jit.qt.grab

Digitize video from an external source

Description

Use the jit.grab object to digitize video from any video digitizer and decompress the signal into a Jitter matrix. On OSX, QuickTime is used; on Windows, DirectX is used.

Discussion

jit.grab also offers a grab-to-disk mode. Although numerous parameters for control are offered, not all features are supported by all digitizers.

Matrix Operator

matrix inputs:1, matrix outputs:1
Name IOProc Planelink Typelink Dimlink Plane Dim Type
out n/a 1 1 1 4 1 char

More about Matrix Operators

The Jitter MOP

Since the matrix is Jitter's focus, it is not surprising that the majority of Jitter objects fall in this category of Matrix Operators. Every Matrix operator has some number of matrix inputs and some number of matrix outputs. Matrix inputs are referred to by the names "in", "in2", "in3", etc., from left to right, and matrix outputs are referred to by the names "out", "out2", "out3", etc., from left to right--i.e. the names are appended by the input/output number except for the first (leftmost) input and first (leftmost) output which are simply named "in" and "out". We will refer to the input or output name names as the "I/O-name".

Matrix inputs and outputs typically each have their own matrices internally where information is kept. This is necessary because Jitter is an asynchronous framework (i.e. all the matrices don't arrive at all inputs at the same time). Various aspects of matrix inputs and outputs can be set using the command [I/O-name] combined with one of the following suffixes: "_dim" which will set the dimensions of the specified I/O matrix, "_type" which will set the type of the specified matrix, "_planecount" which will set the plane of the specified matrix, or "_name" which will set the name of the specified matrix. There is one special case which does not have an internal matrix and this is the first input "in". This is the case since this special input actually triggers the calculation of the matrix operator, so it doesn't need to be cached until a calulation takes place, unlike the other inputs. Therefore there is no mechanism to set the dim, planecount, type, or name of "in".

Matrix operators accept what we'll refer to as "matrix args"--i.e. [planecount (int)] [ type (symbol)] [dim (int list)]. if these arguments are present, the adapt attribute will be turned off, otherwise it will be turned on. If adapt mode is turned on, each time a matrix is received in the first input, there will also be the equivalent of setting the dim, planecount, and type attributes to that of the input matrix. If the other inputs and outputs are linked to these attributes, this will affect their linked attributes as well. See the "MOP" table to determine which inputs and outputs will be linked to which attributes when adapt mode is turned on. For the leftmost input this is not applicable, and hence all columns are labelled "n/a".

The jit.matrix object is a named matrix which may be used to matrix data storage and retrieval, resampling, and matrix type and planecount conversion operations.

MOP Arguments

planecount [int]

Optional

Explicitly sets the number of planes for the output and any righthand inputs. If this is absent, the Matrix Operator will typically adapt to the lefthand incoming matrix attributes, except for special case operators.

type [symbol]

Optional

Explicitly sets the type of the matrix for the output and any righthand inputs. If this is absent, the Matrix Operator will typically adapt to the lefthand incoming matrix attributes, except for special case operators.

dimensions [list]

Optional

Explicitly sets the dimensions of the matrix for the output and any righthand inputs. If this is absent, the Matrix Operator will typically adapt to the lefthand incoming matrix attributes, except for special case operators.

MOP Attributes

adapt [int]

Matrix adaptation flag (default = 0 if matrix arguments are present, otherwise 1) When the flag is set, the jit.matrix object will adapt to the incoming matrix planecount, type, and dimensions.

[in/out]_dim [32 ints]

The matrix data dimensions (default = 1 1)

[in/out]_name [symbol]

The input or output name of the matrix (default = UID)

[in/out]_planecount [int]

The number of planes in matrix input our output data. Except in special cases, this value is equal to the planecount.

[in/out]_type [symbol]

The input or output matrix data type. Except in special cases, this value is equal to type.

[in/out]_type [symbol]

The input or output matrix data type. Except in special cases, this value is equal to type.

outputmode [int]

Output mode (default = 1 (calculate and output matrix))
0 = No output
1 = Calculate and output the matrix
2 = Pass input (no calculation)
3 = Pass output (no calculation)

type [int]

The matrix data type (default = char
Supported data types are char, long, float32, or float64.

