OBS Studio Python Scripting Cheatsheet

Getting started:

• Python
• OBS Studio Scripting

Consider cloning this repo and running examples(they are self contained) in OBS Studio, most of them will operate on existing text soure. Tip: you can create a copy of script, rename it, and add to OBS.So two of identical scripts will be run in parallel with separated namespaces. Also check out issues if you found any error or have a suggestion and discussions for collaboration,ideas and Q&A.

Table of content

• Using classes
• with statement
• Passing arguments to callbacks
• UI
• Property modification
• Additional input
• obs_data
• save settings as json
• Source's and filters with identifier string
• Add source
• Move source
• Add filter to source
• Toggle sceneitem visibility
• Set current scene
• Get set order in scene
• Add scene with sources to current scene
• Events
• Program state
• Signals
• Timing (sequential primitives)
• Hotkeys
• Play sound
• Read and write private data from scripts or plugins
• Browser source interaction
• Debug
• Docs and code examples
• Links
• Contribute

Using classes

class Example:
    def __init__(self,source_name=None):
        self.source_name = source_name

    def update_text(self):
        source = obs.obs_get_source_by_name(self.source_name)
        if source is not None:
            data = str(next(datacycle))
            settings = obs.obs_data_create()
            obs.obs_data_set_string(settings, "text", data)
            obs.obs_source_update(source, settings)
            obs.obs_data_release(settings)
            obs.obs_source_release(source)

Full example

Or more compact:

class _G:
    source_name = ''
    data = None
    flag = False

G = _G()

def script_update(settings):
    G.source_name = ...
    if G.flag:
        pass

with statement

Automatically release .

@contextmanager
def source_auto_release(source_name):
    source = obs.obs_get_source_by_name(source_name)
    try:
        yield source 
    finally:
        obs.obs_source_release(source)
...
# usage
with source_auto_release(self.source_name) as source:
    if source is not None:
        data = str(next(datacycle))
        with data_auto_release() as settings:
            obs.obs_data_set_string(settings, "text", data)
            obs.obs_source_update(source, settings)

Full example
See also :
https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager

Passing arguments to callbacks

from functools import partial
...
flag = obs.obs_data_get_bool(settings,"_obs_bool")
eg.update_text = partial(eg.update_text,flag_func=flag)
...

Full example

UI

Preview
obs.obs_properties_add_button(props, "button1", "Refresh1:",callback)
obs.obs_properties_add_bool(props,"_bool","_bool:")
obs.obs_properties_add_int(props,"_int","_int:",1,100,1)
obs.obs_properties_add_int_slider(props,"_slider","_slider:",1,100,1)
obs.obs_properties_add_text(props, "_text", "_text:", obs.OBS_TEXT_DEFAULT)
obs.obs_properties_add_color(props,"_color","_color:")
obs.obs_properties_add_font(props,"_font","_font:")
obs.obs_properties_add_font(props,"_font","_font:")
bool_p = obs.obs_properties_add_bool(props, "_obs_bool", "Yes/No"); obs.obs_property_set_long_description(bool_p, "Check if yes,else uncheck")

See also :
https://obsproject.com/docs/reference-properties.html#property-object-functions

Property modification

def callback(props, prop, *args, **kwargs):  # pass settings implicitly
    p = obs.obs_properties_get(props, "button")
    n = next(counter)
    obs.obs_property_set_description(p, f"refresh pressed {n} times")
    return True
...
def script_properties():
    props = obs.obs_properties_create()
    b = obs.obs_properties_add_button(
        props, "button", "refresh pressed 0 times", refresh_pressed
    )
    obs.obs_property_set_modified_callback(b, callback)
    return props

Full example
See also :
https://obsproject.com/docs/reference-properties.html#property-modification-functions

Additional input

def callback(props, prop, settings):
    _number = obs.obs_data_get_int(settings, "_int")
    _text_value = obs.obs_data_get_string(settings, "_text")
    text_property = obs.obs_properties_get(props, "_text")
    if _number > 50:
        eg.data = _text_value + str(_number)
        obs.obs_property_set_visible(text_property, True)
        return True
    else:
        eg.data = ""
        obs.obs_property_set_visible(text_property, False)
        return True
...

def script_properties():  # ui

    ...
    number = obs.obs_properties_add_int(props, "_int", "Number", 1, 100, 1)
    text_value = obs.obs_properties_add_text(
        props, "_text", "Additional input:", obs.OBS_TEXT_DEFAULT
    )
    obs.obs_property_set_visible(text_value, False)
    obs.obs_property_set_modified_callback(number, callback)
    ...

