/*

File: QTRDocument.m

Abstract: Sample code for new QTKit capture classes.

Version: 1.0

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*/

#import "QTRDocument.h"

#import <QTKit/QTKit.h>

@interface QTRDocument (QTRDocument_Private)

- (void)refreshDevices;

@end

@implementation QTRDocument

+ (NSSet *)keyPathsForValuesAffectingHasRecordingDevice

{

    return [NSSet setWithObjects:@"selectedVideoDevice", @"selectedAudioDevice", nil];

}

+ (NSSet *)keyPathsForValuesAffectingControllableDevice

{

    return [NSSet setWithObjects:@"selectedVideoDevice", nil];

}

+ (NSSet *)keyPathsForValuesAffectingSelectedVideoDeviceProvidesAudio

{

    return [NSSet setWithObjects:@"selectedVideoDevice", nil];

}

+ (NSSet *)keyPathsForValuesAffectingMediaFormatSummary

{

    return [NSSet setWithObjects:@"selectedVideoDevice", @"selectedAudioDevice", nil];

}

- (void)windowWillClose:(NSNotification *)notification

{

    // Invalidate the level meter timer here to avoid a retain cycle

    if (audioLevelTimer)

        [audioLevelTimer invalidate];

    // Close open devices

    [self setSelectedVideoDevice:nil];

    [self setSelectedAudioDevice:nil];

    // Stop the session

    [session stopRunning];

}

- (void)dealloc

{

    [[NSNotificationCenter defaultCenter] removeObserver:self];

    [session release];

    [videoDeviceInput release];

    [audioDeviceInput release];

    [movieFileOutput release];

    [audioPreviewOutput release];

    [videoDevices release];

    [audioDevices release];

    [videoPreviewFilterDescriptions release];

    [videoPreviewFilterDescription release];

    [super dealloc];

}

- (NSString *)windowNibName

{

    return @"QTRDocument";

}

- (void)windowControllerDidLoadNib:(NSWindowController *) aController

{

    [super windowControllerDidLoadNib:aController];

    // Create a capture session

    session = [[QTCaptureSession alloc] init];

    // Attach preview to session

    [captureView setCaptureSession:session];

    [captureView setDelegate:self]; 

    // Attach outputs to session

    movieFileOutput = [[QTCaptureMovieFileOutput alloc] init];

    [movieFileOutput setDelegate:self];

    [session addOutput:movieFileOutput error:nil];

    audioPreviewOutput = [[QTCaptureAudioPreviewOutput alloc] init];

    [audioPreviewOutput setVolume:0.0];

    [session addOutput:audioPreviewOutput error:nil];   

    // Select devices if any exist

    NSArray *myVideoDevices = [self videoDevices];

    if ([myVideoDevices count] > 0) {

        [self setSelectedVideoDevice:[myVideoDevices objectAtIndex:0]];

    }

    NSArray *myAudioDevices = [self audioDevices];

    if ([myAudioDevices count] > 0) {

        [self setSelectedAudioDevice:[myAudioDevices objectAtIndex:0]];

    }   

    // Start the session

    [session startRunning];     

    // Register for notifications

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(devicesDidChange:) name:QTCaptureDeviceWasConnectedNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(devicesDidChange:) name:QTCaptureDeviceWasDisconnectedNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(connectionFormatWillChange:) name:QTCaptureConnectionFormatDescriptionWillChangeNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(connectionFormatDidChange:) name:QTCaptureConnectionFormatDescriptionDidChangeNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceAttributeWillChange:) name:QTCaptureDeviceAttributeWillChangeNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceAttributeDidChange:) name:QTCaptureDeviceAttributeDidChangeNotification object:nil];

    // Start updating the audio level meter

    audioLevelTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(updateAudioLevels:) userInfo:nil repeats:YES];

}

- (void)alertDidEnd:(NSAlert *)alert returnCode:(NSInteger)returnCode contextInfo:(void *)contextInfo

{

    // Do nothing

}

#pragma mark Device selection

- (void)devicesDidChange:(NSNotification *)notification

{

    [self refreshDevices];

}

- (void)refreshDevices

{

    [self willChangeValueForKey:@"videoDevices"];

    [videoDevices release];

    videoDevices = [[[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeVideo] arrayByAddingObjectsFromArray:[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeMuxed]] retain];

    [self didChangeValueForKey:@"videoDevices"];

    [self willChangeValueForKey:@"audioDevices"];

    [audioDevices release];

    audioDevices = [[NSArray alloc] initWithArray:[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeSound]];

