diff --git a/audio/6.0/IStreamOut.hal b/audio/6.0/IStreamOut.hal
index 91668ba..13a86ec 100644
--- a/audio/6.0/IStreamOut.hal
+++ b/audio/6.0/IStreamOut.hal
@@ -333,4 +333,33 @@
      * @return retval operation completion status.
      */
     setAudioDescriptionMixLevel(float leveldB) generates (Result retval);
+
+    /**
+     * Retrieves current playback rate parameters.
+     *
+     * Optional method
+     *
+     * @return retval operation completion status.
+     * @return playbackRate current playback parameters
+     */
+    getPlaybackRateParameters()
+            generates (Result retval, PlaybackRate playbackRate);
+
+    /**
+     * Sets the playback rate parameters that control playback behavior.
+     * This is normally used when playing encoded content and decoding
+     * is performed in hardware. Otherwise, the framework can apply
+     * necessary transformations.
+     *
+     * Optional method
+     *
+     * If the HAL supports setting the playback rate, it is recommended
+     * to support speed and pitch values at least in the range
+     * from 0.5f to 2.0f, inclusive (see the definition of PlaybackRate struct).
+     *
+     * @param playbackRate playback parameters
+     * @return retval operation completion status.
+     */
+    setPlaybackRateParameters(PlaybackRate playbackRate)
+            generates (Result retval);
 };
diff --git a/audio/6.0/types.hal b/audio/6.0/types.hal
index efc3ea5..8ff618e 100644
--- a/audio/6.0/types.hal
+++ b/audio/6.0/types.hal
@@ -297,3 +297,61 @@
      */
     RR = 3,
 };
+
+/**
+ * Algorithms used for timestretching (preserving pitch while playing audio
+ * content at different speed).
+ */
+@export(name="audio_timestretch_stretch_mode_t", value_prefix="AUDIO_TIMESTRETCH_STRETCH_")
+enum TimestretchMode : int32_t {
+    // Need to be in sync with AUDIO_STRETCH_MODE_* constants in
+    // frameworks/base/media/java/android/media/PlaybackParams.java
+    DEFAULT = 0,
+    /** Selects timestretch algorithm best suitable for voice (speech) content. */
+    VOICE = 1,
+};
+
+/**
+ * Behavior when the values for speed and / or pitch are out
+ * of applicable range.
+ */
+@export(name="audio_timestretch_fallback_mode_t", value_prefix="AUDIO_TIMESTRETCH_FALLBACK_")
+enum TimestretchFallbackMode : int32_t {
+    // Need to be in sync with AUDIO_FALLBACK_MODE_* constants in
+    // frameworks/base/media/java/android/media/PlaybackParams.java
+    /** Play silence for parameter values that are out of range. */
+    MUTE = 1,
+    /** Return an error while trying to set the parameters. */
+    FAIL = 2,
+};
+
+/**
+ * Parameters determining playback behavior. They are used to speed up or
+ * slow down playback and / or change the tonal frequency of the audio content
+ * (pitch).
+ */
+struct PlaybackRate {
+    /**
+     * Speed factor (multiplier). Normal speed has the value of 1.0f.
+     * Values less than 1.0f slow down playback, value greater than 1.0f
+     * speed it up.
+     */
+    float speed;
+    /**
+     * Pitch factor (multiplier). Setting pitch value to 1.0f together
+     * with changing playback speed preserves the pitch, this is often
+     * called "timestretching." Setting the pitch value equal to speed produces
+     * the same effect as playing audio content at different sampling rate.
+     */
+    float pitch;
+    /**
+     * Selects the algorithm used for timestretching (preserving pitch while
+     * playing audio at different speed).
+     */
+    TimestretchMode timestretchMode;
+    /**
+     * Selects the behavior when the specified values for speed and / or pitch
+     * are out of applicable range.
+     */
+    TimestretchFallbackMode fallbackMode;
+};