Class ASF_Object_MediaObjectIndex
This top-level ASF object supplies media object indexing information for the streams of an ASF file. It includes stream-specific indexing information based on an adjustable index entry media object count interval. This object can be used to index all the video frames or key frames in a video stream.
The index is designed to be broken into blocks to facilitate storage that is more space-efficient by using 32-bit offsets relative to a 64-bit base. That is, each index block has a full 64-bit offset in the block header that is added to the 32-bit offset found in each index entry. If a file is larger than 2^32 bytes, then multiple index blocks can be used to fully index the entire large file while still keeping index entry offsets at 32 bits.
Indices into the Media Object Index Object are in terms of media object numbers, with the first frame for a given stream in the ASF file corresponding to entry 0 in the Media Object Index Object. The corresponding Offset field values of the Index Entry are byte offsets that, when combined with the Block Position value of the Index Block, indicate the starting location in bytes of an ASF Data Packet relative to the start of the first ASF Data Packet in the file.
Any ASF file containing a Media Object Index Object shall also contain a Media Object Index Parameters Object in its ASF Header.
Located in /ASF/Object/MediaObjectIndex.php (line 73)
ASF_Object | --ASF_Object_MediaObjectIndex
Constructs the class with given parameters and reads object related data from the ASF file.
- Reader $reader: The reader object.
- Array $options: The options array.
- &$options
- ASF_Object::__construct()
- Constructs the class with given parameters and options.
Returns an array of index entries. Each entry consists of the following keys.
- blockPositions -- Specifies a list of byte offsets of the beginnings of the blocks relative to the beginning of the first Data Packet (for example, the beginning of the Data Object + 50 bytes).
- indexEntryOffsets -- Specifies the offset. An offset value of 0xffffffff indicates an invalid offset value.
Returns the interval between each index entry in number of media objects.
Returns an array of index specifiers. Each entry consists of the following keys.
- streamNumber -- Specifies the stream number that the Index Specifiers refer to. Valid values are between 1 and 127.
- indexType -- Specifies the type of index.
Inherited Methods
Inherited From ASF_Object
ASF_Object::__construct()
ASF_Object::getIdentifier()
ASF_Object::getOffset()
ASF_Object::getOption()
ASF_Object::getOptions()
ASF_Object::getParent()
ASF_Object::getSize()
ASF_Object::setIdentifier()
ASF_Object::setOffset()
ASF_Object::setOption()
ASF_Object::setOptions()
ASF_Object::setParent()
ASF_Object::setSize()
ASF_Object::__get()
ASF_Object::__set()
NEAREST_PAST_CLEANPOINT
= 3
(line 96)
Indicates that the index type is Nearest Past Cleanpoint. The Nearest Past Cleanpoint indexes point to the closest data packet containing an entire object (or first fragment of an object) that has the Cleanpoint Flag set.
Nearest Past Cleanpoint is the most common type of index.
NEAREST_PAST_DATA_PACKET
= 1
(line 80)
Indicates that the index type is Nearest Past Data Packet. The Nearest Past Data Packet indexes point to the data packet whose presentation time is closest to the index entry time.
NEAREST_PAST_MEDIA
= 2
(line 87)
Indicates that the index type is Nearest Past Media. The Nearest Past Object indexes point to the closest data packet containing an entire object or first fragment of an object.
Documentation generated on Fri, 05 Sep 2008 20:19:02 +0300 by phpDocumentor 1.4.1