The API used to be designed in such a way to where it would expect
exports for each individual source/output/encoder/etc. You would export
functions for each and it would automatically load those functions based
on a specific naming scheme from the module.
The idea behind this was that I wanted to limit the usage of structures
in the API so only functions could be used. It was an interesting idea
in theory, but this idea turned out to be flawed in a number of ways:
1.) Requiring exports to create sources/outputs/encoders/etc meant that
you could not create them by any other means, which meant that
things like faruton's .net plugin would become difficult.
2.) Export function declarations could not be checked, therefore if you
created a function with the wrong parameters and parameter types,
the compiler wouldn't know how to check for that.
3.) Required overly complex load functions in libobs just to handle it.
It makes much more sense to just have a load function that you call
manually. Complexity is the bane of all good programs.
4.) It required that you have functions of specific names, which looked
and felt somewhat unsightly.
So, to fix these issues, I replaced it with a more commonly used API
scheme, seen commonly in places like kernels and typical C libraries
with abstraction. You simply create a structure that contains the
callback definitions, and you pass it to a function to register that
definition (such as obs_register_source), which you call in the
obs_module_load of the module.
It will also automatically check the structure size and ensure that it
only loads the required values if the structure happened to add new
values in an API change.
The "main" source file for each module must include obs-module.h, and
must use OBS_DECLARE_MODULE() within that source file.
Also, started writing some doxygen documentation in to the main library
headers. Will add more detailed documentation as I go.
- Add property list callbacks to sources/outputs/encoders so that if
necessary user interface can be automatically generated or perhaps a
property list widget can be used for them.
- Change some of the property API names. obs_property_list_t felt a bit
awkward when actually using it, so I just renamed it to
obs_properties_t.
- Removed the getdata/setdata nad getparam/setparam functions from
sources/services, they will be superseded by the dynamic procedure
call API.
- Add 'set_default' functions to obs-data.*. These functions ensure
that a paramter exists and that the parameter is of a specific type.
If not, it will create or overwrite the value with the default setting
instead.
These functions are meant to be explicitly called before using any of
the 'get' functions. The reason why it was designed this way is to
encourage defaults to be set in a single place/function.
For example, ideal usage is to create one function for your data,
"set_my_defaults(obs_data_t data)", set all the default values within
that function, and then call that function on create/update, that way
all defaults are centralized to a single place.
- Ensure that data passed to sources/encoders/outputs/etc is always
valid, and not a null value.
- While I'm remembering, fix a few defaults of the main program config
file data.
Add a fairly easy to use settings interface that can be passed to
plugins, and replaced the old character string system that was being
used before. The new data interface allows for an easier method of
getting/altering settings for plugins, and is built to be serializable
to/from JSON.
Also, removed another wxFormBuilder file that was no longer in use.
Just a minor fix mostly because I noticed that I kept accidentally
forgetting to add checks to the code properly. This is one of those
cases where macros come in useful, as macros can automate the process
and help prevent these mistakes from happening by accident.
Changed the comments to properly reflect the new callbacks, as I had
forgotten to update the comments for them both.
Also, changed "setbitrate" and "request_keyframe" return values to be
boolean.
- First, I redid the output interface for libobs. I feel like it's
going in a pretty good direction in terms of design.
Right now, the design is so that outputs and encoders are separate.
One or more outputs can connect to a specific encoder to receive its
data, or the output can connect directly to raw data from libobs
output itself, if the output doesn't want to use a designated encoder.
Data is received via callbacks set when you connect to the encoder or
raw output. Multiple outputs can receive the data from a single
encoder context if need be (such as for streaming to multiple channels
at once, and/or recording with the same data).
When an encoder is first connected to, it will connect to raw output,
and start encoding. Additional connections will receive that same
data being encoded as well after that. When the last encoder has
disconnected, it will stop encoding. If for some reason the encoder
needs to stop, it will use the callback with NULL to signal that
encoding has stopped. Some of these things may be subject to change
in the future, though it feels pretty good with this design so far.
Will have to see how well it works out in practice versus theory.
- Second, Started adding preliminary RTMP/x264 output plugin code.
To speed things up, I might just make a direct raw->FFmpeg output to
create a quick output plugin that we can start using for testing all
the subsystems.