    [self didChangeValueForKey:@"audioDevices"];

    if (![videoDevices containsObject:[self selectedVideoDevice]]) {

        [self setSelectedVideoDevice:nil];

    }

    if (![audioDevices containsObject:[self selectedAudioDevice]]) {

        [self setSelectedAudioDevice:nil];

    }   

}

- (NSArray *)videoDevices

{

    if (!videoDevices)

        [self refreshDevices];

    return videoDevices;

}

- (NSArray *)audioDevices

{

    if (!audioDevices)

        [self refreshDevices];

    return audioDevices;

}

- (QTCaptureDevice *)selectedVideoDevice

{

    return [videoDeviceInput device];

}

- (void)setSelectedVideoDevice:(QTCaptureDevice *)selectedVideoDevice

{

    if (videoDeviceInput) {

        // Remove the old device input from the session and close the device

        [session removeInput:videoDeviceInput];

        [[videoDeviceInput device] close];

        [videoDeviceInput release];

        videoDeviceInput = nil;

    }

    if (selectedVideoDevice) {

        NSError *error = nil;

        BOOL success;

        // Try to open the new device

        success = [selectedVideoDevice open:&error];

        if (!success) {

            [[NSAlert alertWithError:error] beginSheetModalForWindow:[[[self windowControllers] objectAtIndex:0] window] modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:NULL];

            return;

        }

        // Create a device input for the device and add it to the session

        videoDeviceInput = [[QTCaptureDeviceInput alloc] initWithDevice:selectedVideoDevice];

        success = [session addInput:videoDeviceInput error:&error];

        if (!success) {

            [[NSAlert alertWithError:error] beginSheetModalForWindow:[[[self windowControllers] objectAtIndex:0] window] modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:NULL];

            [videoDeviceInput release];

            videoDeviceInput = nil;

            [selectedVideoDevice close];

            return;

        }

    }

    // If this video device also provides audio, don't use another audio device

    if ([self selectedVideoDeviceProvidesAudio]) {

        [self setSelectedAudioDevice:nil];

    }

}

- (QTCaptureDevice *)selectedAudioDevice

{

    return [audioDeviceInput device];

}

- (void)setSelectedAudioDevice:(QTCaptureDevice *)selectedAudioDevice

{

    if (audioDeviceInput) {

        // Remove the old device input from the session and close the device

        [session removeInput:audioDeviceInput];

        [[audioDeviceInput device] close];

        [audioDeviceInput release];

        audioDeviceInput = nil;

    }

    if (selectedAudioDevice && ![self selectedVideoDeviceProvidesAudio]) {

        NSError *error = nil;

        BOOL success;

        // Try to open the new device

        success = [selectedAudioDevice open:&error];

        if (!success) {

            [[NSAlert alertWithError:error] beginSheetModalForWindow:[[[self windowControllers] objectAtIndex:0] window] modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:NULL];

            return;

        }

        // Create a device input for the device and add it to the session

        audioDeviceInput = [[QTCaptureDeviceInput alloc] initWithDevice:selectedAudioDevice];

        success = [session addInput:audioDeviceInput error:&error];

        if (!success) {

            [[NSAlert alertWithError:error] beginSheetModalForWindow:[[[self windowControllers] objectAtIndex:0] window] modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:NULL];

            [audioDeviceInput release];

            audioDeviceInput = nil;

            [selectedAudioDevice close];

            return;

        }

    }

}

- (BOOL)selectedVideoDeviceProvidesAudio

{

    return ([[self selectedVideoDevice] hasMediaType:QTMediaTypeMuxed] || [[self selectedVideoDevice] hasMediaType:QTMediaTypeSound]);

}

#pragma mark Capture and recording

- (QTCaptureSession *)session

{

    return session;

}

- (QTCaptureAudioPreviewOutput *)audioPreviewOutput

{

    return audioPreviewOutput;

}

- (BOOL)hasRecordingDevice

{

    return ((videoDeviceInput != nil) || (audioDeviceInput != nil));

}

- (BOOL)isRecording

{

    return ([movieFileOutput outputFileURL] != nil);

}

- (void)setRecording:(BOOL)recording

{

    if (recording != [self isRecording]) {

        if (recording) {

            // Record to a temporary file, which the user will relocate when recording is finished

            char *tempNameBytes = tempnam([NSTemporaryDirectory() fileSystemRepresentation], "QTRecorder_");

