A few days ago I was thinking about the old days and looking at my old archives of my webpages from 1997 and prior.  Back then one of the cool things we were doing was to embed MIDI sound files into your page so when it opened up in the browser the MIDI would start playing automatically.  It’s still possible to playback embedded MIDI natively on Linux with Firefox.  The basic steps are as follows:

1) Install mozplugger and timidity

1a) You actually need to configure timidity to use proper soundfonts (assuming you don’t have a MIDI board in your computer). I’m not going to go into this since it’s documented very well elsewhere, start here if you are using Ubuntu, but I don’t recommend going too far with that help page. Only the section about “Installing Timidity” is important. There are lots of posts on Ubuntu forums and Linuxquestions forums as well to help you. The key is to get a good sounding set of soundfonts otherwise the instruments sound weird.

1b) I also don’t recommend running Timidity as a daemon on a Linux box that uses Pulseaudio. Use a tool such as sysv-rc-conf to remove it from your runlevels so it doesn’t start with the OS.

2) Edit the file /etc/mozpluggerrc and basically delete everything in that file except type in (or edit) the following:

audio/mid:midi,mid:MIDI audio file
audio/x-mid:midi,mid:MIDI audio file
audio/midi:midi,mid:MIDI audio file
audio/x-midi:midi,mid:MIDI audio file
controls noisy stream: timidity "$file"

Basically what you are doing is to tell mozplugger to act as a Firefox plugin only for MIDI files.

3) Restart Firefox and do about:plugins in the address bar to make sure you see mozplugger acting as the plugin for MIDI files. Navigate to a webpage with an embedded MIDI such as this page and test it out.

4) If it doesn’t work and you don’t see the 3 play buttons and don’t hear the music, download a MIDI from somewhere on the Internet and try to play it like “timidity xxxx” in a shell and see what it spits out.

———————————————————————————————

There are two other really cool MIDI programs that are native to Windows but I figured out a way to get them running via Wine and I just think they are really cool so I wanted to share.  Both of these programs are like “environmental sounds” generators like those old school bedside radios you used to see from Sharper Image or the places in the mall that sell expensive off-beat stuff.

Aire Freshener by Peter Hirschberg

Syntrillium’s Wind Chimes

Apparently Syntrillium was bought out by Adobe and Adobe decided not to proceed with development of most of their software such as Wind Chimes or the venerable Cool Edit Pro that many old school computer geeks will fondly remember.  They also had a lot of other really cool software like screen savers that moved to the rhythm of music and stuff like that.  That was really cutting edge back in the mid-90′s.

In order to run these programs in Linux via Wine it’s not so easy to just install the programs and expect them to work with Wine’s Alsa-Midi device.  At least it didn’t work for me that easy.  What I finally discovered to get these programs to work is to first make Wine to see the Timidity MIDI mappers via Alsa.  In order to accomplish this, I created some simple scripts to load Timidity as an Alsa sequencer and then run the programs with Wine.

Firstly, I recommend installing these programs into their own Wine environment so as to not mess with your existing main Wine directory under /home/xxxx/.wine and to avoid any potential problems. In order to use a special “sandbox” Wine environment you specify the WINEPREFIX environment variable something like this: env WINEPREFIX=/home/xxxx/bin/chimes/ wine setup.exe
That will install the program into a Wine environment in /home/xxxx/bin/chimes/ After you get all this figured out it’s on to making and testing the scripts. Below is my script for the Syntrillium wind chimes program.

#!/bin/bash
timidity -iA & disown
export WINEPREFIX="/home/xxxx/bin/chimes/"
cd /home/xxxx/bin/chimes/drive_c/chimes/
wine ./chimes.exe &
wait
killall timidity

Basically what this does is to start up a Timidity Alsa sequencer, then Wine is called to execute the Windows chimes binary, then Timidity is killed after you close the chimes program. Here is my script for the Aire Freshener program (I didn’t use a special Wine environment for this one).

#!/bin/bash
timidity -iA & disown
cd "/home/xxxx/.wine/drive_c/Program Files/Aire Freshener 2.0/"
wine "Aire Freshener.exe" &
wait
killall timidity

Hope you enjoy some old school MIDI on Linux!

