CCodecConfig: support low latency config and set paramters

Test: cts
Bug: 134971304
Change-Id: Iabd7df79b530ce3af7bd2723dfcb2aa5488f5e75
diff --git a/media/codec2/core/include/C2Config.h b/media/codec2/core/include/C2Config.h
index 3820f90..20a0dbc 100644
--- a/media/codec2/core/include/C2Config.h
+++ b/media/codec2/core/include/C2Config.h
@@ -243,6 +243,9 @@
     kParamIndexTimestampGapAdjustment, // input-surface, struct
 
     kParamIndexSurfaceAllocator, // u32
+
+    // low latency mode for decoders
+    kParamIndexLowLatencyMode, // bool
 };
 
 }
@@ -804,6 +807,15 @@
 constexpr char C2_PARAMKEY_PIPELINE_DELAY[] = "algo.delay";
 
 /**
+ * Enable/disable low latency decoding mode.
+ * If true, low latency decoding mode is enabled, and the decoder doesn't hold input and output
+ * data more than required by the codec standards.
+ */
+typedef C2GlobalParam<C2Tuning, C2EasyBoolValue, kParamIndexLowLatencyMode>
+        C2GlobalLowLatencyModeTuning;
+constexpr char C2_PARAMKEY_LOW_LATENCY_MODE[] = "algo.low-latency";
+
+/**
  * Reference characteristics.
  *
  * The component may hold onto input and output buffers even after completing the corresponding
diff --git a/media/codec2/sfplugin/CCodecConfig.cpp b/media/codec2/sfplugin/CCodecConfig.cpp
index 5adcd94..ee3cdf6 100644
--- a/media/codec2/sfplugin/CCodecConfig.cpp
+++ b/media/codec2/sfplugin/CCodecConfig.cpp
@@ -823,6 +823,14 @@
 
     add(ConfigMapper(C2_PARAMKEY_INPUT_TIME_STRETCH, C2_PARAMKEY_INPUT_TIME_STRETCH, "value"));
 
+    add(ConfigMapper(KEY_LOW_LATENCY, C2_PARAMKEY_LOW_LATENCY_MODE, "value")
+        .limitTo(D::DECODER & (D::CONFIG | D::PARAM))
+        .withMapper([](C2Value v) -> C2Value {
+            int32_t value = 0;
+            (void)v.get(&value);
+            return value == 0 ? C2_FALSE : C2_TRUE;
+        }));
+
     /* still to do
     constexpr char KEY_PUSH_BLANK_BUFFERS_ON_STOP[] = "push-blank-buffers-on-shutdown";