Release

MIDI API 1.15.5

SP4CEBAR 2023-09-11 16:23 (Edited)

click here to read what's new

MIDI tools has been cleaned up:

• the code has been refactored
• the variable names are clearer
• the printing functions are separated so that they can be turned off
• Variables that are used in many functions are made global and are given the "G_" prefix

API reference:

• CALL MIDI_START_CLI
  play midi from MIDI tools' command line interface
• CALL MIDI_PREPARE_FILE( "L", 4 )
  load and prepare file local ("L") 4, other locations are external ("E"), both ("B"), and string ("E"), I'm not sure if "B" is supported. This function has to be called before calling any of the following functions, to load a string, you can paste a string in the GET_FILE_STR subprogram.
• CALL ARRAY_PREPARE_FILE( "L", 10 ) works like the MIDI_PREPARE_FILE subprogram, but loads interlaced array files that contain scraped MIDI, and only supports "L" (local) and "E" (external).
• CALL MIDI_READ
  print the midi commands in the prepared file (with "touch to continue" after each command)
• CALL MIDI_PLAY_SINGLE
  plays the prepared MIDI file one track at a time
• CALL MIDI_PLAY
  plays the all tracks of the prepared midi file at the same time
• CALL MIDI_QUANTIZE (15)
  quantizes and encodes the prepared MIDI file to the NX music file format and saves it to file 15
• CALL MIDI_SCRAPE
  is defined right after this call, it defines three arrays: TIMES, TONES, and TRACKS, and it fills them with MIDI data scraped from your file (in time-chronological order). These arrays are then played. Feel free to modify (a copy of) the PLAY_SCRAPED_MIDI function or the SCRAPE_MIDI function to figure out how it works, or to encode the MIDI file to a format of your liking. This subprogram has its own graphics, when using it, please turn off all other graphics from SUB MIDI_VISUALIZERS and SUB GRAPHICS.

Right below it, you'll find some subprograms that are called from various places within the program, within these subprograms, you can call other subprograms:

• SUB MIDI_VISUALIZERS
  This is called after each MIDI command.
  • CALL PRINT_MIDI_TOOLS
    These are the MIDI details from MIDI tools.
  • CALL MIDI_SCHEDULER_INFO
    This prints the times (NX TIMER values) and addresses for the first 16 tracks during the playback of your midi file
• CALL ARRAY_VISUALIZERS( SCRAPE_INDEX, MIDI_LENGTH, DELTA_TIME )
  This is called instead of the MIDI_VISUALIZERS every loop when playing a scraped MIDI array
  • CALL PRINT_PARAMETERS( SCRAPE_INDEX, MIDI_LENGTH, DELTA_TIME )
• SUB VBL_GRAPHICS
  This is called every frame (unless the CPU is at 100%).
  • CALL PEAK_DISPLAY_DEMO
    The demo for this API, you should disable it if you want to use any different MIDI display like the original MIDI details.

Similarity:

This program will be updated together with MIDI tools because they are essentially the same program, the only difference being that MIDI tools will have user input enabled and it has a user manual, and this program won't have user input enabled and it has an API reference.

McPepic 2023-09-13 00:48

Been messing around with it and it works really well!

Could you possibly make the program first check to make sure that there's enough room to load the data to prevent errors when copying the data?

SP4CEBAR 2023-09-13 06:51

I'm glad you like it
You mean enough room in RAM, it should do that already: The RAM_PEEK function maintains the cache in RAM, whenever it's called with an address that isn't cached, it will copy bytes from the file to RAM, it shouldn't be able to copy more than $4000 bytes at once

McPepic 2023-09-13 14:12

@SP4CEBAR
Okay. It would still be worth it to check, because I was getting an error at the line where the program uses the copy command when the file was too big. I could send you an example of the program doing this if it would help.

SP4CEBAR 2023-09-13 17:49

I can't seem to reproduce the error with my collection of NX data midi files, so it's probably something specific to that midi file. So it would likely also occur on older versions of this program.

McPepic 2023-09-13 18:04

@SP4CEBAR
Does the music template do anything, or is it safe to delete?

SP4CEBAR 2023-09-13 18:05

It's used for writing NX files after converting midi files to NX files, it holds some default NX instruments

McPepic 2023-09-13 18:09

This is the error that I'm getting when the file is too big:
ILLEGAL MEMORY ACCESS IN LINE 1371:
COPY ROM(F),S TO $A000

SP4CEBAR 2023-09-13 19:04 (Edited)

Since $A000 is fixed, and both ROM(-1) and ROM(16) would say "invalid parameter" instead of "illegal memory access", and I think it's impossible for ROM(F) go beyond $7FFF (and even if it could, it would still be reading legal data), I can assume that the value of S must be too big for some reason
$5001 Is the first illegal size

SP4CEBAR 2023-09-13 19:15

In the program, S is defined as SIZE(F), so SIZE(F) returned a value greater than $5000, which is indeed possible. It seems like this bit of code is different and likely older than the aforementioned function, so I should merge them

SP4CEBAR 2023-09-13 19:28 (Edited)

you should replace S with MIN(S,$4000)

SP4CEBAR 2023-09-13 19:33 (Edited)

Update

• replaced S with MIN(S,$4000) in COPY ROM(F),S TO $A000

SP4CEBAR 2023-09-29 14:03

@McPepic has the issue been resolved?

SP4CEBAR 2023-10-04 16:19 (Edited)

For everyone wanting to tinker with MIDI files, I've just added the MIDI_SCRAPE subprogram

It defines three arrays: TIMES, TONES, and TRACKS, and it fills them with MIDI data scraped from your file (in time-chronological order). These arrays are then played. Feel free to modify (a copy of) the PLAY_SCRAPED_MIDI subprogram or the SCRAPE_MIDI subprogram, or the MIDI_PLAY subprogram to figure out how they work, or to encode the MIDI file to a format of your liking. Currently, the scraper takes as long as it would normally take to play the file due to the interpreter still being dependent on NX's TIMER variable, but that'll change in a future version.

McPepic 2023-10-06 00:36

@SP4CEBAR
I was stress testing the program a bit and here's what I found after completely filling the ROM:

The audio sounds really good, maybe a little fast
After a while, the program got stuck on a really high note for a bit
It also restarted the audio and layered it on top of what was already playing
The meters that show the activity of the sound channels completely disappeared

Cutting down the audio (I trimmed it to line 250) got rid of the issues.
Program's looking really good BTW. Keep up the good work!

SP4CEBAR 2023-10-06 06:39

Thank you!
I know that the playback speed may not always be correct, to fix that I'll need to research that part in the MIDI protocol a bit more
I also know that some files cause some notes to get stuck, I don't know how to fix that though
I'm not sure what happened when the meters disappeared, I think the playback ended, but then you should see a "playback ended" message
Cutting data off the midi file probably removed the problematic note in your case

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