apple.avfoundation

Class AVMovie

java.lang.Object

org.moe.natj.general.NativeObject

org.moe.natj.objc.ObjCObject

apple.NSObject

apple.avfoundation.AVAsset

apple.avfoundation.AVMovie

All Implemented Interfaces:

AVAsynchronousKeyValueLoading, NSCopying, NSMutableCopying, NSObject

Direct Known Subclasses:

AVFragmentedMovie, AVMutableMovie

public class AVMovie
extends AVAsset
implements NSCopying, NSMutableCopying

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	AVMovie.Block_loadTracksWithMediaCharacteristicCompletionHandler
static interface	AVMovie.Block_loadTracksWithMediaTypeCompletionHandler
static interface	AVMovie.Block_loadTrackWithTrackIDCompletionHandler

Nested classes/interfaces inherited from class apple.avfoundation.AVAsset

AVAsset.Block_findUnusedTrackIDWithCompletionHandler, AVAsset.Block_loadChapterMetadataGroupsBestMatchingPreferredLanguagesCompletionHandler, AVAsset.Block_loadChapterMetadataGroupsWithTitleLocaleContainingItemsWithCommonKeysCompletionHandler, AVAsset.Block_loadMediaSelectionGroupForMediaCharacteristicCompletionHandler, AVAsset.Block_loadMetadataForFormatCompletionHandler

Nested classes/interfaces inherited from class apple.NSObject

NSObject.Function_instanceMethodForSelector_ret, NSObject.Function_methodForSelector_ret

Nested classes/interfaces inherited from interface apple.avfoundation.protocol.AVAsynchronousKeyValueLoading

AVAsynchronousKeyValueLoading.Block_loadValuesAsynchronouslyForKeysCompletionHandler

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AVMovie(org.moe.natj.general.Pointer peer)

Method Summary

Modifier and Type	Method and Description
static boolean	accessInstanceVariablesDirectly()
static AVMovie	alloc()
static AVMovie	allocWithZone(org.moe.natj.general.ptr.VoidPtr zone)
static AVMovie	assetWithURL(NSURL URL)
static boolean	automaticallyNotifiesObserversForKey(java.lang.String key)
static void	cancelPreviousPerformRequestsWithTarget(java.lang.Object aTarget)
static void	cancelPreviousPerformRequestsWithTargetSelectorObject(java.lang.Object aTarget, org.moe.natj.objc.SEL aSelector, java.lang.Object anArgument)
boolean	canContainMovieFragments() [@property] canContainMovieFragments
static NSArray<java.lang.String>	classFallbacksForKeyedArchiver()
static org.moe.natj.objc.Class	classForKeyedUnarchiver()
boolean	containsMovieFragments() [@property] containsMovieFragments
java.lang.Object	copyWithZone(org.moe.natj.general.ptr.VoidPtr zone)
NSData	data() [@property] data
static java.lang.String	debugDescription_static()
AVMediaDataStorage	defaultMediaDataStorage() [@property] defaultMediaDataStorage
static java.lang.String	description_static()
static long	hash_static()
AVMovie	init()
AVMovie	initWithDataOptions(NSData data, NSDictionary<java.lang.String,?> options) initWithData:options:
AVMovie	initWithURLOptions(NSURL URL, NSDictionary<java.lang.String,?> options) initWithURL:options:
static NSObject.Function_instanceMethodForSelector_ret	instanceMethodForSelector(org.moe.natj.objc.SEL aSelector)
static NSMethodSignature	instanceMethodSignatureForSelector(org.moe.natj.objc.SEL aSelector)
static boolean	instancesRespondToSelector(org.moe.natj.objc.SEL aSelector)
boolean	isCompatibleWithFileType(java.lang.String fileType) isCompatibleWithFileType:
static boolean	isSubclassOfClass(org.moe.natj.objc.Class aClass)
static NSSet<java.lang.String>	keyPathsForValuesAffectingValueForKey(java.lang.String key)
void	loadTracksWithMediaCharacteristicCompletionHandler(java.lang.String mediaCharacteristic, AVMovie.Block_loadTracksWithMediaCharacteristicCompletionHandler completionHandler) loadTracksWithMediaCharacteristic:completionHandler:
void	loadTracksWithMediaTypeCompletionHandler(java.lang.String mediaType, AVMovie.Block_loadTracksWithMediaTypeCompletionHandler completionHandler) loadTracksWithMediaType:completionHandler:
void	loadTrackWithTrackIDCompletionHandler(int trackID, AVMovie.Block_loadTrackWithTrackIDCompletionHandler completionHandler) loadTrackWithTrackID:completionHandler:
NSData	movieHeaderWithFileTypeError(java.lang.String fileType, org.moe.natj.general.ptr.Ptr<NSError> outError) movieHeaderWithFileType:error:
static NSArray<java.lang.String>	movieTypes() movieTypes
static AVMovie	movieWithDataOptions(NSData data, NSDictionary<java.lang.String,?> options) movieWithData:options:
static AVMovie	movieWithURLOptions(NSURL URL, NSDictionary<java.lang.String,?> options) movieWithURL:options:
java.lang.Object	mutableCopyWithZone(org.moe.natj.general.ptr.VoidPtr zone)
static AVMovie	new_objc()
static boolean	resolveClassMethod(org.moe.natj.objc.SEL sel)
static boolean	resolveInstanceMethod(org.moe.natj.objc.SEL sel)
static void	setVersion_static(long aVersion)
static org.moe.natj.objc.Class	superclass_static()
NSArray<? extends AVMovieTrack>	tracks() [@property] tracks
NSArray<? extends AVMovieTrack>	tracksWithMediaCharacteristic(java.lang.String mediaCharacteristic) tracksWithMediaCharacteristic:
NSArray<? extends AVMovieTrack>	tracksWithMediaType(java.lang.String mediaType) tracksWithMediaType:
AVMovieTrack	trackWithTrackID(int trackID) trackWithTrackID:
NSURL	URL() [@property] URL
static long	version_static()
boolean	writeMovieHeaderToURLFileTypeOptionsError(NSURL URL, java.lang.String fileType, long options, org.moe.natj.general.ptr.Ptr<NSError> outError) writeMovieHeaderToURL:fileType:options:error:

Methods inherited from class apple.avfoundation.AVAsset

allMediaSelections, availableChapterLocales, availableMediaCharacteristicsWithMediaSelectionOptions, availableMetadataFormats, cancelLoading, canContainFragments, chapterMetadataGroupsBestMatchingPreferredLanguages, chapterMetadataGroupsWithTitleLocaleContainingItemsWithCommonKeys, commonMetadata, containsFragments, creationDate, duration, findUnusedTrackIDWithCompletionHandler, hasProtectedContent, isCompatibleWithAirPlayVideo, isCompatibleWithSavedPhotosAlbum, isComposable, isExportable, isPlayable, isReadable, loadChapterMetadataGroupsBestMatchingPreferredLanguagesCompletionHandler, loadChapterMetadataGroupsWithTitleLocaleContainingItemsWithCommonKeysCompletionHandler, loadMediaSelectionGroupForMediaCharacteristicCompletionHandler, loadMetadataForFormatCompletionHandler, loadTracksWithMediaCharacteristicCompletionHandler, loadTracksWithMediaTypeCompletionHandler, loadTrackWithTrackIDCompletionHandler, loadValuesAsynchronouslyForKeysCompletionHandler, lyrics, mediaSelectionGroupForMediaCharacteristic, metadata, metadataForFormat, minimumTimeOffsetFromLive, naturalSize, overallDurationHint, preferredMediaSelection, preferredRate, preferredTransform, preferredVolume, providesPreciseDurationAndTiming, referenceRestrictions, statusOfValueForKeyError, trackGroups, unusedTrackID

