audio: Factor out offload code

Change-Id: I94a592262016d954318dab3d1339504e54f83681
diff --git a/audio/Android.mk b/audio/Android.mk
index 7b0ee42..cee9642 100644
--- a/audio/Android.mk
+++ b/audio/Android.mk
@@ -21,7 +21,8 @@
 LOCAL_ARM_MODE := arm
 
 LOCAL_SRC_FILES := \
-	audio_hw.c
+	audio_hw.c \
+	compress_offload.c
 
 # TODO: remove resampler if possible when AudioFlinger supports downsampling from 48 to 8
 LOCAL_SHARED_LIBRARIES := \
diff --git a/audio/audio_hw.c b/audio/audio_hw.c
index e260a77..3364e92 100644
--- a/audio/audio_hw.c
+++ b/audio/audio_hw.c
@@ -32,8 +32,6 @@
 #include <stdlib.h>
 #include <math.h>
 #include <dlfcn.h>
-#include <sys/resource.h>
-#include <sys/prctl.h>
 
 #include <cutils/log.h>
 #include <cutils/str_parms.h>
@@ -46,10 +44,10 @@
 #include <audio_effects/effect_aec.h>
 #include <audio_effects/effect_ns.h>
 #include "audio_hw.h"
+#include "compress_offload.h"
 
 #include "sound/compress_params.h"
 
-#define MIXER_CTL_COMPRESS_PLAYBACK_VOLUME "Compress Playback Volume"
 
 /* TODO: the following PCM device profiles could be read from a config file */
 static struct pcm_device_profile pcm_device_playback = {
@@ -753,7 +751,7 @@
     return 0;
 }
 
-static int disable_snd_device(struct audio_device *adev,
+int disable_snd_device(struct audio_device *adev,
                               struct audio_usecase *uc_info,
                               snd_device_t snd_device,
                               bool update_mixer)
@@ -2105,140 +2103,6 @@
     pthread_mutex_unlock(&out->pre_lock);
 }
 
