Ichthyostega
8e250839f4
During the last months, a lot of gradual changes to policies and guidelines had been finalised and documented. Moreover, recent clarifications regarding memory management in the render engine will lead to a clearer definition of the »Vault« Layer's role, with some ''engine code'' expected to move down. On this occasion, I reworked relevant sections in the documentation to confirm the role that now falls to central parts of the overall architecture. Notably I decided to rename those parts related to the application backbone as »Vessel« — to underpin the more active and defining role they assumed.
32 lines
1.7 KiB
Text
32 lines
1.7 KiB
Text
Low-level Services
|
|
==================
|
|
|
|
Towards the _upper side_ of the Lumiera core, in »Steam Layer«,
|
|
several components and subsystems work together to provide functionality
|
|
that is close to the requirements of the _problem domain_ -- editing and
|
|
rendering of media. The implementation of these features however requires
|
|
a foundation of generic, technical services: Memory needs to be allocated,
|
|
working buffers must be provided and managed, work tasks coordinated.
|
|
It is hard to associate these responsibilities directly to
|
|
some specific domain, other than just _data processing._
|
|
|
|
A common trait of all those special aspects of processing is that they
|
|
require special care and attention to achieve the necessary level of
|
|
performance, while they are _technical_ in nature and do not directly
|
|
reflect and model structures of the real world.
|
|
|
|
Data Handling
|
|
-------------
|
|
The task of editing video and processing media requires to read and write
|
|
a significant amount of data, while using the capabilities of the hardware
|
|
to the best degree possible. Lumiera thus needs a foundation layer for
|
|
high volume data access; two kinds of data handling can be distinguished:
|
|
|
|
* The Session and the object models manipulated through the GUI are kept in memory.
|
|
They will be backed by a _storage backend,_ which provides database-like storage
|
|
and especially logging, and controlled execution of _mutating actions._
|
|
* Media data is handled _frame wise_ -- prefetching data asynchronously.
|
|
|
|
The goal is to optimize CPU utilization; large scale data IO will be performed
|
|
asynchronously. Data retrieval and processing of prerequisites will
|
|
be *scheduled* such as to manage the rendering _just in time_.
|