1mpg123(1)                   General Commands Manual                  mpg123(1)
2
3
4

NAME

6       mpg123 - play audio MPEG 1.0/2.0/2.5 stream (layers 1, 2 and 3)
7

SYNOPSIS

9       mpg123 [ options ] file-or-URL...
10

DESCRIPTION

12       mpg123  reads  one  or more files (or standard input if ``-'' is speci‐
13       fied) or URLs and plays them on the audio device (default)  or  outputs
14       them to stdout.  file/URL is assumed to be an MPEG audio bit stream.
15

OPERANDS

17       The following operands are supported:
18
19       file(s) The  path  name(s)  of  one  or more input files.  They must be
20               valid MPEG-1.0/2.0/2.5 audio layer 1, 2 or 3 bit streams.  If a
21               dash  ``-'' is specified, MPEG data will be read from the stan‐
22               dard input.  Furthermore, any name starting with ``http://'' or
23               ``https://''  is  recognized as URL (see next section), while a
24               leading ``file://'' is being stripped for normal local file ac‐
25               cess, for consistency (since mpg123 1.30.1).
26

OPTIONS

28       mpg123  options may be either the traditional POSIX one letter options,
29       or the GNU style long options.  POSIX style options start with a single
30       ``-'',  while GNU long options start with ``--''.  Option arguments (if
31       needed) follow separated by whitespace (not ``='').  Note that some op‐
32       tions  can  be absent from your installation when disabled in the build
33       process.
34