Methods inherited from class apple.NSObject

accessibilityActivate, accessibilityActivationPoint, accessibilityAssistiveTechnologyFocusedIdentifiers, accessibilityAttributedHint, accessibilityAttributedLabel, accessibilityAttributedUserInputLabels, accessibilityAttributedValue, accessibilityContainerType, accessibilityCustomActions, accessibilityCustomRotors, accessibilityDecrement, accessibilityDragSourceDescriptors, accessibilityDropPointDescriptors, accessibilityElementAtIndex, accessibilityElementCount, accessibilityElementDidBecomeFocused, accessibilityElementDidLoseFocus, accessibilityElementIsFocused, accessibilityElements, accessibilityElementsHidden, accessibilityFrame, accessibilityHint, accessibilityIncrement, accessibilityLabel, accessibilityLanguage, accessibilityNavigationStyle, accessibilityPath, accessibilityPerformEscape, accessibilityPerformMagicTap, accessibilityRespondsToUserInteraction, accessibilityScroll, accessibilityTextualContext, accessibilityTraits, accessibilityUserInputLabels, accessibilityValue, accessibilityViewIsModal, addObserverForKeyPathOptionsContext, attemptRecoveryFromErrorOptionIndex, attemptRecoveryFromErrorOptionIndexDelegateDidRecoverSelectorContextInfo, autoContentAccessingProxy, awakeAfterUsingCoder, awakeFromNib, class_objc, classForCoder, classForKeyedArchiver, copy, dealloc, debugDescription, description, dictionaryWithValuesForKeys, didChangeValueForKey, didChangeValueForKeyWithSetMutationUsingObjects, didChangeValuesAtIndexesForKey, doesNotRecognizeSelector, fileManagerShouldProceedAfterError, fileManagerWillProcessPath, finalize_objc, forwardingTargetForSelector, forwardInvocation, hash, indexOfAccessibilityElement, isAccessibilityElement, isEqual, isKindOfClass, isMemberOfClass, isProxy, methodForSelector, methodSignatureForSelector, mutableArrayValueForKey, mutableArrayValueForKeyPath, mutableCopy, mutableOrderedSetValueForKey, mutableOrderedSetValueForKeyPath, mutableSetValueForKey, mutableSetValueForKeyPath, observationInfo, observeValueForKeyPathOfObjectChangeContext, performSelector, performSelectorInBackgroundWithObject, performSelectorOnMainThreadWithObjectWaitUntilDone, performSelectorOnMainThreadWithObjectWaitUntilDoneModes, performSelectorOnThreadWithObjectWaitUntilDone, performSelectorOnThreadWithObjectWaitUntilDoneModes, performSelectorWithObject, performSelectorWithObjectAfterDelay, performSelectorWithObjectAfterDelayInModes, performSelectorWithObjectWithObject, prepareForInterfaceBuilder, provideImageDataBytesPerRowOrigin_Size_UserInfo, removeObserverForKeyPath, removeObserverForKeyPathContext, replacementObjectForCoder, replacementObjectForKeyedArchiver, respondsToSelector, self, setAccessibilityActivationPoint, setAccessibilityAttributedHint, setAccessibilityAttributedLabel, setAccessibilityAttributedUserInputLabels, setAccessibilityAttributedValue, setAccessibilityContainerType, setAccessibilityCustomActions, setAccessibilityCustomRotors, setAccessibilityDragSourceDescriptors, setAccessibilityDropPointDescriptors, setAccessibilityElements, setAccessibilityElementsHidden, setAccessibilityFrame, setAccessibilityHint, setAccessibilityLabel, setAccessibilityLanguage, setAccessibilityNavigationStyle, setAccessibilityPath, setAccessibilityRespondsToUserInteraction, setAccessibilityTextualContext, setAccessibilityTraits, setAccessibilityUserInputLabels, setAccessibilityValue, setAccessibilityViewIsModal, setIsAccessibilityElement, setNilValueForKey, setObservationInfo, setShouldGroupAccessibilityChildren, setValueForKey, setValueForKeyPath, setValueForUndefinedKey, setValuesForKeysWithDictionary, shouldGroupAccessibilityChildren, superclass, validateValueForKeyError, validateValueForKeyPathError, valueForKey, valueForKeyPath, valueForUndefinedKey, willChangeValueForKey, willChangeValueForKeyWithSetMutationUsingObjects, willChangeValuesAtIndexesForKey

Methods inherited from class org.moe.natj.objc.ObjCObject

equals, toString

Methods inherited from class org.moe.natj.general.NativeObject

finalize, getPeer, getPeerPointer

Methods inherited from class java.lang.Object

clone, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AVMovie

protected AVMovie(org.moe.natj.general.Pointer peer)

Method Detail

URL

public NSURL URL()

[@property] URL

The URL with which the instance of AVMovie was initialized; may be nil.

accessInstanceVariablesDirectly

public static boolean accessInstanceVariablesDirectly()

alloc

public static AVMovie alloc()

allocWithZone

public static AVMovie allocWithZone(org.moe.natj.general.ptr.VoidPtr zone)

assetWithURL

public static AVMovie assetWithURL(NSURL URL)

automaticallyNotifiesObserversForKey

public static boolean automaticallyNotifiesObserversForKey(java.lang.String key)

canContainMovieFragments

public boolean canContainMovieFragments()

[@property] canContainMovieFragments

Indicates whether the movie file is capable of being extended by fragments.

