DLMPLAY(1) 147
NAME
dlmplay – play data through multiple DAT-Links.
SYNOPSIS
dlmplay [ –f format ][–N numUnits ][–c numChannels ][–u unitSpec ][–p precision ][–r range ]
D
[ –R repeats ][–S srate ][–E][–A][file ]
ESCRIPTION
dlmplay plays digital audio data via multiple DAT-Link devices. Although multiple invocations of
a
netaudiod(8) and naplay(1) can achieve the same effect, dlmplay is optimized for data throughput and
lso sets up the DAT-Links for correct synchronization.
l
c
If the DAT-Link+ is used, the Sync connectors of each DAT-Link+ should be connected to an externa
lock generator (Part EXTCLK) and the -E option to dlmplay MUST be used. This allows the units to
e
c
be synchronized such that each DAT-Link will start playing at the same time with the same sample-rat
lock. Using this configuration, output data that is stored together in file will be output from the DAT-
b
Link+’s at precisely the same time. Prior versions of the DAT-Link can be sample-rate synchronized
y connecting together their external clock connectors using a BNC cable.
h
b
The input file may be in one of two formats. The most efficient format is a block-interleaved file wit
locks of data for each DAT-Link interleaved. This file format has a header which describes the block
e
a
structure, the precision, and the number of channels. Corresponding arguments on the command lin
re ignored when this type of file is played. dlmplay identifies this format file by a unique magic
T
number contained in the header. This is the default output format for dlmrec(1).
he other format is a packed format with the samples for each DAT-Link interleaved. The file begins
s
t
with the left channel data for datlink0 and ends with the right channel data for datlinknn where nn i
he number of DAT-Links. The command line options to set the precision and number of units must be
e
t
used for files of this format. Note that the extra CPU load created by using this type of file will reduc
he maximum throughput.
If a file is not given on the command line, then standard input will be used. Note that use of standard
r
d
input is not supported on all architectures. Machines which support asynchronous I/O use it fo
lmplay to obtain higher throughput. Standard input cannot be used with asynchronous I/O.
OPTIONS
–f format
Specify format to be used to store digital audio data in file. The following formats are currently
r
recognized:
aw In this format, sampled data is interpreted as consecutive packed binary data with
s
most significant byte first. This is the default format.
wap The byte-ordering in this format is the reverse of the raw format. Note that this
–N numUnits
format increases the CPU overhead of dlmplay.
Specify the number of DAT-Link units. DAT-Link devices 0 through numUnits-1 are used. If
f
u
none of the -N, -c, or -u options are specified then 4 units are used. The maximum number o
nits that can be supported depend on the host speed and the SCSI I/O bandwidth. Typically 4
units is the limit, giving 8 channel record capability at 48,000 samples/second.
s–c numChannel
Specify the number of channels of output desired. DAT-Link devices 0 through numChan-
nels/2 (rounded up) are used.
c–u unitSpe
Specify the DAT-Link units to use for each channel of output. The unitSpec argument is a
.
T
comma-separated list of DAT-Link unit numbers followed by one of the letters: L, R, M, or S
hese signify left, right, mono or stereo respectively. The order of the list determines the map-
D
ping of channels to DAT-Link units. For devices used in stereo mode, the left channel always
AT-Link Reference Last change: 1995/07/29 1
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