[playlist]
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NumberOfEntries=10
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Length2=-2147483648
NumberOfEntries=10
Version=2
File3=mms://a839.l9789244838.c97892.g.lm.akamaistream.net/D/839/97892/v0001/reflector:44838
Title3=Oceaneering International III
Length3=-2147483648
NumberOfEntries=10
Version=2
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NumberOfEntries=10
Version=2
File5=mms://a1031.l9789255030.c97892.g.lm.akamaistream.net/D/1031/97892/v0001/reflector:55030
Title5=Viking Poseidon
Length5=-2147483648
NumberOfEntries=10
Version=2
File6=mms://a1236.l9789237235.c97892.g.lm.akamaistream.net/D/1236/97892/v0001/reflector:37235
Title6=Canyon
Length6=-2147483648
NumberOfEntries=10
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File7=mms://a459.l9789222458.c97892.g.lm.akamaistream.net/D/459/97892/v0001/reflector:22458
Title7=Oceaneering
Length7=-2147483648
NumberOfEntries=10
Version=2
File8=mms://a1176.l9789247175.c97892.g.lm.akamaistream.net/D/1176/97892/v0001/reflector:47175
Title8=Oceaneering International
Length8=-2147483648
NumberOfEntries=10
Version=2
File9=mms://a1146.l9789221145.c97892.g.lm.akamaistream.net/D/1146/97892/v0001/reflector:21145
Title9=Osprey-230
Length9=-2147483648
NumberOfEntries=10
Version=2
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Title10=Canyon
Length10=-2147483648
NumberOfEntries=10
Version=2

#!/bin/bash
read -p "How many seconds to run? ==> " count_secs
if [[ $count_secs -gt 0 ]]
then
rec -r 22050 -c 1 -p | sox -p OUTPUT.mp3 silence 1 0.1 1% -1 0.5 1% &
my_PID=$!
sleep $count_secs
kill -15 $my_PID
fi

When you run the above script it will ask you to input the total recording time in seconds, then end itself when that time expires. I’ve hard coded the sox command to output a 22 kHz, mono, 32 kbps MP3 file. There are still many many ways to modify and improve this script, but this is working for my needs now.

I’ve also learned a lot more about how to use the “silence” option in sox thanks to this blog post which I suggest you read to understand how to tweak the parameters.  The way I hardcoded the volume thresholds and silence detection time works well to my ear as far as cutting silence from scanner radio traffic. YMMV.

I have one other revised script which first uses arecord and then sends the output to sox for trimming.  The method below has an advantage in that you can more finely tweak the initial capture parameters.  The disadvantage to this method is that there is a second separate processing step with sox, instead of doing it all in one shot as in the first script.

#!/bin/bash
#USAGE: ./sox_vox_recorder.sh xxx output.mp3
#USAGE: Records from line-in for xxx seconds to output.mp3, then detects and trims silence
TIME=$1
OUTPUT=$2
arecord -f S16_LE -c1 -r22050 -t raw -d ${TIME} | lame -r -s 22.05 -m m -b 64 - ${OUTPUT} ;
sleep 1 ;
sox ${OUTPUT} ${OUTPUT}_processed.mp3 silence 1 0.1 1% -1 0.5 1% ;

I can see lots of tweaks to both of these scripts, such as capturing with OGG, or making a case-selection menu to choose capture parameters, and so forth. Maybe I’ll play with this in the future.

There’s a number of solutions to these problems which I’ll outline below.

Convert “Any” PAL to NTSC MPEG2-PS (DVD), Soft-Telecine method

mencoder INPUT_PAL.avi -vf scale=720:480,harddup -srate 48000 /
-af lavcresample=48000 -ovc lavc -oac lavc -of mpeg -lavcopts / vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800: /
vbitrate=5000:keyint=15:vstrict=0:acodec=ac3:abitrate=224: /
aspect=16/9 -mpegopts format=dvd:tsaf:tele_src=25: /
tele_dest=30000/1001 -o OUTPUT_NTSC.mpg

This “soft-telecine” method flags the frames for 25 fps to 29.97 fps to make the file NTSC compliant without changing the actual frame rate.

Dealing with the Aspect Ratio problem

The mencoder command above is incomplete because if you’ll notice it assumes you have a source already encoded at 720×480 with a pixel aspect of 1:1 and a display aspect of 16:9.  Of course this is never the case, so you need to make a few modifications.  We need to do some simple math.

Example:  Source file has a display aspect of 2.45:1 and a resolution of 640×261.

Desired output is NTSC-DVD with 16:9 display aspect:  (480)*(16/9)=854, and (854)/(2.45)=349, so we’ll encode to 720×350 and pad/expand the remainder to 480.

mencoder uses the expand method, portions of the above command line would therefore be modified like this “-vf scale=720:350,expand=720:480″ and make sure the -lavcopts part has “aspect=16/9″ in it somewhere.

If you happen to prefer ffmpeg, it uses the padding method and you would achieve the same thing by having the following in the command line “-s 720:350 -padtop 65 -padbottom 65 -aspect 16:9″.

Overall it looks like they improved a bunch of stuff.  I noticed a lot of stupid annoyances with Gnome/Nautilus are gone now, and the new Pulseaudio stuff looks good.

