I have unearthed some historical information describing storage in LAME tags. Can anyone comment on whether this is worthy of inclusion in the specification?
The Replay Gain proposal contains a description of how to store Replay Gain data in ID3 tags. I've added this description to my updated specification-in-progress.
Is anyone aware of important Replay Gain coding (ad-hoc) standards for other metadata system, e.g. broadcast wave format, Vorbis comments, APE, etc.?
I see a suggestion that the ID3v2 specs be ammended.Are we seriously considering mandating how players (software and hardware) as well as applications and utilities are to read and write RG information?
Current spec is at mp3-tech.org. I think you could make reference to it, but you shouldn't make your spec dependent on it. Or are you asking whether we think it should be the standard for storing ReplayGain info in all MP3s?
Why not use the existing RVA2 frame? The specification is incomplete, but it is in use (at least by Quod Libet and Rockbox).
Another option is to do it Foobar2000-style, and use VorbisGain-like information in TXXX frames (also supported by Rockbox).
Please note that as of VorbisGain 0.30, the volume change suggestions arestored in a new format. The following is an example on how it can look: REPLAYGAIN_TRACK_GAIN=-7.03 dB REPLAYGAIN_TRACK_PEAK=1.21822226 REPLAYGAIN_ALBUM_GAIN=-6.37 dB REPLAYGAIN_ALBUM_PEAK=1.21822226Earlier versions stored the information like this: RG_RADIO=-7.03 dB RG_PEAK=1.21822226 RG_AUDIOPHILE=-6.37 dB
There is also now XRVA and the original RVAD. Can anyone shed additional light on current practice with regards to usage of these three tags? RVA2 does appear to have the same basic functionality as RG's ad-hoc RGAD tag. Information at ID3.org indicates that RVA2 supersedes RGAD. I had assumed that the purpose of these mechanisms were more for user-assigned level adjustments and not so much for automatic normalization.
I assume Rockbox does not write RG information.
Does Quod Libet write RG information to any of these other tags?
LAME writes:bytes $A7-$AA : 32 bit floating point "Peak signal amplitude"bytes $AB-$AC : 16 bit "Radio Replay Gain" field
Just to clarify: it also writes an ID3 tag (using "TXXX" instead of the recommended "RGAD", though)
I added some details about MP3Gain/AACGain's APE tagging to the ReplayGain article in the HA wiki. Hopefully it makes sense.
Are we seriously considering mandating how players (software and hardware) as well as applications and utilities are to read and write RG information?
Some people may want gain adjustment but only to the point of no dynamic compression, some may want gain adjustment regardless of any dynamic compression, and some may tolerate some dynamic range compression for some gain normalization. Perhaps Replaygain could calculate different gain adjustments based on different inputs relating to the considerations above, and people could either select one, or have Replaygain write different tags for each so that people can chose which to apply later or dynamically chose based on their specific playlist when playback occurs.I wish I could be more articulate. Part of my inability to explain further results from exactly what is meant by "clipping". I typically think of clipping as reaching the limits of an unknown amplifier working with unknown speakers, but clipping could also mean exceeding the largest value that can be represented digitally. The latter will likely also trigger the former, but the former will not necessarily be a result of the latter. The impact of the actual playback volume further complicates this for me, but hopefully not for others.
To which "first post" are you referring?
We assume that any analog equipment attached to this digital system will clip at or above the level of this maximum digital signal.
push software projects to add support for that standard.
How so, exactly?
I'm not interested in closed-source software.
In order to establish Replay Gain as a standard, compatible feature.
Quote from: singlethread on 02 January, 2011, 04:35:28 PMpush software projects to add support for that standard.How so, exactly?