http://www.itu.int/rec/R-REC-BS.1770/
I wish ReplayGain2 would move to 0LU/-24LKFS as well, instead of adopting all but having enough headroom for ~everything. So far it seems they are sticking with -18 LKFS based on a mere 10 years of history, when 0LU has the potential to be around indefinitely, even as loudness measurement becomes more accurate than it already is. They based -18 LKFS on a paper that doesn't do or mention any research on its own recommendations for loudness targets of -14 LKFS (default), -11 LKFS, and a brutal -8 LKFS. They did say they specifically set out to define a loudness target that "needs only moderate limiting for typical content". That's completely ridiculous, since they are basing "typical content" almost exclusively on the loudness wars, and even there... -8 LKFS? L. O. L. Way to perpetuate the loudness war, instead of solve the problem.
At least the current draft specification of ReplayGain2 has the sense to not completely perpetuate the loudness war.
http://wiki.hydrogenaudio.org/index.php?title=ReplayGain_2.0_specification
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Of course the next subject is then... does your audio processing, if any, maintain a target loudness?
http://www.itu.int/rec/R-REC-BS.1770/
I wish ReplayGain2 would move to 0LU/-24LKFS as well, instead of adopting all but having enough headroom for ~everything. So far it seems they are sticking with -18 LKFS based on a mere 10 years of history, when 0LU has the potential to be around indefinitely, even as loudness measurement becomes more accurate than it already is. They based -18 LKFS on a paper that doesn't do or mention any research on its own recommendations for loudness targets of -14 LKFS (default), -11 LKFS, and a brutal -8 LKFS. They did say they specifically set out to define a loudness target that "needs only moderate limiting for typical content". That's completely ridiculous, since they are basing "typical content" almost exclusively on the loudness wars, and even there... -8 LKFS? L. O. L. Way to perpetuate the loudness war, instead of solve the problem.
At least the current draft specification of ReplayGain2 has the sense to not completely perpetuate the loudness war.
http://wiki.hydrogenaudio.org/index.php?title=ReplayGain_2.0_specification
---
Of course the next subject is then... does your audio processing, if any, maintain a target loudness?
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