[FFmpeg-user] EBU R128 True Peak?

[Manu N]

Hello,


2013/4/24 Boštjan Strojan <bostjan.strojan at gmail.com>

> On Thu, Feb 21, 2013 at 6:33 PM, Clément Bœsch <ubitux at gmail.com> wrote:
> > On Thu, Feb 21, 2013 at 09:41:23AM -0500, Paul Figgiani wrote:
> >> Any plans to add the True Peak value of the source file to the EBU R128
> analysis results?
> > If you want to put more pressure on me, you can open a
> > trac ticket so I have no other choice to do it.
>
> The pressure is basically the fact that r128 is incomplete without it
>
> short audio file workflow (as i imagine it) will have to go through
> stuff like this as well:
> 1. file1 > get Integrated Loudness, apply it > file2
> 2. file2> Check truepeak, if > -1, then suggest dynamic compression of
> file1, goto 1.
>
> You have to keep in mind that the -1 dBTP limit is for PCM codecs. If your
stream is to go thru lossy codecs, you should keep within a tighter limit,
like -3 dBTP.
So if there's a sort of warning, it should be a user setting more than a
hardcoded value.
Besides, depending on the sample format in a PCM stream (fixed vs float),
raising the file1 to the target level might induce irreversible artifact on
peaks (let's say you have a stream whose integrated loudness is -27 LUFS
and max true-peak -3 dBTP, the +4 dB gain will create peakings if you are
in 16 bits PCM).

> Of course i could be wrong, so correct me.
>
> B.
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Manuel