MOP Messages

bang

Equivalent to the outputmatrix message.

clear

Sets all cell values in a matrix to zero.

exportattrs

Arguments

filename [symbol]
Exports an object's current attributes values in XML format. If no filename is specified, a file dialog will open to let you choose a file.

getattributes

Sends a sequence of lists out the object's right outlet describing the object's attributes, one line per attribute. Each line listing line takes the form attribute attribute-name get get-value set foo set-value data-type(s) number-of-values .

getstate

Sends a sequence of lists describing the object's state out the object's right outlet, one line per attribute. Each line listing line takes the form attribute-name attribute-value1 attribute-value2 ... attribute-valueN .

importattrs

Arguments

filename [symbol]
Imports attributes specified in XML format to set the object's attributes. If no filename is specified, a file dialog will open to let you choose a file.

jit_matrix

Arguments

matrix-name [symbol]
Handles input for the named matrix. If this messages is received in the left inlet, output is typically triggered. If this message is received in any other inlet, the data is typically cached until the jit_matrix message is received in the left inlet.

outputmatrix

Sends the matrix out the left outlet.

summary

Sends a sequence of lists describing the object and it attributes and messages out the rightmost outlet of the object. The first output line takes the form summary objectname object-name . The second and third lines describe the number of inlets and outlets for the object in the form summary (matrixinputcount/matrixoutletcount) number-of-(inlets/outlets) . The fourth line describes the matrixoutput in the form summary matrixoutput descriptor planelink planelink-value typelink typelink-value dimlink dimlink-value types data-type(s) . Each attribute for the object is then listed, one attribute per line. Each line listing takes the form summary attribute attribute-name attribute-value1 attribute-value2 ... attribute-valueN .

Attributes

adapt [int]

Adapt output matrix dimensions to native device dimensions. Enabled by default if no dim specified.

automatic [int]

Enable automatic matrix output when bound to jit.world.

bitrate [int]

The sound digitizer bit depth (default = digitizer-specific). 32 bit only.
8 = digitize sound at 8-bit resolution
16 = digitize sound at 16-bit resolution

blacklevel [float]

The video digitizer black level (default = digitizer-specific). 32 bit only.

brightness [float]

The video digitizer brightness level (default = digitizer-specific). 32 bit only.

channels [int]

The sound digitizer channel selection (default = digitizer-specific). 32 bit only.
1 = digitize sound in mono
2 = digitize sound in stereo

codeclist [system-dependent symbols]

g/s(get)

The valid video codecs available on the system
Sending the message getcodeclist will cause a list of all valid codecs (that is, those with a functioning compressor component) to be reported from the dumpout. This list is guaranteed to contain only working codecs, and should be used in preference to the old, static codec list. 32 bit only.

codecquality [int/symbol]

The video digitizer codec quality. This is only active in vmode 2 (default = 4/max). 32 bit only.
0 or min = minimum
1 or low = low
2 or normal = normal
3 or high = high
4 or max = maximum
5 or lossless = lossless

Note that minimum quality is, in many cases, the codec's default quality. Use "low" quality for consistent results.

colormode [symbol]

The output matrix's color encoding (default = argb)

Possible values:

'argb' ( ARGB (alpha, red, green, blue) colormode )
'uyvy' ( UYVY (YUV 4:2:2 packed) colormode )

colorspace [int]

The video digitizer colorspace mode (default = digitizer-specific). 32 bit only.
0 = grayscale
1 = color

contrast [float]

The video digitizer contrast level (default = digitizer-specific). 32 bit only.

drawto [symbol]

A render context name, used when output_texture is enabled.

dropreport [int]

Dropped frames reporting flag (default = 0 (disabled))
When this flag is set, the message dropped will be sent from the rightmost outlet of the jit.grab object, followed by the number of dropped frames, whenever frame-dropping is detected. 32 bit only.

dstrect [4 ints]

The portion of the output matrix used for decompressing media to the internal matrix. (default = 0 0 (matrix width) (matrix height))
The proportions of the rectangle are expressed in the form left top right bottom . All values are relative to the top left corner of the viewing area of the output matrix.

engine [symbol]

Video engine backend. This argument can only be set in the max box. If not specified, it is determined by the Video Engine Max preference. As of this writing, possible values include avf (Mac only), qt , and viddll .

field [int]

The video digitizer field selection (default = digitizer-specific)
0 = digitizer determines field selection
1 = digitizer uses odd field
2 = digitizer uses even field MAC OSX ONLY WITH DFG/1394-1 digitizer (using ASC-s driver, version 2 or higher) 128 = digitizer uses both fields, alternating 129 = digitizer uses both fields, stacked (upper half is odd, lower half is even). 32 bit only.