Full example

Note: properties share similar structure , in Python, Lua, C. Example C See also :
https://obsproject.com/docs/reference-properties.html#property-modification-functions

obs_data

• obs_data_get_string
• obs_data_get_int
• obs_data_get_double
• obs_data_get_bool
• obs_data_get_obj
• obs_data_get_array

Save settings as json

p = Path(__file__).absolute()  # current script path
file = p.parent / "saved_settings.json"
try:
    content = obs.obs_data_get_json(Data._settings_)
    with open(file, "w") as f:
        f.write(content)
except Exception as e:
    print(e, "cannot write to file")

Full example
See also :
https://obsproject.com/docs/reference-settings.html
https://obsproject.com/docs/scripting.html#getting-the-current-script-s-path

Source's and filters with identifier string

To identify with obs_source_get_unversioned_id , or creating source/filter.

Source's

Filters

Add source

Create source and add it to current scene

obs.obs_data_set_string(settings, "text", "The quick brown fox jumps over the lazy dog")
source = obs.obs_source_create_private("text_gdiplus", "test_py", settings)
obs.obs_scene_add(scene, source)

Full example
See also :
https://obsproject.com/docs/reference-scenes.html

Move source

Get current scene , get source name, move source to location

def __init__(self):
    pos = obs.vec2()
    self.location = pos
...
def move_text_source(self):
    current_scene = obs.obs_frontend_get_current_scene()
    source = obs.obs_get_source_by_name("test_py")
    scene = obs.obs_scene_from_source(current_scene)
    scene_item = obs.obs_scene_find_source(scene, "test_py")
    if scene_item:
        dx, dy = 10, 10
        print("old values", self.location.x)
        obs.obs_sceneitem_get_pos(
            scene_item, self.location
        )  # update to last position if its changed from OBS
        self.location.x += dx
        self.location.y += dy
        print("new values", self.location.x)
        obs.obs_sceneitem_set_pos(scene_item, self.location)

Full example

Add filter to source

Filters are sources,they are not listed in obspython module, you need to know its id from obs_source_info

obs.obs_data_set_int(settings, "opacity", 50)
source_color = obs.obs_source_create_private(
    "color_filter", "opacity to 50", settings
)
obs.obs_source_filter_add(source, source_color)

Full example
See also :
Color correction source
https://obsproject.com/docs/reference-sources.html

Toggle sceneitem visibility

def toggle(self):
    current_scene = obs.obs_scene_from_source(obs.obs_frontend_get_current_scene())
    scene_item = obs.obs_scene_find_source(current_scene, self.source_name)
    boolean = not obs.obs_sceneitem_visible(scene_item)
    obs.obs_sceneitem_set_visible(scene_item, boolean)

Full example

Set current scene

def set_current_scene(self):
    scenes = obs.obs_frontend_get_scenes()
    for scene in scenes:
        name = obs.obs_source_get_name(scene)
        if name == self.scene_name:
            obs.obs_frontend_set_current_scene(scene)
...
scenes = obs.obs_frontend_get_scenes() # Dropdown menu UI
for scene in scenes:
    name = obs.obs_source_get_name(scene)
    obs.obs_property_list_add_string(p, name, name) 

