Constants
The following are values for kQTVisualContextTypeKey
, a read-only CFStringRef
that defines the type of the visual context:
Declaration
Constants
-
kQTVisualContextExpectedReadAheadKey
A
CFNumberRef
that defines the number of seconds ahead of real time that the client expects to pull images out of a visual context. Applications using the Core Video display link should set this attribute according to the value returned byCVDisplayLinkGetOutputVideoLatency
. -
kQTVisualContextPixelBufferAttributesKey
A
CFDictionaryRef
that defines the dictionary containing pixel buffer attributes. SeekICMCompressionSessionPropertyID_PixelBufferPool
in ICM Compression Session Properties. -
kQTVisualContextTargetDimensionsKey
A
CFDictionaryRef
that defines the dictionary containingkQTVisualContextTargetDimensions_WidthKey
andkQTVisualContextTargetDimensions_HeightKey
values. This key is used as a hint to optimize certain media types, such as text, that can be rendered at any resolution. If this attribute is not set, the movie will be rendered at its native resolution. -
kQTVisualContextTargetDimensions_WidthKey
A
CFNumberRef
that defines the width, in pixels, of the rendering target. -
kQTVisualContextTargetDimensions_HeightKey
A
CFNumberRef
that defines the height, in pixels, of the rendering target. -
kQTVisualContextType_Direct3DTexture
The
CFString
value for use in dictionaries for identifying Direct3DTexture visual contexts.
The following are aperture mode properties of image descriptions in QuickTime 7.1.
Declaration
enum {
kQTPropertyClass_ImageDescription = 'idsc',
kICMImageDescriptionPropertyID_EncodedWidth = 'encw',
kICMImageDescriptionPropertyID_EncodedHeight = 'ench',
kICMImageDescriptionPropertyID_CleanAperture = 'clap',
kICMImageDescriptionPropertyID_PixelAspectRatio = 'pasp',
kICMImageDescriptionPropertyID_CleanApertureDisplayDimensions = 'cadi',
kICMImageDescriptionPropertyID_ProductionApertureDisplayDimensions = 'prdi',
kICMImageDescriptionPropertyID_EncodedPixelsDimensions = 'endi',
kICMImageDescriptionPropertyID_DisplayWidth = 'disw',
kICMImageDescriptionPropertyID_DisplayHeight = 'dish',
kICMImageDescriptionPropertyID_ProductionDisplayWidth = 'pdsw',
kICMImageDescriptionPropertyID_ProductionDisplayHeight = 'pdsh',
kICMImageDescriptionPropertyID_NCLCColorInfo = 'nclc',
kICMImageDescriptionPropertyID_FieldInfo = 'fiel',
kICMImageDescriptionPropertyID_ClassicTrackWidth = 'claw',
kICMImageDescriptionPropertyID_ClassicTrackHeight = 'clah',
kICMImageDescriptionPropertyID_GammaLevel = 'gama',
kICMImageDescriptionPropertyID_RowBytes = 'rowb',
kICMImageDescriptionPropertyID_StepDuration = 'step',
kICMImageDescriptionPropertyID_CleanApertureClipRect = 'cacr',
kICMImageDescriptionPropertyID_CleanApertureMatrix = 'camx',
kICMImageDescriptionPropertyID_ProductionApertureMatrix = 'pamx',
kICMImageDescriptionPropertyID_SummaryString = 'isum',
};
Constants
-
kQTPropertyClass_ImageDescription
Class identifier for image description properties.
-
kICMImageDescriptionPropertyID_EncodedWidth
The width of the encoded image. Usually, but not always, this is the ImageDescription's width field.
-
kICMImageDescriptionPropertyID_EncodedHeight
The height of the encoded image. Usually, but not always, this is the ImageDescription's height field.
-
kICMImageDescriptionPropertyID_CleanAperture
Describes the clean aperture of the buffer. If not specified explicitly in the image description, the default clean aperture (full encoded width and height) will be returned.
-
kICMImageDescriptionPropertyID_PixelAspectRatio
Describes the pixel aspect ratio. If not specified explicitly in the image description, a square (1:1) pixel aspect ratio will be returned.
