TAAE2 - Stop at time/Loop-duration

triplej

Hello! Just started playing around with the TAAE2 and really liking it so far! I have an idea that I want to try out but can't figure out what the best way to do it is. What I want to do is basically to queue loops and let them play together synchronized with other loops. The thing is that I want to be able to set the regionDuration of an AEAudioFilePlayerModule to less than the entire loop but I want it to loop at it's original length, so instead of the AEAudioFilePlayerModule restarting at the regionDuration which for example could be 2 I would like to use a property that is called "loopDuration" or something that would determine how long the loop should be.

Another solution that I thought about would be to implement some sort of "stopAtTimeAndRestart:" and then in that function stop the module and reschedule it with the "playAtTime".

Does any of these approaches seem reasonable?

Best,
J

Michael

Hey @triplej,

Great!

Hmm... I think the most frictionless way to solve this is to use AEAudioFilePlayerModule's completionBlock. For any players with a regionDuration less than the target loop length, set loop to NO, then set completionBlock to a block that will reschedule the player at the next interval.

triplej

Thanks!

I tried this out but I couldn't get the file player to call the block a second time. Probably doing something wrong.. Right now it loops but only the first time.

Edit: Got it working now! It does however come with some pops and clicks every time it loops.

/J

Michael

Pops and clicks? That doesn't sound right...can you reproduce that within the TAAE sample app? Are you using the latest version from Github?

triplej

Wasn't using the latest version but updated now, still the same thing. Seems like it still is clicks at (almost) every restart/end of the loop. Depending on what loop it is. I thought it might have hade something to do with the microfadeFrames and increased them a lot without noticing any difference. Here's what I'm doing, based on the code from the sample app.

- (void)playPiano {

    NSURL * url = [[NSBundle mainBundle] URLForResource:@"piano" withExtension:@"m4a"];
    if ( [[NSFileManager defaultManager] fileExistsAtPath:url.path] ) {

        // Start player
        AEAudioFilePlayerModule * player =
        [[AEAudioFilePlayerModule alloc] initWithRenderer:self.theSubrenderer URL:url error:NULL];
        player.regionDuration = player.duration/8;
        player.regionStartTime = player.duration/2;
        player.microfadeFrames = 32;
        player.loop = NO;
        if ( !player ) return;

        // Make player available to audio renderer
        self.playerValue.objectValue = player;
        __weak AEAudioController * weakSelf = self;
        player.completionBlock = ^{

            //Restart when playback ends
            [weakSelf playPiano];

        };

        // Go
        [player playAtTime:[self nextSyncTimeForPlayer:player]+AEHostTicksFromSeconds(2)];
    }
}

Michael

Ah! Right you are, I found a bug. Try the latest version, now.

triplej

Genious! Thanks a lot!

I realized that a lot of the clicks were also due to this: Warning: render took 0.011809s, 406.8541% of buffer duration.

Do you have any idea on what I might be doing wrong to cause this? This is the render-function:

AEVarispeedModule * varispeed = [[AEVarispeedModule alloc] initWithRenderer:renderer subrenderer:subrenderer];
    subrenderer.block = ^(const AERenderContext * _Nonnull context) {
        // Run all the players, though the aggregator
        AEModuleProcess(aggregator, context);

        // See if we have an active player
        __unsafe_unretained AEAudioFilePlayerModule * player
        = (__bridge AEAudioFilePlayerModule *)AEManagedValueGetValue(playerValue);

        // Play recorded file, if playing
        if ( player ) {
            // Play
            AEModuleProcess(player, context);

            // Put on output
            //AERenderContextOutput(context, 1);
        }

        AERenderContextOutput(context, 0);
    };

    self.varispeed = varispeed;
    // Setup top-level renderer. This is all performed on the audio thread, so the usual
    // rules apply: No holding locks, no memory allocation, no Objective-C/Swift code.
    renderer.block = ^(const AERenderContext * _Nonnull context) {

        // Run varispeed unit, which will run its own render loop, above
        AEModuleProcess(varispeed, context);

        // Put the resulting buffer on the output
        AERenderContextOutput(context, 1);
    };

Michael

Are you still seeing that behaviour? It was occurring because of the same bug, but that should be fixed now.

Edit: Actually, now I remember, it wasn't that bug at all, but a problem with your code; this:

    [player playAtTime:[self nextSyncTimeForPlayer:player]+AEHostTicksFromSeconds(2)];

The sample app's nextSyncTimeForPlayer function can return zero, so you're specifying an invalid host time by then adding 2 seconds to that (absolute) timestamp. You should see warnings in the console about that.

triplej

@Michael thanks for your help!

I've been trying to figure out where the problem lies. I no longer get the warning (removed the seconds) and the clipping has become a lot less apparent with the microfades. But it's still there quite often and when there should be no clipping (like at the start of a non clipping audio file).

I could go with really long fades but that doesn't feel like the main problem. Do you have any idea where I should start troubleshooting?

Now I call the player with: [player playAtTime:[self timeForSyncTime:self.firstSyncTime]

and then that function looks like this:

- (AEHostTicks)timeForSyncTime:(AESeconds)syncTimeInEigths {
    AEHostTicks now = AECurrentTimeInHostTicks();

    //Identify time-keeper
    AEAudioFilePlayerModule * timekeeper = self.timekeeperPlayer;

    if ( timekeeper ) {
        // Determine sync interval
        AESeconds oneBarInterval = (self.timekeeperPlayer.duration/4)*_numberOfBars;

        // Work out how far into this interal the timekeeper is
        AESeconds timeIntoBarInterval = fmod(AEAudioFilePlayerModuleGetPlayhead(timekeeper, now), oneBarInterval);

        AESeconds nextSyncTime = (((self.timekeeperPlayer.duration/4)/8)*syncTimeInEigths) - timeIntoBarInterval;

        if (nextSyncTime<0) {
            nextSyncTime+=oneBarInterval;
        }

        // Calculate time to next interval
        AEHostTicks nextIntervalTime
        = now + AEHostTicksFromSeconds(nextSyncTime) / self.varispeed.playbackRate;

        return nextIntervalTime;
    }

    return 0;
}

triplej

Hm. I was mistaken, the warnings are still there but only appear when the app is run on a device.

"Warning: render took 0.003463s, 119.3284% of buffer duration."

I'm 100% sure that I'm doing something wrong here cause the players that just loop using the "player.loop" works as a charm.

Michael

Hmmm.. I think I might need to see a sample app to debug further. Would you perhaps bundle your changes that're causing problems into the TAAE sample app and send me a copy? This is still my problem, as even if you're doing something wrong, TAAE should be seeing that and warning you