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The Datafile PD-CD 4
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DATAFILE_PDCD4.iso
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1994-02-22
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ARPlayer - Desktop Movie Player
==============================
The purpose of ARPlayer is to play Acorn Replay movies. On-line help is
provided on all operations via the !Help application.
There are two basic playback modes referred to below as video and sound
playback modes.
Video mode occurs when playing a movie containing video information (it may
have sound as well) and when video is enabled from the Setup window.
Playback is single-tasking (all other tasks running on your computer are
suspended) until the movie has finished playing.
Sound mode occurs when playing a movie file that only contains sound tracks
or when the video tracks have been disabled from the Setup window. This mode
of operation is multi-tasking. The counter updates as the movie plays (if
the time bar is enabled) and other tasks run as normal. The sound data is
loaded from the movie file on disc as it is needed.
Icon bar
--------
ARPlayer installs an icon on the icon bar.
Click SELECT on this icon to open a movie window. If the 'Multiple windows'
option is enabled then this will always open a new window otherwise it will
open a window or bring the open window to the front.
The icon bar menu gives the following options
Info
Global choices ...
Multiple windows
Save choices
Quit
- 'Info' leads to the standard program information box.
- 'Global choices ...' opens the global choices window. See below for
details.
- 'Multiple windows' is a switch. If it is disabled then only one movie
window will ever be displayed. If it is enabled then a new window will be
opened whenever you click SELECT on the icon bar.
- 'Save choices' saves the current setup to disc as the default. Two files
are saved.
The contents of the 'Movie setup' window and the switches detailed above are
stored in a file within the !ARPlayer application. This file is read each
time the application is run.
The state of the system variables set by the 'Global choices' window is saved
in a separate file that may be in one of two places. If the variable
'Choices$Write' is set then it will save the file as
'<Choices$Write>.Boot.PreDesk.ARPlayer' otherwise it saves it as '<ARPlayer$Dir>.!State'.
Display window
--------------
The display window is in two sections. The main picture area where the movie
is displayed and a tool pane below containing control buttons and a time bar.
If a blank window is opened then the default ARMovie 'Replay' sprite is
displayed. When a movie is loaded then the helpful sprite from the movie
header will be shown. The title bar will show the movie description if it has
one, otherwise it will show the filename of the movie.
The window will resize itself to the correct size for the movie. Note
however that the tool pane below will not resize.
The display menu is as follows.
File Info ...
Save frame
Save data
Edit Copy frame
Clear clipboard
Movie setup ...
Time bar
Tool bar
Play
- 'File.Info' will open the Movie Info dialogue box (see below).
- 'File.Save frame' leads to a standard save dialogue box which will save
out the current movie frame exactly as displayed in the display window.
- 'File.Save data' leads to a save dialogue box with option buttons to choose
which elements of the movie to extract. Dragging the directory icon to a
directory display will run the 'Extract' utility and write out the elements
selected.
The components of a movie you can extract are:-
- Images. These is the compressed chunks of video data.
- Sound. All sound tracks present will be saved, the name depends on the
type of sample and the track number. See document 'ToUseJoin' for details.
- Keys. These are the uncompressed key frames stored with the movie to
improve access times.
- Sprite. This is the helpful sprite shown when the movie is first loaded and
often used as a thumbnail identifier.
- Header. This is the textual header to a movie which contains the data shown
in the movie info window.
- 'Edit.Copy frame' copies the displayed movie frame to the clipboard
from where it can be imported by any application that supports the clipboard
protocol.
- 'Edit.Clear clipboard' clears the clipboard if it contains a frame from
ARPlayer. This option will not be selectable if the clipboard is empty or owned
by another application.
- 'Movie setup' opens a window allowing all the various playback configure
options for Acorn Replay to be setup. The options set only affect the movie
in the display window.
- 'Time bar' will toggle the time bar and time counter display on and off.
- 'Tool bar' will toggle the movie controls on and off. If the tool
bar is not shown then a movie can be controlled using the mouse buttons:
SELECT will pause the movie until it is pressed again
MENU (or ESCAPE) will stop playback
ADJUST will pause the movie whilst it is held down
In sound-only playback the movie is stopped by clicking ADJUST.
- 'Play' will start playback.
Time bar
--------
This is in two sections. A slider bar in the main section, and a time
counter to the right showing the current time in minutes, seconds and frames.
Note that the frame count is from 0 to (number of frames in one second - 1). In
the case of a movie with a fractional frame rate then the number of frames in
one second will vary. eg a 12.5 frames per second movie an even numbered chunk
will have 12 frames (eg 00:00.00 to 00:00.11) and an odd chunk 13 frames (eg
00:01.00 to 00:01.12).
The start point for playback can be set by clicking and dragging with SELECT
on the slider bar. When the mouse button is released then the new frame will be
found and displayed (which takes a few seconds). To just set the start point
without loading the new frame drag to the desired point on the time bar
holding down the CTRL key.
Note that the slider will update as a movie is playing except in the following
cases.
- When the movie is not playing in the Desktop
- When the current mode has only 2 or 4 colours
- When any part of the slider is off the screen
- When the slider overlaps the movie frame area
Note also that the time counter will only update during playback if you are
playing sound only.
Tool bar
--------
This has six control icons.
- 'Stop' will stop playback, whether video or sound.
- 'Play' will start playback from the current point shown on the time bar
slider. Whether playback is multi-tasking or not depends on the settings in
the Movie setup window.
- 'Play big' will start playback from the current point and attempt to play
the movie full screen. The default big mode is mode 13 (320x256 in 256 colours)
but you can define which mode should be used for play big requests from the
Global Choices window.
- 'Pause' will toggle pause state on and off. If the movie was stopped when
Pause was pressed then it will start playing and immediately enter Pause
mode.
- 'Single step' plays one frames worth of video and/or sound. If the player
is currently playing then it enters pause mode first. Note that single
stepping video from stopped mode takes a few seconds to retrieve the next
frame.
- 'Mute' enables or disables the sound track. This can be used before,
during or after video or sound playback independently of any other controls.
Movie info window
-----------------
This window shows information about the movie from its header.
- The first three lines have general descriptive text about the movie.
Typically these will be a longish description of the contents, any copyright
message, and who performed the digitisation/editing.
Below this is information about the format of the movie.
- The video compression type, followed by name of the compression type and
a copyright message for this type. Note that if the Info file for this
compression type cannot be found then it will just say Video type X where X
is the type number.
- the size of each video frame in pixels
- The format of the video data in the following order. Bits per pixel, frame
rate and whether key frames are present.
- The