I use this box as my main PC as well as MythTV frontend/backend with one other PC on the network as a frontend only.  My capture card is the Hauppauge PVR-250.  I run a heavily patched version of 0.21-fixes from SVN built to my needs.  For Karmic I had to update it to r20877 due to some weirdness with glibc 2.10+, anyway that was the easy part…

After compiling and attempting to run it, I wasn’t getting any audio, and the video was choppy.  My first thought was to blame pulseaudio due to the debug messages I was getting and also the fact that if I changed my “profile” in the new gnome-volume-control panel it would make audio come and go, but this fact actually turned out to be a semi red herring.

After a little investigating I discovered to my surprise that grabbing video directly from the PVR-250 via “cat /dev/video0 > output.mpg” was also producing the same screwed up video/audio as Myth live TV.  Then I checked the behavior of my frontend only machine, same problem there…  Strange, what could be causing this?  IVTV it must be.  Jaunty had IVTV module v1.4.0, Karmic has v1.4.1 which appears to be non-stable at the present time.

So I wanted to try and compile a 1.4.0 module for Karmic but couldn’t find the source on the IVTV page, so I gave up on that.  Anyway long story short, I ended up solving these very strange problems by doing the following:

1)  I found out that for some very strange reason, the ivtv module needs to be re-loaded AFTER the mythbackend is started!  WTF!  and why does this fix the problem?  Any feedback on this would be appreciated.  Does it have something to do with this weird new Karmic thing where they start all the init programs in strange order to improve the boot speed?

2)  Declare EXPERIMENTALLY_ALLOW_PULSE_AUDIO=1 in my .profile.

All is well again.  Now to go enjoy Karmic.

UPDATE: I finally figured out what was giving me the problem with ivtv, it’s PEBKAC. Back in Feisty (I think) I added the command “v4l2-ctl -b off” to my mythbackend init script. I did this as a workaround to an Xv rendering playback bug with VLC and recordings made from PVR cards with the VBI closed-captioning enabled. Anyway, I guess with the newer ivtv module it screws things up, because now I removed that command and all is back to normal.

It turns out this extremely annoying problem is due to stupid gnome-screensaver!  At least it was on my machine.  Take a look at this.  It’s supposed to be fixed in Gnome 2.26+.  Well, I just thought I’d put this one out there, because it’s very difficult to debug, and I see occasional posts about jittery video playback in Linux.  Of course, a great majority of those problems are due to proprietary video drivers though.

Here are some examples:

rec -r 44100 -p | sox -p OUTPUT.mp3 silence -l 1 00:00:00.5 -45d -1 00:00:00.5 -45d

rec -r 22050 -c 1 -p | sox -p OUTPUT.mp3 silence -l 1 00:00:00.5 -45d -1 00:00:00.5 -45d

The first one will give you a 44.1 kHz, stereo, 128 kbps MP3. The second one will give you a 22.05 kHz, mono, 32 kbps MP3.

The rec command does the recording, -r specifies the sampling rate and -c sets the amount of audio channels, “-p” means the input is piped to another command. The sox pipe also needs a “-p” to tell it that its input is coming from a pipe, in this case the rec command.

The crypt CLI switches in the piped sox command “silence -l 1 00:00:00.5 -45d -1 00:00:00.5 -45d” is what does the silence detection and trimming. It means to cut silence from the beginning of the file and parts within the middle and end. “xx:xx:xx.x” is in hh:mm:ss.s format and tells sox the minimum duration to consider valid audio. In my examples I have this set to 0.5 seconds for valid audio. The “-45d” means -45dB and is the minimum valid audio level to do trimming. In other words, if you were to say -100d, basically everything would be considered valid and there would be no trimming, you will need to play with this depending on your input levels.

I made a test for almost 2 hours with my scanner connected and scanning the aircraft bands. I ended up with a 22 minute file. Very nice!! Now I’d say we have a very nice Linux-style “scanner recorder” program, and it’s a hell of a lot slicker than anything you’d find in Windows.

If you are a Debian or Ubuntu user, you will need to compile your own version of SoX if you want to encode to MP3. This bug explains that the version of SoX in the Debian repos was compiled without MP3 support. Anyway, all you need to do is download the latest source, make sure you have all the build deps (apt-get build-dep sox), make sure you have the libmp3lame and libmp3lame-dev packages installed, then just do ./configure, make, make install.

When you do the ./configure you’ll see a list at the end of the output of what capabilities will be compiled into sox, just make sure that it says you will have MP3 support. Your compiled version will go into /usr/local by default, so you don’t need to uninstall the repo version of sox, since that one is in /usr and programs in /usr/local always take precedance. You can verify that by doing “which sox” after installing it and it should show you “/usr/local/bin/sox”.

In Linux I’ve been able to get Rec-All Pro to work, but it’s kind of a kludge since you have to use Wine.  It works, but you cannot encode directly to MP3, I assume this is because of the way the Wine programs use DLLs.  I never was able to figure it out.  Anyway, I prefer to use a Linux native method.

