OBS源
OBS源类型注册函数obs_register_source
2024-03-21
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OBS的插件模块通过obs_register_source函数注册“源”。该函数通过obs_source_info结构体提供源相关的属性信息和回调函数。
#define obs_register_source(info) \
obs_register_source_s(info, sizeof(struct obs_source_info))
注册使用struct obs_source_info来标识数组成员信息
/**
* Source definition structure
*/
struct obs_source_info {
/* ----------------------------------------------------------------- */
/* Required implementation*/
/** Unique string identifier for the source */
const char *id;
/**
* Type of source.
*
* OBS_SOURCE_TYPE_INPUT for input sources,
* OBS_SOURCE_TYPE_FILTER for filter sources, and
* OBS_SOURCE_TYPE_TRANSITION for transition sources.
*/
enum obs_source_type type;
/** Source output flags */
uint32_t output_flags;
/**
* Get the translated name of the source type
*
* @param type_data The type_data variable of this structure
* @return The translated name of the source type
*/
const char *(*get_name)(void *type_data);
/**
* Creates the source data for the source
*
* @param settings Settings to initialize the source with
* @param source Source that this data is associated with
* @return The data associated with this source
*/
void *(*create)(obs_data_t *settings, obs_source_t *source);
/**
* Destroys the private data for the source
*
* Async sources must not call obs_source_output_video after returning
* from destroy
*/
void (*destroy)(void *data);
/** Returns the width of the source. Required if this is an input
* source and has non-async video */
uint32_t (*get_width)(void *data);
/** Returns the height of the source. Required if this is an input
* source and has non-async video */
uint32_t (*get_height)(void *data);
/* ----------------------------------------------------------------- */
/* Optional implementation */
/**
* Gets the default settings for this source
*
* @param[out] settings Data to assign default settings to
* @deprecated Use get_defaults2 if type_data is needed
*/
void (*get_defaults)(obs_data_t *settings);
/**
* Gets the property information of this source
*
* @return The properties data
* @deprecated Use get_properties2 if type_data is needed
*/
obs_properties_t *(*get_properties)(void *data);
/**
* Updates the settings for this source
*
* @param data Source data
* @param settings New settings for this source
*/
void (*update)(void *data, obs_data_t *settings);
/** Called when the source has been activated in the main view */
void (*activate)(void *data);
/**
* Called when the source has been deactivated from the main view
* (no longer being played/displayed)
*/
void (*deactivate)(void *data);
/** Called when the source is visible */
void (*show)(void *data);
/** Called when the source is no longer visible */
void (*hide)(void *data);
/**
* Called each video frame with the time elapsed
*
* @param data Source data
* @param seconds Seconds elapsed since the last frame
*/
void (*video_tick)(void *data, float seconds);
/**
* Called when rendering the source with the graphics subsystem.
*
* If this is an input/transition source, this is called to draw the
* source texture with the graphics subsystem using the specified
* effect.
*
* If this is a filter source, it wraps source draw calls (for
* example applying a custom effect with custom parameters to a
* source). In this case, it's highly recommended to use the
* obs_source_process_filter function to automatically handle
* effect-based filter processing. However, you can implement custom
* draw handling as desired as well.
*
* If the source output flags do not include SOURCE_CUSTOM_DRAW, all
* a source needs to do is set the "image" parameter of the effect to
* the desired texture, and then draw. If the output flags include
* SOURCE_COLOR_MATRIX, you may optionally set the "color_matrix"
* parameter of the effect to a custom 4x4 conversion matrix (by
* default it will be set to an YUV->RGB conversion matrix)
*
* @param data Source data
* @param effect Effect to be used with this source. If the source
* output flags include SOURCE_CUSTOM_DRAW, this will
* be NULL, and the source is expected to process with
* an effect manually.
*/
void (*video_render)(void *data, gs_effect_t *effect);
/**
* Called to filter raw async video data.
*
* @note This function is only used with filter sources.
