[SoX-users] Sox input device large delay

[Brendon C. <bre...@gm...>]

Hi all,

I am using sox with a program of mine. My program opens a named pipe
and expects to read 1 channel 16KHz little endian 32 bit floating
point data directly from the pipe. I am using sox to read from the
default input device and write the data to the pipe. The problem is
that I am seeing a large delay on the input.

My sox command is something like:
sox -V4 -d --channels 1 --encoding floating-point --rate 16k --type
raw --bits 32 --buffer 1280 /tmp/pipename

Is there some way I can reduce this delay? I am seeing maybe a 1 sec
delay at least 500ms for the energy meter in sox to show the input.
The other 500ms i cant easily account for, but I am wondering if a
portion of it is on the output of sox (My app may be the problem too,
but if i can at least fix the input side that would be great).

In case it helps I have included the output from sox -V4 which also
includes a uname describing my Ubunti system

Thanks,
Brendon.




bcosta@bcosta-laptop:~$ sox -V4 -d --channels 1 --encoding
floating-point --rate 16k --type raw --bits 32 --buffer 1280
/tmp/axon_clientlib_*
sox DBUG formats: opening format plugin `lsx_alsa_format_fn': library
0x15063f0, entry point 0x7f7132636450

sox DBUG formats: opening format plugin `lsx_ao_format_fn': library
0x1507380, entry point 0x7f7132152b70

sox DBUG formats: opening format plugin `lsx_caf_format_fn': library
0x1507fb0, entry point 0x7f7131d4a290

sox DBUG formats: opening format plugin `lsx_fap_format_fn': library
0x150a460, entry point 0x7f7130e8c290

sox DBUG formats: opening format plugin `lsx_ffmpeg_format_fn':
library 0x150ac40, entry point 0x7f7130c883e0

sox DBUG formats: opening format plugin `lsx_flac_format_fn': library
0x150e890, entry point 0x7f712efa98e0

sox DBUG formats: opening format plugin `lsx_gsm_format_fn': library
0x150f5d0, entry point 0x7f712eb9daa0

sox DBUG formats: opening format plugin `lsx_lpc10_format_fn': library
0x150fcf0, entry point 0x7f712e99ab50

sox DBUG formats: opening format plugin `lsx_mat4_format_fn': library
0x1510400, entry point 0x7f712e7972b0

sox DBUG formats: opening format plugin `lsx_mat5_format_fn': library
0x1510c10, entry point 0x7f712e593290

sox DBUG formats: opening format plugin `lsx_mp3_format_fn': library
0x1511390, entry point 0x7f712e38e900

sox DBUG formats: opening format plugin `lsx_oss_format_fn': library
0x15125f0, entry point 0x7f712dd54a10

sox DBUG formats: opening format plugin `lsx_paf_format_fn': library
0x1512d00, entry point 0x7f712db51290

sox DBUG formats: opening format plugin `lsx_pulseaudio_format_fn':
library 0x1513660, entry point 0x7f712d94d9f0

sox DBUG formats: opening format plugin `lsx_pvf_format_fn': library
0x1519900, entry point 0x7f712b6bb290

sox DBUG formats: opening format plugin `lsx_sd2_format_fn': library
0x151a040, entry point 0x7f712b4b7290

sox DBUG formats: opening format plugin `lsx_sndfile_format_fn':
library 0x151a840, entry point 0x7f712b2b3250

sox DBUG formats: opening format plugin `lsx_vorbis_format_fn':
library 0x151b010, entry point 0x7f712b0af5f0

sox DBUG formats: opening format plugin `lsx_w64_format_fn': library
0x151b770, entry point 0x7f712aeab290

sox DBUG formats: opening format plugin `lsx_wavpack_format_fn':
library 0x151bdf0, entry point 0x7f712aca7340

sox DBUG formats: opening format plugin `lsx_xi_format_fn': library
0x151cc30, entry point 0x7f712a87b290

sox: SoX v14.3.0
time:  Aug 29 2009 15:10:27
issue: Debian GNU/Linux
uname: Linux bcosta-laptop 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12
04:38:19 UTC 2010 x86_64
gcc:   4.4.1
arch:  1288 48 88 L OMP

Input File     : 'default' (alsa)
Channels       : 2
Sample Rate    : 48000
Precision      : 16-bit
Sample Encoding: 16-bit Signed Integer PCM
Endian Type    : little
Reverse Nibbles: no
Reverse Bits   : no


Output File    : '/tmp/axon_clientlib_pid26817_devid1_input' (raw)
Channels       : 1
Sample Rate    : 16000
Precision      : 16-bit
Sample Encoding: 32-bit Floating Point PCM
Endian Type    : little
Reverse Nibbles: no
Reverse Bits   : no
Comment        : 'Processed by SoX'

sox DBUG remix: 0:
sox DBUG remix: 	0 0.5
sox DBUG remix: 	1 0.5
sox DBUG rate: i/o=3; 3:4 @ level 1
sox DBUG effects_i_dsp: 1 0.29345 1.5
sox DBUG effects_i_dsp: make_lpf(n=119, Fc=0.301638 beta=13.7461
dc-norm=1 scale=4)
sox DBUG rate: fir_len=30 phases=4 coef_interp=0 mult=1 size=960
sox DBUG effects_i_dsp: 0.4655 0.020248 0.5
sox DBUG effects_i_dsp: make_lpf(n=409, Fc=0.479752 beta=12.8525
dc-norm=1 scale=1)
sox DBUG rate: fir_len=409 dft_length=4096 Fp=0.931 att=125 mult=1
sox DBUG effects_i_dsp: 0.32 0.105642 0.5
sox DBUG effects_i_dsp: make_lpf(n=81, Fc=0.394358 beta=12.8525
dc-norm=1 scale=1)
sox DBUG rate: fir_len=81 dft_length=4096 Fp=0.64 att=125 mult=1
sox DBUG rate: stage=0  pre_post=0  pre=0  preload=40
sox DBUG rate: stage=1  pre_post=29 pre=0  preload=14
sox DBUG rate: stage=2  pre_post=0  pre=0  preload=204
sox INFO sox: effects chain: input      48000Hz 2 channels 16 bits (multi)
sox INFO sox: effects chain: channels   48000Hz 1 channels 32 bits (multi)
sox INFO sox: effects chain: rate       16000Hz 1 channels 32 bits
sox INFO sox: effects chain: dither     16000Hz 1 channels 32 bits
sox INFO sox: effects chain: output     16000Hz 1 channels 16 bits (multi)