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Text File | 1995-02-11 | 21.7 KB | 429 lines

***************************************************************************** * SBDSP Read Me file * * ================== * * * * SBDSP is Copyright (C) 1994, 1995 by Romesh Prakashpalan, * * all rights reserved * ***************************************************************************** Table Of Contents: ================== 1) Introduction to SBDSP 2) Features and System Requirements 3) Getting Started 4) Modifications necessary to work with Turbo Pascal 6.0 5) Implementing REAL TIME FX 6) Structure of the RPD file format 7) Notes on the future + Contacting the author ***************************************************************************** * Introduction to SBDSP * ***************************************************************************** SBDSP is a Pascal Unit that allows one to utilize the FULL power of the Sound Blaster's Digital channel. At one stage in my game programming projects I realized that I was going to need digital sound and music in my games! After all, the PC Speaker was just NOT going to be good enough for a production level game (BTW, I still haven't released anything as of this writing), but to my dismay, all of the books and literature seemed to use the darn libraries that Creative ships with "genuine" (albeit noisy) Sound Blasters. This meant that people without the drivers would not be able to run my programs! So, I contacted Creative, and found out that their developer's kit costs 100 U.S Dollars! I then hunted on the Internet, and found a few docs here and there, and I eventually managed to create the SBDSP and SBFM libraries. Anyways, I am releasing this unit to the public for those who need the capability of digital sound, and my code surpasses the information found in the SDK made by Creative. There are 2 Programs attached to the SBDSP unit itself, and those illustrate how to play back and record a sample (from Disk). The rest of this document will give some information on the unit, as well as file formats utilized (RPD), and some tips on REAL TIME FX. - Romesh Prakashpalan (1/23/95) (hacscb93@huey.csun.edu) Disclaimer: The author (Romesh Prakashpalan) specifically disclaims ========== responsibility for any loss of profit or any consequential, incidental, or other damages. The Turbo Pascal code attached to this document is FREEWARE and includes the following programs/ units/files: (SBDSP.PAS - Turbo Pascal Unit) (VOC2RPD.PAS - Turbo Pascal Program) (WAV2RPD.PAS - Turbo Pascal Program) (RPD2VOC.PAS - Turbo Pascal Program) (TESTDSP.PAS - Turbo Pascal Program Demonstrating Playback) (RECDSP.PAS - Turbo Pascal Program Demonstrating Recording) (SBDSP.TXT - This Document) These programs/units can be incorporated in your programs in full/ partial form, but this package is NOT to be distributed modified! If you feel as if this package needs changing, contact me, and we can work on changes TOGETHER, and release a new version. P.S: If you feel as if this unit is worth some money, please send some over my way ;-) This way, I can fund my research and game programming projects, and upgrade my computer. Or, at the very least include my name in the credits section of whatever you release that uses the SBDSP unit. But, note that a donation is NOT necessary, as this is FREEWARE, not SHAREWARE! ***************************************************************************** * Features implemented in SBDSP 2.0ß * ***************************************************************************** [X] FULL Support for the Sound Blaster DSP chip [X] DIRECT ACCESS to the Sound Blaster, none of Creative Lab's drivers are needed! [X] DMA Driven, no CPU intervention neccessary [X] Play from Disk w/a small buffer in memory (File can be any size, but Buffer is <= 64K). [X] Double Buffering implemented in order to reduce "clicks" [X] Play straight from memory (up to 64K) [X] Software mixing of samples [X] Stereo output for the SB-PRO or higher [X] Full support for the SB-PRO mixer chip [X] Conversion from the most popular PC Sound Formats (VOC, WAV) [X] Conversion to the VOC file format [X] Real Time Software Volume adjustment [X] Recording option (8-bit), and supports the SB-PRO filters, and is capable of switching from Line-In, Mic and CD inputs (SBPRO or higher) [X] DOS Re-entrancy problem "appears" to have been fixed. ***************************************************************************** * Features NOT implemented in 2.0ß (but will be in 2.0) * ***************************************************************************** [ ] 16 bit sound will be included in 2.0 (final release) [ ] Surround