docs: Add encoder ROI functions/struct

docs/sphinx/reference-encoders.rst

@@ -163,6 +163,7 @@ Encoder Definition Structure (obs_encoder_info)
    values:
 
    - **OBS_ENCODER_CAP_DEPRECATED** - Encoder is deprecated
+   - **OBS_ENCODER_CAP_ROI** - Encoder supports region of interest feature
 
 
 Encoder Packet Structure (encoder_packet)
@@ -265,6 +266,27 @@ Raw Frame Data Structure (encoder_frame)
    Presentation timestamp.
 
 
+Encoder Region of Interest Structure (obs_encoder_roi)
+-----------------------------------------
+
+.. struct:: obs_encoder_roi
+
+   Encoder region of interest structure.
+
+.. member:: uint32_t top
+            uint32_t bottom
+            uint32_t left
+            uint32_t right
+   
+   The rectangle edges of the region are specified as number of pixels from the input video's top and left edges (i.e. row/column 0).
+
+.. member:: float priority
+
+   Priority is specified as a float value between *-1.0f* and *1*.
+   These are converted to encoder-specific values by the encoder.
+   Values above 0 tell the encoder to increase quality for that region, values below tell it to worsen it.
+   Not all encoders support negative values and they may be ignored.
+
 General Encoder Functions
 -------------------------
 
@@ -517,6 +539,42 @@ General Encoder Functions
 
 ---------------------
 
+.. function:: bool obs_encoder_add_roi(obs_encoder_t *encoder, const struct obs_encoder_roi *roi)
+
+    Adds a new region of interest to the encoder if ROI feature is supported.
+
+   :return: *true* if adding succeeded, *false* otherwise.
+
+---------------------
+
+.. function:: bool obs_encoder_has_roi(obs_encoder_t *encoder)
+
+   :return: *true* if encoder has ROI regions set, *false* otherwise.
+
+---------------------
+
+.. function:: void obs_encoder_clear_roi(obs_encoder_t *encoder)
+
+    Clear region of interest list, if any.
+
+---------------------
+
+.. function:: void obs_encoder_enum_roi(obs_encoder_t *encoder, void (*enum_proc)(void *, struct obs_encoder_roi *), void *param)
+
+    Enumerate currently configured ROIs by invoking callback for each entry, in reverse order of addition (i.e. most recent to oldest).
+    
+    **Note:** If the encoder has scaling enabled the struct passed to the callback will be scaled accordingly.
+
+---------------------
+
+.. function:: uint32_t obs_encoder_get_roi_increment(const obs_encoder_t *encoder)
+
+   Encoders shall refresh their ROI configuration if the increment value changes.
+    
+   :return: Increment/revision of ROI list
+
+---------------------
+
 
 Functions used by encoders
 --------------------------