The value of this property is YES if an 'mvex' box is present in the 'moov' box. The 'mvex' box is necessary in order to signal the possible presence of later 'moof' boxes.

cancelPreviousPerformRequestsWithTarget

public static void cancelPreviousPerformRequestsWithTarget(java.lang.Object aTarget)

cancelPreviousPerformRequestsWithTargetSelectorObject

public static void cancelPreviousPerformRequestsWithTargetSelectorObject(java.lang.Object aTarget,
                                                                         org.moe.natj.objc.SEL aSelector,
                                                                         java.lang.Object anArgument)

classFallbacksForKeyedArchiver

public static NSArray<java.lang.String> classFallbacksForKeyedArchiver()

classForKeyedUnarchiver

public static org.moe.natj.objc.Class classForKeyedUnarchiver()

containsMovieFragments

public boolean containsMovieFragments()

[@property] containsMovieFragments

Indicates whether the movie file is extended by at least one movie fragment.

The value of this property is YES if canContainMovieFragments is YES and at least one 'moof' box is present after the 'moov' box.

copyWithZone

public java.lang.Object copyWithZone(org.moe.natj.general.ptr.VoidPtr zone)

Specified by:

copyWithZone in interface NSCopying

Overrides:

copyWithZone in class AVAsset

data

public NSData data()

[@property] data

The data block with which the instance of AVMovie was initialized; may be nil.

debugDescription_static

public static java.lang.String debugDescription_static()

defaultMediaDataStorage

public AVMediaDataStorage defaultMediaDataStorage()

[@property] defaultMediaDataStorage

The default storage container for media data added to a movie.

The value of this property is an AVMediaDataStorage object that indicates where sample data that is added to a movie should be written by default.

description_static

public static java.lang.String description_static()

hash_static

public static long hash_static()

init

public AVMovie init()

Overrides:

init in class AVAsset

initWithDataOptions

public AVMovie initWithDataOptions(NSData data,
                                   NSDictionary<java.lang.String,?> options)

initWithData:options:

Creates an AVMovie object from a movie header stored in an NSData object.

You can use this method to operate on movie headers that are not stored in files. In general you should avoid loading an entire movie file with its media data into an instance of NSData!

By default, the defaultMediaDataStorage property will be nil and each associated AVMovieTrack's mediaDataStorage property will be nil. If you want to create an AVMutableMovie from an NSData object and then append sample buffers to any of its tracks, you must first set one of these properties to indicate where the sample data should be written.

Parameters:

data - An NSData object containing a movie header.

options - An NSDictionary object that contains keys for specifying options for the initialization of the AVMovie object.

Returns:

An AVMovie object

initWithURLOptions

public AVMovie initWithURLOptions(NSURL URL,
                                  NSDictionary<java.lang.String,?> options)

initWithURL:options:

Creates an AVMovie object from a movie header stored in a QuickTime movie file or ISO base media file.

By default, the defaultMediaDataStorage property will be nil and each associated AVMovieTrack's mediaDataStorage property will be nil. If you want to create an AVMutableMovie from a file and then append sample buffers to any of its tracks, you must first set one of these properties to indicate where the sample data should be written.

Parameters:

URL - An NSURL object that specifies a file containing a movie header.

options - An NSDictionary object that contains keys for specifying options for the initialization of the AVMovie object.

Returns:

An AVMovie object

instanceMethodForSelector

public static NSObject.Function_instanceMethodForSelector_ret instanceMethodForSelector(org.moe.natj.objc.SEL aSelector)

instanceMethodSignatureForSelector

public static NSMethodSignature instanceMethodSignatureForSelector(org.moe.natj.objc.SEL aSelector)

instancesRespondToSelector

public static boolean instancesRespondToSelector(org.moe.natj.objc.SEL aSelector)

isCompatibleWithFileType

public boolean isCompatibleWithFileType(java.lang.String fileType)

isCompatibleWithFileType:

Indicates whether a movie header for the AVMovie object can be created for the specified file type.