INPUT OPTIONS

36       -k num, --skip num
37              Skip first num frames.  By default the decoding  starts  at  the
38              first frame.
39
40       -n num, --frames num
41              Decode  only  num frames.  By default the complete stream is de‐
42              coded.
43
44       --fuzzy
45              Enable fuzzy seeks (guessing byte offsets or  using  approximate
46              seek  points  from  Xing TOC).  Without that, seeks need a first
47              scan through the file before they can jump  at  positions.   You
48              can decide here: sample-accurate operation with gapless features
49              or faster (fuzzy) seeking.
50
51       -y, --no-resync
52              Do NOT try to resync and continue decoding if an error occurs in
53              the  input  file.  Normally,  mpg123  tries to keep the playback
54              alive at all costs,  including  skipping  invalid  material  and
55              searching  new  header  when  something  goes  wrong.  With this
56              switch you can make it bail out  on  data  errors  (and  perhaps
57              spare  your ears a bad time). Note that this switch has been re‐
58              named from --resync.  The old name still works, but is  not  ad‐
59              vertised or recommended to use (subject to removal in future).
60
61       -F, --no-frankenstein
62              Disable support for Frankenstein streams. Normally, mpg123 stays
63              true to the concept of MPEG audio being just a concatenation  of
64              MPEG  frames. It will continue decoding even if the type of MPEG
65              frames varies wildly. With this switch, it will only decode  the
66              input  as long as it does not change its character (from layer I
67              to layer III, changing sampling  rate,  from  mono  to  stereo),
68              silently  assuming  end  of  stream on such occasion. The switch
69              also stops decoding of compatible MPEG frames if  there  was  an
70              Info  frame  (Xing  header, Lame tag) that contained a length of
71              the track in MPEG frames.  This comes a bit closer to the notion
72              of a MP3 file as a defined collection of MPEG frames that belong
73              together, but gets rid of the flexibility that  can  be  fun  at
74              times  but  mostly  is hell for the programmer of the parser and
75              decoder ...
76
77       --network  backend
78              Select network  backend (helper program),  choices  are  usually
79              auto,  wget,  and  curl.   Auto means to try the first available
80              backend.
81
82       --resync-limit bytes
83              Set number of bytes to search for valid MPEG data once  lost  in
84              stream;  <0  means  search  whole stream.  If you know there are
85              huge chunks of invalid data in your files... here is  your  ham‐
86              mer.   Note:  Only  since  version  1.14 this also increases the
87              amount of junk skipped on beginning.
88
89       -u auth, --auth auth
90              HTTP authentication to use when receiving files via  HTTP.   The
91              format  used  is  user:password. Mpg123 will clear this quickly,
92              but it may still appear in sight of other users or even just  in
93              your  shell  history.  You  may seek alternative ways to specify
94              that to your network backend.
95
96       --auth-file authfile
97              Provide the authentication info via given file instead  of  com‐
98              mand line directly.
99
100       --ignore-mime
101              Ignore  MIME  types given by HTTP server. If you know better and
102              want mpg123 to decode something the server thinks is  image/png,
103              then just do it.
104
105       --no-icy-meta
106              Do not accept ICY meta data.
107
108       --streamdump filename
109              Dump  a  copy  of  the  input data (as read by libmpg123) to the
110              given file.  This enables you to store  a  web  stream  to  disk
111              while playing, or just create a concatenation of the local files
112              you play for ... why not?
113
114       --icy-interval bytes
115              This setting enables you to play a stream  dump  containing  ICY
116              metadata  at  the given interval in bytes (the value of the icy-