Full example

Get set order in scene

def get_order(scene_items=None):
    order = list()
    for i, s in enumerate(scene_items):
        source = obs.obs_sceneitem_get_source(s)
        name = obs.obs_source_get_name(source)
        order.append({"index": i, "name": name, "scene_item": s})
    return order


def reorder():
    current_scene = obs.obs_frontend_get_current_scene()
    with scene_ar(current_scene) as scene:
        with scene_enum(scene) as scene_items:
            order = get_order(scene_items)
            # change second index with pre last
            order[1]["index"], order[-2]["index"] = (
                order[-2]["index"],
                order[1]["index"],
            )
            for s in sorted(order, key=lambda i: i["index"]):
                obs.obs_sceneitem_set_order_position(s["scene_item"], s["index"])

Full example

Add scene with sources to current scene

def add_random_text_source(scene):
    r = " random text # " + str(randint(0, 10))
    with data_ar() as settings:
        obs.obs_data_set_string(settings, "text", f"random text value {r}")
        with source_create_ar("text_ft2_source", f"random text{r}", settings) as source:
            pos = obs.vec2()
            pos.x = randint(0, 1920)
            pos.y = randint(0, 1080)
            scene_item = obs.obs_scene_add(scene, source)
            obs.obs_sceneitem_set_pos(scene_item, pos)

def add_scene_with_sources():
    current_scene_source = obs.obs_frontend_get_current_scene()
    with scene_from_source_ar(current_scene_source) as scene_source:
        with scene_create_ar("_nested_scene") as _scene:
            py_scene_source = obs.obs_scene_get_source(_scene)

            with scene_from_source_ar(py_scene_source) as scene:
                add_random_text_source(scene)
                add_random_text_source(scene)
                add_random_text_source(scene)

            # add created scene to current scene ( nested scene)
            _scene_source = obs.obs_scene_get_source(scene)
            obs.obs_scene_add(scene_source, _scene_source)

Note: sometimes OBS crashes if one of such scenes has been deleted.

• Full example

Events

def on_event(event):
    if event == obs.OBS_FRONTEND_EVENT_SCENE_CHANGED:
        raise Exception("Triggered when the current scene has changed.")


def script_load(settings):
    obs.obs_frontend_add_event_callback(on_event)

Full example
See also:
https://obsproject.com/docs/reference-frontend-api.html#structures-enumerations

Program state

Those functions return true or false :

• obs.obs_frontend_preview_program_mode_active()
• obs.obs_frontend_replay_buffer_active()
• obs.obs_frontend_recording_active()
• obs.obs_frontend_recording_paused()
• obs.obs_frontend_streaming_active()

Signals

Signals , callbacks , differences from C

Core signals

sh = obs.obs_get_signal_handler()
obs.signal_handler_connect(sh,"source_create",callback)
def callback(calldata):
    source = obs.calldata_source(cd,"source")
    print(obs.obs_source_get_name(source))

source_create, source_destroy, source_remove, source_save, source_load, source_activate, source_deactivate, source_show, source_hide, source_rename, source_volume, source_transition_start, source_transition_video_stop, source_transition_stop, channel_change, master_volume, hotkey_layout_change, hotkey_register, hotkey_unregister, hotkey_bindings_changed

https://obsproject.com/docs/reference-core.html#core-obs-signals

Scene signals

def connect_cur_scene():
    source = obs.obs_frontend_get_current_scene()
    sh = obs.obs_source_get_signal_handler(source)
    obs.signal_handler_connect(sh, "item_add", callback)
    obs.obs_source_release(source)


def callback(calldata):
    scene_item = obs.calldata_sceneitem(calldata, "item")
    #scene = obs.calldata_source(cd,"scene") # bad utf symbols 
    scene =  obs.obs_sceneitem_get_scene(scene_item)
    name = obs.obs_source_get_name
    source = obs.obs_sceneitem_get_source
    scene_source = obs.obs_scene_get_source
    scene_name = name(scene_source(scene))
    scene_item_name = name(source(scene_item))
    print(f"item {scene_item_name} has been added to scene {scene_name}")