I start off by setting up the radio to the station I want to record, then I use the PulseAudio VU meter along with the Alsa Mixer to set my Line-In level and Capture level to the proper amplitude, by watching feedback from the VU meter.  Then I execute the following to begin the recording:

arecord -D plughw:0,0 -f cd | lame -m s -a -b 64 - FILE.mp3
or
arecord -D plughw:0,0 -f S16_LE -c1 -r22050 -t raw | lame -r -s 22.05 -m m -b 64 - FILE.mp3

The first command will produce a file called “FILE.mp3″ with 16 bit resolution, 44.1 kHz sampling, mono. The second command will encode to 16 bit, 22 kHz, mono.

When you are finished recording do a Ctrl-C to end arecord. Now we need to do the silence detection.

mp3splt -s -p th=-30,min=1,rm FILE.mp3

The command above will split the input file using a silence threshold of -30 dB, a minimum silence duration of 1 second, and removes the silence from the resulting split files. And you will end up with a directory full of “Track 0*.mp3″ files. Now we just need to join all these files into one file. So go ahead and execute:

mpgjoin *.mp3 -o JOINED.mp3

Below is a little script to automate all of this. The only thing you need to change before running it is the bit in the arecord command “-d 300″. Change the 300 part to however many seconds you want to run the recording for.

#!/bin/sh
#USAGE: Records from line-in for -d xx seconds, then splits tracks removing silence between tracks, and combines all into one file
arecord -D plughw:0,0 -f S16_LE -c1 -r22050 -t raw -d 300 | lame -r -s 22.05 -m m -b 64 - Recording.mp3 ;
sleep 3 ;
mp3splt -s -p th=-30,min=1,rm Recording.mp3 ;
sleep 2 ;
mv Recording.mp3 Recording.mp3.original ;
sleep 2 ;
mpgjoin *.mp3 -o Joined_Output.mp3 ;
sleep 2 ;
rm Track*.mp3 ;

Say you have some hardware which is not supported, or Ubuntu’s driver is buggy.  First you need to find drivers, for example, the Atheros wifi driver in Ubuntu has bugs that cause system freezes, or I want to get my webcam working.  So you need to do this research first.  Then just follow the instructions for compiling and installing the module.

In the case of the webcam module, after compiling the module was installed at

/lib/modules/2.6.27-11-generic/extra/ov51x-jpeg.ko

To load this module I type:

sudo modprobe ov51x_jpeg
then run “dmesg” and you should see the messages that the hardware was found and registered, assuming you had the hardware connected when you loaded the module.

You should also run “lsmod” to make sure your module is loaded.  Something like “lsmod | grep ov” with provide an output showing modules with “ov” in their name.  I do that just to limit the output and make it easier to find specific things.

To unload a module:

sudo modprobe -r MODULE

Most if not all modules have options available to them.  You may be wondering where a lot of options for hardware devices are hiding in Linux.  This is the place.  In order to see what options are available just type:

modinfo MODULE

In the case of my webcam, this showed me about 25 options ranging from control of the LED to the autogain and backlighting controls and so forth.  Very useful to say the least.

As root, edit the file “/etc/modprobe.d/options” and add a line like this:

options MODULE OPT1=x OPT2=x

where MODULE is the module name, and OPT1, OPT2 and so on, are the names of the options you got when running modinfo.  So a real world example would be like “options ov51x_jpeg led=1 autogain=0 backlight=1″

In order to figure out what variables these options will take, sometime it will tell you when you run modinfo, other times you might need to go to the driver documentation or the source code.  For example, in the *.c files (the source code) for the webcam driver, the devs were nice enough to include lots of comments about what the options do and how to use them.

Note that the options that you add to /etc/modprobe.d/options will always apply whether you load the module manually or during boot.  If you need to temporairly change or disable the options, just comment out the line, then unload and reload the module.

In closing, once you are satisfied that the newly compiled and installed module is working and you have the options set to your needs, to automatically load the module during bootup, as root edit “/etc/modules” and add the module’s name to the bottom of the file.

I also just discovered a nice comprehensive frontend called Gelide. This is one of those frontends that you see often in Windows which gathers all your ROMs and emulators into one frontend and lets you launch the ROMs in the appropriate emulator, kind of like a frontend to many other frontends. Similar to QuickPlay for Windows.

It’s a very early release, but it looks like the dev has a great deal of features covered; snaps, customization of emulators, parameter customization, easy to understand interface, etc.. I haven’t played with it much yet, but what I have tried so far has impressed me. For example, I noticed that the default setup doesn’t have anything for C64 emulation. So all I had to do was right click on the games library and add an entry for the Commodore 64, then in the lower box I right clicked and added a definition and parameters for the emulator I use. Then I told it the directory to find the ROMs and supporting files, refreshed the list, then double clicked a game and off it went!! Very nice!!