117              metaint HTTP response header). Without it, such  a  stream  will
118              play, but will cause regular decoding glitches with resync.
119
120       --no-seekbuffer
121              Disable the default micro-buffering of non-seekable streams that
122              gives the parser a safer footing.
123
124       -@ file, --list file
125              Read filenames and/or URLs of MPEG audio streams from the speci‐
126              fied  file in addition to the ones specified on the command line
127              (if any).  Note that file can be either an ordinary file, a dash
128              ``-''  to  indicate  that a list of filenames/URLs is to be read
129              from the standard input, or an URL pointing to a an  appropriate
130              list  file.   Note: only one -@ option can be used (if more than
131              one is specified, only the last one will  be  recognized).  Fur‐
132              thermore,  for HTTP resources, the MIME type information will be
133              used to re-open an actual MPEG stream as such instead of  treat‐
134              ing it as playlist file. So you could just always use -@ for web
135              resources without bothering if it is a playlist or  already  the
136              resolved stream address.
137
138       -l n, --listentry n
139              Of  the playlist, play specified entry only.  n is the number of
140              entry starting at 1. A value of 0 is the default and means play‐
141              ing  the whole list,  a negative value means showing of the list
142              of titles with their numbers...
143
144       --continue
145              Enable playlist continuation mode. This changes  frame  skipping
146              to apply only to the first track and also continues to play fol‐
147              lowing tracks in playlist after the selected one. Also, the  op‐
148              tion  to  play  a  number  of  frames  only applies to the whole
149              playlist. Basically, this tries to treat the playlist more  like
150              one  big stream (like, an audio book).  The current track number
151              in list (1-based) and frame number (0-based) are printed at exit
152              (useful if you interrupted playback and want to continue later).
153              Note that the continuation info is printed  to  standard  output
154              unless the switch for piping audio data to standard out is used.
155              Also, it really makes sense to work with actual  playlist  files
156              instead of lists of file names as arguments, to keep track posi‐
157              tions consistent.
158
159       --loop times
160              for looping track(s) a certain number of times, < 0 means  infi‐
161              nite loop (not with --random!).
162
163       --keep-open
164              For  remote  control  mode: Keep loaded file open after reaching
165              end.
166
167       --timeout seconds
168              Timeout in (integer) seconds before declaring a stream dead  (if
169              <= 0, wait forever).
170
171       -z, --shuffle
172              Shuffle play.  Randomly shuffles the order of files specified on
173              the command line, or in the list file.
174
175       -Z, --random
176              Continuous random play.  Keeps picking a random  file  from  the
177              command  line or the play list.  Unlike shuffle play above, ran‐
178              dom play never ends, and plays individual songs more than once.
179
180       -i, --index
181              Index / scan through the track before playback.  This fills  the
182              index  table  for seeking (if enabled in libmpg123) and may make
183              the operating system cache the file contents for smoother  oper‐
184              ating on playback.
185
186       --index-size size
187              Set the number of entries in the seek frame index table.
188
189       --preframes num
190              Set  the number of frames to be read as lead-in before a seeked-
191              to position.  This serves to fill the  layer  3  bit  reservoir,
192              which  is  needed  to faithfully reproduce a certain sample at a
193              certain position.  Note that for layer 3, a minimum of 1 is  en‐
194              forced  (because  of frame overlap), and for layer 1 and 2, this
195              is limited to 2 (no bit reservoir in that case, but engine spin-
196              up anyway).
197
198