• Full example

item_add, item_remove, reorder, refresh, item_visible, item_locked, item_select, item_deselect, item_transform

https://obsproject.com/docs/reference-scenes.html#scene-signals

Source signals

sh = obs.obs_source_get_signal_handler(some_source)
obs.signal_handler_connect(sh,"show",callback)
def callback(calldata):
    source = obs.calldata_source(cd,"source")
    print("on source show",obs.obs_source_get_name(source))

destroy, remove, save, load, activate, deactivate, show, hide, mute, push_to_mute_changed, push_to_mute_delay, push_to_talk_changed, push_to_talk_delay, enable, rename, volume, update_properties, update_flags, audio_sync, audio_mixers, filter_add, filter_remove, reorder_filters, transition_start, transition_video_stop, transition_stop, media_started, media_ended, media_pause, media_play, media_restart, media_stopped, media_next, media_previous

https://obsproject.com/docs/reference-sources.html#source-signals

Output signals

def connect_to_rec():
    sh = obs.obs_output_get_signal_handler(obs.obs_frontend_get_recording_output())
    obs.signal_handler_connect(sh, "pause", callback)

def callback(calldata):
    #out = obs.calldata_ptr(calldata, "output") # bad type
    print('output paused')

start, stop, pause, unpause, starting, stopping, activate, deactivate, reconnect, reconnect_success

https://obsproject.com/docs/reference-outputs.html#output-signals

Timing (sequential primitives)

def script_update(settings):
    eg.source_name = obs.obs_data_get_string(settings, "source")
    obs.timer_remove(eg.update_text)
    if eg.source_name != "":
        obs.timer_add(eg.update_text, 1 * 1000)

Full example
Note: each time script updated it's removed first
See also :
Version with globals and only one timer allowed.
https://obsproject.com/docs/scripting.html#script-timers

Thread

def callback(pressed):
    if pressed:
        toggle_thread()


def busy_thread():
    while True:
        if not data.thread_paused:
            sleep(0.02)
            data.status = "active"
            # print to stdoud crashes OBS on exit
        else:
            sleep(0.5)
            data.status = "inactive"


print('Press the "~" to toggle on/off')
hook("OBS_KEY_ASCIITILDE", "id_", callback)
obs.timer_add(lambda: print(data.status), 500)
t = threading.Thread(target=busy_thread)
t.start()

• Full example

Hotkeys

This hotkey example will create hotkeys in settings , but you need to bind it manually.

class Hotkey:
    def __init__(self, callback, obs_settings, _id):
        self.obs_data = obs_settings
        self.hotkey_id = obs.OBS_INVALID_HOTKEY_ID
        self.hotkey_saved_key = None
        self.callback = callback
        self._id = _id

        self.load_hotkey()
        self.register_hotkey()
        self.save_hotkey()

...

class h:
    htk_copy = None  # this attribute will hold instance of Hotkey

...
h1 = h()
h2 = h()
...
def script_load(settings):
    h1.htk_copy = Hotkey(cb1, settings, "h1_id")
    h2.htk_copy = Hotkey(cb2, settings, "h2_id")


def script_save(settings):
    h1.htk_copy.save_hotkey()
    h2.htk_copy.save_hotkey()

This hotkey example will create hotkeys on fly from json settings , but you need to know internal id.

ID = "htk_id"
JSON_DATA = '{"%s":[{"key":"OBS_KEY_1"}]}' % ID

def on_obs_key_1(pressed):
    if pressed:
        raise Exception("hotkey 1 pressed")

def script_load(settings):
    s = obs.obs_data_create_from_json(JSON_DATA)
    a = obs.obs_data_get_array(s, ID)
    h = obs.obs_hotkey_register_frontend(ID, ID, on_obs_key_1)
    obs.obs_hotkey_load(h, a)

Here is how send hotkey to OBS

def send_hotkey(obs_htk_id, key_modifiers=None):
    if key_modifiers:
        shift = key_modifiers.get("shift")
        control = key_modifiers.get("control")
        alt = key_modifiers.get("alt")
        command = key_modifiers.get("command")
    ...
    combo = obs.obs_key_combination()
    combo.modifiers = modifiers
    combo.key = obs.obs_key_from_name(obs_htk_id)
    ...
    obs.obs_hotkey_inject_event(combo, False)
    obs.obs_hotkey_inject_event(combo, True)
    obs.obs_hotkey_inject_event(combo, False)

• Full example
• Example with global
• Full example with json
• Full example with send hotkey

