Sound Group Example

[cdigit]

I want to use sound groups in my code to help manage lists of sounds. I imagine instead of looping through all sounds to manipulate them (start, stop, etc.), I could assign sounds on the same "track" to a group and apply changes to them in a cleaner way.

After poking around, I see that there are no examples related to using sound groups, I guess because the API is the same as ma_sound. Despite that, I'm not clear on how to make sound groups work. I have a simple example below. In my mind a possible scenario is this:

• init sound group with a pointer to engine and a pointer to soundGroup
• Add a sound to the group: init a sound with pointer to soundGroup
• start the soundGroup to play all sounds in the group ??

Code:
In the code below If have result = ma_sound_group_start(&soundGroup);, which does not produce any sound. I'm wondering what I'm missing?

#define MINIAUDIO_IMPLEMENTATION
// #define MA_DEBUG_OUTPUT
#include "../../../miniaudio/miniaudio.h"
#include <stdio.h>

void play(char *path)
{
    ma_result result;
    ma_engine engine;
    ma_sound_group_config soundGroupConfig;  // is this needed?
    ma_sound_group soundGroup;

    result = ma_engine_init(NULL, &engine);
    if (result != MA_SUCCESS)
    {
        printf("Failed to initialize audio engine.");
        exit(1);
    }
    // ma_engine* pEngine, ma_uint32 flags, ma_sound_group* pParentGroup, ma_sound_group* pGroup)
    result =  ma_sound_group_init(&engine, 0, NULL, &soundGroup);
    if (result != MA_SUCCESS)
    {
        printf("Failed to init sound group.");
        exit(1);
    }
    
    ma_sound sound;
    
    
    result = ma_sound_init_from_file(&engine, path, MA_SOUND_FLAG_DECODE | MA_SOUND_FLAG_STREAM | MA_SOUND_FLAG_NO_SPATIALIZATION, &soundGroup, NULL, &sound);
    if (result != MA_SUCCESS)
    {
        printf("Failed to load sound file.");
        exit(1);
    }
    
    
    
    //ma_node_attach_output_bus(&soundGroup, 0, ma_engine_get_endpoint(&engine), 0);

    
    
    result = ma_sound_group_start(&soundGroup);
    if (result != MA_SUCCESS)
    {
        printf("Failed to start sound group.");
        exit(1);
    }
    
    
    
    //ma_sound_start(&sound);
   
    while (ma_sound_at_end(&sound) == 0)
    {
    }
    ma_sound_stop(&sound);
    ma_engine_uninit(&engine);
    return;
}

int main()
{
    printf("starting simple sound group\n");
    char * filePath = "/Users/admin/Downloads/testing123.wav";
    play(filePath);
    return 0;
}

[cdigit]

Update

I've added the code below right after initializing the sound and I can hear changes in the volume and pitch when I do :
ma_sound_start(&sound);

    ma_sound_group_set_pitch(&soundGroup,  2);
    ma_sound_group_set_volume(&soundGroup, 1);

It seems that ma_sound_group_start(&soundGroup); does not really do anything. It does not start the sound(s) in the group, only ma_sound_start does that. If I comment ma_sound_group_start out, I can still hear the changes when using ma_sound_start. So maybe I'm assuming the wrong thing. Is it possible to start and stop all sounds in the group with ma_sound_group_start and ma_sound_group_stop ? Or is there something missing here.

Update 2

It seems that I have to start the the sound with ma_sound_start, before I can start it with ma_sound_group_start, then I can stop it with ma_sound_group_stop and start with ma_sound_group_start. Is that expected behavior? Is it not possible to simply use ma_sound_group_start without having to start the sound outside of the group?

Updated code:

#define MINIAUDIO_IMPLEMENTATION
//#define MA_DEBUG_OUTPUT
#include "../../../miniaudio/miniaudio.h"
#include <stdio.h>

void play(char *path)
{
    ma_result result;
    ma_engine engine;
    ma_sound_group_config soundGroupConfig;  // is this needed?
    ma_sound_group soundGroup;

    result = ma_engine_init(NULL, &engine);
    if (result != MA_SUCCESS)
    {
        printf("Failed to initialize audio engine.");
        exit(1);
    }
    // ma_engine* pEngine, ma_uint32 flags, ma_sound_group* pParentGroup, ma_sound_group* pGroup)
    result =  ma_sound_group_init(&engine, 0, NULL, &soundGroup);
    if (result != MA_SUCCESS)
    {
        printf("Failed to init sound group.");
        exit(1);
    }
    
    ma_sound sound;
    
    
    result = ma_sound_init_from_file(&engine, path, MA_SOUND_FLAG_DECODE | MA_SOUND_FLAG_STREAM | MA_SOUND_FLAG_NO_SPATIALIZATION, &soundGroup, NULL, &sound);
    if (result != MA_SUCCESS)
    {
        printf("Failed to load sound file.");
        exit(1);
    }
    
    
    
    //ma_node_attach_output_bus(&soundGroup, 0, ma_engine_get_endpoint(&engine), 0);

    
    ma_sound_group_set_pitch(&soundGroup,  2);
    ma_sound_group_set_volume(&soundGroup, 1);
    ma_sound_start(&sound);

    
    result = ma_sound_group_stop(&soundGroup);
    
   ma_sound_group_start(&soundGroup);
   
    while (ma_sound_at_end(&sound) == 0)
    {
    }
    ma_sound_stop(&sound);
    ma_engine_uninit(&engine);
    return;
}

int main()
{
    printf("starting simple sound group\n\n");
    char * filePath = "/Users/admin/Downloads/testing123.wav";
    play(filePath);
    return 0;
}

[mackron]

I want to use sound groups in my code to help manage lists of sounds.

Sound groups will not help you with that. There is no way to easily retrieve the list of sounds attached to a group (there's a lot of non-trivial details relating to lock-free stuff). It's expected that you will have your own list of sounds that you manage yourself. The idea of a sound group is to apply some audio processing (such as an effect or volume control) to a group of sounds after they've been mixed together. It's not for managing the state of your ma_sound objects.

It seems that I have to start the the sound with ma_sound_start, before I can start it with ma_sound_group_start, then I can stop it with ma_sound_group_stop and start with ma_sound_group_start. Is that expected behavior? Is it not possible to simply use ma_sound_group_start without having to start the sound outside of the group?

Yes, this is expected behaviour. Like I mentioned above, sounds groups are not for managing the state of individual ma_sound objects. What if you have a sound attached to a group that you want to leave in a stopped state after the group has been started? Also, starting and stopping sounds in a group needs to be atomic, and having the group internally iterate over each attached sound and start/stop it would break that atomicity.

[cdigit]

Got it. Thanks for the clarification.