OUTPUT and PROCESSING OPTIONS

200       -o module, --output module
201              Select  audio  output  module. You can provide a comma-separated
202              list to use the first one that works.  Also see -a.
203
204       --list-modules
205              List the available modules.
206
207       --list-devices
208              List the available output devices for given  output  module.  If
209              there  is no functionality to list devices in the chosen module,
210              an error will be printed and mpg123 will exit  with  a  non-zero
211              code.
212
213       -a dev, --audiodevice dev
214              Specify  the  audio  device  to use.  The default as well as the
215              possible values depend on the active output. For the  JACK  out‐
216              put,  a  comma-separated  list  of ports to connect to (for each
217              channel) can be specified.
218
219       -s, --stdout
220              The decoded audio samples are written to  standard  output,  in‐
221              stead  of  playing  them  through the audio device.  This option
222              must be used if your audio hardware is not supported by  mpg123.
223              The output format per default is raw (headerless) linear PCM au‐
224              dio data, 16 bit, stereo, host byte order (you can force mono or
225              8bit).
226
227       -O file, --outfile
228              Write  raw  output  into  a  file (instead of simply redirecting
229              standard output to a file with the shell).
230
231       -w file, --wav
232              Write output as WAV file. This will cause the MPEG stream to  be
233              decoded and saved as file file , or standard output if - is used
234              as file name. You can also use --au and --cdr  for  AU  and  CDR
235              format,  respectively.  Note that WAV/AU writing to non-seekable
236              files, or redirected stdout, needs some thought.  Since  1.16.0,
237              the  logic  changed  to writing the header with the first actual
238              data. This avoids spurious WAV headers in a pipe,  for  example.
239              The  result  of  decoding nothing to WAV/AU is a file consisting
240              just of the header when it is seekable and really  nothing  when
241              not  (not  even a header). Correctly writing data with prophetic
242              headers to stdout is no easy business.
243
244       --au file
245              Does not play the MPEG file but writes it to file in  SUN  audio
246              format.  If - is used as the filename, the AU file is written to
247              stdout. See paragraph about WAV writing for header fun with non-
248              seekable streams.
249
250       --cdr file
251              Does not play the MPEG file but writes it to file as a CDR file.
252              If - is used as the filename, the CDR file is written to stdout.
253
254       --reopen
255              Forces reopen of the audiodevice after ever song
256
257       --cpu decoder-type
258              Selects a certain decoder (optimized for specific CPU), for  ex‐
259              ample i586 or MMX.  The list of available decoders can vary; de‐
260              pending on the build and what your CPU supports.  This option is
261              only  available  when  the build actually includes several opti‐
262              mized decoders.
263
264       --test-cpu
265              Tests your CPU and prints a list of possible choices for --cpu.
266
267       --list-cpu
268              Lists all available decoder choices, regardless  of  support  by
269              your CPU.
270
271       -g gain, --gain gain
272              [DEPRECATED]  Set  audio  hardware  output  gain (default: don't
273              change). The unit of the gain value is hardware and output  mod‐
274              ule  dependent.   (This parameter is only provided for backwards
275              compatibility and may be removed in the future without prior no‐
276              tice.  Use the audio player for playing and a mixer app for mix‐
277              ing, UNIX style!)
278
279       -f factor, --scale factor
280              Change scale factor (default: 32768).
281
282       --rva-mix, --rva-radio
283              Enable RVA (relative volume adjustment) using the values  stored
284              for  ReplayGain  radio  mode  / mix mode with all tracks roughly
285              equal loudness.  The first valid information found in ID3V2 Tags
286              (Comment  named  RVA  or the RVA2 frame) or ReplayGain header in
287              Lame/Info Tag is used.
288
289       --rva-album, --rva-audiophile
290              Enable RVA (relative volume adjustment) using the values  stored
291              for ReplayGain audiophile mode / album mode with usually the ef‐
292              fect of adjusting album loudness but keeping  relative  loudness
293              inside  album.   The first valid information found in ID3V2 Tags
294              (Comment named RVA_ALBUM or the RVA2 frame) or ReplayGain header
295              in Lame/Info Tag is used.
296
297       -0, --single0; -1, --single1
298              Decode only channel 0 (left) or channel 1 (right), respectively.
299              These options are available for stereo MPEG streams only.
300
301       -m, --mono, --mix, --singlemix
302              Mix both channels / decode mono. It takes  less  CPU  time  than
303              full stereo decoding.
304
305       --stereo
306              Force stereo output
307
308       -r rate, --rate rate
309              Set  sample  rate  (default: automatic).  You may want to change
310              this if you need a constant  bitrate  independent  of  the  mpeg
311              stream  rate. mpg123 automagically converts the rate. You should
312              then combine this with --stereo or --mono.
313
314       --resample method
315              Set resampling method to  employ  if  forcing  an  output  rate.
316              Choices  (case-insensitive)  are NtoM, dirty, and fine. The fine
317              resampler is the default.  It  employs  libsyn123's  low-latency
318              fairly  efficient  resampler  to  postprocess  the  output  from
319              libmpg123 instead of the fast but very crude NtoM decoder  (drop
320              sample  method) that mpg123 offers since decades. If you are re‐
