[raspberry-vi] Re: Progress
- From: Rodney Haynie <RodneyH@xxxxxxxxxx>
- To: "raspberry-vi@xxxxxxxxxxxxx" <raspberry-vi@xxxxxxxxxxxxx>
- Date: Wed, 9 Apr 2014 11:30:44 +0000
So, so, so awesome Mike. And I have always loved the phrase "... than you can
shake a stick at."
-----Original Message-----
From: raspberry-vi-bounce@xxxxxxxxxxxxx
[mailto:raspberry-vi-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Ray
Sent: Tuesday, April 08, 2014 9:42 PM
To: raspberry-vi@xxxxxxxxxxxxx
Subject: [raspberry-vi] Progress
Hello list.
You're all very quiet.
I thought it was time to let you know how things are going here with efforts to
get stuff going. So in order of significance, from high to low:
I finally have speech-dispatcher running on both Raspbian and Arch Linux.
I have taken a long time over this for three very good reasons:
1. Using the espeak synthesizer with the 'espeakup' program to connect speakup
to espeak has proven to be unusable on the Pi.
Despite trying very hard to get latency tweaks to stop the stuttering, still
the speech is very poor with espeakup, and too much loading on the latency,
while it smooths the voice a bit, also produces a sluggish and unresponsive
keyboard.
2. And this is the most compelling reason to use speech-dispatcher; if I am to
get Orca running in LXDE, or some other X Windows configuration, we need
speech-dispatcher to be running, because Orca needs it.
3. It took ages to get it to work :(. Open Source is fantastic but
documentation is thin on the ground. Often it is a case of just chucking stuff
at a wall until something sticks.
Now a problem...pulseaudio. The default configuration of speech-dispatcher is
to use pulseaudio, which I hate with a passion.
And what's more I could not get pulseaudio to run reliably and it constantly
crashes.
ALSA? Well...I was using ALSA originally, but ALSA is not good with more than
one audio stream at a time, so listening to a screen-reader while listening to
streamed music might make the Pi choke a bit. Not that I am encouraging you to
run more than a couple of things in one go, poor little Pi.
Then Rill and I were looking at Knoppix. This is a flavour of Linux, not
running on the Pi currently, that has some accessible variants, notably
something called Adriane. Anyway while we were playing with Knoppix I noticed
that it uses speech-dispatcher configured using an audio library called libao.
Don't ask me what the 'ao' bit is, 'audio output' maybe?
Anyway now I have speech-dispatcher running on both Raspbian and Arch with
libao, and......drum roll....ABSOLUTELY NO stuttering!!
I have had to do some tweaking of the program 'speechd-up', a program which
connects speakup to speech-dispatcher. For example speakup was saying
'capital' all the time for capital letters until I hacked the source of
speechd-up and stopped it.
I also made some other interesting discoveries about speech-dispatcher that I
could not find documented anywhere. Among these are:
1. Just commenting out a 'AddModule' directive in the config file does NOT
stop sd loading it. The actual module has also to be removed from the module
path, and not just renamed, otherwise sd recognises it as a module and loads it
anyway.
And also because of the stuff with triplets in path names (like
'/usr/lib/arm-linux-gnueabihf', where the 'arm-linux-gnueabihf' bit is called a
triplet), sd gets very confused aboute paths to modules and libao plugins. I
could have hacked the Makefiles to solve this but it was easier to just make
soft links to simulate the right paths.
speech-dispatcher and the espeak API. Like a lot of the programs that call
espeak, sd does not implement the full espeak API, although it does better than
most. So I have been able to make some tweaks to things like sample-rate and
buffer size in the espeak.conf file of sd.
Incidentally using sd I have been able to reverse the latency tweaks I made to
the espeak source while we were trying to use espeakup.
One problem that remains is that Emacspeak is still stuttering. This is because
Emacspeak does not use speech-dispatcher, but the espeak server that it uses
interfaces directly to espeak. I am looking into writing an 'Emacspeak to
speech-dispatcher' connector.
All this effort has meant I have been writing SD cards faster than I can eat
chocolate, and that's fast. Infact I have busted two SD cards in the process.
The little plastic combs between the gold contacts have come away and sprung
up. Rather than risk damaging the delicate card slot on a Pi, or leaving small
fragments of plastic in the card slot in my screamingly fast desktop Linux
machine, I threw these cards away. I have now switched to using the little
metal micro-SD to SD adaptors, on the grounds that these will not break.
Because I have been configuring and reconfiguring the Pi so much, I have
written a mechanism which will run a series of scripts one after the other.
These scripts can be grouped into collections which reflect what I am trying to
achieve.
The mechanism which runs these scripts I am calling my 'sausage machine', for
reasons which should be obvious, and the individual script packages I am
calling 'sausage packs'.
I have packs for:
Arch Linux using speech-dispatcher and libao Arch Linux using espeakup Raspbian
using speech-dispatcher and libao Raspbian using speech-dispatcher and ALSA
Raspbian using speech-dispatcher and installing Orca on LXDE.
and some others. Some packs run after others. For example the one which
configures Arch for console speech can be followed by one which installs LXDE
and Orca etc.
Now we have had Orca speaking on Raspbian and LXDE a couple of times, with help
from Rill's young sighted friend Morgan. But I have taken a step back from
that to get speech-dispatcher running solidly on both Raspbian and Arch.
Now we have that, with Rill's continueing help, I can go back to trying to get
Orca up and running and speaking immediately you type 'startx' to go into X.
So far we have done this with LXDE for a couple of reasons:
1. Raspbian already has LXDE installed so it should be a matter of just
uninstalling inaccessible apps when we have Orca speaking.
2. Wikipaedia has a page comparing desktop environments and LXDE comes out on
top as the leanest. And after all, if it says that on Wikipaedia, it must be
true, huh?
3. Because both Raspbian and Knoppix use LXDE I have some reference systems to
look at.
4. The OpenBox window manager that Raspbian uses is very flexible for use of
the keyboard, e.g. not using the mouse.
So...after a lot of rambling, a summary:
I am about to unleash Arch Linux onto Rill to see if she can break it, before I
release it on the site for download. When I release it on the site it is
likely to come without Emacspeak initially, until I can get the Emacspeak to
speech-dispatcher connector written.
Then with that done, I will get back to getting Orca running out-of-the-box on
Raspbian.
I am beginning to think that given a couple of more weeks or so we can see a
few different images up on the web site for download, including some which are
talking GUIs.
And within a couple of months or so, more accessible images than you can shake
a stick at.
Mike
--
Michael A. Ray
Analyst/Programmer
Witley, Surrey, South-east UK
The box said: 'install Windows XP, 7 or better'. So I installed Linux
Interested in accessibility on the Raspberry Pi?
Visit: http://www.raspberryvi.org/
From where you can join our mailing list for visually-impaired Pi hackers
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Mike Ray, list creator, January 2013
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Archives: //www.freelists.org/archives/raspberry-vi
Administrative contact: <mike.ray@xxxxxxxxxxxxxx>
-----------------------------------------------------------
Raspberry Pi and the Raspberry Pi logo are trademarks of the Raspberry Pi
Foundation.
This list is not affiliated to the Raspberry Pi Foundation and the views and
attitudes expressed by the subscribers to this list do not reflect those of the
Foundation.
Mike Ray, list creator, January 2013
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