Syncpoint info is missing and cannot stop the current channel's playback

Unity
2

Hi,

Thank you for sharing the information and code snippets.

It looks like you need to use Sound::getSyncPoint to fetch FMOD_SYNCPOINT and then query it with Sound::getSyncPointInfo.

Here is a modified version of your callback code that may resolve the issue:

    [AOT.MonoPInvokeCallback(typeof(CHANNELCONTROL_CALLBACK))]
    static RESULT ChannelStopCallback(IntPtr channelcontrol, CHANNELCONTROL_TYPE controltype, CHANNELCONTROL_CALLBACK_TYPE callbacktype, IntPtr commanddata1, IntPtr commanddata2)
    {
        if (callbacktype == FMOD.CHANNELCONTROL_CALLBACK_TYPE.SYNCPOINT)
        {
            // The "syncPointOffset" is always 0 and the other debug info is empty
            /*sound.getSyncPointInfo(commanddata1, out var syncPointName, "StopPoint".Length, out var syncPointIndex, TIMEUNIT.MS);*/
            /*sound.getSyncPointInfo(commanddata1, out var syncPointOffset, TIMEUNIT.MS);*/
            /*Debug.LogWarning($"syncPointOffset: {syncPointOffset}, syncPointIndex: {syncPointIndex}, raw commanddata1: {commanddata1}");*/

            // "[FMOD] assert : assertion: 'mUserCallbackThreadId == 0' failed" error occurs
            /*channel.stop();*/

            var newChannel = new FMOD.Channel(channelcontrol);
            newChannel.setPaused(true); // Workaround. This is the only working way.
            newChannel.getCurrentSound(out FMOD.Sound sound);

            sound.getSyncPoint((int)commanddata1, out IntPtr syncpoint);
            sound.getSyncPointInfo(syncpoint, out var syncPointName, "StopPoint".Length, out var syncPointOffset, TIMEUNIT.MS);
            UnityEngine.Debug.LogWarning($"syncPointOffset: {syncPointOffset}, syncPointName: {syncPointName}");
        }
        return RESULT.OK;
    }

Please note that as the callback method must be static, you’ll need to find alternative methods to manage data typically handled by instance variables.

I have managed to reproduce the error message you mentioned.

After discussing with the Dev team, the error you’re encountering likely occurs because attempting to stop a channel directly within a callback can lead to FMOD issuing another callback for the stop event, which is not permissible from within another callback. This is a safety measure to prevent potential recursive callbacks or other threading issues.

Your workaround using ChannelControl::setPaused is actually a legitimate and recommended approach under these circumstances.

Hope this helps, let me know if you have questions.

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