Docs For Class ISO14496_Box

Description

The Sub-Sample Information Box is designed to contain sub-sample information.

A sub-sample is a contiguous range of bytes of a sample. The specific definition of a sub-sample shall be supplied for a given coding system (e.g. for ISO/IEC 14496-10, Advanced Video Coding). In the absence of such a specific definition, this box shall not be applied to samples using that coding system.

If subsample_count is 0 for any entry, then those samples have no subsample information and no array follows. The table is sparsely coded; the table identifies which samples have sub-sample structure by recording the difference in sample-number between each entry. The first entry in the table records the sample number of the first sample having sub-sample information.

Note: It is possible to combine subsamplePriority and discardable such that when subsamplePriority is smaller than a certain value, discardable is set to

However, since different systems may use different scales of priority

values, to separate them is safe to have a clean solution for discardable sub-samples.

author: Sven Vollbehr <svollbehr@gmail.com>
version: $Rev: 92 $
copyright: Copyright (c) 2008 The PHP Reader Project Workgroup
license: New BSD License

Located in /ISO14496/Box/SUBS.php (line 71)

ISO14496_Box
   |
   --ISO14496_Box_Full
      |
      --ISO14496_Box_SUBS

Method Summary

ISO14496_Box_SUBS __construct (Reader $reader, [ &$options = array()])

Array getSubSampleTable ()

Variables

Inherited Variables

Inherited from ISO14496_Box_Full

ISO14496_Box_Full::$_flags
ISO14496_Box_Full::$_version

Inherited from ISO14496_Box

ISO14496_Box::$_reader

Methods

Constructor __construct (line 82)

Constructs the class with given parameters and reads box related data from the ISO Base Media file.

access: public

ISO14496_Box_SUBS __construct (Reader $reader, [ &$options = array()])

Reader $reader: The reader object.
&$options

Redefinition of:

ISO14496_Box_Full::__construct(): Constructs the class with given parameters and reads box related data from the ISO Base Media file.

getSubSampleTable (line 134)

Returns an array of values. Each entry is an array containing the following keys.

sampleDelta -- an integer that specifies the sample number of the sample having sub-sample structure. It is coded as the difference between the desired sample number, and the sample number indicated in the previous entry. If the current entry is the first entry, the value indicates the sample number of the first sample having sub-sample information, that is, the value is the difference between the sample number and zero (0).

subsampleSize -- an integer that specifies the size, in bytes, of the current sub-sample.
subsamplePriority -- an integer specifying the degradation priority for each sub-sample. Higher values of subsamplePriority, indicate sub-samples which are important to, and have a greater impact on, the decoded quality.
discardable -- equal to 0 means that the sub-sample is required to decode the current sample, while equal to 1 means the sub-sample is not required to decode the current sample but may be used for enhancements, e.g., the sub-sample consists of supplemental enhancement information (SEI) messages.

access: public

Array getSubSampleTable ()

Inherited Methods

Inherited From ISO14496_Box_Full

ISO14496_Box_Full::__construct()
ISO14496_Box_Full::getFlags()
ISO14496_Box_Full::getVersion()
ISO14496_Box_Full::hasFlag()
ISO14496_Box_Full::setFlags()
ISO14496_Box_Full::setVersion()
ISO14496_Box_Full::__toString()

Inherited From ISO14496_Box

ISO14496_Box::__construct()
ISO14496_Box::addBox()
ISO14496_Box::constructBoxes()
ISO14496_Box::getBoxes()
ISO14496_Box::getBoxesByIdentifier()
ISO14496_Box::getContainer()
ISO14496_Box::getOffset()
ISO14496_Box::getOption()
ISO14496_Box::getOptions()
ISO14496_Box::getParent()
ISO14496_Box::getSize()
ISO14496_Box::getType()
ISO14496_Box::hasBox()
ISO14496_Box::isContainer()
ISO14496_Box::setContainer()
ISO14496_Box::setOffset()
ISO14496_Box::setOption()
ISO14496_Box::setOptions()
ISO14496_Box::setParent()
ISO14496_Box::setSize()
ISO14496_Box::setType()
ISO14496_Box::__get()
ISO14496_Box::__isset()
ISO14496_Box::__set()
ISO14496_Box::__toString()
ISO14496_Box::__unset()

Class ISO14496_Box_SUBS

Inherited Variables

Inherited Methods