See also:
https://github.com/obsproject/obs-studio/blob/master/libobs/obs-hotkeys.h https://github.com/Palakis/obs-websocket/pull/595

Play sound

def play_sound():
    ...
    mediaSource = obs.obs_source_create_private(
        "ffmpeg_source", "Global Media Source", None
    )
    s = obs.obs_data_create()
    obs.obs_data_set_string(s, "local_file", script_path() + "alert.mp3")
    obs.obs_source_update(mediaSource, s)
    obs.obs_source_set_monitoring_type(
        mediaSource, obs.OBS_MONITORING_TYPE_MONITOR_AND_OUTPUT
    )
    ...

• Full example

Read and write private data from scripts or plugins

Write in one script

def send_to_private_data(data_type, field, result):
    settings = obs.obs_data_create()
    set = getattr(obs, f"obs_data_set_{data_type}")
    set(settings, field, result)
    obs.obs_apply_private_data(settings)
    obs.obs_data_release(settings)

def write_private_data():
    result = "private value from " + str(__file__) + " " + str(randint(1, 10))
    send_to_private_data("string", "__private__", result)

Read from another

@contextmanager
def p_data_ar(data_type, field):
    settings = obs.obs_get_private_data()
    get = getattr(obs, f"obs_data_get_{data_type}")
    try:
        yield get(settings, field)
    finally:
        obs.obs_data_release(settings)

def print_private_data():
    with p_data_ar("string", "__private__") as value:
        print(value)

Lua is also supported

local obs = obslua
local settings = obs.obs_data_create()
obs.obs_data_set_int(settings,"__private__", 7)
obs.obs_apply_private_data(settings)
obs.obs_data_release(settings)

• Full example read
• Full example write

Browser source interaction

def send_hotkey_to_browser(source, obs_htk_id, key_modifiers=None, key_up=False):

    key = obs.obs_key_from_name(obs_htk_id)
    vk = obs.obs_key_to_virtual_key(key)
    event = obs.obs_key_event()
    event.native_vkey = vk
    event.modifiers = get_modifiers(key_modifiers)
    event.native_modifiers = event.modifiers  # https://doc.qt.io/qt-5/qkeyevent.html
    event.native_scancode = vk
    event.text = ""
    obs.obs_source_send_key_click(source, event, key_up)


def press_tab(*p):
    with source_auto_release(G.source_name) as source:
        send_hotkey_to_browser(source, "OBS_KEY_TAB")
        send_hotkey_to_browser(source, "OBS_KEY_TAB", key_up=True)


def press_shift_tab(*p):
    with source_auto_release(G.source_name) as source:
        send_hotkey_to_browser(source, "OBS_KEY_TAB", {"shift": True})
        send_hotkey_to_browser(source, "OBS_KEY_TAB", {"shift": True}, key_up=True)

• Full example read

Debug

There is no stdin therefore you can't use pdb , options are:

• using print
• using pycharm remote debugging (localhost)
• using vscode attach to the process:
  • Load python extension
  • open script file , pip install debugpy , place debugpy.breakpoint() somewhere
    • Run (F5) select configuration ( Attach using Process ID)
    • select obs (on windows obs64.exe)
    • View select Debug Console (ctrl+shift+y)
• Example debugpy obs

Docs and code examples

Generated export.md contains all variables and functions available in obspython formatted with markdown. Table consist of links to appropriate search terms in OBS Studio repository, and obswebsocket,links to scripts in obspython and obslua with each script within github code search.gs_* and matrix_* functions exluded from that table.
Full example
Note : starting from 2020.12.17 Github Code Search no longer works as it was, see also this thread

Links

• Scripts forum , Github topic obs-scripts , Github topic obs-script
• OBS Studio Repo , obs-scripting-python.c
• Docs , Docs/scripting , Docs/plugins , Docs index
• obspython Gist , Github , grep.app
• obslua Gist , Github , grep.app
• A Python bundle for integration with OBS scripting
• Lua tips and tricks
• Python 3.6.8 , 64 bit installer

Contribute

Contributions are welcome!