-
-/* must be called with out->lock locked */
-static int send_offload_cmd_l(struct stream_out* out, int command)
-{
-    struct offload_cmd *cmd = (struct offload_cmd *)calloc(1, sizeof(struct offload_cmd));
-
-    ALOGVV("%s %d", __func__, command);
-
-    cmd->cmd = command;
-    list_add_tail(&out->offload_cmd_list, &cmd->node);
-    pthread_cond_signal(&out->offload_cond);
-    return 0;
-}
-
-/* must be called iwth out->lock locked */
-static void stop_compressed_output_l(struct stream_out *out)
-{
-    out->send_new_metadata = 1;
-    if (out->compr != NULL) {
-        compress_stop(out->compr);
-        while (out->offload_thread_blocked) {
-            pthread_cond_wait(&out->cond, &out->lock);
-        }
-    }
-}
-
-static void *offload_thread_loop(void *context)
-{
-    struct stream_out *out = (struct stream_out *) context;
-    struct listnode *item;
-
-    setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_AUDIO);
-    set_sched_policy(0, SP_FOREGROUND);
-    prctl(PR_SET_NAME, (unsigned long)"Offload Callback", 0, 0, 0);
-
-    ALOGV("%s", __func__);
-    lock_output_stream(out);
-    for (;;) {
-        struct offload_cmd *cmd = NULL;
-        stream_callback_event_t event;
-        bool send_callback = false;
-
-        ALOGVV("%s offload_cmd_list %d out->offload_state %d",
-              __func__, list_empty(&out->offload_cmd_list),
-              out->offload_state);
-        if (list_empty(&out->offload_cmd_list)) {
-            ALOGV("%s SLEEPING", __func__);
-            pthread_cond_wait(&out->offload_cond, &out->lock);
-            ALOGV("%s RUNNING", __func__);
-            continue;
-        }
-
-        item = list_head(&out->offload_cmd_list);
-        cmd = node_to_item(item, struct offload_cmd, node);
-        list_remove(item);
-
-        ALOGVV("%s STATE %d CMD %d out->compr %p",
-               __func__, out->offload_state, cmd->cmd, out->compr);
-
-        if (cmd->cmd == OFFLOAD_CMD_EXIT) {
-            free(cmd);
-            break;
-        }
-
-        if (out->compr == NULL) {
-            ALOGE("%s: Compress handle is NULL", __func__);
-            pthread_cond_signal(&out->cond);
-            continue;
-        }
-        out->offload_thread_blocked = true;
-        pthread_mutex_unlock(&out->lock);
-        send_callback = false;
-        switch(cmd->cmd) {
-        case OFFLOAD_CMD_WAIT_FOR_BUFFER:
-            compress_wait(out->compr, -1);
-            send_callback = true;
-            event = STREAM_CBK_EVENT_WRITE_READY;
-            break;
-        case OFFLOAD_CMD_PARTIAL_DRAIN:
-            compress_next_track(out->compr);
-            compress_partial_drain(out->compr);
-            send_callback = true;
-            event = STREAM_CBK_EVENT_DRAIN_READY;
-            break;
-        case OFFLOAD_CMD_DRAIN:
-            compress_drain(out->compr);
-            send_callback = true;
-            event = STREAM_CBK_EVENT_DRAIN_READY;
-            break;
-        default:
-            ALOGE("%s unknown command received: %d", __func__, cmd->cmd);
-            break;
-        }
-        lock_output_stream(out);
-        out->offload_thread_blocked = false;
-        pthread_cond_signal(&out->cond);
-        if (send_callback) {
-            out->offload_callback(event, NULL, out->offload_cookie);
-        }
-        free(cmd);
-    }
-
-    pthread_cond_signal(&out->cond);
-    while (!list_empty(&out->offload_cmd_list)) {
-        item = list_head(&out->offload_cmd_list);
-        list_remove(item);
-        free(node_to_item(item, struct offload_cmd, node));
-    }
-    pthread_mutex_unlock(&out->lock);
-
-    return NULL;
-}
-
-static int create_offload_callback_thread(struct stream_out *out)
-{
-    pthread_cond_init(&out->offload_cond, (const pthread_condattr_t *) NULL);
-    list_init(&out->offload_cmd_list);
-    pthread_create(&out->offload_thread, (const pthread_attr_t *) NULL,
-                    offload_thread_loop, out);
-    return 0;
-}
-
-static int destroy_offload_callback_thread(struct stream_out *out)
-{
-    lock_output_stream(out);
-    send_offload_cmd_l(out, OFFLOAD_CMD_EXIT);
-
-    pthread_mutex_unlock(&out->lock);
-    pthread_join(out->offload_thread, (void **) NULL);
-    pthread_cond_destroy(&out->offload_cond);
-
-    return 0;
-}
-
 static int uc_release_pcm_devices(struct audio_usecase *usecase)
 {
     struct stream_out *out = (struct stream_out *)usecase->stream;
@@ -2358,7 +2222,7 @@
     return ret;
 }
 
-static int disable_output_path_l(struct stream_out *out)
+int disable_output_path_l(struct stream_out *out)
 {
     struct audio_device *adev = out->dev;
     struct audio_usecase *uc_info;
@@ -2377,7 +2241,7 @@
     return 0;
 }
 
-static void enable_output_path_l(struct stream_out *out)
+void enable_output_path_l(struct stream_out *out)
 {
     struct audio_device *adev = out->dev;
     struct audio_usecase *uc_info;
@@ -2404,15 +2268,8 @@
     ALOGV("%s: enter: usecase(%d: %s)", __func__,
           out->usecase, use_case_table[out->usecase]);
 
-    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD &&
-            adev->offload_fx_stop_output != NULL) {
-        adev->offload_fx_stop_output(out->handle);
+    stop_output_offload_stream(out, &do_disable);
 
-        if (out->offload_state == OFFLOAD_STATE_PAUSED ||
-                out->offload_state == OFFLOAD_STATE_PAUSED_FLUSHED)
-            do_disable = false;
-        out->offload_state = OFFLOAD_STATE_IDLE;
-    }
     if (do_disable)
         ret = disable_output_path_l(out);
 