-
kICMImageDescriptionPropertyID_CleanApertureDisplayDimensions
The dimensions at which the image can be displayed on a square-pixel display, generally calculated using the clean aperture and pixel aspect ratio. Note that this value is returned as a FixedPoint; the width and height can also be read separately as rounded SInt32s via
kICMImageDescriptionPropertyID_CleanApertureDisplayWidth
andkICMImageDescriptionPropertyID_CleanApertureDisplayHeight
. -
kICMImageDescriptionPropertyID_ProductionApertureDisplayDimensions
The dimensions at which the image could be displayed on a square-pixel display, disregarding any clean aperture but honoring the pixel aspect ratio. This may be useful for authoring applications that want to expose the edge-processing region. For general viewing, use
kICMImageDescriptionPropertyID_CleanApertureDimensions
instead. Note that this value is returned as a FixedPoint; the width and height can also be read separately as rounded SInt32s viakICMImageDescriptionPropertyID_ProductionApertureDisplayWidth
andkICMImageDescriptionPropertyID_ProductionApertureDisplayHeight
. -
kICMImageDescriptionPropertyID_EncodedPixelsDimensions
Describes the dimensions of the encoded image. Note that this value is returned as a FixedPoint for convenience; the width and height can also be read separately as SInt32s via
kICMImageDescriptionPropertyID_EncodedWidth
andkICMImageDescriptionPropertyID_EncodedHeight
. -
kICMImageDescriptionPropertyID_CleanApertureDisplayWidth
A width at which the buffer's image could be displayed on a square-pixel display, possibly calculated using the clean aperture and pixel aspect ratio.
-
kICMImageDescriptionPropertyID_CleanApertureDisplayHeight
A height at which the buffer's image could be displayed on a square-pixel display, possibly calculated using the clean aperture and pixel aspect ratio.
-
kICMImageDescriptionPropertyID_ProductionApertureDisplayWidth
A width at which the image could be displayed on a square-pixel display, disregarding any clean aperture but honoring the pixel aspect ratio. This may be useful for authoring applications that want to expose the edge processing region. For general viewing, use
kICMImageDescriptionPropertyID_DisplayWidth
instead. -
kICMImageDescriptionPropertyID_ProductionApertureDisplayHeight
A height at which the image could be displayed on a square-pixel display, disregarding any clean aperture but honoring the pixel aspect ratio. This may be useful for authoring applications that want to expose the edge processing region. For general viewing, use
kICMImageDescriptionPropertyID_DisplayHeight
instead. -
kICMImageDescriptionPropertyID_DisplayWidth
Synonym for
kICMImageDescriptionPropertyID_CleanApertureDisplayHeight
. -
kICMImageDescriptionPropertyID_DisplayHeight
Synonym for
kICMImageDescriptionPropertyID_CleanApertureDisplayHeight
. -
kICMImageDescriptionPropertyID_ProductionDisplayWidth
Synonym for
kICMImageDescriptionPropertyID_ProductionApertureDisplayWidth
. -
kICMImageDescriptionPropertyID_ProductionDisplayHeight
Synonym for
kICMImageDescriptionPropertyID_ProductionApertureDisplayHeight
. -
kICMImageDescriptionPropertyID_NCLCColorInfo
Color information, if available in the
NCLCColorInfoImageDescriptionExtension
format. -
kICMImageDescriptionPropertyID_CGColorSpace
A CGColorSpaceRef for the colorspace described by the image description, constructed from video color information or ICC Profile. It is important to note that the YCbCr matrix from the video color info is not represented in the
CGColorSpaceRef
. The caller ofGetProperty
is responsible for releasing this, for example, by callingCGColorSpaceRelease
. Only supported on Mac OS X. -
kICMImageDescriptionPropertyID_ICCProfile
A CFDataRef containing the serialized ICC profile described by the image description. The caller of
GetProperty
is responsible for releasing this, for example, by callingCFRelease
. -
kICMImageDescriptionPropertyID_FieldInfo
Information about the number and order of fields, if available.
