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DMP.DOC Documentation for the Dual Module Player v4.00 Copyright (C) 1992,1995 Otto Chrons. All rights reserved Dual Module Player is a program for playing music modules on different sound systems on IBM PC compatible machines. It uses DSMI sound programming interface (Digital Sound & Music Interface) to achieve high quality sound and wide sound card support. This packet includes both the realmode (DMP.EXE) and protected mode (DMP32.EXE) versions of DMP. Usually DMP32 gives you better performance and also more memory in the DOS shell but it may not work very well under some multitaskers. You shouldn't even try to run either version as a background task under Windows. DMP32 and M2AMF use the PMODE/W DOS extender to run in 32-bit protected mode under plain DOS. Thanks for PMODE/W go to Charles Scheffold and Thomas Pytel. DMP is careware so you can freely copy it to your friends and distribute it to BBSes etc. If you like DMP you should send me some money that will be directed to charity. See the end screen of DMP for more information. Currently DMP supports following module formats: MOD,NST The original Amiga module format (SoundTracker, NoiseTracker). Also supported by many PC trackers. Original format supported only 4 channels but many variants can support up to 32 channels. STM,S3M Scream Tracker format. S3M can support up to 16 channels while STM is limited to 4. 669 Composer669 module format using 8 channels. FAR Farandole tracker format capable of using 16 channels. MTM MultiTracker format. It's a MOD variant with up to 32 channels. AMF DSMI's internal module format. You can convert all the previous formats to AMF with M2AMF but not vice versa. Using AMF format saves you disk space because AMFs are usually smaller than other module formats. DMP can also load AMFs faster than other formats. But remember that you cannot play AMFs on any other player, nor can you convert AMFs back to any other format. DMP is a simple program without any fancy graphics or mouse support. Most DMP options can be set with command line parameters, or by setting them into DMP envrionment variable or DMP.INI setup file. This is the command line syntax of DMP: DMP [options] [modulename] [@listfile] [options] where, [modulename] Name of the module (or modules) to play. Wild cards are allowed. [@listfile] name of a file containing a list of module names. You can also use wild cards within the list file. [options] DMP settings -H, -? Show help screen about options. -Nxx Set default panning to xx. Most module formats don't support default panning, the channels are either left or right. With this option you can bring the channels close to the middle position. Value 0 means middle panning, 63 sets the channels as much apart as possible and 100 forces surround sound. -Fxx Select digital effect xx as the default effect. Digital effects are defined in DMP.INI -E Disable extended (BPM) tempos. Use this option if you encounter tempo problems with old modules. -L Inhibit looping. If you are playing just one module DMP will by default loop the module forever. -O Randomize the playing order of modules. -B Disable EMS usage. -W[command] Run [command] after staring to play the module. If you want to give command line parameters to [command], put quotation marks (") around the option i.e. "-Wdir *.mod" If [command] exits with error level 68, DMP terminates immediately. -X Inhibit all output. DMP writes absolutely nothing on the screen. Using default options --------------------- If you find yourself using the same options all the time you can make them default options by setting up a DMP evironment variable or including them into DMP.INI. For example, You always want to use quality mode and sampling rate of 22kHz and mono mode, put following line into your AUTOEXEC.BAT SET DMP=-q -s22 -m NOTE! You cannot override single letter options (-l,-o,-m,-q) with command line parameters. All other options can be overriden. Alternatively you can use the CmdLine parameter in DMP.INI for same purpose. Setting up your sound system ---------------------------- Before running DMP you must select and setup the sound driver with the included DSETUP program. The program will let you choose a sound card and then select the hardware setup and other options for that sound device. Finally it saves the configuration into SOUND.CFG which DMP uses to load and initialize the sound card