321              ally low on CPU time, choose  NtoM,  as  the  resampler  usually
322              needs  more  time than the MPEG decoder itself.  The mpg123 pro‐
323              gram is smart enough to combine the 2to1  or  4to1  downsampling
324              modes with the postprocessing for extreme downsampling.
325
326       -2, --2to1; -4, --4to1
327              Performs  a  downsampling of ratio 2:1 (22 kHz from 44.1 kHz) or
328              4:1 (11 kHz) on the output stream, respectively. Saves some  CPU
329              cycles,  but  of course throws away the high frequencies, as the
330              decoder does not bother producing them.
331
332       --pitch value
333              Set a pitch change (speedup/down,  0  is  neutral;  0.05  is  5%
334              speedup).   When  not enforcing an output rate, this changes the
335              output sampling rate, so it only works in the range  your  audio
336              system/hardware  supports.  When  you  combine this with a fixed
337              output rate, it modifies a software resampling ratio instead.
338
339       --8bit Forces 8bit output
340
341       --float
342              Forces f32 encoding
343
344       -e enc, --encoding enc
345              Choose output sample encoding. Possible  values  look  like  f32
346              (32-bit  floating  point),  s32  (32-bit  signed  integer),  u32
347              (32-bit unsigned integer) and the variants with  different  num‐
348              bers of bits (s24, u24, s16, u16, s8, u8) and also special vari‐
349              ants like ulaw and alaw  8-bit.   See  the  output  of  mpg123's
350              longhelp for actually available encodings.
351
352       -d n, --doublespeed n
353              Only  play every n'th frame.  This will cause the MPEG stream to
354              be played n times faster, which can be used for special effects.
355              Can  also  be combined with the --halfspeed option to play 3 out
356              of 4 frames etc.  Don't expect great sound  quality  when  using
357              this option.
358
359       -h n, --halfspeed n
360              Play  each frame n times.  This will cause the MPEG stream to be
361              played at 1/n'th speed (n times slower), which can be  used  for
362              special effects. Can also be combined with the --doublespeed op‐
363              tion to double every third frame or things like that.  Don't ex‐
364              pect great sound quality when using this option.
365
366       -E file, --equalizer
367              Enables  equalization,  taken from file.  The file needs to con‐
368              tain 32 lines of data, additional comment lines may be  prefixed
369              with  #.  Each data line consists of two floating-point entries,
370              separated by whitespace.  They specify the multipliers for  left
371              and  right  channel  of  a certain frequency band, respectively.
372              The first line corresponds to the lowest, the 32nd to the  high‐
373              est frequency band.  Note that you can control the equalizer in‐
374              teractively with the generic control interface.  Also note  that
375              these  are  the  32 bands of the MPEG codec, not spaced like you
376              would see for a usual graphic  equalizer.  The  upside  is  that
377              there  is  zero  computational cost in addition to decoding. The
378              downside is that you roughly have bass in band 0,  (upper)  mids
379              in band 1, treble in all others.
380
381       --gapless
382              Enable  code  that  cuts  (junk) samples at beginning and end of
383              tracks, enabling gapless transitions between MPEG files when en‐
384              coder  padding  and  codec delays would prevent it.  This is en‐
385              abled per default beginning with mpg123 version 1.0.0 .
386
387       --no-gapless
388              Disable the gapless code. That gives you MP3 decodings that  in‐
389              clude encoder delay and padding plus mpg123's decoder delay.
390
391       --no-infoframe
392              Do  not  parse  the  Xing/Lame/VBR/Info frame, decode it instead
393              just like a stupid old MP3 hardware player.  This  implies  dis‐
394              abling  of  gapless  playback as the necessary information is in
395              said metadata frame.
396
397       -D n, --delay n
398              Insert a delay of n seconds before each track.
399
400       -o h, --headphones
401              Direct audio output to the headphone  connector  (some  hardware
402              only; AIX, HP, SUN).
403
404       -o s, --speaker
405              Direct  audio  output  to the speaker  (some hardware only; AIX,
406              HP, SUN).
407
408       -o l, --lineout
409              Direct audio output to the  line-out  connector  (some  hardware
410              only; AIX, HP, SUN).
411
412       -b size, --buffer size
413              Use  an  audio  output buffer of size Kbytes.  This is useful to
414              bypass short periods of heavy system activity, which would  nor‐
415              mally  cause  the  audio  output  to be interrupted.  You should
416              specify a buffer size of at least 1024 (i.e. 1 Mb, which  equals
417              about 6 seconds of audio data) or more; less than about 300 does
418              not make much sense.  The default is 0,  which  turns  buffering
419              off.
420
421       --preload fraction
422              Wait  for  the  buffer  to be filled to fraction before starting
423              playback (fraction between 0 and 1).  You  can  tune  this  pre‐
424              buffering to either get faster sound to your ears or safer unin‐
425              terrupted web radio.  Default is 0.2 (wait for 20 % of buffer to
426              be full, changed from 1 in version 1.23).
427
428       --devbuffer seconds
429              Set  device buffer in seconds; <= 0 means default value. This is
430              the small buffer between the application and the audio  backend,
431              possibly directly related to hardware buffers.
432
433       --smooth
434              Keep  buffer  over track boundaries -- meaning, do not empty the
435              buffer between tracks for possibly some added smoothness.
436
437

