mpg123 is a
real time MPEG 1.0/2.0/2.5 audio player/decoder for layers 1,2 and 3 (MPEG 1.0 layer 3 aka MP3 most commonly tested).
Among others working with Linux, MacOSX, FreeBSD, SunOS4.1.3, Solaris 2.5, HPUX 9.x, SGI Irix and Cygwin or plain MS Windows.
It is free software licensed under LGPL 2.1 (the officially released sources, some files in subversion repository may differ).
Improved portability of SSE code (with speed improvement, even), windows network streaming (merged into trunk), lower levels of API... simple audio output library using mpg123's output plugins... stuff.
GNU/Linux distributions that employ multilib will really want to upgrade to this one because, after elaborate debates on various bug trackers (wine and gentoo, at least), I finally disarmed the largefile consistency check in the mpg123 header. It was not compatible with multilib setups that failed to provide a separate header for 32 bit (with explicitly enabled large file support) and 64 bit (large file support implicit).
Of course, that is not all. More to the core of mpg123, there are important bug fixes for gapless decoding and the feeder mode of the library (reliable handling of garbage and (apparent) free format streams). The full list of goodies:
You see, this upgrade is a no-brainer. I gets a number of bugs out of the way to add more fun stuff to the next release, 1.11.0 . Get it from the usual places.
Update: I fixed the link to current mpg123 to actually point to the current version. Oh, and, I must admit that indeed, mpg123 is to blame for an oversight regarding IPv6 support which can trouble you with your broken DNS server (DSL router): It asks for IPv6 name resolution even if your setup does not feature IPv6 interfaces... together with glibc 2.10, that is rather annoying (see the web for stories). A future release will fix that, but lacking time for that, I point to the svn trunk, which has it fixed, or this little patch that should apply to a reasonable number of past releases:
--- src/resolver.c (Revision 2607) +++ src/resolver.c (Revision 2608) @@ -277,6 +277,7 @@ memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = AF_UNSPEC; /* We accept both IPv4 and IPv6 ... and perhaps IPv8;-) */ hints.ai_socktype = SOCK_STREAM; + hints.ai_flags = AI_ADDRCONFIG; /* Only ask for addresses that we have configured inerfaces for. */ addrcount = getaddrinfo(host->p, port->p, &hints, &addrlist);
For older news see the news archive
This is a rough log of an automated compliance test on the mpg123 webserver (Athlon-XP, GNU/Linux), using each one test bitstream from the ISO MPEG reference set. At least the floating point output should really be close enough to the reference.
Regarding the method: This is comparing mpg123's output (with gapless code deactivated) from reference bitstreams to the reference output. A simple RMS error measure is employed, relative to full scale, just summing over mono or stereo data indiscriminently. This is my interpretation of the rules... maximum allowed RMS=8.80967e-06, maximum signal difference 6.10352e-05.
compliance test for mpg123-20100311000000 First decoder in this list will be tested first, then generic: Supported decoders: SSE 3DNowExt 3DNow MMX i586 i586_dither i386 generic generic_dither Testing default decoder... ==== Layer 1 ==== --> 16 bit signed integer output fl1.bit: RMS=4.364373e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl2.bit: RMS=4.353138e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl3.bit: RMS=4.348759e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl4.bit: RMS=4.403421e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl5.bit: RMS=4.323457e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl6.bit: RMS=4.389618e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl7.bit: RMS=3.826083e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl8.bit: RMS=4.362205e-06 (PASS) maxdiff=7.629395e-06 (PASS) --> 32 bit integer output fl1.bit: RMS=1.966499e-08 (PASS) maxdiff=1.518056e-07 (PASS) fl2.bit: RMS=1.971040e-08 (PASS) maxdiff=1.117587e-07 (PASS) fl3.bit: RMS=2.002126e-08 (PASS) maxdiff=1.378357e-07 (PASS) fl4.bit: RMS=1.903406e-08 (PASS) maxdiff=1.266599e-07 (PASS) fl5.bit: RMS=3.629701e-08 (PASS) maxdiff=1.192093e-07 (PASS) fl6.bit: RMS=3.123047e-08 (PASS) maxdiff=1.788139e-07 (PASS) fl7.bit: RMS=1.768818e-08 (PASS) maxdiff=8.568168e-08 (PASS) fl8.bit: RMS=1.857690e-08 (PASS) maxdiff=8.568168e-08 (PASS) --> 32 bit floating point output fl1.bit: RMS=1.966507e-08 (PASS) maxdiff=1.518056e-07 (PASS) fl2.bit: RMS=1.971032e-08 (PASS) maxdiff=1.117587e-07 (PASS) fl3.bit: RMS=2.002131e-08 (PASS) maxdiff=1.378357e-07 (PASS) fl4.bit: RMS=1.903395e-08 (PASS) maxdiff=1.266599e-07 (PASS) fl5.bit: RMS=3.629702e-08 (PASS) maxdiff=1.192093e-07 (PASS) fl6.bit: RMS=3.123049e-08 (PASS) maxdiff=1.788139e-07 (PASS) fl7.bit: RMS=1.768797e-08 (PASS) maxdiff=8.568168e-08 (PASS) fl8.bit: RMS=1.857691e-08 (PASS) maxdiff=8.568168e-08 (PASS) ==== Layer 2 ==== --> 16 bit signed integer output fl10.bit: RMS=3.512100e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl11.bit: RMS=3.837267e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl12.bit: RMS=3.901071e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl13.bit: RMS=4.379583e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl14.bit: RMS=4.112578e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl15.bit: RMS=4.388568e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl16.bit: RMS=4.147495e-06 (PASS) maxdiff=7.688999e-06 (PASS) --> 32 bit integer output fl10.bit: RMS=1.777913e-08 (PASS) maxdiff=8.381903e-08 (PASS) fl11.bit: RMS=1.789437e-08 (PASS) maxdiff=9.313226e-08 (PASS) fl12.bit: RMS=1.780945e-08 (PASS) maxdiff=8.195639e-08 (PASS) fl13.bit: RMS=1.760690e-08 (PASS) maxdiff=4.470348e-08 (PASS) fl14.bit: RMS=3.641389e-08 (PASS) maxdiff=1.192093e-07 (PASS) fl15.bit: RMS=2.416479e-08 (PASS) maxdiff=1.788139e-07 (PASS) fl16.bit: RMS=1.922802e-08 (PASS) maxdiff=1.490116e-07 (PASS) --> 32 bit floating point output fl10.bit: RMS=1.777907e-08 (PASS) maxdiff=8.381903e-08 (PASS) fl11.bit: RMS=1.789437e-08 (PASS) maxdiff=9.313226e-08 (PASS) fl12.bit: RMS=1.780943e-08 (PASS) maxdiff=8.195639e-08 (PASS) fl13.bit: RMS=1.760693e-08 (PASS) maxdiff=4.470348e-08 (PASS) fl14.bit: RMS=3.641389e-08 (PASS) maxdiff=1.192093e-07 (PASS) fl15.bit: RMS=2.416472e-08 (PASS) maxdiff=1.788139e-07 (PASS) fl16.bit: RMS=1.922769e-08 (PASS) maxdiff=1.490116e-07 (PASS) ==== Layer 3 ==== --> 16 bit signed integer output compl.bit: RMS=4.300908e-06 (PASS) maxdiff=7.688999e-06 (PASS) --> 32 bit integer output compl.bit: RMS=1.904423e-08 (PASS) maxdiff=1.415610e-07 (PASS) --> 32 bit floating point output compl.bit: RMS=1.904423e-08 (PASS) maxdiff=1.415610e-07 (PASS) Now the generic decoder: ==== Layer 1 ==== --> 16 bit signed integer output fl1.bit: RMS=4.364373e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl2.bit: RMS=4.353138e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl3.bit: RMS=4.348747e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl4.bit: RMS=4.403421e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl5.bit: RMS=4.323446e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl6.bit: RMS=4.389573e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl7.bit: RMS=3.826083e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl8.bit: RMS=4.362205e-06 (PASS) maxdiff=7.629395e-06 (PASS) --> 32 bit integer output fl1.bit: RMS=1.852264e-08 (PASS) maxdiff=1.129229e-07 (PASS) fl2.bit: RMS=1.858920e-08 (PASS) maxdiff=9.639189e-08 (PASS) fl3.bit: RMS=1.860519e-08 (PASS) maxdiff=9.080395e-08 (PASS) fl4.bit: RMS=1.827816e-08 (PASS) maxdiff=9.802170e-08 (PASS) fl5.bit: RMS=3.011849e-08 (PASS) maxdiff=1.245644e-07 (PASS) fl6.bit: RMS=2.662860e-08 (PASS) maxdiff=1.455192e-07 (PASS) fl7.bit: RMS=1.738850e-08 (PASS) maxdiff=8.288771e-08 (PASS) fl8.bit: RMS=1.799578e-08 (PASS) maxdiff=8.079223e-08 (PASS) --> 32 bit floating point output fl1.bit: RMS=1.853064e-08 (PASS) maxdiff=1.126900e-07 (PASS) fl2.bit: RMS=1.860675e-08 (PASS) maxdiff=9.685755e-08 (PASS) fl3.bit: RMS=1.861782e-08 (PASS) maxdiff=9.080395e-08 (PASS) fl4.bit: RMS=1.829747e-08 (PASS) maxdiff=9.685755e-08 (PASS) fl5.bit: RMS=3.145808e-08 (PASS) maxdiff=1.192093e-07 (PASS) fl6.bit: RMS=2.694313e-08 (PASS) maxdiff=1.490116e-07 (PASS) fl7.bit: RMS=1.740548e-08 (PASS) maxdiff=8.940697e-08 (PASS) fl8.bit: RMS=1.800653e-08 (PASS) maxdiff=8.195639e-08 (PASS) ==== Layer 2 ==== --> 16 bit signed integer output fl10.bit: RMS=3.512100e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl11.bit: RMS=3.837267e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl12.bit: RMS=3.901071e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl13.bit: RMS=4.379583e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl14.bit: RMS=4.112572e-06 (PASS) maxdiff=7.629395e-06 (PASS) fl15.bit: RMS=4.388568e-06 (PASS) maxdiff=7.688999e-06 (PASS) fl16.bit: RMS=4.147492e-06 (PASS) maxdiff=7.688999e-06 (PASS) --> 32 bit integer output fl10.bit: RMS=1.753398e-08 (PASS) maxdiff=9.825453e-08 (PASS) fl11.bit: RMS=1.761345e-08 (PASS) maxdiff=8.195639e-08 (PASS) fl12.bit: RMS=1.753216e-08 (PASS) maxdiff=7.753260e-08 (PASS) fl13.bit: RMS=1.748657e-08 (PASS) maxdiff=4.121102e-08 (PASS) fl14.bit: RMS=2.851873e-08 (PASS) maxdiff=1.147855e-07 (PASS) fl15.bit: RMS=2.142128e-08 (PASS) maxdiff=1.455192e-07 (PASS) fl16.bit: RMS=1.823392e-08 (PASS) maxdiff=9.615906e-08 (PASS) --> 32 bit floating point output fl10.bit: RMS=1.755612e-08 (PASS) maxdiff=9.872019e-08 (PASS) fl11.bit: RMS=1.763760e-08 (PASS) maxdiff=8.195639e-08 (PASS) fl12.bit: RMS=1.754899e-08 (PASS) maxdiff=7.823110e-08 (PASS) fl13.bit: RMS=1.750654e-08 (PASS) maxdiff=4.097819e-08 (PASS) fl14.bit: RMS=2.884949e-08 (PASS) maxdiff=1.148474e-07 (PASS) fl15.bit: RMS=2.161260e-08 (PASS) maxdiff=1.452863e-07 (PASS) fl16.bit: RMS=1.831598e-08 (PASS) maxdiff=9.685755e-08 (PASS) ==== Layer 3 ==== --> 16 bit signed integer output compl.bit: RMS=4.300908e-06 (PASS) maxdiff=7.688999e-06 (PASS) --> 32 bit integer output compl.bit: RMS=1.878697e-08 (PASS) maxdiff=1.431908e-07 (PASS) --> 32 bit floating point output compl.bit: RMS=1.880739e-08 (PASS) maxdiff=1.415610e-07 (PASS)
Depending on what integer quality mode you choose at compile time (and the decoder in use), the 16bit output can vary between PASS and LIMITED for fully or limited accuracy compliance.
But keep in mind:
For the integer output, you have to give +-1 for rounding... that's what I append to any integer number read from some measurement device anyway, by default.
That minimum possible deviation already brings the output close (or over) the border of full compliance... that really does not mean that the output sounds bad!
It shall be noted that a measure to improve subjective quality, namely the dithering before rounding to integers, can also increase the theoretical decoding error.
In the end, RMS values in the order of 10 to the power of -5 should sound just fine.
To get 16bit output to PASS, you usually need to enable proper rounding using the --enable-int-quality configure flag.
It is not on by default because it mostly (yeah, there are odd cases) needs somewhat more CPU time and the simple truncation is fine for most people...
For comparisong with other decoders (as well as older incarnations of the mpg123 engine), have a read of the Underbit compliance tests. Actually, my testing method follows that example, including their quoting of ISO MPEG rules.
A test (GNU/Linux OS) with 0.60-beta2 showed 3% to 4% CPU usage on decoding high quality VBR MP3 with a pentiumII laptop with 366MHz, while a pentium 100MHz can easily handle two mpg123 instances in realtime (plus the mixing daemon that works on decoded data).
Also, we have reports from such devices as nintendo DS or Sony PSP, or various embedded systems...
Plays Layer 3 in stereo on an AMD-486-120Mhz or (of course) a faster machine.
Just for info: mpg123 plays an average 128bps stream, with about 66%
in full quality on an AMD 486-133MHz machine.