This method returns a BOOL that indicates whether a movie header of the specified type can be created for the receiver. For example, this method returns NO if the movie contains tracks whose media types or media subtypes are not allowed by the specified file type.

Parameters:

fileType - A UTI indicating a movie file format (e.g. AVFileTypeQuickTimeMovie for a QuickTime movie).

isSubclassOfClass

public static boolean isSubclassOfClass(org.moe.natj.objc.Class aClass)

keyPathsForValuesAffectingValueForKey

public static NSSet<java.lang.String> keyPathsForValuesAffectingValueForKey(java.lang.String key)

movieHeaderWithFileTypeError

public NSData movieHeaderWithFileTypeError(java.lang.String fileType,
                                           org.moe.natj.general.ptr.Ptr<NSError> outError)

movieHeaderWithFileType:error:

Creates an NSData object containing the movie header of the AVMovie object.

The movie header will be a pure reference movie, with no base URL, suitable for use on the pasteboard.

Parameters:

fileType - A UTI indicating the specific file format of the movie header (e.g. AVFileTypeQuickTimeMovie for a QuickTime movie).

outError - If an error occurs reading the movie header, describes the nature of the failure.

Returns:

An NSData object.

movieTypes

public static NSArray<java.lang.String> movieTypes()

movieTypes

Provides the file types the AVMovie class understands.

Returns:

An NSArray of UTIs identifying the file types the AVMovie class understands.

movieWithDataOptions

public static AVMovie movieWithDataOptions(NSData data,
                                           NSDictionary<java.lang.String,?> options)

movieWithData:options:

Creates an AVMovie object from a movie header stored in an NSData object.

You can use this method to operate on movie headers that are not stored in files; this might include movie headers on the pasteboard (which do not contain media data). In general you should avoid loading an entire movie file with its media data into an instance of NSData! By default, the defaultMediaDataStorage property will be nil and each associated AVMovieTrack's mediaDataStorage property will be nil. If you want to create an AVMutableMovie from an NSData object and then append sample buffers to any of its tracks, you must first set one of these properties to indicate where the sample data should be written.

Parameters:

data - An NSData object containing a movie header.

options - An NSDictionary object that contains keys for specifying options for the initialization of the AVMovie object.

Returns:

An AVMovie object

movieWithURLOptions

public static AVMovie movieWithURLOptions(NSURL URL,
                                          NSDictionary<java.lang.String,?> options)

movieWithURL:options:

Creates an AVMovie object from a movie header stored in a QuickTime movie file or ISO base media file.

By default, the defaultMediaDataStorage property will be nil and each associated AVMovieTrack's mediaDataStorage property will be nil. If you want to create an AVMutableMovie from a file and then append sample buffers to any of its tracks, you must first set one of these properties to indicate where the sample data should be written.

Parameters:

URL - An NSURL object that specifies a file containing a movie header.

options - An NSDictionary object that contains keys for specifying options for the initialization of the AVMovie object.

Returns:

An AVMovie object

mutableCopyWithZone

public java.lang.Object mutableCopyWithZone(org.moe.natj.general.ptr.VoidPtr zone)

Specified by:

mutableCopyWithZone in interface NSMutableCopying

new_objc

public static AVMovie new_objc()

resolveClassMethod

public static boolean resolveClassMethod(org.moe.natj.objc.SEL sel)

resolveInstanceMethod

public static boolean resolveInstanceMethod(org.moe.natj.objc.SEL sel)

setVersion_static

public static void setVersion_static(long aVersion)

superclass_static

public static org.moe.natj.objc.Class superclass_static()

trackWithTrackID

public AVMovieTrack trackWithTrackID(int trackID)

trackWithTrackID:

Provides an instance of AVMovieTrack that represents the track of the specified trackID.

Becomes callable without blocking when the key @"tracks" has been loaded

Overrides:

trackWithTrackID in class AVAsset

Parameters:

trackID - The trackID of the requested AVMovieTrack.

Returns:

An instance of AVMovieTrack; may be nil if no track of the specified trackID is available.

tracks

public NSArray<? extends AVMovieTrack> tracks()

[@property] tracks

The tracks in a movie.