*
* @param data Filter data
* @param frame Video frame to filter
* @return New video frame data. This can defer video data to
* be drawn later if time is needed for processing
*/
struct obs_source_frame *(*filter_video)(
void *data, struct obs_source_frame *frame);
/**
* Called to filter raw audio data.
*
* @note This function is only used with filter sources.
*
* @param data Filter data
* @param audio Audio data to filter.
* @return Modified or new audio data. You can directly modify
* the data passed and return it, or you can defer audio
* data for later if time is needed for processing. If
* you are returning new data, that data must exist
* until the next call to the filter_audio callback or
* until the filter is removed/destroyed.
*/
struct obs_audio_data *(*filter_audio)(void *data,
struct obs_audio_data *audio);
/**
* Called to enumerate all active sources being used within this
* source. If the source has children that render audio/video it must
* implement this callback.
*
* @param data Filter data
* @param enum_callback Enumeration callback
* @param param User data to pass to callback
*/
void (*enum_active_sources)(void *data,
obs_source_enum_proc_t enum_callback,
void *param);
/**
* Called when saving a source. This is a separate function because
* sometimes a source needs to know when it is being saved so it
* doesn't always have to update the current settings until a certain
* point.
*
* @param data Source data
* @param settings Settings
*/
void (*save)(void *data, obs_data_t *settings);
/**
* Called when loading a source from saved data. This should be called
* after all the loading sources have actually been created because
* sometimes there are sources that depend on each other.
*
* @param data Source data
* @param settings Settings
*/
void (*load)(void *data, obs_data_t *settings);
/**
* Called when interacting with a source and a mouse-down or mouse-up
* occurs.
*
* @param data Source data
* @param event Mouse event properties
* @param type Mouse button pushed
* @param mouse_up Mouse event type (true if mouse-up)
* @param click_count Mouse click count (1 for single click, etc.)
*/
void (*mouse_click)(void *data, const struct obs_mouse_event *event,
int32_t type, bool mouse_up, uint32_t click_count);
/**
* Called when interacting with a source and a mouse-move occurs.
*
* @param data Source data
* @param event Mouse event properties
* @param mouse_leave Mouse leave state (true if mouse left source)
*/
void (*mouse_move)(void *data, const struct obs_mouse_event *event,
bool mouse_leave);
/**
* Called when interacting with a source and a mouse-wheel occurs.
*
* @param data Source data
* @param event Mouse event properties
* @param x_delta Movement delta in the horizontal direction
* @param y_delta Movement delta in the vertical direction
*/
void (*mouse_wheel)(void *data, const struct obs_mouse_event *event,
int x_delta, int y_delta);
/**
* Called when interacting with a source and gain focus/lost focus event
* occurs.
*
* @param data Source data
* @param focus Focus state (true if focus gained)
*/
void (*focus)(void *data, bool focus);
/**
* Called when interacting with a source and a key-up or key-down
* occurs.
*
* @param data Source data
* @param event Key event properties
* @param focus Key event type (true if mouse-up)
*/
void (*key_click)(void *data, const struct obs_key_event *event,
bool key_up);
/**
* Called when the filter is removed from a source
*
* @param data Filter data
* @param source Source that the filter being removed from
*/
void (*filter_remove)(void *data, obs_source_t *source);
/**
* Private data associated with this entry
*/
void *type_data;
/**
* If defined, called to free private data on shutdown
*/
void (*free_type_data)(void *type_data);
bool (*audio_render)(void *data, uint64_t *ts_out,
struct obs_source_audio_mix *audio_output,
uint32_t mixers, size_t channels,
size_t sample_rate);
/**
* Called to enumerate all active and inactive sources being used
* within this source. If this callback isn't implemented,
* enum_active_sources will be called instead.
*
* This is typically used if a source can have inactive child sources.
*
* @param data Filter data
* @param enum_callback Enumeration callback
* @param param User data to pass to callback
*/
void (*enum_all_sources)(void *data,
obs_source_enum_proc_t enum_callback,
void *param);
void (*transition_start)(void *data);
void (*transition_stop)(void *data);
/**
* Gets the default settings for this source
*
* If get_defaults is also defined both will be called, and the first
* call will be to get_defaults, then to get_defaults2.
