Distorted sound in jo_demo when launched from multiplayer

[fafling]

On the console with the Satiator and in Kronos v2.1.5, when jo_demo is launched from the multiplayer screen, all sounds are distorted.

In Kronos, maintain A when launching the iso or when resetting until multiplayer screen displays, then select "Start application".

On the console with the Satiator, launch the demo once, then maintain A when pressing reset until multiplayer screen displays and select "Start application".

In both case, the problem doesn't occur when resetting without going through multiplayer screen.

[ponut64]

OK, I got to reproduce it in Bizhawk. Real hardware (with Satiator) failed to reproduce the bug in multiple tested demos (jo_demo, my game, a testing demo, metal orange, and wolf3d). The bug from Bizhawk (which could be a different emulator-unrelated bug) sounded like the pitchword was improperly set (which would be a bug in the linked library). The issue also did not occur after the first soft reset. The game crashed after the first soft-reset and then soft-reset itself again after pressing START (without ABC being held). Then the issue occurred.

I doubt its a deeper issue than an emulator one, but you did say you reproduced it on hardware. I'm curious to see it recorded from an NTSC system.

[ponut64]

As per discussion on Discord, the issue has been narrowed down slightly to occurring only on 320-wide resolutions (and by extension, 640-wide). 352-wide resolutions (or 704) are unaffected.

If anyone out there does care about this issue, there are two solutions: A - Use a 352-wide resolution. It increases the system clock speed, you might as well do it. B - If for some reason you do not want to use a 352-wide (or 704) resolution, follow the procedures to initialize the system at a 352-wide resolution then switch back to whatever resolution you want.

[fafling]

In load_driver_binary in pcm_sys.c, if I clear the SCSP slot register area, the sounds are no longer distorted after a reset via multiplayer.

void    load_driver_binary(Sint8 * filename, void * buffer, int master_adx_frequency)
{

    GfsHn s_gfs;
    Sint32 file_size;

    Sint32 local_name = GFS_NameToId(filename);

    //Open GFS
    s_gfs = GFS_Open((Sint32)local_name);
    //Get file information (mostly, the file size)
    GFS_GetFileInfo(s_gfs, NULL, NULL, &file_size, NULL);

    GFS_Close(s_gfs);

    GFS_Load(local_name, 0, (Uint32 *)buffer, file_size);

    //The immediacy of these commands is important.
    //As per SEGA technical bulletin 51, the Sound CPU is not to be turned off for more than 0.5 seconds.
    // Turn off Sound CPU
    smpc_issue_command(SMPC_CMD_SNDOFF);
    smpc_wait_till_ready();
    //Set max master volume + 4mbit memory 
    *master_volume = 0x20F; 
    // Clear SCSP Slot Control Register
    for (int i = 0; i < 508; i+=2){
        *(volatile unsigned short *)(SNDRAM + 0x100000 + i) = 0x0000;
    }
    //Copy the driver binary (code) over to sound RAM. The binary includes the vector table information.
    slDMACopy(buffer, (void*)SNDRAM, file_size);
    slDMAWait();
    //Set the ADX coefficients for the driver to use, if one was selected.
    if(master_adx_frequency == ADX_MASTER_768)
    {
        m68k_com->drv_adx_coef_1 = ADX_768_COEF_1;
        m68k_com->drv_adx_coef_2 = ADX_768_COEF_2;
    } else if(master_adx_frequency == ADX_MASTER_1152){
        m68k_com->drv_adx_coef_1 = ADX_1152_COEF_1;
        m68k_com->drv_adx_coef_2 = ADX_1152_COEF_2;
    } else if(master_adx_frequency == ADX_MASTER_1536){
        m68k_com->drv_adx_coef_1 = ADX_1536_COEF_1;
        m68k_com->drv_adx_coef_2 = ADX_1536_COEF_2;
    } else if(master_adx_frequency == ADX_MASTER_2304){
        m68k_com->drv_adx_coef_1 = ADX_2304_COEF_1;
        m68k_com->drv_adx_coef_2 = ADX_2304_COEF_2;
    } else {
        m68k_com->drv_adx_coef_1 = 1;
        m68k_com->drv_adx_coef_2 = 1;
    }
    // Turn on Sound CPU again
    smpc_wait_till_ready();
    smpc_issue_command(SMPC_CMD_SNDON);
    //
}

[ponut64]

vbt-senpai said he tested that.... Anyway, will push into the repo.

[fafling]

I confirm that the problem is solved in the demo with the updated driver 👍