@@ -2685,39 +2542,6 @@
     return 0;
 }
 
-static int parse_compress_metadata(struct stream_out *out, struct str_parms *parms)
-{
-    int ret = 0;
-    char value[32];
-    struct compr_gapless_mdata tmp_mdata;
-
-    if (!out || !parms) {
-        return -EINVAL;
-    }
-
-    ret = str_parms_get_str(parms, AUDIO_OFFLOAD_CODEC_DELAY_SAMPLES, value, sizeof(value));
-    if (ret >= 0) {
-        tmp_mdata.encoder_delay = atoi(value); /* what is a good limit check? */
-    } else {
-        return -EINVAL;
-    }
-
-    ret = str_parms_get_str(parms, AUDIO_OFFLOAD_CODEC_PADDING_SAMPLES, value, sizeof(value));
-    if (ret >= 0) {
-        tmp_mdata.encoder_padding = atoi(value);
-    } else {
-        return -EINVAL;
-    }
-
-    out->gapless_mdata = tmp_mdata;
-    out->send_new_metadata = 1;
-    ALOGV("%s new encoder delay %u and padding %u", __func__,
-          out->gapless_mdata.encoder_delay, out->gapless_mdata.encoder_padding);
-
-    return 0;
-}
-
-
 static int out_set_parameters(struct audio_stream *stream, const char *kvpairs)
 {
     struct stream_out *out = (struct stream_out *)stream;
@@ -2777,18 +2601,8 @@
                 if (do_standby)
                     do_out_standby_l(out);
                 else {
-                    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-                        uc_info = get_usecase_from_id(adev, USECASE_AUDIO_PLAYBACK);
-                        if (uc_info == NULL) {
-                           ALOGE("%s: Could not find the usecase (%d) in the list",
-                                  __func__, USECASE_AUDIO_PLAYBACK);
-                        }
-                        if (uc_info != NULL && uc_info->out_snd_device == SND_DEVICE_OUT_SPEAKER_AND_HEADPHONES) {
-                           ALOGV("Out_set_param: spk+headset enabled\n");
-                           disable_snd_device(adev, uc_info, SND_DEVICE_OUT_SPEAKER, true);
-                           uc_info->out_snd_device = SND_DEVICE_OUT_HEADPHONES;
-                        }
-                    }
+                    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD)
+                        out_set_offload_parameters(adev, uc_info);
                     select_devices(adev, out->usecase);
                 }
             }
@@ -2889,37 +2703,13 @@
 {
     struct stream_out *out = (struct stream_out *)stream;
     struct audio_device *adev = out->dev;
-    int offload_volume[2];//For stereo
 
     if (out->usecase == USECASE_AUDIO_PLAYBACK_MULTI_CH) {
         /* only take left channel into account: the API is for stereo anyway */
         out->muted = (left == 0.0f);
         return 0;
     } else if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        struct mixer_ctl *ctl;
-        struct mixer *mixer = NULL;
-
-        offload_volume[0] = (int)(left * COMPRESS_PLAYBACK_VOLUME_MAX);
-        offload_volume[1] = (int)(right * COMPRESS_PLAYBACK_VOLUME_MAX);
-
-        mixer = mixer_open(MIXER_CARD);
-        if (!mixer) {
-            ALOGE("%s unable to open the mixer for card %d, aborting.",
-                    __func__, MIXER_CARD);
-            return -EINVAL;
-        }
-        ctl = mixer_get_ctl_by_name(mixer, MIXER_CTL_COMPRESS_PLAYBACK_VOLUME);
-        if (!ctl) {
-            ALOGE("%s: Could not get ctl for mixer cmd - %s",
-                  __func__, MIXER_CTL_COMPRESS_PLAYBACK_VOLUME);
-            mixer_close(mixer);
-            return -EINVAL;
-        }
-        ALOGV("out_set_volume set offload volume (%f, %f)", left, right);
-        mixer_ctl_set_array(ctl, offload_volume,
-                            sizeof(offload_volume)/sizeof(offload_volume[0]));
-        mixer_close(mixer);
-        return 0;
+        out_set_offload_volume(left, right);
     }
 
     return -ENOSYS;
@@ -3022,37 +2812,7 @@
 false_alarm:
 