-
kICMImageDescriptionPropertyID_ClassicTrackWidth
A track width suitable for passing to
NewMovieTrack
when creating a new track to hold this image data. -
kICMImageDescriptionPropertyID_ClassicTrackHeight
A track height suitable for passing to
NewMovieTrack
when creating a new track to hold this image data. -
kICMImageDescriptionPropertyID_GammaLevel
A Fixed for the gammma level described by the image description.
-
kICMImageDescriptionPropertyID_RowBytes
The offset in bytes from the start of one row to the next. Only valid if the codec type is a chunky pixel format.
-
kICMImageDescriptionPropertyID_StepDuration
Defines a duration for quantizing time. This is applicable for cases where a single media sample generates visual output that varies continuously through its duration. By interpreting this property, such a sample may be considered to have internal "step points" at multiples of the stepping duration. This can be used to throttle frame generation during playback, and when stepping using InterestingTime APIs. Setting a step duration with value zero removes any current step duration.
-
kICMImageDescriptionPropertyID_CleanApertureClipRect
The clean aperture as a FixedRect in source coordinates, within the rectangle defined by the image description width and height, suitable for use as a source rectangle in a decompression sequence. For historical reasons, the DVCPROHD codecs store the production aperture display dimensions in the image description width and height; the actual encoded dimensions are smaller. For DVCPROHD, the clip rect will be relative to the image description width and height, not the encoded dimensions.
-
kICMImageDescriptionPropertyID_CleanApertureMatrix
A matrix transforming the clean aperture clip rect to the origin, scaled to the clean aperture display dimensions. For historical reasons, the DVCPROHD codecs store the production aperture display dimensions in the image description width and height; the actual encoded dimensions are smaller. For DVCPROHD, the matrix will be relative to the image description width and height, not the encoded dimensions.
-
kICMImageDescriptionPropertyID_ProductionApertureMatrix
A matrix transforming the image to the origin, scaled to the production aperture display dimensions. For historical reasons, the DVCPROHD codecs store the production aperture display dimensions in the image description width and height; the actual encoded dimensions are smaller. For DVCPROHD, the matrix will be relative to the image description width and height, not the encoded dimensions.
-
kICMImageDescriptionPropertyID_SummaryString
A localized, human readable string summarizing the image as a CFString, that is, "Apple DV, 720 x 480 (640 x 480), Millions". The elements are: the codec name, the encoded pixels dimensions, then parenthetically the clean aperture mode dimensions, but only if they are different from the encoded pixels dimensions; then the depth. The codec name shall be from the localized decompressor component name string if exactly one decompressor with the correct cType is available; otherwise the string in the image description shall be used. The caller of GetProperty is responsible for releasing this CFString, for example, by calling CFRelease.
The following are DV Compressor component properties in QuickTime 7.1.
Declaration
enum {
kQTPropertyClass_DVCompressor = 'dvco',
kDVCompressorPropertyID_ProgressiveScan = 'prog',
kDVCompressorPropertyID_AspectRatio16x9 = '16x9',
};
Constants
-
kQTPropertyClass_DVCompressor
The property class for DV compressors. (Applicable to DV25, DV50, NTSC, PAL, PROPAL.)
-
kDVCompressorPropertyID_ProgressiveScan
If set, indicates that the compressed frames should be marked as progressive-scan. By default, this flag is clear, meaning that frames should be marked as interlaced.
-
kDVCompressorPropertyID_AspectRatio16x9
If set, indicates that the compressor should use a 16:9 picture aspect ratio. If clear, the compressor will use the default 4:3 picture aspect ratio.
The following are visual properties of movies for aperture modes in QuickTime 7.1.
Declaration
enum {
kQTVisualPropertyID_ApertureMode = 'apmd',
};
Constants
-
kQTVisualPropertyID_ApertureMode
You can set the aperture mode property on a movie to indicate whether aspect ratio and clean aperture correction should be performed (
kQTPropertyClass_Visual
/kQTVisualPropertyID_ApertureMode
). When a movie is in clean, production or encoded pixels aperture mode, each track's dimensions are overriden by special dimensions for that mode. The original track dimensions are preserved and can be restored by setting the movie into classic aperture mode. Aperture modes are not saved in movies. You can set the aperture mode property on a decompression session options object to indicate whether pixel buffers should be tagged to enable aspect ratio and clean aperture correction (kQTPropertyClass_ICMDecompressionSessionOptions
/kICMDecompressionSessionOptionsPropertyID_ApertureMode
).
