Gentoo Archives: gentoo-user

From: Adam Carter <adamcarter3@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Re: ffmpeg video+audio capture question
Date: Tue, 24 Sep 2019 05:15:22
Message-Id: CAC=wYCFRi53nm9dRa7GSvunfqJOKOx8eNcQews7zfdEiYU2YJw@mail.gmail.com
In Reply to: [gentoo-user] Re: ffmpeg video+audio capture question by Ian Zimmerman
1 >
2 > > Youtube is a bad example to use. There are various other HTML5
3 > > streaming websites, which don't work with youtube-dl. Plus I also want
4 > > to be able to record video games and any other desktop app in general.
5 > > What I want is to "tee" the audio output so that I can record while
6 > > monitoring it.
7 >
8 > Long ago, I digitized my vinyl and audio tape collection this way, with
9 > the input coming over good old analog audio cable. I did it with pure
10 > ALSA, no jack was needed. I _think_ there was a knob either in
11 > alsamixer or in arecord to do the "tee", but I don't really remember.
12 >
13
14 When you're digitising audio you can just connect the tape/LP output to a
15 line in input. AFAICT the "tee" is only needed for capturing digital output
16 that's coming from the PC itself.
17
18 Also, for LPs, if you don't run the LP output into an amplifier phono
19 input, it will miss out on the EQ reversal that occurs there. The physical
20 characteristics of vinyl media mean that some frequencies are harder to
21 encode in a vinyl groove than others (cant remember if its high or low
22 freqs) so as part of the manufacturing process they put the signal through
23 a filter before its written to vinyl, then the phono input on the amp
24 reverses that filter to restore the signal. I'd imagine you could use a
25 digital EQ to restore the signal if you don't have an amp with phono input
26 handy.