driver. Playing modules --------------- DMP automatically goes to the file selection screen if no valid modules have been selected on the command line. You can also build up play lists for DMP (with an external shell program for example). DMP reads this list file and scans each line for a module name. There should be only one file name per line. The name extension apply also for module names in play list. Example: DMP beyond.mod *.NST @goodmods goodmods is a text file containing following lines: occ-san.stm stars.mod intro3.s3m DMP will play following modules: BEYOND.MOD, OCC-SAN.STM, STARS.MOD, INTRO3.S3M and all .NST-files in the current directory. Module file selector -------------------- A new feature in DMP 4.00 is a handy module file selector that lets you interactively make a playlist of modules and edit that list. You can select modules from different directories and disk drives. Modules can be sorted by filename, extension, module name, size and data both in ascending and descending order. There is also a speed search function with which you can quickly jump to a module matching the search pattern. This feature works both for file name and module name. Active key commands can be seen on the right side of the screen. DMP configuration file DMP.INI ------------------------------ DMP has a config file called DMP.INI. It should be placed in the same directory with DMP.EXE but DMP will also find it if it's somewhere in the PATH. See the file itself for explanations on config switches and strings. DMP play screen and keys ------------------------ After DMP has loaded the first module and started to play it you see the playback screen. In this screen you can find a lot of information on the currently playing module, like the song name, how much memory is used by the module, where the player is currently playing etc. You also see channel specific information showing you the instrument name that is playing on that track and also other sound parameters. On the right are volume bars that give you an approximation of the sound volume on that track. Under the channel information is a list of instrument names. It is quite common that composers use this space for some messages instead of real instrument names. Pressing 'H' brings up a quick-help showing keys that control the program. Keys: F Go to module file selector. P Pause module playback. Pressing any key resumes. 1-9,0 Turn track 1-9 on/off. 0 turns selected track on/off. S Set selected track to solo mode i.e. all other tracks are muted. Pressing 'S' again on the same track unmutes other channels. up/down Select a track. left/right Jump to previous/next pattern. pgup/pgdn Scroll instrument list up/down F1-F10,+,- Set playback volume. [,] Decrease/increase speed (module tempo). {,} Decrease/increase module BPM tempo. L,M,R,U Set panning to full left/middle/right or surround. , . Pan to left/right V Select real/fake volume bars. Default is real. E Select digital effect (not available on GUS). Shows a menu where you can select the effect with up/down or with numbers 0-9 and X. N Stop playing current module and load next module. B Stop playing current module and load previously played module. D DOS shell (write 'EXIT' to get back to DMP) ESC Exit DMP. Technical information ===================== DMP uses software mixing routines to play up to 32 different digital sounds on one mono/stereo digital channel of your sound system. With Gravis Ultrasound, however, DMP uses the GUS onboard processor to do all the sound mixing. The software mixing routines are highly optimized assembly language and there are multiple routines to achieve best performance with any sound system. Quality mode ------------ Quality mode was orignally implemented only on 8-bit sounds cards to overcome the dynamic limitation of 8-bits. It uses 16-bit mixing routines to achieve 96dB dynamic range (instead of 48dB) and post processes the 16-bit data into 8-bits with a look-up table that amplifies the sound. Because of this post processing, the Quality mode takes more processor power but it's worth it. To further amplify the sound you can use '-Axx' command line option. Quality mode is always enabled with 8-bit sound cards. For 16-bit cards there's no need to use Quality mode to improve the quality of the sound. But with up to 32 channels the dynamics of individual channels go worse i.e. the volume is lower. You can of course select an aplification option in the sound setup