            NSString *tempName = [[[NSString alloc] initWithBytesNoCopy:tempNameBytes length:strlen(tempNameBytes) encoding:NSUTF8StringEncoding freeWhenDone:YES] autorelease];

            [movieFileOutput recordToOutputFileURL:[NSURL fileURLWithPath:[tempName stringByAppendingPathExtension:@"mov"]]];

        } else {

            [movieFileOutput recordToOutputFileURL:nil];

        }

    }

}

// File output delegate methods

- (void)captureOutput:(QTCaptureFileOutput *)captureOutput didOutputSampleBuffer:(QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection

{

}

- (void)captureOutput:(QTCaptureFileOutput *)captureOutput willStartRecordingToOutputFileAtURL:(NSURL *)fileURL forConnections:(NSArray *)connections

{

    NSLog(@"Will start recording to %@", [fileURL description]);

}

- (void)captureOutput:(QTCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL forConnections:(NSArray *)connections

{

    NSLog(@"Did start recording to %@", [fileURL description]);

}

- (BOOL)captureOutput:(QTCaptureFileOutput *)captureOutput shouldChangeOutputFileAtURL:(NSURL *)outputFileURL forConnections:(NSArray *)connections dueToError:(NSError *)error

{

    NSLog(@"Should change file due to error %@", [error description]);

    return NO;

}

- (void)captureOutput:(QTCaptureFileOutput *)captureOutput mustChangeOutputFileAtURL:(NSURL *)outputFileURL forConnections:(NSArray *)connections dueToError:(NSError *)error

{

    NSLog(@"Must change file due to error %@", [error description]);

}

- (void)captureOutput:(QTCaptureFileOutput *)captureOutput willFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL forConnections:(NSArray *)connections dueToError:(NSError *)error

{

    NSLog(@"Will finish recording to %@ due to error %@", [outputFileURL description], [error description]);

    // This delegate method may not be called on the main thread, so do all UI updates using performSelectorOnMainThread:

    [self performSelectorOnMainThread:@selector(willFinishRecording) withObject:nil waitUntilDone:NO];

}

- (void)willFinishRecording

{

    [self willChangeValueForKey:@"recording"];

}

- (void)captureOutput:(QTCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL forConnections:(NSArray *)connections dueToError:(NSError *)error

{

    NSLog(@"Recorded:\n%llu Bytes\n%@ Duration", [captureOutput recordedFileSize], QTStringFromTime([captureOutput recordedDuration]));

    [self didChangeValueForKey:@"recording"];

    if (error && ![[[error userInfo] objectForKey:QTErrorRecordingSuccesfullyFinishedKey] boolValue]) {

        [[NSAlert alertWithError:error] beginSheetModalForWindow:[[[self windowControllers] objectAtIndex:0] window] modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:NULL];

        return;

    }

    // Move the recorded temporary file to a user-specified location

    NSSavePanel *savePanel = [NSSavePanel savePanel];

    [savePanel setAllowedFileTypes:[NSArray arrayWithObject:@"mov"]];

    [savePanel setCanSelectHiddenExtension:YES];

    [savePanel beginSheetModalForWindow:[self windowForSheet] completionHandler:^(NSInteger result) 

    {

        NSError *error = nil;

        if (result == NSOKButton) 

        {

            [[NSFileManager defaultManager] removeItemAtURL:[savePanel URL] error:nil]; // attempt to remove file at the desired save location before moving the recorded file to that location

            if ([[NSFileManager defaultManager] moveItemAtURL:outputFileURL toURL:[savePanel URL] error:&error]) 

            {

                [[NSWorkspace sharedWorkspace] openURL:[savePanel URL]];

            } 

            else 

            {

                [savePanel orderOut:self];

                [self presentError:error modalForWindow:[self windowForSheet] delegate:self didPresentSelector:@selector(didPresentErrorWithRecovery:contextInfo:) contextInfo:NULL];

            }

        } 

        else 

        {

            // remove the temporary recording file if it's not being saved

            [[NSFileManager defaultManager] removeItemAtURL:outputFileURL error:nil];

        }

    }];

}

#pragma mark Video preview filter

- (NSArray *)videoPreviewFilterDescriptions

{

    if (!videoPreviewFilterDescriptions) {

        // Build an array of dictionaries describing filters that can be used in the video preview

        NSArray *filterNames = [NSArray arrayWithObjects:

