Release of unixcw version 3.1.0
Changes since version 3.0.2:
unixcw:
- Added support for PulseAudio. All applications from unixcw that produce audio output benefit from this. PulseAudio is the default audio backend on machines with installed and accessible PulseAudio server. If audio backend hasn't been specified by user, the applications try to access different sound backends in following order: PulseAudio -> OSS -> ALSA -> console buzzer. The usual restrictions for console buzzer output (root privileges required) still apply. Running application from unixcw package (cw, cwcp, xcwcp) with ALSA selected as sound backend while PulseAudio server is running will result in all kinds of different problems. User is warned about such situation by the application.
- Added 'Null' audio system as an optional audio backend. No sound is being played if this system is selected, libcw is spending its time only on generating tones of proper length and sending then in proper moments to a pseudo-device. Pass '-s n' option to unixcw application to use this 'audio' backend.
- Thanks to changes in libcw, unixcw doesn't 'require' ALSA or PulseAudio libraries, or PulseAudio server on target system, even if support for the two audio backends was compiled in. The two audio backends are now only recommended, thanks to linking to the libraries at run time.
- Build system now uses libtool. 'libtool' script is in release archive, so there are no new compile-time requirements related to this (at least 'make distcheck' completes successfully with libtool package uninstalled).
- It is possible to explicitly disable support for audio backends at compile time. Pass '--disable-{console|oss|alsa|pulseaudio}' to ./configure to do this.
- It is possible to explicitly disable compilation of cwcp and xcwcp. Pass '--disable-{cwcp|xcwcp}' to ./configure to do this.
- Build system now uses Makefile.am files as a basis to generate Makefile files.
- Build system now supports and correctly builds 'make distcheck' target.
- This version closes following Debian bugs: #237891, #567394, #567392.
libcw:
- Added support for PulseAudio. There are still some things to be improved in code implementing support for PulseAudio, but pretty solid basics are there.
- Added support for Null pseudo audio system. Not sure if it will be useful, I just thought that someone would like to use libcw without generating any sound. Perhaps some simple platforms without audio devices, perhaps practicing sending/keying without playback. Who knows. It was easy to do, so I did it.
- If you compare libcw.c files from this and
previous release, you will notice lots of
changes. This is because I've changed the
algorithm that controls time periods when
generating tones (generating sine wave).
Until now the periods were measured with
itimers. The tricky part was to keep two
processed in sync: turning sine wave on
and off, and sending the content of audio
buffer with sine wave to audio
backend. I'm calling it 'tricky' because
it works fine only for small sizes of
audio buffer, as was is in case of OSS
(~128 samples). With larger buffer sizes
forced by ALSA (~1k samples) the two
processes de-synchronize. I had to come up
with better design, and the side effect of
the design is total rewrite of parts of
libcw.c (for my own purposes I call the
rewrite a 'butchering', but that is a
different story).
New design relies on blocking writes to
audio systems, and their property of being
able to play only X samples (Y
milliseconds) at a time (with given sample
rate).
This small image below shows the benefits of new design. Upper part of the screenshot is sound of two letters 'h', produced by libcw3, the lower part shows sound of the same letters produced by libcw4. (The screenshot shows wave plot in Audacity).
-
Following functions are deprecated:
- cw_check_representation(),
- cw_lookup_representation(),
- cw_lookup_character().
Use these instead:
- cw_representation_is_valid(),
- cw_representation_to_character(),
- cw_character_to_representation().
- library's soname changed from 3.0.1 to 4.0.0. Library's version becomes independent from version of unixcw.
cwcp:
- Fixing small bug in user interface: till now modifying practice time didn't work correctly, any attempts to do so resulted in resetting the time to zero. Now this is fixed.