MISC OPTIONS

439       -t, --test
440              Test mode.  The audio stream is decoded, but no output occurs.
441
442       -c, --check
443              Check for filter range violations (clipping),  and  report  them
444              for each frame if any occur.
445
446       -v, --verbose
447              Increase  the  verbosity level.  For example, displays the frame
448              numbers during decoding.
449
450       -q, --quiet
451              Quiet.  Suppress diagnostic messages.
452
453       -C, --control
454              Enable terminal control keys. This is enabled automatically if a
455              terminal  is  detected.   By default use 's' or the space bar to
456              stop/restart (pause, unpause) playback, 'f' to jump  forward  to
457              the  next  song,  'b' to jump back to the beginning of the song,
458              ',' to rewind, '.' to fast forward, and 'q' to quit.   Type  'h'
459              for a full list of available controls.
460
461       --no-control
462              Disable terminal control even if terminal is detected.
463
464       --title
465              In  an xterm, rxvt, screen, iris-ansi (compatible, TERM environ‐
466              ment variable is examined), change the  window's  title  to  the
467              name of song currently playing.
468
469       --name name
470              Set  the name of this instance, possibly used in various places.
471              This sets the client name for JACK output.
472
473       --long-tag
474              Display ID3 tag info always in long format  with  one  line  per
475              item (artist, title, ...)
476
477       --utf8 Regardless  of  environment, print metadata in UTF-8 (otherwise,
478              when not using UTF-8 locale, you'll get ASCII stripdown).
479
480       -R, --remote
481              Activate generic control interface.  mpg123 will then  read  and
482              execute commands from stdin. Basic usage is ``load <filename> ''
483              to play some file and the obvious ``pause'', ``command.   ``jump
484              <frame>''  will  jump/seek to a given point (MPEG frame number).
485              Issue ``help'' to get a full list of commands and syntax.
486
487       --remote-err
488              Print responses for generic control mode to standard error,  not
489              standard out.  This is automatically triggered when using -s.
490
491       --fifo path
492              Create  a  fifo  / named pipe on the given path and use that for
493              reading commands instead of standard input.
494
495       --aggressive
496              Tries to get higher priority
497
498       -T, --realtime
499              Tries to gain realtime priority.  This option  usually  requires
500              root privileges to have any effect.
501
502       -?, --help
503              Shows short usage instructions.
504
505       --longhelp
506              Shows long usage instructions.
507
508       --version
509              Print the version string.
510

HTTP SUPPORT

512       In  addition to reading MPEG audio streams from ordinary files and from
513       the standard input, mpg123 supports retrieval of MPEG audio streams  or
514       playlists  via  the HTTP  protocol, which is used in the World Wide Web
515       (WWW).  Such files are specified using a so-called  URL,  which  starts
516       with http:// or https://.  When a file with that prefix is encountered,
517       mpg123 since 1.30.0 will by default call  an  external  helper  program
518       (either  wget(1)  or curl(1), see the --network option) to retrieve the
519       resource. You can configure access via a proxy server using  the  stan‐
520       dard  environment  variables those programs support. The --proxy option
521       that mpg123 before 1.30.0 used for its internal network code is gone in
522       the default build now and will probably disappear for good with 1.31.1.
523
524       Note  that,  in order to play MPEG audio files from a WWW server, it is
525       necessary that the connection to that server is fast enough.  For exam‐
526       ple,  a  128  kbit/s MPEG file requires the network connection to be at
527       least 128 kbit/s (16 kbyte/s) plus protocol overhead.   If  you  suffer
528       from  short  network  outages, you should try the -b option (buffer) to
529       bypass such outages.  If your network connection is generally not  fast
530       enough to retrieve MPEG audio files in realtime, you can first download
531       the files to your local harddisk (e.g. using  wget(1))  and  then  play
532       them from there.
533
534       Streams  with  embedded  ICY metadata are supported, the interval being
535       communicated via HTTP headers or --icy-interval.
536

INTERRUPT

538       When in terminal control mode, you can quit via  pressing  the  q  key,
539       while  any time you can abort mpg123 by pressing Ctrl-C. If not in ter‐
540       minal control mode, this will skip to the next file (if  any).  If  you
541       want  to  abort playing immediately in that case, press Ctrl-C twice in
542       short succession (within about one second).
543
544       Note that the result of quitting mpg123 pressing Ctrl-C  might  not  be
545       audible  immediately,  due to audio data buffering in the audio device.
546       This delay is system dependent, but it is usually not more than one  or
547       two seconds.
548
549