            @"CIKaleidoscope",

            @"CIGaussianBlur",

            @"CIZoomBlur",

            @"CIColorInvert",

            @"CISepiaTone",

            @"CIBumpDistortion",

            @"CICircularWrap",

            @"CIHoleDistortion",

            @"CITorusLensDistortion",

            @"CITwirlDistortion",

            @"CIVortexDistortion",

            @"CICMYKHalftone",

            @"CIColorPosterize",

            @"CIDotScreen",

            @"CIHatchedScreen",

            @"CIBloom",

            @"CICrystallize",

            @"CIEdges",

            @"CIEdgeWork",

            @"CIGloom",

            @"CIPixellate",

            nil];

        NSMutableArray *myVideoPreviewFilterDescriptions = [NSMutableArray arrayWithCapacity:[filterNames count]];

        NSEnumerator *filterNamesEnumerator = [filterNames objectEnumerator];

        NSString *filterName;

        while ((filterName = [filterNamesEnumerator nextObject])) {

            [myVideoPreviewFilterDescriptions addObject:[NSDictionary dictionaryWithObjectsAndKeys:filterName, @"filterName", [CIFilter localizedNameForFilterName:filterName], @"localizedName", nil]];

        }

        videoPreviewFilterDescriptions = [[NSArray alloc] initWithArray:myVideoPreviewFilterDescriptions];

    }

    return videoPreviewFilterDescriptions;

}

- (NSDictionary*)videoPreviewFilterDescription

{

    return videoPreviewFilterDescription;

}

- (void)setVideoPreviewFilterDescription:(NSDictionary *)theVideoPreviewFilterDescription

{

    if (theVideoPreviewFilterDescription != videoPreviewFilterDescription) {

        [videoPreviewFilterDescription release];

        videoPreviewFilterDescription = [theVideoPreviewFilterDescription copy];

        [captureView setNeedsDisplay:YES];

    }

}

- (CIImage *)view:(QTCaptureView *)view willDisplayImage:(CIImage *)image

{

    NSDictionary *theVideoPreviewFilterDescription = [self videoPreviewFilterDescription];

    if (!theVideoPreviewFilterDescription) {

        return image; // do nothing

    }

    CIFilter *filter = [CIFilter filterWithName:[theVideoPreviewFilterDescription objectForKey:@"filterName"]];

    [filter setDefaults];

    [filter setValue:image forKey:@"inputImage"];  

    return [filter valueForKey:@"outputImage"];

}

#pragma mark Media format summary

- (NSString *)mediaFormatSummary

{

    if (!videoDeviceInput && !audioDeviceInput)

        return nil;

    NSMutableString *mediaFormatSummary = [NSMutableString stringWithCapacity:0];

    NSEnumerator *videoConnectionEnumerator = [[videoDeviceInput connections] objectEnumerator];

    QTCaptureConnection *videoConnection;

    while ((videoConnection = [videoConnectionEnumerator nextObject])) {

        [mediaFormatSummary appendString:[[videoConnection formatDescription] localizedFormatSummary]];

        [mediaFormatSummary appendString:@"\n"];

    }

    NSEnumerator *audioConnectionEnumerator = [[audioDeviceInput connections] objectEnumerator];

    QTCaptureConnection *audioConnection;

    while ((audioConnection = [audioConnectionEnumerator nextObject])) {

        [mediaFormatSummary appendString:[[audioConnection formatDescription] localizedFormatSummary]];

        [mediaFormatSummary appendString:@"\n"];

    }   

    return mediaFormatSummary;

}

- (void)connectionFormatWillChange:(NSNotification *)notification

{

    id owner = [[notification object] owner];

    if ((owner == videoDeviceInput) || (owner == audioDeviceInput)) {

        [self willChangeValueForKey:@"mediaFormatSummary"];

    }

}

- (void)connectionFormatDidChange:(NSNotification *)notification

{

    id owner = [[notification object] owner];

    if ((owner == videoDeviceInput) || (owner == audioDeviceInput)) {

        [self didChangeValueForKey:@"mediaFormatSummary"];

    }

}

#pragma mark UI updating

- (void)updateAudioLevels:(NSTimer *)timer

{

    // Get the mean audio level from the movie file output's audio connections

    float totalDecibels = 0.0;

    QTCaptureConnection *connection = nil;

    NSUInteger i = 0;

    NSUInteger numberOfPowerLevels = 0; // Keep track of the total number of power levels in order to take the mean

    for (i = 0; i < [[movieFileOutput connections] count]; i++) {

        connection = [[movieFileOutput connections] objectAtIndex:i];

        if ([[connection mediaType] isEqualToString:QTMediaTypeSound]) {

            NSArray *powerLevels = [connection attributeForKey:QTCaptureConnectionAudioAveragePowerLevelsAttribute];

