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vdp

Control a videodisk player through a serial port

Description

The vdp object works with serially-controlled videodisk players (remember them?) that are compatible with the Pioneer 4200 or 8000 standard. Each command received by the vdp object sends a stream of numbers out the object's left outlet, intended to be connected to the serial object. The description of each command discusses what effect the command has on the player, not the exact character stream sent by vdp.

Because videodisc players have relatively buffer-less serial interfaces, vdp places each command it receives in a queue, and sends it out only when the player has finished executing its most recent command. This "feature" may cause a delay between the time a command is sent to the vdp object and the time it is actually sent out the serial port.

Any message received in the right inlet will behave exactly as if it had been received in the left inlet, except that it will be put at the front of the queue, to be the very next command sent out to the player.

Examples

Basic configuration of vdp and serial objects... 'Scrubbing' with a slider or MIDI controller

Arguments

None.

Attributes

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

int

Arguments

frame-number [int]
In left inlet: Same as play from a specified frame number to the end of the disc.

In middle inlet: vdp expects responses from the player to be fed from the serial object into its middle inlet. When vdp sees "received" (the letter R followed by the return character) from the player, it sends the next command from its queue of pending commands. The example shows how to connect the vdp and serial objects together.

chapter

In left inlet: Asks the player what its current chapter number is and sends the response (received in the middle inlet) out the middle-right outlet.

clear

In left inlet: Removes any pending commands from the queue and resets the object.

cmd

Arguments

ASCII-primitive-command-code [list]
In left inlet: The cmd message can be used to send "primitive" commands consisting of ASCII codes to the video disk player. Commands usually consist of two-letter codes preceded by numeric arguments. For example, searching to frame 5000 could be accomplished with the message cmd 5000 SE. Refer to the owner's manual of your player for details. The cmd message is particularly useful with the Pioneer 8000 player, since it has a number of special features not supported by the regular messages of the vdp object.

control

Arguments

action-ID [int]
In left inlet: The word control, followed by a number, tells the videodisc player to perform one of the following operations:

Number Operation
0 --------- Initialize and reset player
1 --------- Eject disk
2 --------- Audio off
3 --------- Audio 1 on
4 --------- Audio 2 on
5 --------- Stereo on
6 --------- Picture on
7 --------- Picture off
8 --------- Display frame numbers on
9 --------- Display frame numbers off
11 ------- Frame access mode
12 ------- Time access mode
13 ------- Chapter access mode

fps

Arguments

playback-speed (frames-per-second) [list]
In left inlet: Sets the playing speed. The fps message is followed by a number (frames per second) or an adjective. The following adjectives and numbers are equivalent (at least for the Pioneer 4200):

slowest 1
slower 10
slow 15
normal 30
fast 60
faster 90
fastest 120

frame

In left inlet: Asks the player what its current frame number is and sends the response (received in the middle inlet) out the middle-right outlet.

name

In left inlet: Asks the player what the current name is and sends the response (received in the middle inlet) out the middle-right outlet.

play

Arguments

first-frame [int]
last-frame [int]
speed [int]
In left inlet: With no arguments, play starts playing at the current speed from the current location to the end of the disk (or until the player receives another command). With one argument (a frame number), play searches to the specified frame number and begins playing to the end of the disk. With two arguments, play searches to the location specified by the first number and plays until the disc reaches the second frame number.

scan

Arguments

forward/backward [list]
In left inlet: Initiates a "fast forward" or "rewind" operation. scan forward moves forward, scan backward moves backward.

Arguments

start-frame-number [int]
display-flag (0 or non-zero) [int]
In left inlet: The first argument indicates a frame number to search to. The second, optional argument, if non-zero, instructs the player to keep the picture on while searching. If searching a great distance from the current location, the player may not be able to keep from blanking the screen. Once the player arrives at the desired frame, it will display the (still) image from that frame.

step

Arguments

previous/next-step (-1 or 1) [int]
In left inlet: Followed by -1, step pauses the player (if playing) and displays the previous frame. Followed by 1, step pauses the player (if playing) and displays the next frame.

stop

In left inlet: Pauses the player.

restrict

Arguments

start-frame-number [int]
end-frame-number [int]
The word restrict followed by a starting frame-number and an ending frame-number will restrict all future messages to perform their actions restricted between the two frames.

setskip

Arguments

number-of-skipped-frames [int]
In left inlet: Followed by a number, sets the number of frames to jump (forward or backward) from the current frame location when using the skip message.

skip

Arguments

backward/forward-flag (-1 or 1) [int]
In left inlet: Followed by -1, skips backward by a number of frames specified in the setskip message. Followed by 1, skips forward by a number of frames specified in the setskip message.

Output

bang

Out middle-left outlet: After sending a command out its left outlet, vdp begins "polling" the serial object for a response from the player by sending bang messages out this outlet approximately every 20 milliseconds, until vdp receives a "received" signal from the player in its right inlet. (A bang sent to a serial object causes any characters received in that serial port to be sent out the serial object's outlet.)

int

Out left outlet: A stream of characters, coded instructions to the videodisc player, for each command. These numbers are intended to be sent to the left inlet of a serial object.

int

Out middle-right outlet: Current frame number, received from the player in response to a frame message.

int

Out right outlet: Not implemented.

See Also

Name Description
Using Max with Hardware Using Max with Hardware
serial Send and receive from a serial port