You can set the aperture mode property on a movie to indicate whether aspect ratio and clean aperture correction should be performed (kQTPropertyClass_Visual/kQTVisualPropertyID_ApertureMode)
. When a movie is in clean, production or encoded pixels aperture mode, each track’s dimensions are overriden by special dimensions for that mode. The original track dimensions are preserved and can be restored by setting the movie into classic aperture mode. Aperture modes are not saved in movies. You can set the aperture mode property on a decompression session options object to indicate whether pixel buffers should be tagged to enable aspect ratio and clean aperture correction (kQTPropertyClass_ICMDecompressionSessionOptions
/ kICMDecompressionSessionOptionsPropertyID_ApertureMode
). The movie will be recalculated (laid out again) after one of the following happens: the movie’s aperture mode is changed; a track property corresponding to the current aperture mode is changed (that is, kQTVisualPropertyID_EncodedWidth
for kQTApertureMode_EncodedPixels
). Track and movie matrices will stay constant unless explicitly changed. The aperture mode of a movie can be set during NewMovieFromProperties
, and set/get using SetMovieProperties
and GetMovieProperties
. NewMovieFromProperties
defaults to kQTApertureMode_Classic
. Decompression session options also support this property.
Declaration
enum {
kQTApertureMode_Classic = 'clas',
kQTApertureMode_CleanAperture = 'clea',
kQTApertureMode_ProductionAperture = 'prod',
kQTApertureMode_EncodedPixels = 'enco'
};
Constants
-
kQTApertureMode_Classic
An aperture mode which gives compatibility with behavior in QuickTime 7.0.x and earlier. A movie in classic aperture mode uses track dimensions as set in
NewMovieTrack
andSetTrackDimensions
. A decompression session in classic aperture mode does not set the clean aperture or pixel aspect ratio attachments on emitted pixel buffers. Movies default to classic aperture mode. If you callSetTrackDimensions
on a track, the movie is automatically switched into classic aperture mode. -
kQTApertureMode_CleanAperture
An aperture mode for general display. Where possible, video will be displayed at the correct pixel aspect ratio, trimmed to the clean aperture. A movie in clean aperture mode sets each track's dimensions to match its
kQTVisualPropertyID_CleanApertureDimensions
. A decompression session in clean aperture mode sets the clean aperture and pixel aspect ratio attachments on emitted pixel buffers based on the image description. -
kQTApertureMode_ProductionAperture
An aperture mode for modal use in authoring applications. Where possible, video will be displayed at the correct pixel aspect ratio, but without trimming to the clean aperture so that the edge processing region can be viewed. A movie in production aperture mode sets each track's dimensions to match its
kQTVisualPropertyID_ProductionApertureDimensions
. A decompression session in production aperture mode sets the pixel aspect ratio attachments on emitted pixel buffers based on the image description. -
kQTApertureMode_EncodedPixels
An aperture mode for technical use. Displays all encoded pixels with no aspect ratio or clean aperture compensation. A movie in encoded pixels aperture mode sets each track's dimensions to match its
kQTVisualPropertyID_EncodedPixelsDimensions
. A decompression session in encoded pixels aperture mode does not set the clean aperture or pixel aspect ratio attachments on emitted pixel buffers.
The following are the vsual properties of tracks for aperture modes. A track's dimensions may vary depending on the movie's aperture mode. The dimensions for a given aperture mode may be accessed using these properties.
Declaration
enum {
kQTVisualPropertyID_ClassicDimensions = 'cldi',
kQTVisualPropertyID_CleanApertureDimensions = 'cadi',
kQTVisualPropertyID_ProductionApertureDimensions = 'prdi',
kQTVisualPropertyID_EncodedPixelsDimensions = 'endi',
kQTVisualPropertyID_HasApertureModeDimensions = 'hamd',
};
Constants
-
kQTVisualPropertyID_ClassicDimensions
The track dimensions used in QuickTime 7.0.x and earlier. Setting this property is equivalent to calling SetTrackDimensions, except that SetTrackDimensions also changes the aperture mode to
kQTApertureMode_Classic
, and setting this property does not. -
kQTVisualPropertyID_CleanApertureDimensions
The track dimensions to use in clean aperture mode.
