libobs: Add obs_encoder_scaling_enabled()

Returns whether rescaling is enabled for an encoder.  This will be used
with texture-based encoders to determine whether to fall back to
RAM-based encoding instead.

docs/sphinx/reference-encoders.rst

@@ -380,6 +380,13 @@ General Encoder Functions
 
 ---------------------
 
+.. function:: bool obs_encoder_scaling_enabled(const obs_encoder_t *encoder)
+
+   :return: *true* if pre-encode (CPU) scaling enabled, *false*
+            otherwise.
+
+---------------------
+
 .. function:: uint32_t obs_encoder_get_width(const obs_encoder_t *encoder)
               uint32_t obs_encoder_get_height(const obs_encoder_t *encoder)
 

libobs/obs-encoder.c

@@ -694,6 +694,14 @@ void obs_encoder_set_scaled_size(obs_encoder_t *encoder, uint32_t width,
 	encoder->scaled_height = height;
 }
 
+bool obs_encoder_scaling_enabled(const obs_encoder_t *encoder)
+{
+	if (!obs_encoder_valid(encoder, "obs_encoder_scaling_enabled"))
+		return false;
+
+	return encoder->scaled_width || encoder->scaled_height;
+}
+
 uint32_t obs_encoder_get_width(const obs_encoder_t *encoder)
 {
 	if (!obs_encoder_valid(encoder, "obs_encoder_get_width"))

libobs/obs.h

@@ -1983,6 +1983,9 @@ EXPORT enum obs_encoder_type obs_encoder_get_type(const obs_encoder_t *encoder);
 EXPORT void obs_encoder_set_scaled_size(obs_encoder_t *encoder, uint32_t width,
 					uint32_t height);
 
+/** For video encoders, returns true if pre-encode scaling is enabled */
+EXPORT bool obs_encoder_scaling_enabled(const obs_encoder_t *encoder);
+
 /** For video encoders, returns the width of the encoded image */
 EXPORT uint32_t obs_encoder_get_width(const obs_encoder_t *encoder);