Questions re EBUR128 normalize function

[DHL]

I just got my version of the CD ripper and Music converter. Great software, but some of the DSP effects need better explanation.

For example, just what does the EBUR128 function do? I used it to normalize the volume levels from some String Cheese Incident live concert files I downloaded the other day, as these were very "hot" on playback. It seems to have done wonders for the processed file, not only reducing overall levels but producing track to track normalization (and it seems left to right balance as well). Is this my imagination?

Does this function do any compression?

Also, after processing the ID tag data on the volume levels seems to stay as in the non-processed file, but I know they have changed. Is this a bug?

In addition, after processing, the file compression level (FLAC) has increased and the file size is smaller. Why is that? Am I loosing any information?

[Spoon]

Re: Questions re EBUR128 normalize function

FLAC is lossless, which DSP effect are you using? because there are now several which use EBUR128, some just write the normalize value to the ID Tags (for a compatible player to use), others do the normalize of audio.

[DHL]

Re: Questions re EBUR128 normalize function

I am referring to the DSP function "EBUR128 Normaliize".

I used the RG replay gain while ripping, but that does not change the playback levels. My player (a Bryston BDP-1) does not utilize the tag data to re-normalize levels, so if I want this it must be done by DBPA.

But after ripping to FLAC with RG enabled (volume levels written to tag file), then processing with the file converter and DSP function "EBUR128 Normalize", the actual volume level is indeed reduced, but the tag data on the volume levels has not changed from the values prior to processing. Why? I thought the EBUR Normalize was supposed to re-write the new levels in the tag file?

Also, why has the compression level of the file changed after using EBUR128 Normalize? Have I lost any information?

[Spoon]

Re: Questions re EBUR128 normalize function

Each time you convert, the existing ReplayGain tag values should be removed. If you should not have replaygain and normalize dsp effects at the same time.

[DHL]

Re: Questions re EBUR128 normalize function

What do you mean "should be removed"? Manually I should do this or does the software do this? Do I need to remove previous gain tags before I re-process with EBUR128 Normalize? I was not doing this with BOTH RP gain and EBUR128 Normalize enabled (simultaneously).

I am getting very strange gain results

[DHL]

Re: Questions re EBUR128 normalize function

OK. I used the tag edit DSP tool to remove the four gain tags in the originally ripped file (had only RG enabled in original rip). Then I took that file and processed with the EBUR128 Normalize function.

Now I have no gain values in the processed file. The Normalize did not write any gain values to the tag.

What I need is to have the new levels re-written into the file. The new gain levels after EBUR128 processing. Can you explain how to do that please? Do I have to have to use EBUR128 Normalize followed by RG?

[Spoon]

Re: Questions re EBUR128 normalize function

If you normalize the file using EBU, then there is no need to have gain tags, because the gain would be 0 dB (as gain is already applied).

[DHL]

Re: Questions re EBUR128 normalize function

I would like the gain tags so I can tell if a ripped file has had the EBUR128 correction applied or not. I know I could put in comments manually but this is a bit tedious. And I still don't know the new peak/avg gain values.

Plus if RG is used after EBUR128 Normalize Volume, I get weird numbers like gain values of +6 to +7 dB and peak values of .2. I did not think average gain could go above 0 dB.

So what can I use to document the true applied gain (in the tag files) after EBUR128 Normalize is used?

[DHL]

Re: Questions re EBUR128 normalize function

I did some more research on this by playing the original ripped file and the EBUR128 processed file through Foobar and looking at the levels.

First, the processed file has both peak levels and average VU levels almost 10 dB below the original. I'm not sure why you say the file is 0 dB after processing. I am now concerned there is considerable low level info missing in the processed file, but if you could clarify. Is the digital noise floor reduced? IE if the original signal is 16 bit ( 0-96 dB) in range, does the EBUR128 just shift it down by 10 dB to a range of -10 to -106?

If not, I guess that is why so many suggest NOT using this volume normalization function.

[Spoon]

Re: Questions re EBUR128 normalize function

>I'm not sure why you say the file is 0 dB after processing

If you had a loud track which EBU wants to make quiet by 12dB, then if you apply the normalize the signal would be 4x less.

If afterwards you calculate the EBU replaygain tags, it should be 0dB on that file, because the audio is already at the volume level it desires (4x less)