framerate [float]

The video digitizer frame rate (default = digitizer-specific).
The digitizer has to be closed and re-opened before changes to framerate take effect.

framereport [int]

Frame reporting flag (default = 0)
When enabled, the message framecalc will be sent from the rightmost outlet of the jit.grab object as each frame is processed, followed by the number of milliseconds spent doing so.

gain [float]

The sound digitizer gain (default = digitizer-specific)

gamma [3 floats]

The video digitizer gamma (default = digitizer-specific)

hue [float]

The video digitizer hue adjustment (default = digitizer-specific)

input [int]

The current video digitizer input (default = digitizer-specific)

interp [int]

Image interpolation flag (default = 0)

maxfps [float]

g/s(get)

The video digitizer's maximum frame rate (default = digitizer-specific). 32 bit only.

output_texture [int]

Enable OpenGL texture output (default = 0). When enabled an OpenGL texture is output instead of a Jitter matrix. The object's drawto attribute must be set to a valid gl context. An RGBA texture is output using the movie's native dimensions. When enabled, the following attributes have no effect:
adapt
colormode
dim
dstrect
srcrect
usedstrect
usesrcrect

playthru [int]

Sound digitizer playthrough flag (default = digitizer-specific). 32 bit only.

pll [int]

The phase locked loop (PLL) type (default = digitizer-specific). 32 bit only.
0 = broadcast mode
1 = VTR mode

samplerate [int]

Sound digitizer sample rate (default = digitizer-specific). 32 bit only.
48000 = 48kHz
44100 = 44.1kHz
32000 = 32kHz
22050 = 22.050kHz
22254 = 22kHz
16000 = 16kHz
11127 = 11kHz
11025 = 11.025kHz
8000 = 8000 Hz

saturation [float]

Video digitizer saturation level (default = digitizer-specific). 32 bit only.

sharpness [float]

Video digitizer sharpness level (default = digitizer-specific). 32 bit only.

singlefield [int]

Single field flag (default = 1 (enabled))
When the flag is set, an attempt is made to decompress one field of an interlaced frame at high quality, and then scale the image to the frame size. If the digitizer doesn't provide interlaced frames, this flag does nothing. 32 bit only.

snd_active [int]

g/s(set)

Sound digitizer enable flag (default = 0). 32 bit only.

sndcodec [symbol]

Sound digitizer codec mode (used for recording) (default = digitizer-specific). 32 bit only.
none = no compression
raw = raw compression
big16 = 16-bit big endian
little16 = 16-bit little endian
float32 = 32-bit floating point
float64 = 64-bit floating point
24bit = 24-bit integer
32bit = 32-bit integer
little32 = 32-bit little endian
mace3 = MACE 3:1
mace6 = MACE 6:1
cdxa4 = CD/XA 4:1
cdxa2 = CD/XA 2:1
ima = IMA 4:1
ulaw = uLaw 2:1
alaw = aLaw 2:1
adpcm = Microsoft ADPCM (ACM code 2)
dviima = DVI/Intel IMA ADPCM (ACM code 17)
dvaudio = DV Audio
qdesign = QDesign music
qdesign2 = QDesign2 music
qualcomm = Qualcomm PureVoice
mp3 = MPEG Layer 3 (CBR or VBR)

snddevice [int]

The current sound digitizer (default = 0). 32 bit only.

sndinput [int]

The current sound input for the selected sound digitizer (default = 0). 32 bit only.

srcrect [4 ints]

Source rect from digitizer frame (default = 0 0 (matrix width) (matrix height))

standard [symbol]

g/s(set)

The video digitizer standard selection (default = digitizer-specific). 32 bit only.
ntsc = NTSC
pal = PAL
secam = SECAM

texture_name [symbol]

Output texture name, when output_texture is enabled.

unique [int]

Unique frame filter flag (default = 0 (disabled))
When the flag is set, only new frames from the digitizer are output when the object receives a bang. If no new frame has been received from the digitizer, the jit.grab object will not respond to the bang.

uniqueid [int]

g/s(get)

Unique camera ID. 32 bit only.

usedstrect [int]

Destination rect flag (default = 0) When the flag is set, the dstrect attributes are used when copying an input matrix to the internal matrix.

usesrcrect [int]

Source rect flag (default = 0) When the flag is set, the srcrect attributes are used when copying an input matrix to the internal matrix.

vdevice [int]

The current video digitizer (default = 0)

vmode [int]