            NSUInteger j, powerLevelCount = [powerLevels count];

            for (j = 0; j < powerLevelCount; j++) {

                NSNumber *decibels = [powerLevels objectAtIndex:j];

                totalDecibels += [decibels floatValue];

                numberOfPowerLevels++;

            }

        }

    }

    if (numberOfPowerLevels > 0) {

        [audioLevelMeter setFloatValue:(pow(10., 0.05 * (totalDecibels / (float)numberOfPowerLevels)) * 20.0)];

    } else {

        [audioLevelMeter setFloatValue:0];

    }

}

#pragma mark Device controls

- (QTCaptureDevice *)controllableDevice

{

    QTCaptureDevice *selectedVideoDevice = [self selectedVideoDevice];

    if (selectedVideoDevice) {

        // Make sure that the the device has AVC transport controls

        if (![selectedVideoDevice attributeForKey:QTCaptureDeviceAVCTransportControlsAttribute] || [selectedVideoDevice attributeIsReadOnly:QTCaptureDeviceAVCTransportControlsAttribute])

        {

            selectedVideoDevice = nil;

        }

    }

    return selectedVideoDevice;

}

- (BOOL)isDevicePlaying

{

    NSDictionary *transportControls = [[self controllableDevice] attributeForKey:QTCaptureDeviceAVCTransportControlsAttribute];

    if (transportControls) {

        QTCaptureDeviceAVCTransportControlsSpeed speed = [[transportControls objectForKey:QTCaptureDeviceAVCTransportControlsSpeedKey] longValue];

        QTCaptureDeviceAVCTransportControlsPlaybackMode playbackMode = [[transportControls objectForKey:QTCaptureDeviceAVCTransportControlsPlaybackModeKey] unsignedLongValue];

        return ((speed == QTCaptureDeviceAVCTransportControlsNormalForwardSpeed) && (playbackMode == QTCaptureDeviceAVCTransportControlsPlayingMode));

    }

    return NO;

}

- (void)setDevicePlaying:(BOOL)playing

{

    QTCaptureDevice *device = [self controllableDevice];

    if (device != nil)

    {

        QTCaptureDeviceAVCTransportControlsSpeed speed = playing ? QTCaptureDeviceAVCTransportControlsNormalForwardSpeed : QTCaptureDeviceAVCTransportControlsStoppedSpeed;

        NSDictionary *attr = [[NSDictionary alloc] initWithObjectsAndKeys:

            [NSNumber numberWithLong:speed], QTCaptureDeviceAVCTransportControlsSpeedKey,

            [NSNumber numberWithUnsignedLong:QTCaptureDeviceAVCTransportControlsPlayingMode], QTCaptureDeviceAVCTransportControlsPlaybackModeKey,

            nil];

        [device setAttribute:attr forKey:QTCaptureDeviceAVCTransportControlsAttribute];

    }

}

- (IBAction)stopDevice:(id)sender

{

    QTCaptureDevice* device = [self controllableDevice];

    if (device != nil)

    {

        NSDictionary *attr = [[NSDictionary alloc] initWithObjectsAndKeys:

            [NSNumber numberWithLong:QTCaptureDeviceAVCTransportControlsStoppedSpeed], QTCaptureDeviceAVCTransportControlsSpeedKey,

            [NSNumber numberWithUnsignedLong:QTCaptureDeviceAVCTransportControlsNotPlayingMode], QTCaptureDeviceAVCTransportControlsPlaybackModeKey,

            nil];

        [device setAttribute:attr forKey:QTCaptureDeviceAVCTransportControlsAttribute];

    }

}

- (BOOL)isDeviceRewinding

{

    NSDictionary *transportControls = [[self controllableDevice] attributeForKey:QTCaptureDeviceAVCTransportControlsAttribute];

    if (transportControls) {

        QTCaptureDeviceAVCTransportControlsSpeed speed = [[transportControls objectForKey:QTCaptureDeviceAVCTransportControlsSpeedKey] longValue];

        switch (speed) {

        case QTCaptureDeviceAVCTransportControlsSlowestReverseSpeed:

        case QTCaptureDeviceAVCTransportControlsVerySlowReverseSpeed:

        case QTCaptureDeviceAVCTransportControlsSlowReverseSpeed:

        case QTCaptureDeviceAVCTransportControlsNormalReverseSpeed:

        case QTCaptureDeviceAVCTransportControlsFastReverseSpeed:

        case QTCaptureDeviceAVCTransportControlsVeryFastReverseSpeed:

        case QTCaptureDeviceAVCTransportControlsFastestReverseSpeed:

            return YES;

        default:

            return NO;

