ALSA support for the Bt878a and Fedora Core 4
Versión en Castellano
1.1 -
Components
1.2 -
Setup
1.3 - ALSA version update
1.4 - Check
2.1 - Mixer
3.1 - Capture test (1)
3.2 - Patch aplay.c
3.3 - Capture test (2)
4.1 - SoX under ALSA
4.2 - Capture test SoX ALSA Ensoniq
4.3 - Capture test SoX ALSA Bt878a
5.1 - Native GNUradio connection
1.1 -
Components
Fedora Core 4
Linux Kernel 2.6.11
ALSA 1.0.9rc4
Ensoniq 1371 sound card
Modified
Bt878a capture board
1.2 -
Setup
Linux out of the box.
The installer has detected the Ensoniq 1371 sound card but the Bt878a don't.
/etc/modprobe.conf
alias eth0 3c59x
alias snd-card-0 snd-ens1371
options snd-card-0 index=0
options snd-ens1371 index=0
remove snd-ens1371 { /usr/sbin/alsactl store 0 >/dev/null 2>&1 || : ; }; /sbin/modprobe
-r --ignore-remove snd-ens1371
alias usb-controller uhci-hcd
Add the following lines at the /etc/modprobe.conf file to load automatically the ALSA support for the Bt87x.
alias snd-card-1 snd-bt87x
alias sound-slot-1 snd-bt87x
options snd-bt87x index=1 load_all
Setting this way the Creative sound card with number 0 and the Bt878
audio stage with number 1. Is very important the "load_all" option to
load the module successfully.
1.3 - ALSA version update
We should get the latest stable files from here: http://www.alsa-project.org/ . I downloaded: alsa-driver-1.0.9rc4a.tar.bz2, alsa-lib-1.0.9rc4.tar.bz2, alsa-utils-1.0.9rc4a.tar.bz2 y alsa-oss-1.0.9rc4.tar.bz2.
# cd alsa-lib-1.0.9rc4
# ./configure
# make
# make install
# cd alsa-driver-1.0.9rc4a
# ./configure --with-cards=ens1371,bt87x
# make
# make install
# cd alsa-utils-1.0.9rc4a
# ./configure
# make
# make install
# cd alsa-oss-1.0.9rc4
# ./configure
# make
# make install
Restart the PC.
1.4 - Check
After restart the modules in memory looks like this:
# lsmodModule Size Used by lp 13001 0 autofs4 29253 2 rfcomm 42333 0 l2cap 30661 5 rfcomm bluetooth 56133 4 rfcomm,l2cap sunrpc 167813 1 video 15941 0 button 6609 0 battery 9413 0 ac 4805 0 md5 4033 1 ipv6 268097 8 uhci_hcd 35152 0 bt878 10457 0 bttv 161393 1 bt878 video_buf 23749 1 bttv i2c_algo_bit 9289 1 bttv v4l2_common 5825 1 bttv btcx_risc 4937 1 bttv tveeprom 13017 1 bttv videodev 9537 1 bttv shpchp 94405 0 parport_pc 28933 0 parport 40585 2 lp,parport_pc i2c_viapro 8017 0 i2c_core 21569 4 bttv,i2c_algo_bit,tveeprom,i2c_viapro snd_bt87x 16712 3 snd_ens1371 32224 3 gameport 18633 1 snd_ens1371 snd_rawmidi 30880 1 snd_ens1371 snd_ac97_codec 79484 1 snd_ens1371 snd_seq_oss 39424 0 snd_seq_midi_event 8704 1 snd_seq_oss snd_seq 63504 4 snd_seq_oss,snd_seq_midi_event snd_seq_device 9356 3 snd_rawmidi,snd_seq_oss,snd_seq snd_pcm_oss 51872 0 snd_mixer_oss 18560 4 snd_pcm_oss snd_pcm 100104 5 snd_bt87x,snd_ens1371,snd_ac97_codec,snd_pcm_oss snd_timer 34180 2 snd_seq,snd_pcm snd 56932 16 snd_bt87x,snd_ens1371,snd_rawmidi,snd_ac97_codec,snd_seq_oss,snd_seq,snd_seq_device,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer soundcore 10913 4 snd snd_page_alloc 10244 2 snd_bt87x,snd_pcm 3c59x 45033 0 mii 5441 1 3c59x floppy 65269 0 dm_snapshot 17413 0 dm_zero 2113 0 dm_mirror 26029 0 ext3 132553 2 jbd 86233 1 ext3 dm_mod 58101 6 dm_snapshot,dm_zero,dm_mirror
Check the ALSA sound devices:
# ll /dev/snd/
total 0
crw------- 1 root root 116, 0 Aug 7 20:17 controlC0
crw------- 1 root root 116, 32 Aug 7 20:17 controlC1
crw------- 1 root root 116, 8 Aug 7 20:17 midiC0D0
crw------- 1 root root 116, 24 Aug 7 20:17 pcmC0D0c
crw------- 1 root root 116, 16 Aug 7 20:17 pcmC0D0p
crw------- 1 root root 116, 17 Aug 7 20:17 pcmC0D1p
crw------- 1 root root 116, 56 Aug 7 20:17 pcmC1D0c
crw------- 1 root root 116, 57 Aug 7 20:17 pcmC1D1c
crw------- 1 root root 116, 1 Aug 7 20:17 seq
crw------- 1 root root 116, 33 Aug 7 20:17 timer
pcmC1D0c belongs to the Bt878 digital audio input and pcmC1D1c to the analog input.
2.1 - Mixer
Install gnome-alsamixer. Seems that the mixer included in Fedora Core 4 connects with the emulated OSS mixer and not with the native one from ALSA. (?)
Official gnome-alsamixer page
http://www.paw.co.za/projects/gnome-alsamixer/ .
They have some problem in
their FTP server. Finally I'd get the 0.9.6 version from here:
http://rpm.pbone.net/index.php3/stat/4/idpl/1699907/com/gnome-alsamixer-0.9.6-3.1.fc3.rf.i386.rpm.html.
Install gnome-alsamixer-0.9.6-3.1.fc3.rf.i386.rpm
Gnome ALSA Mixer Ensoniq 1371
Gnome ALSA Mixer Bt878
Increase the volume at maximum and select TV Tuner input (see image).
3.1 - Capture test (1)
We do a capture test using the native arecord utility from ALSA:
# arecord -D hw:1,1 -r 448000 -f S16_LE -t wav test.wav
arecord: main:456: bad speed value 448000
-D hw:1,1 1 for the second physical device (0 is
the first one, in my case the SoundBlaster) and 1 for the second logical device
(0 is the first one, the digital audio interface from the Bt878a)
-r 448000 Samples per second
-f S16_LE Format signed word little-endian
Fails. arecord is limited to 192000 Sps. Let's patch it.
3.2 - Patch aplay.c
We will modify aplay.c to obtain the maximum sampling speed. Go to the ALSA utilities folder we have previously compiled. The arecord utility is an alias from aplay.
# cd alsa-utils-1.0.9rc4a/aplay/
# gedit aplay.c
Place the cursor in line 456 and modify the value 192000 to 1792000:
if (tmp < 2000 || tmp > 1792000) { |
Save and compile.
# cd ..
# make
# make install
3.3 - Capture test (2)
Capture test again:
# arecord -D hw:1,1 -r 896000 -f S16_LE -t wav test.wav Recording WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 896000 Hz, Mono
And works perfect. Now we have ALSA working at 896000 Sps. We get the following spectrum using the "cable around TV" technique (as previously explained).
baudline spectrogram
4.1 - SoX under ALSA
SoX supports ALSA but is necessary to compile it to be able use the native device. (?) Download the last stable version (sox-12.17.7.tar.gz) from here: http://sox.sourceforge.net/.
