This library is licensed under the Apache 2.0 License.
The Amazon Kinesis Video Streams Parser Library for Java enables Java developers to parse the streams returned by GetMedia
calls to Amazon Kinesis Video.
It contains:
- A streaming Mkv Parser called
StreamingMkvReader
that provides an iterative interface to read theMkvElement
s in a stream. - Applications such as
OutputSegmentMerger
andFragmentMetadataVisitor
built using theStreamingMkvReader
. - A callback based parser called
EBMLParser
that minimizes data buffering and copying.StreamingMkvReader
is built on top ofEBMLParser
- Unit tests for the applications and parsers that demonstrate how the applications work.
After you've downloaded the code from GitHub, you can build it using Maven. Use this command: mvn clean install
StreamingMkvReader
which provides an iterative interface to read MkvElement
s from a stream.
A caller calls nextIfAvailable
to get the next MkvElement
. An MkvElement
wrapped in an Optional
is returned if a complete element is available.
It buffers an individual MkvElement
until it can return a complete MkvElement
.
The mightHaveNext
method returns true if there is a chance that additional MkvElements
can be returned.
It returns false when the end of the input stream has been reached.
There are three types of MkvElement
vended by a MkvStreamReader
:
MkvDataElement
: This encapsulates Mkv Elements that are not master elements and contain data.MkvStartMasterElement
: This represents the start of a master Mkv element that contains child elements. Child elements can be other master elements or data elements.MkvEndMasterElement
: This represents the end of master element that contains child elements.
The MkvElementVisitor
is a visitor pattern that helps process the events in the MkvElement
hierarchy. It has a visit
method for each type of MkvElement
.
A GetMedia
call to Kinesis Video vends a stream of fragments where each fragment is encapsulated in a Mkv stream containing EBML and Segment elements.
OutputSegmentMerger
can be used to merge consecutive fragments that share the same EBML and Track data into a single Mkv stream with
a shared EBML and Segment. This is useful for passing the output of GetMedia
to any downstream processor that expects a single Mkv stream
with one Segment. Its use can be seen in OutputSegmentMergerTest
FragmentMetadataVisitor
is a MkvElementVisitor
that collects the Kinesis Video specific meta-data (such as FragmentNumber and Server Side Timestamp )
for the current fragment being processed. The getCurrentFragmentMetadata
method can be used to get the current fragment's metadata. Similarly
getPreviousFragmentMetadata
can be used get the previous fragment's metadata. The getMkvTrackMetadata
method can be used to get
the details of a particular track.
ElementSizeAndOffsetVisitor
is a visitor that writes out the metadata of the Mkv elements in a stream. For each element
the name, offset, header size and data size is written out. The output uses indentation to indicate the hierarchy of master elements
and their child elements. ElementSizeAndOffsetVisitor
is useful for looking into Mkv streams, where mkvinfo fails.
CountVisitor
is a visitor that can be used to count the number of Mkv elements of different types in a Mkv stream.
CompositeMkvElementVisitor
is a visitor that is made up of a number of constituent visitors. It calls accept on the
visited MkvElement
for each constituent visitor in the order in which the visitors are specified.
##Example
KinesisVideoExample
is an example that shows how the StreamingMkvReader
and the different visitors can be integrated
with the AWS SDK for the Kinesis Video. This example provides examples for
- Create a stream, deleting and recreating if the stream of the same name already exists.
- Call PutMedia to stream video fragments into the stream.
- Simultaneously call GetMedia to stream video fragments out of the stream.
- It uses the StreamingMkvParser to parse the returned the stream and apply the
OutputSegmentMerger
,FragmentMetadataVisitor
visitors along with a local one as part of the sameCompositeMkvElementVisitor
visitor.
- Add example that shows integration with Kinesis Video Streams.
- Remove unnecessary import.
- Update to include the url for Amazon Kinesis Video Streams in the pom.xml
- First release of the Amazon Kinesis Video Parser Library.
- Supports Mkv elements up to version 4.
- Known issues:
- EBMLMaxIDLength and EBMLMaxSizeLength are hardcoded as 4 and 8 bytes respectively
- Unknown EBML elements not specified in
MkvTypeInfos
are not readable by the user usingStreamingMkvReader
. - Unknown EBML elements not specified in
MkvTypeInfos
of unknown length lead to an exception. - Does not do any CRC validation for any Mkv elements with the
CRC-32
element.