*
* @param type_data The type_data variable of this structure
* @param[out] settings Data to assign default settings to
*/
void (*get_defaults2)(void *type_data, obs_data_t *settings);
/**
* Gets the property information of this source
*
* @param data Source data
* @param type_data The type_data variable of this structure
* @return The properties data
*/
obs_properties_t *(*get_properties2)(void *data, void *type_data);
bool (*audio_mix)(void *data, uint64_t *ts_out,
struct audio_output_data *audio_output,
size_t channels, size_t sample_rate);
/** Icon type for the source */
enum obs_icon_type icon_type;
/** Media controls */
void (*media_play_pause)(void *data, bool pause);
void (*media_restart)(void *data);
void (*media_stop)(void *data);
void (*media_next)(void *data);
void (*media_previous)(void *data);
int64_t (*media_get_duration)(void *data);
int64_t (*media_get_time)(void *data);
void (*media_set_time)(void *data, int64_t miliseconds);
enum obs_media_state (*media_get_state)(void *data);
/* version-related stuff */
uint32_t version; /* increment if needed to specify a new version */
const char *unversioned_id; /* set internally, don't set manually */
/** Missing files **/
obs_missing_files_t *(*missing_files)(void *data);
/** Get color space **/
enum gs_color_space (*video_get_color_space)(
void *data, size_t count,
const enum gs_color_space *preferred_spaces);
/**
* Called when the filter is added to a source
*
* @param data Filter data
* @param source Source that the filter is being added to
*/
void (*filter_add)(void *data, obs_source_t *source);
};
根据源码分析,OBSCore提供了4种类型的“源”,这4种类型的源分别存储于不同的obs_source_info_array_t中。
enum obs_source_type {
OBS_SOURCE_TYPE_INPUT,
OBS_SOURCE_TYPE_FILTER,
OBS_SOURCE_TYPE_TRANSITION,
OBS_SOURCE_TYPE_SCENE,
};
这四种类型分别对应于struct obs_core 中的：
struct obs_core {
...
obs_source_info_array_t source_types; //每种类型都存储
obs_source_info_array_t input_types; //只存储OBS_SOURCE_TYPE_INPUT
obs_source_info_array_t filter_types;//只存储OBS_SOURCE_TYPE_FILTER
obs_source_info_array_t transition_types;/只存储OBS_SOURCE_TYPE_TRANSITION
...
}
相关的代码如下：
void obs_register_source_s(const struct obs_source_info *info, size_t size){
struct obs_source_info data = {0};
obs_source_info_array_t *array = NULL;
if (info->type == OBS_SOURCE_TYPE_INPUT) {
array = &obs->input_types;
} else if (info->type == OBS_SOURCE_TYPE_FILTER) {
array = &obs->filter_types;
} else if (info->type == OBS_SOURCE_TYPE_TRANSITION) {
array = &obs->transition_types;
} else if (info->type != OBS_SOURCE_TYPE_SCENE) {
source_warn("Tried to register unknown source type: %u",info->type);
goto error;
}
...
if (array)
da_push_back(*array, &data);
da_push_back(obs->source_types, &data);
return;
对于每一个源，其id和version作为惟的标识，通过get_source_info2定位是否已经存在
//判断该id的类型是否已经存在了
if (get_source_info2(info->id, info->version)) {
source_warn("Source '%s' already exists! "
"Duplicate library?",
info->id);
goto error;
}
其判断存在的方法也比较简单，就是在所有中查找比较：
struct obs_source_info *get_source_info2(const char *unversioned_id,
uint32_t ver){
for (size_t i = 0; i < obs->source_types.num; i++)
{
struct obs_source_info *info = &obs->source_types.array[i];
if (strcmp(info->unversioned_id, unversioned_id) == 0
&& info->version == ver)
return info;
}
return NULL;
}
