FLAC -> MPC conversion: lose RG info!

2004-06-22 14:56:39

Hi all,

** first post comment: **
Just before the question, I must say that only 2 weeks ago, I was still using Winamp as my primary playback device.  I'm now totaly addited to fb2k! it has so much features!
** end first post comment **

Question:
It seems that converting <insert source codec here> to <insert target codec name here> using diskwriter doesn't transcode the Replaygain metadata.   

Is anybody got the same issue?  what's wrong? Isn't RG info only 8 bytes of data in the header of a file??!?

Thanks

be020261

FLAC -> MPC conversion: lose RG info!

Reply #1 – 2004-06-22 15:11:38

The replaygain values of different lossy encodes tend to slightly differ from each other.

This is the reason why the fb2k diskwriter does not transfer these during encoding. They have to be recalculated after reencoding.

FLAC -> MPC conversion: lose RG info!

Reply #2 – 2004-06-22 16:38:21

Hi,

Is it worth spending days and nights to recalculate RG values when the differencies is around ±0.01dB ?!

example; Ive taken a 16mins track from FLAC to MPC@Extreme and recalculated the RG values:

Original Flac:
replaygain_track_gain = -7.28 dB
replaygain_track_peak = 1.000000replaygain_album_gain = -7.31 dB
replaygain_album_peak = 1.000000
FLAC_vendor = reference libFLAC 1.1.0 20030126
bitrate = 935
samplerate = 44100
channels = 2
bitspersample = 16
codec = FLAC
----------
42588840 samples @ 44100Hz
File size: 112 917 108 bytes

Converted MPC:
bitrate = 209
samplerate = 44100
channels = 2
mpc_profile = 'Xtreme'
mpc_encoder = Beta 1.14
mpc_streamversion = 7
mpc_accurate_length = yes
codec = Musepack
replaygain_track_gain = -7.27 dB
replaygain_track_peak = 1.175275 ----------
42588840 samples @ 44100Hz
File size: 25 265 051 bytes


Is it because of the replaygain_track/album_peak values?!?! (It has something to do with the lossy codec induced clipping, right?)
Does "use peak info to scale down track that still clip after applying replaygain" the only option that benefits these peak values?? (say, vs DSP Advanced limiter?)

Thanks!

be020261

FLAC -> MPC conversion: lose RG info!

Reply #3 – 2004-06-22 17:11:26

Uhm.

The reason why the replaygain values are not copied over is that they're going to be different for the source and the encoded file, period.

One of the consequences of that is exactly what you have pointed out - the incorrect peak values may lead to clipping. Don't forget that DSP effects may be used during encoding, too.

If you don't feel like rescanning the encoded files, you are free to use replaygain while diskwriting.

FLAC -> MPC conversion: lose RG info!

Reply #4 – 2004-06-23 02:44:29

Ok thanks for the reply,

Of course I could apply replaygain and/or DSP effect in diskwriting... but, I want to be able to switch from track to album gain...

I guess i'll have to leave my PC running all night for the batch conversion / replaygaining thing... 

be020261