        }

    }

    return NO;

}

- (void)setDeviceRewinding:(BOOL)rewinding

{

    QTCaptureDevice* device = [self controllableDevice];

    if (device != nil)

    {

        QTCaptureDeviceAVCTransportControlsSpeed speed = rewinding ? QTCaptureDeviceAVCTransportControlsFastReverseSpeed : QTCaptureDeviceAVCTransportControlsStoppedSpeed;

        // Preserve the playback mode already set for the device

        NSDictionary *originalAttr = [device attributeForKey:QTCaptureDeviceAVCTransportControlsAttribute];

        NSNumber *playbackMode = [originalAttr objectForKey:QTCaptureDeviceAVCTransportControlsPlaybackModeKey];

        NSDictionary *attr = [[NSDictionary alloc] initWithObjectsAndKeys:

            [NSNumber numberWithLong:speed], QTCaptureDeviceAVCTransportControlsSpeedKey,

            playbackMode, QTCaptureDeviceAVCTransportControlsPlaybackModeKey,

            nil];

        [device setAttribute:attr forKey:QTCaptureDeviceAVCTransportControlsAttribute];

    }

}

- (BOOL)isDeviceFastforwarding

{

    NSDictionary *transportControls = [[self controllableDevice] attributeForKey:QTCaptureDeviceAVCTransportControlsAttribute];

    if (transportControls) {

        QTCaptureDeviceAVCTransportControlsSpeed speed = [[transportControls objectForKey:QTCaptureDeviceAVCTransportControlsSpeedKey] longValue];

        switch (speed) {

        case QTCaptureDeviceAVCTransportControlsSlowestForwardSpeed:

        case QTCaptureDeviceAVCTransportControlsVerySlowForwardSpeed:

        case QTCaptureDeviceAVCTransportControlsSlowForwardSpeed:

        case QTCaptureDeviceAVCTransportControlsFastForwardSpeed:

        case QTCaptureDeviceAVCTransportControlsVeryFastForwardSpeed:

        case QTCaptureDeviceAVCTransportControlsFastestForwardSpeed:

            return YES;

        default:

            return NO;

        }

    }

    return NO;

}

- (void)setDeviceFastforwarding:(BOOL)fastforwarding

{   

    QTCaptureDevice* device = [self controllableDevice];

    if (device != nil)

    {

        QTCaptureDeviceAVCTransportControlsSpeed speed = fastforwarding ? QTCaptureDeviceAVCTransportControlsFastForwardSpeed : QTCaptureDeviceAVCTransportControlsStoppedSpeed;

        // Preserve the playback mode already set for the device

        NSDictionary *originalAttr = [device attributeForKey:QTCaptureDeviceAVCTransportControlsAttribute];

        NSNumber *playbackMode = [originalAttr objectForKey:QTCaptureDeviceAVCTransportControlsPlaybackModeKey];

        NSDictionary *attr = [[NSDictionary alloc] initWithObjectsAndKeys:

            [NSNumber numberWithLong:speed], QTCaptureDeviceAVCTransportControlsSpeedKey,

            playbackMode, QTCaptureDeviceAVCTransportControlsPlaybackModeKey,

            nil];

        [device setAttribute:attr forKey:QTCaptureDeviceAVCTransportControlsAttribute];

    }

}

- (void)deviceAttributeWillChange:(NSNotification *)notification

{

    if (([notification object] == [self controllableDevice]) && [[[notification userInfo] objectForKey:QTCaptureDeviceChangedAttributeKey] isEqualToString:QTCaptureDeviceAVCTransportControlsAttribute]) {

        [self willChangeValueForKey:@"devicePlaying"];

        [self willChangeValueForKey:@"deviceFastforwarding"];

        [self willChangeValueForKey:@"deviceRewinding"];

    }

}

- (void)deviceAttributeDidChange:(NSNotification *)notification

{   

    if (([notification object] == [self controllableDevice]) && [[[notification userInfo] objectForKey:QTCaptureDeviceChangedAttributeKey] isEqualToString:QTCaptureDeviceAVCTransportControlsAttribute]) {

        [self didChangeValueForKey:@"devicePlaying"];

        [self didChangeValueForKey:@"deviceFastforwarding"];

        [self didChangeValueForKey:@"deviceRewinding"];

    }

}

@end