-
kQTVisualPropertyID_ProductionApertureDimensions
The track dimensions to use in production aperture mode.
-
kQTVisualPropertyID_EncodedPixelsDimensions
The track dimensions to use in encoded pixels aperture mode.
-
kQTVisualPropertyID_HasApertureModeDimensions
True if aperture mode dimensions have been set on this movie, even if they are all identical to the classic dimensions (as is the case for content with square pixels and no edge processing region). This property can also be tested on a movie, where it is true if any track has aperture mode dimensions.
Defines media characteristics for aperture modes.
Declaration
enum {
kCharacteristicSupportsApertureModes = 'apmd',
}
Constants
-
kCharacteristicSupportsApertureModes
Indicates that a media handler supports aperture modes, which enable video to be automatically scaled and cropped to compensate for non-square pixel aspect ratios and to trim possibly-dirty edge processing regions. The dimensions of such a track may change when the movie’s aperture mode is changed.
Defines scaling modes.
Declaration
enum {
kQTSpecialScalingMode_FitWithinDimensions = 'fit '
};
Constants
-
kQTSpecialScalingMode_FitWithinDimensions
Adjusts destination dimensions so that the source fits within the dimensions specified with
kQTSettingsImageWidth
andkQTSettingsImageHeight
by fitting to the shortest side, and scales the source to the destination. Internally, the default scaling mode, which is based on the source aperture mode, is used for compression session, instead of this scaling mode..
Defines settings for video and image sizes, clean aperture and pixel aspect ratios.
Declaration
enum {
kQTSettingsVideoSize = 'isiz'
kQTSettingsImageWidth = 'iwdt'
QTSettingsImageHeight = 'ihgt'
kQTSettingsCleanAperture = 'clap'
kQTSettingsPixelAspectRatio = 'pasp'
kQTSettingsScalingMode = 'scam'
kQTSettingsUseCodecEnforcedDimensions = 'uenf'
kQTSettingsDeinterlaceSource = 'dint'
};
Constants
-
kQTSettingsVideoSize
The video size-related container.
-
kQTSettingsImageWidth
The destination width. If this is zero, it means the source width.
-
QTSettingsImageHeight
The destination height. If this is zero, it means the source height.
-
kQTSettingsCleanAperture
The clean aperture for compression sessions. If this is all zeros, it means no clean aperture (that is, full width and height).
-
kQTSettingsPixelAspectRatio
The pixel aspect ratio for compression sessions. If this is all zeros, it means square pixels (that is, 1:1).
-
kQTSettingsScalingMode
The scaling mode for compression sessions. If this is zero, it means scaling mode based on the source aperture mode.
-
kQTSettingsUseCodecEnforcedDimensions
If
TRUE
, compressor’s enforced dimension overrides the image size settings. -
kQTSettingsDeinterlaceSource
If
TRUE
, deinterlacing is applied to source frames.
Defines properties of decompression session options objects.
Declaration
enum {
kICMDecompressionSessionOptionsPropertyID_ApertureMode = 'apmd', // OSType,
Read/Write
};
Constants
-
kICMDecompressionSessionOptionsPropertyID_ApertureMode
You can set the aperture mode property on a decompression session options object to indicate whether pixel buffers should be tagged to enable aspect ratio and clean aperture correction. The default aperture mode for a decompression session is clean aperture mode.
Defines properties of compression sessions options objects.
Declaration
enum {
kICMCompressionSessionOptionsPropertyID_ExtraAspectRatioStretchFactor = 'exsf', // Fixed,
Default fixed1,
Read/Write
};
Constants
-
kICMCompressionSessionOptionsPropertyID_ExtraAspectRatioStretchFactor
Requests additional distortion to be applied to the aspect ratio in the
kICMScalingMode_Letterbox
andkICMScalingMode_Trim
scaling modes. Values greater than fixed1 mean wider, values less than fixed1 mean narrower. For example, a value of X2Fix(2.0) would make the picture aspect ratio twice as wide.