Sound MIGHT be included (I'm not sure, as I'll have to allocate buffers dynamically which might be detrimental to a Real Mode program. ***************************************************************************** * System Requirements * ***************************************************************************** [ ] IBM PC Compatible with a 80386 processor or higher [ ] Sound Blaster Card, Pro required for Stereo output, and 16 required for 16-bit playback [ ] AT LEAST 16K of memory set aside for Double Buffering (buffers can be smaller, but system performance and sound quality will degrade) [ ] Turbo Pascal V7.0 (can run in 6.0 with minor modifications) [ ] A Human (or any sentient being) required to appreciate the sounds ;-) ***************************************************************************** * Getting Started... * ***************************************************************************** I) Playing a file from disk... OK, now you have the unit, and have all of the system requirements, so how do we output a simple sound? If you have a favorite VOC or WAV file, convert it to a RPD file first, and make sure that it falls in the following parameters: [ ] 8-bits/sample in Stereo/Mono in any sample rate (make sure that your harware can actually play sounds of this type first!) Then, in the beginning of your program (or anywhere before actually using the Sound Card), use the ResetDSP command: ResetDSP (BaseAddress, IRQ, DMAChannel, HighDMAChannel); Where Base = 1 for 210h 2 for 220h 3 for 230h, etc... IRQ is typically 7 for older cards, and 5 for the newer ones DMAChannel is usually 1 (SB16 owners note this is the LOW DMA channel) HighDMA is usually 5 for SB16 owners, people without a SB16 (or AWE32), should leave this at 0. Then, we just use the following command to play the RPD file: PlaySoundRPD (Filename); Where Filename is the name of your sound file (RPD). The Sound will be played in the background, while your program is free to do what it wants in the foreground. So, if you have a loop similiar to this: PlaySoundRPD (Filename) While SomeCondition do Begin (* Do something *) If not Playing then PlaySoundRPD (SomeOtherFile); End This above loop is the basis of a "JukeBox" type app, where when the sound is done playing, we load in the next song in the list. NOTE: The playing variable indicates if a sample is still playing over the Sound Card. II) Playing a Sound from Memory. The above procedure works just great for long samples (speech, music), but what about when we want to play a sample from memory repeatedly? When I say repeatedly, I mean something like a machine gun shot, it would sound lousy, and be pretty inefficient if we had to load the sound from disk every time the user presses the fire button! That's why we have another function called: LoadSoundRPD (Filename, SoundBuffer, AllocMem); Where Filename is the name of your file, SoundBuffer is a buffer in memory of type: BaseSoundType, and AllocMem is True if you want the procedure to allocate memory for you, else it is False. First, we issue the LoadSoundRPD command: LoadSoundRPD (Filename, SoundBuffer); Now, we have the sound safely stored in a buffer in memory ready for the PlaySound command whenever we want to play it back! So, we can have a loop like this: LoadSoundRPD (Filename, BulletBuffer, True); While Somecondition do Begin If (FireButtonPressed) and (not Playing) then PlaySound (BulletBuffer); End; { Free the memory allocated: } FreeMem (BulletBuffer.Buffer, BulletBuffer.BufferSize); III) Recording a sample to disk: Version 2.0ß was the first to implement recording (to disk), and was implemented for someone who needed it urgently. So, the recording function is less than perfect. The steps needed for recording to disk are: 1) * Set Input source via the SetInputSource command 2) * Set Volume level for your input source via one of the following commands: - SetMicVolume - SetLineInVolume - SetCDVolume 3) Issue the RecordSoundRPD command: RecordSoundRPD (Filename, Freq); Where Filename is the Filename to be recorded to, and Freq is the Frequency at which you want to sample at. 4) When you are done, issue the StopRecording command, and the file will be closed, and all info will be saved for future use. Note: Items marked with a * are only available on the SB-PRO or higher! Problems with recording option: 1) Currently only supports 8 bit mono. 2) Will write ALL of the last buffer in memory to disk, so it takes up more disk space than necessary (File Size = N*BufferSize + SizeOf (Header)). Where N is the number of times the buffer has been recorded to. IV) Tweaking for optimum performance: If you look at the interface section, you