[flac-dev] R128gain & metaflac

Olav Sunde ogs at olavsunde.net
Mon Jun 16 04:09:04 PDT 2014


You are probably right. If RP 2.0 is underway and R128-as-RP is not final it may be too early to add it to flac. The page you refer to is rather old though.

Still, the basic code for calculation of Ebu r128 needed for metaflac and flac could be written for testing. I know JRiver has moved its Volume Leveling analyzer to r128, but writes to RG tags and still honors ordinary RG tags.
Here is one of the many threads on the subject at JR's forum http://yabb.jriver.com/interact/index.php?topic=82102.0 Note that Matt Ashland refers to David Robinson re.: how to deal with r128 values in RP tags



At 11:22 16.06.2014, you wrote:
>As far as I know, R128 as ReplayGain isn't really considered final yet (see <http://wiki.hydrogenaud.io/index.php?title=ReplayGain_2.0_specification>http://wiki.hydrogenaud.io/index.php?title=ReplayGain_2.0_specification for example), so it would probably be a bit early to update this in the FLAC source.
>
>op 16-06-14 10:15, Olav Sunde schreef:
>>I mention metaflac because there are a few shell scripts that use it to write RG tags in a flac music library on Linux. With support for Ebu R128 gain in metaflac (the calculation according to specification, not an external program) it would be easy to use, just change the cmd line for metaflac in the script. Now that metaflac supports sample rates higher than 48kHz this would be a good thing in my view. Of course it would be nice to have this in flac too.
>>
>>As for R128GAIN, I've tried several versions but could not make it work on any of my Linux distros.
>>libebur128 requires compiling. Unfortunately I am not a programmer and I never compile.
>>
>>I am aware that there are discussions on how to insert R128 tags in place of RG tags and make it work properly. I have used RG for a long time, but R128 tags does a better at adjusting perceived volume between albums so I prefer R128.
>>
>>I store music files on a Linux NAS and would like to perform calculations on the same box. With foobar2000 (or JRiver win) I'd have to do this across a Samba mount which is slow(ish)
>>
>>
>>At 00:19 16.06.2014, you wrote:
>>>Olav Sunde wrote:
>>>
>>>> has anyone looked at adding R128gain code to metaflac so we can select
>>>> to use this calculation for RP tags rather than replay gain?
>>>
>>>Why metaflac only? flac is also able to calculate RG values.
>>>
>>>And, as far as I can see R128GAIN ( http://r128gain.sourceforge.net/)
>>>is a standalone app, not a library. So probably it would be difficult
>>>to reuse its code in flac/metaflac.
>>>
>>>There is also libebur128 ( https://github.com/jiixyj/libebur128/) -
>>>"libebur128 is a library that implements the EBU R 128 standard for
>>>loudness normalisation. All source code is licensed under the MIT license";
>>>foobar2000 uses it to calculate ReplayGain values.
>>>
>>>
>>>
>>>The use of R128 also raises the question about "REPLAYGAIN_REFERENCE_LOUDNESS"
>>>tag. Currently flac/metaflac writes "REPLAYGAIN_REFERENCE_LOUDNESS=89.0 dB"
>>>but doesn't use it when decoding (it seems that nothing uses this tag).
>>>R128 defines reference level differently, so this tag makes little sense for it.
>>>IMHO it's better not to write this tag when (meta)flac uses R128 algorithm.
>>>
>>>(David Robinson, the author of ReplayGain, thinks that such tags are useless:
>>>http://www.hydrogenaud.io/forums/index.php?s=&showtopic=67823&view=findpost&p=603622 )
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