The value of this property is an array of tracks the movie contains; the tracks are of type AVMovieTrack.

Overrides:

tracks in class AVAsset

tracksWithMediaCharacteristic

public NSArray<? extends AVMovieTrack> tracksWithMediaCharacteristic(java.lang.String mediaCharacteristic)

tracksWithMediaCharacteristic:

Provides an array of AVMovieTracks of the asset that present media with the specified characteristic.

Becomes callable without blocking when the key @"tracks" has been loaded

Overrides:

tracksWithMediaCharacteristic in class AVAsset

Parameters:

mediaCharacteristic - The media characteristic according to which the receiver filters its AVMovieTracks. (Media characteristics are defined in AVMediaFormat.h)

Returns:

An NSArray of AVMovieTracks; may be empty if no tracks with the specified characteristic are available.

tracksWithMediaType

public NSArray<? extends AVMovieTrack> tracksWithMediaType(java.lang.String mediaType)

tracksWithMediaType:

Provides an array of AVMovieTracks of the asset that present media of the specified media type.

Becomes callable without blocking when the key @"tracks" has been loaded

Overrides:

tracksWithMediaType in class AVAsset

Parameters:

mediaType - The media type according to which the receiver filters its AVMovieTracks. (Media types are defined in AVMediaFormat.h)

Returns:

An NSArray of AVMovieTracks; may be empty if no tracks of the specified media type are available.

version_static

public static long version_static()

writeMovieHeaderToURLFileTypeOptionsError

public boolean writeMovieHeaderToURLFileTypeOptionsError(NSURL URL,
                                                         java.lang.String fileType,
                                                         long options,
                                                         org.moe.natj.general.ptr.Ptr<NSError> outError)

writeMovieHeaderToURL:fileType:options:error:

Writes the movie header to a destination URL.

Note that modifications to instances of AVMutableMovie, to their constituent AVMutableMovieTracks, or to their collections of metadata are committed to storage when their movie headers are written.

Parameters:

URL - An NSURL object indicating where to write the movie header.

fileType - A UTI indicating the specific file format (e.g. AVFileTypeQuickTimeMovie for a QuickTime movie).

options - An NSUInteger whose bits specify options for the writing of the movie header. See AVMovieWritingOptions above.

outError - If an error occurs writing the movie header, describes the nature of the failure.

loadTrackWithTrackIDCompletionHandler

public void loadTrackWithTrackIDCompletionHandler(int trackID,
                                                  AVMovie.Block_loadTrackWithTrackIDCompletionHandler completionHandler)

loadTrackWithTrackID:completionHandler:

Loads an instance of AVMovieTrack that represents the track of the specified trackID.

Parameters:

trackID - The trackID of the requested AVMovieTrack.

completionHandler - A block that is called when the loading is finished, with either the loaded track (which may be nil if no track of the specified trackID is available) or an error.

loadTracksWithMediaCharacteristicCompletionHandler

public void loadTracksWithMediaCharacteristicCompletionHandler(java.lang.String mediaCharacteristic,
                                                               AVMovie.Block_loadTracksWithMediaCharacteristicCompletionHandler completionHandler)

loadTracksWithMediaCharacteristic:completionHandler:

Loads an array of AVMovieTracks of the asset that present media with the specified characteristic.

Parameters:

mediaCharacteristic - The media characteristic according to which AVAsset filters its AVMovieTracks. (Media characteristics are defined in AVMediaFormat.h.)

completionHandler - A block that is called when the loading is finished, with either the loaded tracks (which may be empty if no tracks with the specified characteristic are available) or an error.

loadTracksWithMediaTypeCompletionHandler

public void loadTracksWithMediaTypeCompletionHandler(java.lang.String mediaType,
                                                     AVMovie.Block_loadTracksWithMediaTypeCompletionHandler completionHandler)

loadTracksWithMediaType:completionHandler:

Loads an array of AVMovieTracks of the asset that present media of the specified media type.

Parameters:

mediaType - The media type according to which AVAsset filters its AVMovieTracks. (Media types are defined in AVMediaFormat.h.)

completionHandler - A block that is called when the loading is finished, with either the loaded tracks (which may be empty if no tracks of the specified media type are available) or an error.