Command line afplay, August 2016.
afplay -h
Usage:
afplay [option…] audio_file
Options: (may appear before or after arguments)
{-v | --volume} VOLUME
set the volume for playback of the file
{-h | --help}
print help
{ --leaks}
run leaks analysis
{-t | --time} TIME
play for TIME seconds
{-r | --rate} RATE
play at playback rate
{-q | --rQuality} QUALITY
set the quality used for rate-scaled playback (default is 0 - low quality, 1 - high quality)
{-d | --debug}
debug print output
===============================================================================
Example of usage, (assumes afplay is in the $PATH):-
afplay -v 0.5 -t 1.0 -r 0.5 -q 0.5 -d /path/to/soundfile.ext
The “.ext” CANNOT be raw, RAW, as afplay does not have the switches or flags to cope with it.
-v is a floating point value between 0.0, volume minimum, and 1.0, volume maximum.
This is NOT a linear scaling but relative to a logarithmic output volume level,
so do NOT assume a value 0.5 is literally half volume.
-t is an integer OR floating point value of arbitrary length inside the full playing time of
the file to be played. Value 0.0 is the same as not have having the -t flag in the command,
in other words it becomes disabled.
-r is a floating point value of 0.0 or practical limits of about 0.4 to 3.0.
It is not really a RATE change at all but plays almost exactly the same as the original
sound but at a quicker or slower speed, the frequncies are not altered to any extent
but the time taken to go through the whole file can create some humourous effects.
A value of 0.0 disables the -r switch.
-q is a floating point value between 0.0 and 1.0. The audible results are purely subjective on
a music file that has huge amounts of amplitude compression, (“LOUDNESS WARS” anyone?),
so don’t expect too much from this switch.
-d is not really debug in its entirety but also a verbose mode and gives some technical data
about the file being played.
– leaks is certainly a debug mode but requires username and password to give a file something
like below:-
“”"
Memory leak analysis of afplay (pid 497):
An admin user name and password is required to enter Developer Mode.
Admin user name (myhomefolder): myhomefolder
Password:
2016-08-19 13:40:55.587 leaks[499:4803] *** Symbolication: libsystem_c.dylib
is the same in the target process as in the analysis process, but it was loaded
at a different address. That means the dyld shared cache is not up to date,
which could affect system performance. To update the dyld shared cache, run
‘sudo update_dyld_shared_cache’ and reboot.
Process: afplay [497]
Path: /usr/bin/afplay
Load Address: 0x104bcf000
Identifier: afplay
Version: ??? (???)
Code Type: X86-64 (Native)
Parent Process: bash [454]
Date/Time: 2016-08-19 13:40:55.307 +0100
OS Version: Mac OS X 10.7.5 (11G63)
Report Version: 7
leaks Report Version: 2.0
Process 497: 4447 nodes malloced for 574 KB
Process 497: 0 leaks for 0 total leaked bytes.
“”"
And finally…
-h the quick help file at the top.
The player is capable or playing a number of formats:-
WAV, AAC, MP3, M4A, AIFC just to name but a few.
A rawfile, RAW, is NOT catered for see above.
A practical example:-
This plays a time limited 1 second playable file at slightly reduced volume and at a slightly quicker
speed where the quality is supposedly better than the default low and creates a verbose echo to screen.
“”"
MyPrompt> afplay -v 0.5 -t 1 -r 1.5 -q 0.5 -d /Users/myhomefolder/Movies/test.aifc
Playing file: /Users/myhomefolder/Movies/test.aifc
Playing format: AudioStreamBasicDescription: 2 ch, 44100 Hz, ‘lpcm’ (0x0000000E) 24-bit big-endian signed integer
Buffer Byte Size: 132300, Num Packets to Read: 22050
Enable rate-scaled playback (rate = 1.50) using Time Domain algorithm
“”"
I hope this is of help to all those new to the afplay command line audio player.