10.使用C语言创建一个MIDI格式的文件

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使用C语言在Windows中创建一个MIDI格式的文件

1.使用C语言在Windows中创建一个MIDI格式的文件(未能成功)

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdint.h>

typedef struct {
    char chunk_type[5]; // Chunk type
    uint32_t header_size; // Header size
    uint16_t format_type; // Format type
    uint16_t track_count; // Number of tracks
    uint16_t division; // Ticks per quarter note
} MidiHeader;

typedef struct {
    char chunk_type[5]; // Chunk type
    uint32_t track_size; // Track size
    uint8_t* events; // Pointer to MIDI events
    size_t event_count; // Number of events
} MidiTrack;

void write_midi_header(FILE* file) {
    MidiHeader header = {
        .chunk_type = "MThd",
        .header_size = 6,
        .format_type = 0, // Format type 0
        .track_count = 1, // One track
        .division = 480 // Ticks per quarter note
    };

    // Write MIDI file header
    fwrite(header.chunk_type, 1, 4, file); // Chunk type
    fwrite(&header.header_size, 4, 1, file); // Header size
    fwrite(&header.format_type, 2, 1, file); // Format type
    fwrite(&header.track_count, 2, 1, file); // Track count
    fwrite(&header.division, 2, 1, file); // Division
}

void write_midi_track(FILE* file, MidiTrack* track) {
    // Write MIDI track header
    fwrite(track->chunk_type, 1, 4, file); // Chunk type
    fwrite(&track->track_size, 4, 1, file); // Placeholder for track size

    // Write note events
    for (size_t i = 0; i < track->event_count; i++) {
        fputc(track->events[i], file); // Write each event
    }

    // Update track size
    long current_pos = ftell(file);
    track->track_size = current_pos - 8; // 8 bytes for "MTrk" and size
    fseek(file, -4, SEEK_CUR); // Move to track size position
    fwrite(&track->track_size, 4, 1, file); // Write track size
    fseek(file, current_pos, SEEK_SET); // Move back to the end
}

int main() {
    FILE* file = fopen("output.mid", "wb");
    if (!file) {
        perror("Unable to create MIDI file");
        return 1;
    }

    write_midi_header(file);

    // Create a MIDI track
    MidiTrack track = {
        .chunk_type = "MTrk",
        .track_size = 0,
        .event_count = 0
    };

    // Allocate memory for events (for "do re mi fa so la ti do")
    uint8_t events[256]; // Buffer for events
    size_t event_index = 0;

    // Note values for "do re mi fa so la ti do"
    uint8_t notes[] = { 60, 62, 64, 65, 67, 69, 71, 72 }; // MIDI note numbers
    uint8_t note_count = sizeof(notes) / sizeof(notes[0]);

    // Write note events
    for (int i = 0; i < note_count; i++) {
        // Note On event
        events[event_index++] = 0x00; // Delta time
        events[event_index++] = 0x90; // Note On, channel 1
        events[event_index++] = notes[i]; // Note number
        events[event_index++] = 0x7F; // Velocity

        // Note Off event after a delay
        events[event_index++] = 0x80; // Delta time (128 ticks)
        events[event_index++] = 0x80; // Note Off, channel 1
        events[event_index++] = notes[i]; // Note number
        events[event_index++] = 0x00; // Velocity
    }

    // Set tempo (120 BPM)
    events[event_index++] = 0x00; // Delta time
    events[event_index++] = 0xFF; // Meta event
    events[event_index++] = 0x51; // Set tempo
    events[event_index++] = 0x03; // Length of the event
    events[event_index++] = 0x07; // Tempo in microseconds per quarter note (120 BPM)
    events[event_index++] = 0xA1;
    events[event_index++] = 0x20;

    // End of track event
    events[event_index++] = 0x00; // Delta time
    events[event_index++] = 0xFF; // Meta event
    events[event_index++] = 0x2F; // End of track
    events[event_index++] = 0x00; // Length of the event

    // Set the event count and allocate the events
    track.event_count = event_index;
    track.events = events;

    // Write the MIDI track
    write_midi_track(file, &track);

    fclose(file);
    printf("MIDI file created: output.mid\n");
    return 0;
}