Compile:
# cd sox-12.17.7
# ./configure
I got this Warning but can be ignored:
...
configure: WARNING: sound/asound.h: present but cannot be compiled
configure: WARNING: sound/asound.h: check for missing prerequisite headers?
configure: WARNING: sound/asound.h: see the Autoconf documentation
configure: WARNING: sound/asound.h: section "Present But Cannot Be Compiled"
configure: WARNING: sound/asound.h: proceeding with the preprocessor's result
configure: WARNING: sound/asound.h: in the future, the compiler will take precedence
configure: WARNING: ## --------------------------------------------- ##
configure: WARNING: ## Report this to cbagwell@users.sourceforge.net ##
configure: WARNING: ## --------------------------------------------- ##
...
# make
# make install
The installer failed to place the SoX binary file. Let's copy it manually:
# cd src
# ll /usr/bin/sox
-rwxr-xr-x 1 root root 275584 May 12 16:09 /usr/bin/sox
# ll sox
-rwxr-xr-x 1 root root 756042 Aug 7 19:39 sox
# mv /usr/bin/sox /usr/bin/sox.old
# cp sox /usr/bin/
Check the Sox installation and we can see ALSA as one supported "file format":
# sox -Vh sox: Version 12.17.7 Usage: [ gopts ] [ fopts ] ifile [ fopts ] ofile [ effect [ effopts ] ] gopts: -e -h -p -v volume -V fopts: -r rate -c channels -s/-u/-U/-A/-a/-i/-g/-f -b/-w/-l/-d -x effect: avg band bandpass bandreject chorus compand copy dcshift deemph earwax echo echos fade filter flanger highp highpass lowp lowpass mask mcompand noiseprof noisered pan phaser pick pitch polyphase rate repeat resample reverb reverse silence speed stat stretch swap synth trim vibro vol effopts: depends on effect Supported file formats: aiff al alsa au auto avr cdr cvs dat vms gsm hcom la lu maud nul ossdsp prc raw sb sf sl smp sndt sph 8svx sw txw ub ul uw voc vorbis vox wav wve
4.2 - Capture test SoX ALSA Ensoniq
# sox -V -r 48000 -w -t alsa /dev/snd/pcmC0D0c -t .wav test.wav
sox: Input file /dev/snd/pcmC0D0c: using sample rate 48000
size shorts, encoding signed (2's complement), 1 channel
sox: Writing Wave file: Microsoft PCM format, 1 channel, 48000 samp/sec
sox: 96000 byte/sec, 2 block align, 16 bits/samp
sox: Output file test.wav: using sample rate 48000
size shorts, encoding signed (2's complement), 1 channel
sox: Output file: comment "Processed by SoX"
sox: Finished writing Wave file, 983040 data bytes 491520 samples
Works fine.
4.3 - Capture test SoX ALSA Bt878a
# sox -V -r 48000 -w -t alsa /dev/snd/pcmC1D1c -t .wav test.wav
sox: Failed reading /dev/snd/pcmC1D1c: ioctl operation failed 22
Fails.
Now the problem is that SoX gives the error "ioctl operation failed 22" with every parameters combination I've tried.
# sox -V -r 448000 -sw -t alsa /dev/snd/pcmC1D1c -t .wav test.wav
sox: Failed reading /dev/snd/pcmC1D1c: ioctl operation failed 22
-V Verbose
-r Sample rate
-w Word
/dev/snd/pcmC0D0c Native device from ALSA for the Ensoniq
1371.
/dev/snd/pcmC1D1c Native device from ALSA for the Bt878a. D1 is the
second logical device (D0 is the digital audio interface from the Bt878). The c
letter in the device name stands for capture (and p for play).
I've successfully checked that SoX captures thru ALSA with the Ensoniq card (/dev/snd/pcmC0D0c) but not with our beloved chip.
To be continued...
5.1 - Native GNUradio connection
Once GNUradio successfully
compiled is very easy to connect it to the Bt878 with the ALSA native device.
Example audio_fft_alsa.py
450Khz FFT from a 896000 Sps signal
- Credits
Clemens Ladisch
Chris Bagwell
- Author:
Juan Domenech Fernandez
http://www.domenech.org
v1.1 26-august-2005
v0 11-october-2004