These constants indicate how source frames to a compression session should be scaled if the dimensions and/or display aspect ratio do not match.
Declaration
enum {
kICMScalingMode_StretchCleanAperture = 'sc2c',
kICMScalingMode_StretchProductionAperture = 'sp2p',
kICMScalingMode_Letterbox = 'lett',
kICMScalingMode_Trim = 'trim'
};
Constants
-
kICMScalingMode_StretchCleanAperture
The clean aperture of the source frames is scaled to the clean aperture of the destination.
-
kICMScalingMode_StretchProductionAperture
The full width and height of source frames is scaled to the full width and height of the destination. This is the default if no other scaling mode is specified.
-
kICMScalingMode_Letterbox
The clean aperture of the source frames is scaled to fit inside the clean aperture of the destination, preserving the original display aspect ratio. If the display aspect ratios are different, the source frames are centered with black bars above and below, or to the left and right.
-
kICMScalingMode_Trim
The clean aperture of the source frames is scaled to cover the clean aperture of the destination, preserving the original display aspect ratio. If the display aspect ratios are different, the source frames are centered and cropped.
The type of atom that stores information for video correction in the movie resource. A child of the 'track'
atom.
Declaration
enum {
TrackApertureModeDimensionsAID = 'tapt',
TrackCleanApertureDimensionsAID = 'clef',
TrackProductionApertureDimensionsAID = 'prof',
TrackEncodedPixelsDimensionsAID = 'enof',
};
Constants
The following are enforced properties (introduced in QuickTime 7.0.4) for image compressor components. Image compressors that sometimes or always restrict image dimensions, clean aperture and/or pixel aspect ratio should support these properties. If these properties can change dynamically for a compressor (for example, in response to user interaction) then the properties should be listenable, and the compressor should call the listeners whenever the properties change. (In this case, the component's GetComponentPropertyInfo
function should set the kComponentPropertyFlagWillNotifyListeners
flag.) If a compressor has a mode in which these properties are flexible, then when the component is in that mode, (a) the component's GetComponentProperty
function should return kQTPropertyAskLaterErr
for these properties, and (b) the component's GetComponentPropertyInfo
function should set the kComponentPropertyFlagCanGetLater
flag for these properties.
Declaration
enum {
kICMImageCompressorPropertyID_EnforcedEncodedWidth = 'enwi',
kICMImageCompressorPropertyID_EnforcedEncodedHeight = 'enhe',
kICMImageCompressorPropertyID_EnforcedCleanAperture = 'encl',
kICMImageCompressorPropertyID_EnforcedPixelAspectRatio = 'enpa',
kICMImageCompressorPropertyID_EnforcedFieldInfo = 'enfi',
};
Constants
-
kICMImageCompressorPropertyID_EnforcedEncodedWidth
The encoded width enforced for compressed frames.
-
kICMImageCompressorPropertyID_EnforcedEncodedHeight
The encoded height enforced for compressed frames.
-
kICMImageCompressorPropertyID_EnforcedCleanAperture
The clean aperture enforced for compressed frames.
-
kICMImageCompressorPropertyID_EnforcedPixelAspectRatio
The pixel aspect ratio enforced for compressed frames.
-
kICMImageCompressorPropertyID_EnforcedFieldInfo
The number and order of fields enforced for compressed frames.
The following is a list of the new audio properties available in QuickTime 7.1.
