OGG and MP3 Car Player Project Contents

OGG & MP3 Car Player Project - Software for the Car-PC
(last modified 14.05.2004)

Contents:

Operating system (Windows or DOS ?)
OGG or MP3 ?
Data storage of music files
Creating M3U play lists ("PlaylistBuilder.exe")
"MPxPlay.exe" as player program
"PlayIt.exe" as front-end
Problem of shutting down the harddisk (HDD sleep)
Using a RAM disk
Description of the complete sequence
Useful tools and their description

Operating system (Windows or DOS ?):

Pros & Cons for pure Windows:

Support of harddisks with more than 10GB.
Drivers are available.
A lot of MP3 / OGG players to choose.
Needs some MB on the harddisk.
Runs not stable over long time.
Critically if the PC is switched off without shutdown.
Needs long time to boot and to shut down.

Pros & Cons pure DOS:

Support of harddisks only up to 4 or 8GB (as I know, this depends on the DOS version).
Problem of availability of drivers (sound card ?).
As I know there is only one MP3 / OGG player (MPxPlay).
Needs only little harddisk space.
Very stable.
Switching of the PC without shutdown is possible without problems.
Boots up quickly and does not need to be shut down.

The compromise:

Use the DOS mode of Windows95.
That combines the advantages of a pure Windows and a pure DOS.
All installed Windows drivers and the support of 32GB harddisks are available under DOS.
MPxPlay runs with problems.
Simply switching off without shutdown works without problems, even with activated Smartdrv (I tested it several times).
The boot time isn't as quick as with pure DOS, but 30s are still acceptable.
Powering down (if you do it) is very quick.
If you need it, you always have a Windows available too in case some tools are not running under DOS (e.g. sort data).

OGG or MP3 ?:

For sure, MP3 is the more common format.
Music downloads from the internet are mostly available as MP3.
OGG files, in comparison with MP3 at the same bit rate (I'm using 128kBit/s), are smaller and have better quality.
Everybody should compare MP3 and OGG for himself (with same bit rate !), before deciding deffinitely to use one or the other.
In my comparison tests I found out for me, that OGG contains more base and treble and in general sounds more transparent and therfore gets nearer to the CD original.
In my opinion OGG is only useful, if you want to play the music files only on PC's.
If you want to play music files also on MP3 CD compatible devices (car radios, CD players...) or MP3 portables (Apple iPod), then MP3 for sure is the better choice.
I'm only using music files in my car player. Maybe sometime later also on a second device together with my home stereo. Therefore I have decided to have less HDD capacity occupied and to have better sound quality. So OGG is my choice.
Never the less, my car player should be able to play also MP3 files. So I'm able to play also not self encoded music.
By the way, MPxPlay plays MP3 and OGG (and even some more formats) without any further plug-ins.

Data storage of music files:
I decided to use the following scheme for storing music files:

All music is stored to sub-directories below C:\Music.
The directories below are defined by the genre.
Below this, there are directories for each CD named like:

The music titels of every CD directory are named like:

So the whole thing looks e.g. like:
C:\Music\Rock-Pop\Rolling Stones - Still Alive - D - 1981\01 - Under My Thumb.ogg
C:\Music\Rock-Pop\Rolling Stones - Still Alive - D - 1981\02 - Let's Spend The Night Together.ogg
...

Creating M3U play lists ("PlaylistBuilder.exe"):

M3U play lists can be created with the PlaylistBuilder.
The program is able to create Windows play lists (with long file names) and DOS play lists (with 8.3 DOS convention).
It can be downloaded in the Download Area.
The calling syntax is described in the ReadMe.txt file.
The contents of such a play list e,g, looks like:

With long names:
_ListWIN.m3u
# "Rolling Stones - Still Live - A - 1981" 01 - Under My Thumb.ogg 02 - Let's Spend The Night Together.ogg

With 8.3 DOS names:
_ListDOS.m3u
# "Rolling Stones - Still Live - A - 1981" 01-UND~1.OGG 02-LET~1.OGG

Following items have to be regarded:

MPxPlay is not able to handle some special characters and then doesn't play the title.
Therfore don't use such characters in file names.
Use the car player PC (but using Windows) to create 8.3 play lists.
That's because the PlaylistBuilder is converting Windows names to 8.3 names. If more than one file is beginning with the same characters, then the PlaylistBuilder needs a chance to evaluate the file structure and to find out whether it has to name the file ~1 or ~2.