will notice two procedures: CheckBufferSize and ChangeBufferSize. These two procedures will return and change the Size of the Double Buffer. Experience has shown that buffer sizes in the range of 8K (for mono 11Khz at 8bits/sample) -> 64K (stereo 44.1Khz) are the best ranges (BTW: 64K is the MAXIMUM buffer size). ChangeBufferSize returns True if the buffer size was changed successfully, and False otherwise. The only time it will return False is if you are recording/playing back a sample. CheckBufferSize simply returns the size of the allocated buffer in memory. ***************************************************************************** * Modifications necessary to work with Turbo Pascal 6.0 * ***************************************************************************** So, you say that you have Turbo Pascal 6.0, and the unit gives you a few errors when you want to compile? Well, then this section is for you: SBDSP 2.0ß was made to run/compile under Turbo Pascal version 7.0, so a few changes are necessary in order to make it work with Turbo Pascal 6.0. (Note: I myself upgraded from 5.5 to 7.0, and NEVER had 6.0, so this is based on discussions with my friends who had Turbo Pascal 6.0) First: SBDSP requires use of the In Line Assembler, so it is incompatible with versions of Turbo Pascal < 6.0, so an assembly module would be required in order to get the same functionality out of it if you are using Turbo Pascal 5.5 or lower. As far as I know, Turbo Pascal 6.0 DID NOT have the PChar type. For those of you who have Turbo Pascal 6, PChar is a string type similar to that of C's. In TP 7.0, pointer arithmetic is ONLY defined for this type, so it makes it quite convenient to use this type when dealing with pointers! I have made use of this type in the following procedures: ChangeSampleVol MixSamples Now, fixing this in Turbo Pascal 6.0 would require the following changes: In the interface section of the unit create a new type definition: CharArr = Array [0..$FFFE] of Char; PChar = ^CharArr; Now, anytime where we see a variable of PChar type being referenced as an array, reference it as a POINTER ARRAY. For instance, in my code when you see: TempC[I] := Char (20); Change this to: TempC^[I] := Char (20); If at any time, you get a "type mismatch" error when passing pointers, just re-cast your pointer to the PChar type -> PChar (YourPointer), and this should do the trick! There's one last thing, TP 6.0 doesn't default to having EXTENDED SYNTAX ON, so make sure that the {$X} switch is on: {$X+}, as TP 6.0 defaults to {$X-} This should be all for owners of Turbo Pascal 6.0, but I could be wrong, as I don't have the Compiler myself, so if anything gives you any troubles, mail me, and I shall try to find out what is wrong... Borland Pascal 7.0 should NOT be used to create PROTECTED MODE programs with this unit, as it works with Segments:Offsets in REAL MODE, and NOT with Selectors and Offsets! You will get really screwed up sound output if you do try to use the unit with BP 7.0, so beware! ***************************************************************************** * Implementing REAL TIME FX * ***************************************************************************** For those of you interested in doing REAL TIME FX, a few guidelines follow: First, you have to know how the data is stored, FX engines have to work with uncompressed samples in order to work at all (unless you have a DSP chip, and know how to program it). Eight bit samples are ideal for this purpose. The data is stored as a series of unsigned 8-bit quantities in the RPD file. This means that we can have a resolution of 1 part in 256 (0 - 255). Consequently, all transformations have to be done in this range, or else we will get VERY distorted results. The way my SBDSP unit works is as follows: I) We have a buffer of up to 64K in memory. a) This Buffer is "split" into 2 chunks, Buffer1 and Buffer2. b) When Buffer1 is playing, Buffer2 is being loaded from disk, and vice versa. II) After a certain buffer is loaded from disk, THAT is the ideal time to do our operations on it (this is what makes it REAL TIME). Since we are using DMA xfers (that don't need CPU intervention within a buffer) this technique works well. For a VERY simple FX, try to understand my VOICE AMPLIFICATION Function, this is a very simple function to get started on. The above technique works well if you are using a reasonable buffer size, and the operations that you perform are not TOO complicated (unless of course, you are using a Pentium(TM) Processor ;-) ). ***************************************************************************** * Structure of the RPD file format: * ***************************************************************************** The RPD file format was created by myself as an alternative sound format for games (mine in particular). I got tired of reading in complicated VOC files, and WAV files (WAV files are easier, but are still too much for a game). So, I created a new file format for myself, as well as tools to convert from the VOC and WAV file formats to RPD. I had no idea how popular that my Sound Library would become (about 100 people wanted/got my Library in the space of a couple of months), so I have started bundling the VOC2RPD and WAV2RPD programs with SBDSP. Version 2.0ß will also have a converter that converts a RPD file to the VOC and/or WAV file formats. But, people need to know the basic structure of the RPD file format, so here it is: RPD file format, version 1.01 ============================= Byte Offset Description ----------- ----------- 0-2 Signature -> "RPD" 3-4 Version (1 Word), Lo Byte = Major Version, Hi Byte = Minor Version 5 DAC Type (Bits/Sample), see table below 6 Mono = 0, Stereo = 1, Surround = 2 7 # of Digital Channels in the Sample 8 Method of Laying down channels 9-12 Size of sample (LongInt) 13 Signed/Unsigned 16-bit sample (v1.01) 0 indicates a Unsigned sample (16-bit) 1 indicates a Signed sample (16-bit) 14-44 Reserved for future expansion 45-EOF Sample Data DAC Type Table: =============== DACType Description ------- ----------- 0B6h Sixteen Bit Sound 014h Eight Bit Sound 016h Two Bit ADPCM compression 017h Two Bit ADPCM w/Reference byte 074h Four Bit ADPCM compression 075h Four Bit ADPCM w/Reference byte 076h 2.6 Bit ADPCM compression 077h 2.6 Bit ADPCM w/Reference byte Channel Method -------------- 0 - Indicates that Channel 1 Byte comes first, then Channel 2 Byte, etc... 1 - Indicates that Channel 1 data comes for Sample Size bytes, then comes Channel 2 data for Sample Size Bytes, etc... This is an example of the same file with different channel methods: Channel Method 0: # of Channels = 3 Size of Sample = 1260 Byte: 0 1 2 3 4 5 6 7 ... 1260 +------+------+------+------+------+------+------+------+ | Ch 1 | Ch 2 | Ch 3 | Ch 1 | Ch 2 | Ch 3 | Ch 1 | Ch 2 ... +------+------+------+------+------+------+------+------+ Channel Method 1: # of Channels = 3 Size of Sample = 1260 / 3 = 420 Byte:0 419 838 1260 +-----------------+-----------------+-----------------+ | Ch 1 | Ch 2 | Ch 3 | +-----------------+-----------------+-----------------+ ***************************************************************************** * Notes on the future... * ***************************************************************************** This unit (2.0ß) is just a pre-release (ßeta), and a lot of the features that will/should be present in 2.0 are missing. Most notable of these is 16-bit sound. I am currently having some problems on 16-bit playback, so I do not have any release dates planned. Release 2.0 will also convert a 16-bit sound to 8-bit in Real Time (for users without a SB 16), so that you don't have to worry about what type of sound to use (but it won't sound good at all!) However, this unit does give you pretty much all you need in order to make a game/music player, and exploits all the capabilities of cards up to the Pro. This package as it stands is pretty general, and should cover all of your needs for digital sound playback. I am debating whether to implement EMS memory for storage of samples (instead of disk xfers, when there is enough room), as Turbo Pascal 7.0 makes this pretty painless with the TEMSStream object, but I'm not sure if TP 6.0 has this, and if it doesn't, then I will have widened the gap between the users of TP 6.0 and those who use TP 7.0 :-(. But, I have to remind myself that I'm not getting paid to do this, and this is my final semester. That by the way is the reason that I can't make the REAL version of this package (2.0) available before June! I'm taking 7 subjects + working 20hrs a week, so I'm exhausted mentally and physically by the time that I get home. Though I have to remind myself that people like Ethan Brodsky and myself are the only ones that are making Sound Libraries for *FREE*, and people depend on us for *good* quality code (even more important now that we have lost Mike Tedder to the GUS). - Romesh Prakashpalan (hbcsc294@huey.csun.edu) 02/11/95 Or, write to me at the following (snail mail) address: 17304 Westbury Dr. Granada Hills, CA 91344 U.S.A Software (C) 1995 by Romesh Prakashpalan, All rights reserved. IBM is a registered trademark of International Business Machines Corp. Pentium is a registered trademark of Intel Corp. Sound Blaster is a registered trademark of Creative Labs Corp.