The video digitizer mode (default = 0 (sequence grab)). 32 bit only.
0 = sequence grab mode
1 = vdig mode (necessary/desirable for some digitizers)
2 = DV high quality mode

volume [float]

The sound digitizer volume (default = digitizer-specific). 32 bit only.

whitelevel [float]

The video digitizer white level (default = digitizer-specific). 32 bit only.

window [symbol]

Window name (default = none) If this attribute is set, the jit.grab object will render directly into the named jit.window object, thus able to use hardware decompression and interpolation as permitted by QuickTime. The window must have noaccel set to 1 in order for this to work.
If no symbol argument is given, the jit.grab object's default behavior of rendering to and outputting a matrix is used. 32 bit only.

write_audio [int]

Audio track write flag (default = 0) When the flag is set, an audio track is written when grabbing images to disc. 32 bit only.

write_length [int]

The length (in frames) to limit write operations to (default = 0 (inactive)) When non-zero, limits the disk grab to the specified number of frames. The write operation will stop automatically. If you are grabbing sound only, write_length has no effect. 32 bit only.

write_preview [int]

Image preview flag (default = 0) When the flag is set, images can be previewed when grabbing images to disc. 32 bit only.

write_split [int]

Split file write flag (default = 0) When the flag is set, separate disk files for audio and video are written when grabbing images to disc. Otherwise, a single file containing both is written. 32 bit only.

write_video [int]

Video track write flag (default = 1) When the flag is set, a video track is written when grabbing images to disc. 32 bit only.

Common Box Attributes

annotation [symbol]

Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.

background [int] (default: 0)

Adds or removes the object from the patcher's background layer. background 1 adds the object to the background layer, background 0 removes it. Objects in the background layer are shown behind all objects in the default foreground layer.

color [4 floats]

Sets the color for the object box outline.

fontface [int]

Sets the type style used by the object. The options are:

plain
bold
italic
bold italic

Possible values:

0 = 'regular'
1 = 'bold'
2 = 'italic'
3 = 'bold italic'

fontname [symbol]

Sets the object's font.

fontsize [float]

Sets the object's font size (in points).

Possible values:

'8'
'9'
'10'
'11'
'12'
'13'
'14'
'16'
'18'
'20'
'24'
'30'
'36'
'48'
'64'
'72'

hidden [int] (default: 0)

Toggles whether an object is hidden when the patcher is locked.

hint [symbol]

Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.

ignoreclick [int] (default: 0)

Toggles whether an object ignores mouse clicks in a locked patcher.

patching_rect [4 floats] (default: 0. 0. 100. 0.)

Sets the position and size of the object in the patcher window.

position [2 floats]

g/s(set)

Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.

presentation [int] (default: 0)

Sets whether an object belongs to the patcher's presentation.

presentation_rect [4 floats] (default: 0. 0. 0. 0.)

Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.

rect [4 floats]

g/s(set)

Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).

size [2 floats]

g/s(set)

Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.

textcolor [float]

Sets the color for the object's text in RGBA format.

textjustification [int]

Text Justification

Possible values:

0 = 'left'
1 = 'center'
2 = 'right'

varname [symbol]

Sets the patcher's scripting name, which can be used to address the object by name in pattr, scripting messages to thispatcher, and the js object.

Messages

close

Closes an open sequence grab component. The component is automatically closed when the object is freed.

defaults

Restores digitizer image control defaults. 32 bit only.

exportimage

Arguments

filename [symbol]
file-type [symbol]
Export the current frame as an image file with the name specified by the first argument. The second argument sets the file type (default = png). Available file types are png, tiff, and jpeg.
You can use the Max Preferences to specify a default image resolution for png image types.

getiidclist

MAC OSX ONLY, requires open IIDC device. Reports a list of available IIDC features for the open IIDC component from the jit.grab object's dump outlet, preceded by the symbol iidclist. 32 bit only.

getiidc_caps

Arguments

feature name [symbol]
MAC OSX ONLY, requires open IIDC device. Reports a list of capabilities for a specific IIDC feature (see the getiidclist message for information on getting IIDC features) from the jit.grab object's dump outlet. These capabilities are used to set the state of the IIDC feature. Since every IIDC device might support different features, and each feature might support different capabilities, the capabilities list provides a means of knowing which symbols are valid to set the state (using the iidc_state message) for any particular feature of a specific device. The capabilities list typically is formatted as follows: iidc_state feature-name variable capabilities data . 32 bit only.

