Gentoo Archives: gentoo-user

From: "Canek Peláez Valdés" <caneko@×××××.com>
To: gentoo-user@l.g.o, gentoo-amd64@l.g.o
Subject: [gentoo-user] libmad sound artifacts
Date: Wed, 26 Mar 2008 06:26:04
1 Hi; sorry to crosspost, but I know for a fact that gentoo-amd64 has a
2 much lower traffic than gentoo-user.
4 Some weeks ago I noticed serious artifacts in the sound quality of my
5 desktop machine, when playing MP3's with Rhythmbox. It actually sounds
6 like a hardware problem; a speaker cable which is shorting, or a
7 speaker with a broken diaphragm, so at first I though my hardware was
8 broken.
10 But then I noticed that mpg123 and MPlayer don't have the artifacts,
11 with the same MP3's, so then I shifted the blame to GStreamer, because
12 Totem has also the problem. Finally, I was able to locate the problem:
13 it's libmad, because madplay have the artifacts too.
15 Everything that uses libmad sounds like crap, and I've recompiled the
16 library with any option that it offers, but to no avail: the artifacts
17 are still there (I can make them WORSE, with the default fixed point
18 math). I see bug reports that *seems* to be similar, but for ppc and
19 sparc, and those solutions didn't work for me.
21 Other thing: if I decode the MP3 to a WAV file with madplay
22 --output=wave:file.wav, the artifacts disappear.
24 Anyone has *any* idea of what can I do? I'm not using normal speakers;
25 I'm using an old stereo system, plugging the output from my sound card
26 to the video input of the stereo. But it sounds really nice if I'm not
27 using libmad.
29 Any help will be *really* appreciated.
30 --
31 Canek Peláez Valdés
32 Facultad de Ciencias, UNAM