"MPxPlay.exe" as player program:

As I know, MPxPlay is the only MP3/Ogg player program for DOS.
It is freeware :-)))
The DOS screen is very simple, but who is interested in this, without having a monitor ?
The sound quality is not worse than in other players (at least I was not able to hear out any differences to WinAmp, MediaPlayer and Sonique).
Supports a lot of possible sound cards and encoding formats.
It has a great variety of possible configurations, that is a great advantage while controlling it with a num pad.
It is excellent to be controlled by command lines, what made the control via PlayIt generally possible.
The Player is contained in the complete installation in the Download Area.
Newer releases of MPxPlay can be downloaded on the PDSoft Homepage.

"PlayIt.exe" as front-end:

PlayIt is a front-end, that receives keyboard input and controls MPxPlay via command lines.
The file "PlayIt.ini" configures PlayIt.
The file "Playlist.ini" contains the association between 3-digit number and path link to the according play list.
It realizes a function, that continues playing at the point, where it was stopped before switching off the PC (as a CD changer does).
A shutdown can be initiated by pressing a key for two times (configurable, I'm using NUM).
It plays acustic error and status messages.
The typed number is announced acustically.
The program can be downloaded in the Download Area and it is additionally contained in the complete installation.
As per default of the complete installation, the num pad keys are defined in the following way (BLUE: MPxPlay function, RED: PlayIt function):

NUM
2x pressed, shuts down the PC.
/, x, -, ENTER
without function
7
very fast backward (5s each key press)
8
volume up
9
very fast forward (5s each key press)
4
1 titel back
5
pause / resume play
6
1 titel forward
1
fast backward (1s each key press)
2
volume down
3
fast forward (1s each key press)
0
repeat title
,
terminate MPxPlay
+
randow play

Problem of shutting down the harddisk (HDD sleep):

Background of this idea is to protect desktop harddisks against mechanical shocks.
The principle of this is, to copy all the music data to a RAM disk.
After this, the harddisk is set to sleep mode, that means it is powered off (formerly we called this parking).
In this mode, the harddisk is not anymore sensible against mechanical shocks.
The problem in this is, that harddisks are extremly sensible against shocks while running up again. The reason for this is, that the write/read heads are floating on a air stream, that protects them from having a head crash. While spinning up the harddisk, this air stream has to be re-build up.
Furthermore, copying of ca. 30MB of compressed music data per album to the RAM disk takes a while.

In the following explanations I want to describe the principle, how it principally worked in my car player.
But I have to tell you, that I never tryied this out practically. A expert of harddisk hardware of Western Digital told me explicitly to not do it !

Preparing actions while booting:

Following lines have to be included to the "Config.sys":

DEVICE=C:\WINDOWS\himem.sys

Loading high memory driver

DEVICE=C:\WINDOWS\ramdrive.sys 30000 /e

Creating a RAM disk with maximum size (here 30MB) in the extended memory.

ATTENTION:

With RAM disks >30MB, MPxPlay gets crazy while playing play lists !

Following lines have to be included the "Autoexec.bat":

COPY c:\mpxplay\*.* d:

Copying MpxPlay files to the RAM disk.

COPY c:\batch\mpxram.bat d:

Copying the MpxPlay starter batch to the RAM disk.

Sequence with PlayIt:

A 3-digit number is typed in
Searching Playlist.ini gives e.g. the following result:

"c:\Music\BRASIL~1\CHICLE~1"

PlayIt.exe calls the MpxPlay starter batch MpxRam.bat as follows:

SHELL "d:\mpxram.bat c:\Music\BRASIL~1\CHICLE~1"

MpxRam.bat takes over with the following sequence:

Copying all data to the RAM disk

COPY %1\*.* d: = COPY c:\Music\BRASIL~1\CHICLE~1\*.* d:

Change drive to the RAM disk to desable any further call to C:

Put C drive in sleep mode

c:\tools\HDPwrOff.exe

Start MPxPlay on the RAM disk

mpxplay.exe *.*

Delete all music data on the RAM disk after terminating MPxPlay

DELTREE /Y *.mp3

DELTREE /Y *.ogg

DELTREE /Y *.m3u

Change back to the directory of PlayIt.exe

CD c:\playit

PlayIt.exe continues automatically, when the SHELL command has ended.

Using a RAM disk:

A RAM disk can be used to reduce the accesses to the harddisk to a minimum.
If the sequence is realized without a RAM disk, then PlayIt and especially MPxPlay will execute consecutive read accesses to the harddisk while permanently reading music data.
Maybe this is the reason why the harddisk of my player survived until now.
To be honest I have to tell you, that I never tryied it out to work without RAM disk. Therefore I don't really know, if this is as useful as I imagine.
While starting up the PC, there are directory copies created on the RAM disk and the contained data is copied.