Declaration
enum {
kQTAudioRenderQuality_PlaybackDefault = 0x8000,
kQTAudioPropertyID_RenderQuality = 'qual',
kQTMovieAudioExtractionAudioPropertyID_RenderQuality = 'qual',
kQTAudioPropertyID_DeviceASBD = 'dasd',
kQTAudioPropertyID_SummaryASBD = 'sasd',
kQTAudioPropertyID_RateChangesPreservePitch = 'aucp',
kQTAudioPropertyID_Pitch = 'pitc',
kQTSCAudioPropertyID_RenderQuality = 'qlty',
};
Constants
-
kQTAudioPropertyID_DeviceASBD
This is a get-only property and returns the
AudioStreamBasicDescription
of the device the movie is playing to. The interesting fields are the sample rate, which reflects device’s current state, and the number of channels, which matches what is reported bykQTAudioPropertyID_DeviceChannelLayout
. -
kQTAudioPropertyID_SummaryASBD
Get-only. Returns the
AudioStreamBasicDescription
corresponding to the Summary Mix of a movie. This describes non-interleaved,Float32
linear PCM data, with a sample rate equal to the highest audio sample rate found among the sound tracks contributing to the AudioContext mix, and a number of channels that matches what is reported bykQTAudioPropertyID_SummaryChannelLayout
. -
kQTAudioPropertyID_RateChangesPreservePitch
This property was introduced in QuickTime 7 and must be set in order for pitch changes to take effect. When the playback rate is not unity, audio must be resampled in order to play at the new rate. The default resampling affects the pitch of the audio (for example, playing at 2x speed raises the pitch by an octave, 1/2x lowers an octave). If this property is set on the Movie, an alternative algorithm may be used, which alters the speed without changing the pitch. Because this is more computationally expensive, this property may be silently ignored on some slow CPUs. Media handlers may query this movie property and honor it when performing Scaled Edits. This property can be specified as a property to the
NewMovieFromProperties
API. Currently, it has no effect when set on an open movie. -
kQTAudioPropertyID_Pitch
The movie pitch adjustment. This adjusts the pitch of all audio tracks that contribute to the AudioContext mix. Pitch control takes effect only if
kQTAudioPropertyID_RateChangesPreservePitch
is in effect; otherwise, returnskQTMessageNotHandledErr
. TheFloat32
value is specified in cents: 0.0 == no change, 1.0 == one cent up, 100.0 == one semi-tone up, -1.0 == one cent down. The most useful ranges for pitch are +/- 1200, that is, one octave. -
kQTAudioPropertyID_RenderQuality
Movie audio render quality takes effect for movie playback.
UInt32
values are as defined in AudioUnit/AudioUnitProperties.h and vary from 0x00 (kRenderQuality_Min
) to 0x7F (kRenderQuality_Max
). A special valuekQTAudioRenderQuality_PlaybackDefault
) is also defined which resets the quality settings of the playback processing chain to values that are chosen to be an optimal balance of performance and quality. -
kQTMovieAudioExtractionAudioPropertyID_RenderQuality
Sets the render quality to be used for this audio extraction session.
UInt32
values are as defined in AudioUnit/AudioUnitProperties.h and vary from 0x00(kRenderQuality_Min
) to 0x7F (kRenderQuality_Max
). A special value (kQTAudioRenderQuality_PlaybackDefault
) is also defined which resets the quality settings to the same values that were chosen by default for playback. -
kQTSCAudioPropertyID_RenderQuality
Specifies the quality with which QuickTime should render the audio stream during the compression/decompression/transcode operation. Accepted constants are those used by AudioUnits (defined in AudioUnitProperties.h):
kRenderQuality_Max
,kRenderQuality_High
,kRenderQuality_Medium
,kRenderQuality_Low
,kRenderQuality_Min
. Available in QuickTimeComponents.h.
The following is a list of new metadata constants available in QuickTime 7.1:
Declaration
enum {
kQTMetaDataCommonKeyAlbum = 'albm',
kQTMetaDataCommonKeyArtist = 'arts',
kQTMetaDataCommonKeyArtwork = 'artw',
kQTMetaDataCommonKeyChapterName = 'chap',
kQTMetaDataCommonKeyComposer = 'comp',
kQTMetaDataCommonKeyDescription = 'desc',
kQTMetaDataCommonKeyGenre = 'genr',
kQTMetaDataCommonKeyOriginalFormat = 'orif',
kQTMetaDataCommonKeyOriginalSource = 'oris',
kQTMetaDataCommonKeyPerformers = 'perf',
kQTMetaDataCommonKeySoftware = 'soft',
kQTMetaDataCommonKeyWriter = 'wrtr'
};
Constants
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