This box may be present in any visual sample entry. This box indicates the
scaling method that is applied when the width and height of the visual
material (as declared by the width and height values in any visual sample
entry) do not match the track width and height values (as indicated in the
track header box).
Implementation of this box is optional; if this box is present and can be
interpreted by the decoder, all samples shall be displayed according to the
scaling behaviour that is specified in this box. Otherwise, all samples are
scaled to the size that is indicated by the width and height field in the
Track Header Box.
If the size of the image is bigger than the size of the presentation region
and 'hidden' scaling is applied in the Sample Scale Box, it is not possible
to display the whole image. In such a case, it is useful to provide the
information to determine the region that is to be displayed. The centre
values would then indicate the centre of the region of high priority in each
visual sample. The decoder can display the region of high priority according
to these values. The centre values imply a consistent crop for all the images
in a sequence. The offset values are positive when the desired visual centre
is below or to the right of the image centre, and negative for offsets above
or to the left.
Fields inherited from class net.sourceforge.jaad.mp4.boxes.FullBox
java.io.IOException - if an error occurs while reading
public boolean isConstrained()
If this flag is set, all samples described by this sample entry shall be
scaled according to the method specified by the field 'scale_method'.
Otherwise, it is recommended that all the samples be scaled according to
the method specified by the field 'scale_method', but can be displayed in
an implementation dependent way, which may include not scaling the image
(i.e. neither to the width and height specified in the track header box,
nor by the method indicated here).
true if the samples should be scaled by the scale method
public int getDisplayCenterX()
The horizontal offset in pixels of the centre of the region that should
be displayed by priority relative to the centre of the image. Default
value is zero. Positive values indicate a display centre to the right of
the image centre.
the horizontal offset
public int getDisplayCenterY()
The vertical offset in pixels of the centre of the region that should be
displayed by priority relative to the centre of the image. Default value
is zero. Positive values indicate a display centre below the image
the vertical offset
public int getScaleMethod()
The scale method is an integer that defines the scaling mode to be used.
Of the 256 possible values the values 0 through 127 are reserved for use
by ISO and values 128 through 255 are user-defined and are not specified
in this International Standard; they may be used as determined by the
application. Of the reserved values the following modes are currently
1: scaling is done by 'fill' mode.
2: scaling is done by 'hidden' mode.
3: scaling is done by 'meet' mode.
4: scaling is done by 'slice' mode in the x-coordinate.
5: scaling is done by 'slice' mode in the y-coordinate.