getiidc_state

Arguments

feature name [symbol]
MAC OSX ONLY, requires open IIDC device. Reports the current state of a specific IIDC feature (see the getiidclist message for information on getting IIDC features) from the jit.grab object's dump outlet. The state list typically is formatted as follows: iidc_state feature-name val feature-value variable additional data . 32 bit only.

getinputlist

Reports the list of available inputs to the video digitizer from the object's right outlet, preceded by the word inputlist. Note that the digitizer must be open in order for this method to function.

getsnddevlist

Reports the list of available sound digitizers from the object's right outlet, preceded by the word snddevlist. 32 bit only.

getsndinputlist

Reports the list of available inputs for the current sound digitizer from the object's right outlet, preceded by the word sndinputlist. Note that the digitizer must be open in order for this method to function. 32 bit only.

getvdevlist

Reports the list of available video digitizers from the object's right outlet, preceded by the word vdevlist.

iidc_state

Arguments

feature name [symbol]
feature-specific data [list]
MAC OSX ONLY, requires open IIDC device. Sets the current state of a specific IIDC feature (see the getiidclist message for information on getting IIDC features). Typically, to set the numeric value of a particular feature, the symbol val followed by a number is used. For other data (on/off, auto/manual, etc.), valid symbols used to set the state can be acquired using the getiidc_caps message. 32 bit only.

getiidc_csr

Arguments

offset [int]
0/1 [int]
MAC OSX ONLY, requires open IIDC device. Reports the current value of an IIDC register from the jit.grab object's dump outlet, preceded by the symbol iidc_csr. The offset argument specifies the byte offset to read from. The second argument, if present and 1, specifies that the byte offset is relative to the initial unit space (FFFF Fxxx xxxx). Otherwise, the byte offset is relative to the initial register space (FFFF F000 0000). 32 bit only.

iidc_csr

Arguments

data [int]
offset [int]
0/1 [int]
MAC OSX ONLY, requires open IIDC device. Directly sets the state of an IIDC register. The data argument specifies the new value for the register. The offset argument, if present, specifies the byte offset to set (if absent, the byte offset is assumed to be 0). The third argument, if present and 1, specifies that the byte offset is relative to the initial unit space (FFFF Fxxx xxxx). Otherwise, the byte offset is relative to the initial register space (FFFF F000 0000). 32 bit only.

open

Opens a sequence grab component. A component must be explicitly opened before the jit.grab object will began digitizing.

settings

Opens the standard video digitizer settings dialog box. 32 bit only.

snd_settings

Opens the standard sound digitizer settings dialog box. 32 bit only.

stop

Stops grabbing to disk.

write

Arguments

videofilename [symbol]
audiofilename [symbol]
FPS [float]
codec [symbol]
spatialquality [symbol]
temporalquality [symbol]
keyframes [symbol]

Starts grabbing to disk. If the write_split attribute is disabled, only one filename argument is required; Otherwise, the video and audio filenames are required. If no filename arguments are supplied, a file dialog box will open.

The default FPS is 30. frames/sec.

The default codec is raw. The following list of codecs is deprecated (retained for reference). See codeclist for the preferred method to list valid system codecs.
Supported codecs are raw, cinepak, graphics, animation, video, componentvideo, jpeg, mjpega, mjpegb, sgi, planarrgb, macpaint, gif, photocd, qdgx, avrjpeg, opendmljpeg, bmp, winraw, vector, qd, h261, h263, dvntsc, dvpal, dvpropal, flc, targa, png, tiff, componentvideosigned, componentvideounsigned, cmyk, microsoft, sorenson, indeo4, argb64, rgb48, alphagrey32, grey16, mpegyuv420, yuv420, sorensonyuv9 and mpeg4.

The default spatialquality and temporalquality values are max. Supported quality settings are lossless, max, min, low, normal, and high.

Note that minimum quality is, in many cases, the codec's default quality. Use "low" quality for consistent results.

The default keyframes is 0, which will cause keyframes to be inserted automatically, as necessary.

See Also

Name Description
Working with Video in Jitter Working with Video in Jitter
jit.movie Play or edit a QuickTime movie
jit.record Record a QuickTime movie
jit.qt.effect QuickTime Effects for Jitter matrices
jit.dx.grab Digitize video using DirectX (Windows)
jit.dx.videoout Output video to DirectX (Windows)
jit.qt.videoout Output video to QuickTime video output component
Tutorial 21: Working With Live Video Input Tutorial 21: Working With Live Video Input