to amplify the sound but there is always a risk of click and noise if the sound overruns. This is where 16-bit Quality mode comes in. It uses a temporary 32-bit buffer to do the mixing and post processes the buffer by clipping values that can't fit to 16-bits. Unlike 8-bit Quality mode, there is no default amplification in 16-bit Quality mode. 16-bit quality mode is not enabled unless you use an amplification mode that enables it. Digital effects --------------- New to DMP 3.00 was the support for digital effects. Currently you can do reverb/echo style of effects and simple lowpass filtering. These effects are only available on sound systems where DMP does the mixing in software (i.e. the final sound data can be post processed), so you cannot use them with GUS. You can have up to 10 predefined effects (defined in DMP.INI) and select between them while playing by pressing 'E' or with command line parameter '-Fxx'. Filters You can use two different lowpass filters to filter the noise caused by aliasing in mixing routines. These filters are really simple so they don't use much processor power. Filter 1 algorithm is defined as: y(n) = 0.5*x(n) + 0.5*x(n-1) Filter 2 is: y(n) = 0.75*x(n) + 0.25*x(n-1) Of course the actual filter routines use simple additions and shifts instead of floating point multiplications to achieve best possible speed. See DMP.INI how to use these filters. By default DMP uses the Filter 2 (this can be changed in DMP.INI or with '-Fxx' command line parameter). Reverb/echo effects DMP uses a user definable reverb/echo engine to create effects from massive reverbs to funny sounding echos. Here is the diagram of that engine. ┌─────┐ ┌────────┐ │Input├─────────────────────────────────┬──┤ │ ┌──────┐ └─────┘ ┌────────┐ │ │ Filter ├──────────┤Output│ ┌──────────────────────┤ ├────│──┤ │ └──────┘ │ ┌─────────────┤ Filter │ │ └────────┘ │ │ ┌───────┤ ├─┐ │ │ │ │ └────────┘ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ -----│ │ │ │ feedback\ G /│ G = gain "echos"│ │ │ \_/ │ / \ / \ / \ │ │ D = delay / G1\ / G2\ / G3\ │ │ ----- ----- ----- │ │ │ │ │ ┌┴──┴┐ │ │ │ │ ++ │ │ │ │ └──┬─┘ │ │ │ │ │ │ │ │ D1 │ D2 │ D3 │ │ ┌───┴────────┴─────┴───────────────┐ │ ┌─┤ delay line │ │ │ └──────────────────────────────────┘ │ │ │ │ │ └─────────────────────────────────────────┘ The number of echos can be from one to eight and each has its own position on the delay line and its own gain value. You can change the number of echos and paramters for each echo in DMP.INI [DigitalEffects] section. You can also set the "feedback" value. You can also use negative gain values to create a 180 degree phase shift. The filters used in reverb are the same as in filter 1. Setting a reverb in DMP.INI looks like following: Effect1 = <effect_name> R <feedback> <echo 1 delay> <echo 1 gain> ... See DMP.INI for examples on reverbs and echos. Reverb performance Calculating one echo in reverb engine requires a few simple arithmetic instructions and one multiplication. In addition calculating feedback requires another multiplication. So with a 6 echo reverb the routine must do seven multiplications and lots of simple instructions for EACH AND EVERY SAMPLE from input. In comparison the mixing routines in the actual sample playback engine require only a few simple instructions per sample. Unless you have a powerful 486 it's not wise to use stereo mode because this doubles the reverb overhead. Even on a 486/33 using reverb with 44kHz stereo data can bring the machine on its knees. On slower machines you will start to hear the playback buffer repeating as DMP can't keep up with sound card DMA. Using simple echos requires a lot less processor computing power, it's all dependant on the number of echos. Also notice that the reverb engine in DMP32 a bit more powerful than the one used in DMP because DMP32 can effectively make use of 32-bit instructions. Contacting the author ===================== If you have suggestions/questions/problems about DMP, feel free to contact the author. Email is preferred. Mail address: Otto Chrons Vaajakatu 5 K 199 FIN-33720 TAMPERE FINLAND Internet e-mail: otto.chrons@cs.tut.fi Internet WWW page: http://www.cs.tut.fi/~c142092 Getting new versions of DMP --------------------------- Newest version is always available at: Internet FTP: ------------- ftp.cdrom.com /pub/demos/music/programs/players For a distribution site near you, check out SUPPORT.DMP. See DMP.REV for revision history.