PLAYBACK STATUS LINE

551       In verbose mode, mpg123 updates a line with various information center‐
552       ing around the current playback position. On any decent  terminal,  the
553       line  also  works  as  a  progress bar in the current file by reversing
554       video for a fraction of the line according to the current position.  An
555       example for a full line is this:
556
557            >  0291+0955   00:01.68+00:28.22  [00:05.30]  mix 100=085 192 kb/s
558       576 B acc   18 clip p+0.014
559
560       The information consists of, in order:
561
562       >      single-character playback state (``>'' for  playing,  ``=''  for
563              pausing/looping, ``_'' for stopped)
564
565       0291+0955
566              current  frame  offset  and number of remaining frames after the
567              plus sign
568
569       00:01.68+00:28.22
570              current position from and remaining time in human terms  (hours,
571              minutes, seconds)
572
573       [00:05.30]
574              fill of the output buffer in terms of playback time, if the buf‐
575              fer is enabled
576
577       mix    selected RVA mode (possible values: mix, alb  (album),  and  ---
578              (neutral, off))
579
580       100=085
581              set volume and the RVA-modified effective volume after the equal
582              sign
583
584       192 kb/s
585              current bitrate
586
587       576 B  size of current frame in bytes
588
589       acc    if positions are accurate, possible values are ``acc'' for accu‐
590              rate  positions  or ``fuz'' for fuzzy (with guessed byte offsets
591              using mean frame size)
592
593       18 clip
594              amount of clipped samples, non-zero only if decoder reports that
595              (generic does, some optimized ones not)
596
597       p+0.014
598              pitch change (increased/decreased playback sampling rate on user
599              request)
600
601

NOTES

603       MPEG audio decoding requires a good deal of CPU performance, especially
604       layer-3.   To  decode  it  in  realtime,  you  should  have at least an
605       i486DX4, Pentium, Alpha, SuperSparc or equivalent processor.   You  can
606       also  use the -m option to decode mono only, which reduces the CPU load
607       somewhat for layer-3 streams.  See also the -2 and -4 options.
608
609       If everything else fails, have mpg123 decode to a file and then use  an
610       appropriate  utility to play that file with less CPU load.  Most proba‐
611       bly you can configure mpg123 to produce a format suitable for your  au‐
612       dio device (see above about encodings and sampling rates).
613
614       If  your  system  is  generally  fast enough to decode in realtime, but
615       there are sometimes periods of heavy system  load  (such  as  cronjobs,
616       users  logging  in remotely, starting of ``big'' programs etc.) causing
617       the audio output to be interrupted, then you should use the  -b  option
618       to use a buffer of reasonable size (at least 1000 Kbytes).
619

EXIT CODE

621       Up  to version 1.25.x, mpg123 always returned exit code 0 also for com‐
622       plete junk on the input side. Fatal errors  were  only  considered  for
623       output.  With  version  1.26.0, this changed to the behaviour described
624       below.
625
626       When not using the remote control interface (which returns input errors
627       as  text messages), the process exit code is zero (success) only if all
628       tracks in a playlist had at least one frame parsed, even if it did  not
629       decode  cleanly, or are empty, MPEG-wise (perhaps only metadata, or re‐
630       ally an empty file).  When you decode nothing, nothing  is  the  result
631       and that is fine. When a track later aborts because of parser errors or
632       breakdown of the network communication, this is treated  as  end  of  a
633       track,  but  does not make the process as such fail. One really bad (or
634       non-existing) stream in the playlist results in a non-zero error  code,
635       consistent with other UNIX tools.
636
637       An  error in audio output results in the process ending with a non-zero
638       exit code immediately, regardless of how much data  has  been  success‐
639       fully played before. The forgiveness is only on the input side.
640

BUGS

642       Mostly MPEG-1 layer 2 and 3 are tested in real life.  Please report any
643       issues and provide test files to help fixing them.
644
645       No CRC error checking is performed. But the decoder is built and tested
646       to behave nicely with damaged streams. Mostly, damaged frames will just
647       be silent.
648
649       Some platforms lack audio hardware support; you may be able to use  the
650       -s  switch  to  feed  the decoded data to a program that can play it on
651       your audio device.
652

AUTHORS

654       Maintainer:
655              Thomas Orgis <maintainer@mpg123.org>, <thomas@orgis.org>
656
657       Original Creator:
658              Michael Hipp
659
660       Uses code or ideas from various people, see the AUTHORS file accompany‐
661       ing the source code.
662

LICENSE

664       mpg123 is licensed under the GNU Lesser/Library General Public License,
665       LGPL, version 2.1 .
666

WEBSITE

668       http://www.mpg123.org
669       http://sourceforge.net/projects/mpg123
670
671
672
673                                  11 Jul 2022                        mpg123(1)
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