(call of "Cpy2Ram.bat" in "Autoexec.bat" for DOS)

After that, there is a change to drive D: (=RAM disk) and PlayIt is started there.
In "PlayIt.ini", the call of MPxPlay is configured with parameter "-bl". That causes MPxPlay to buffer the music file to the RAM.
If PlayIt is left, "PowerOff.bat" (configured in "PlayIt.ini") is executed.
"PowerOff.bat" executes first "RstrRam.bat".
That restores the meanwhile modified files of MPxPlay and PlayIt back to their source directories on the harddisk.
That's necessary to have these files with updated information back on the RAM disk after the next start up.
Next "PowerOff.bat" executes the command "PausExec.exe 1".
That pauses the batch execution for 1s, so the HDD cache has time enough to really empty itself to the harddisk and so it is guaranted that the data physically reaches its destination.
At last "PowerOff.bat" executes "PowerOff.exe", that finally powers off the PC.

Description of the complete sequence:

After the PC was switched on, it boots in the DOS mode of Windows.
A 2MB large RAM disk is created in "Config.sys".
"DosLFN.com" is loaded in "Autoexec.bat".
"Cpy2Ram.bat" copies all relevant data to the RAM disk.
After all, "PlayIt.exe" is started.
PlayIt plays acustically the start message ("LoadUp.ogg").
With reading the file "Lastplay.ed", PlayIt finds out the number of the last played album (e.g. 100).
PlayIt writes the names of three OGG files to the play list file "Playnr.m3u", that represent the number

e.g.:

d:\playit\number.ogg\One.ogg

d:\playit\number.ogg\Zero.ogg

PlayIt calls MPxPlay in "D:\MPxPlMsg" with the play list "Playnr.m3u".
In that way the number of the last played album is announced acustically.
PlayIt opens the file "PlayList.ini", searches for the number (e.g. 100) and reads the path link to the play list (in that example e.g. "c:\music\ROCKPO~1\BBM-AR~1\_ListDOS.m3u").
Now PlayIt calls MPxPlay in "D:\MPxPlay" with the play list "c:\music\ROCKPO~1\BBM-AR~1\_ListDOS.m3u".
MPxPlay has stored the last played title and frame in "Mpxplay.ini" (last 3 lines) and continues playing exactly were it stopped the last time.
MPxPlay can now be terminated and PlayIt gets active again, if you type in "," on the num pad.
PlayIt plays acustically "PlayEnd.ogg" as MPxPlay end confirmation.
After that PlayIt is waiting for the next 3-digit number input.
If a new 3-digit number is typed in, the sequence starts once again.
If the number can not be found in "PlayList.ini", PlayIt plays acustically "NoNumber.ogg".
If the number can be found, but the related path link to the play list is not valid (play list or directory not existing), then PlayIt plays acustically "PlLstErr.ogg".
If every thing is ok, then MPxPlay is started again with the new play list (as before).
While PlayIt is active and is waiting for a number input, NUM may be pressed 2 times to power off the PC.
PlayIt plays acustically the shutdown message "Shutdown.ogg".
After that "PowerOff.bat" is started.
"PowerOff.bat" calls "RstrRam.bat" and the relevant data is restored from D: to its source directories on C:
Afterwards "PausExec.exe 1" is executed in "PowerOff.bat", that pauses the batch execution for 1s, so the HDD cache has time enough to really empty itself to the harddisk.
Finally "PowerOff.exe" is executed that powers off the PC.

Useful tools and their description:

"DosLFN.com" (DOS long file name)	DOS	Displays long file names instead of 8.3 file and path names under Windows-DOS. So the MPxPlay file view shows long names, what is pretty convenient to detect errors in file names.
"PausExec.exe"	DOS	Pauses the batch execution. The calling syntax is "PausExec <x>", where x specifies the duration of the pause in seconds.
"PlaylistBuilder.exe"	Windows	Creates M3U play lists (see Description)
"PowerOff.exe"	DOS	"Shuttdown" (Power-Down) for PC's under DOS.
"Shutdown.exe"	Windows	Shuttdown for PC's under Windows. (see Description)
"Tastatur.exe"	DOS	Shows key codes, scan codes and the shift status of the keyboard. That tool is useful to find out unknown key codes for the operation with MPxPlay to be configured in the configuration file "Mpxplay.ini".
"Hdpwroff.exe"	DOS	Powers off the harddisks of a IDE port. The calling syntax is "Hdpwroff <number of the IDE port> The file is only necessary if you want to work with HDD Sleep (see Description).