     if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        ALOGVV("%s: writing buffer (%d bytes) to compress device", __func__, bytes);
-
-        if (out->offload_state == OFFLOAD_STATE_PAUSED_FLUSHED) {
-            ALOGV("start offload write from pause state");
-            pthread_mutex_lock(&adev->lock);
-            enable_output_path_l(out);
-            pthread_mutex_unlock(&adev->lock);
-        }
-
-        if (out->send_new_metadata) {
-            ALOGVV("send new gapless metadata");
-            compress_set_gapless_metadata(out->compr, &out->gapless_mdata);
-            out->send_new_metadata = 0;
-        }
-
-        ret = compress_write(out->compr, buffer, bytes);
-        ALOGVV("%s: writing buffer (%d bytes) to compress device returned %d", __func__, bytes, ret);
-        if (ret >= 0 && ret < (ssize_t)bytes) {
-            send_offload_cmd_l(out, OFFLOAD_CMD_WAIT_FOR_BUFFER);
-        }
-        if (out->offload_state != OFFLOAD_STATE_PLAYING) {
-            compress_start(out->compr);
-            out->offload_state = OFFLOAD_STATE_PLAYING;
-        }
-        pthread_mutex_unlock(&out->lock);
-#ifdef PREPROCESSING_ENABLED
-        if (in) {
-            /* This mutex was left locked iff in != NULL */
-            pthread_mutex_unlock(&adev->lock_inputs);
-        }
-#endif
+        ret = out_write_offload(stream, buffer, bytes);
         return ret;
     } else {
 #ifdef PREPROCESSING_ENABLED
@@ -3158,16 +2918,8 @@
 {
     struct stream_out *out = (struct stream_out *)stream;
     *dsp_frames = 0;
-    if ((out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) && (dsp_frames != NULL)) {
-        lock_output_stream(out);
-        if (out->compr != NULL) {
-            compress_get_tstamp(out->compr, (unsigned long *)dsp_frames,
-                    &out->sample_rate);
-            ALOGVV("%s rendered frames %d sample_rate %d",
-                   __func__, *dsp_frames, out->sample_rate);
-        }
-        pthread_mutex_unlock(&out->lock);
-        return 0;
+    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
+        return out_get_render_offload_position(out, dsp_frames);
     } else
         return -EINVAL;
 }
@@ -3204,16 +2956,7 @@
     lock_output_stream(out);
 
     if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        if (out->compr != NULL) {
-            compress_get_tstamp(out->compr, &dsp_frames,
-                    &out->sample_rate);
-            ALOGVV("%s rendered frames %ld sample_rate %d",
-                   __func__, dsp_frames, out->sample_rate);
-            *frames = dsp_frames;
-            ret = 0;
-            /* this is the best we can do */
-            clock_gettime(CLOCK_MONOTONIC, timestamp);
-        }
+        ret = out_get_presentation_offload_position(out, frames, timestamp);
     } else {
         /* FIXME: which device to read from? */
         if (!list_empty(&out->pcm_dev_list)) {
@@ -3261,17 +3004,8 @@
     struct stream_out *out = (struct stream_out *)stream;
     int status = -ENOSYS;
     ALOGV("%s", __func__);
-    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        lock_output_stream(out);
-        if (out->compr != NULL && out->offload_state == OFFLOAD_STATE_PLAYING) {
-            status = compress_pause(out->compr);
-            out->offload_state = OFFLOAD_STATE_PAUSED;
-            pthread_mutex_lock(&out->dev->lock);
-            status = disable_output_path_l(out);
-            pthread_mutex_unlock(&out->dev->lock);
-        }
-        pthread_mutex_unlock(&out->lock);
-    }
+    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD)
+        status = out_pause_offload(out);
     return status;
 }
 
@@ -3280,18 +3014,8 @@
     struct stream_out *out = (struct stream_out *)stream;
     int status = -ENOSYS;
     ALOGV("%s", __func__);
-    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        status = 0;
-        lock_output_stream(out);
-        if (out->compr != NULL && out->offload_state == OFFLOAD_STATE_PAUSED) {
-            pthread_mutex_lock(&out->dev->lock);
-            enable_output_path_l(out);
-            pthread_mutex_unlock(&out->dev->lock);
-            status = compress_resume(out->compr);
-            out->offload_state = OFFLOAD_STATE_PLAYING;
-        }
-        pthread_mutex_unlock(&out->lock);
-    }
+    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD)
+        status = out_resume_offload(out);
     return status;
 }
 
@@ -3300,14 +3024,8 @@
     struct stream_out *out = (struct stream_out *)stream;
     int status = -ENOSYS;
     ALOGV("%s", __func__);
-    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        lock_output_stream(out);
-        if (type == AUDIO_DRAIN_EARLY_NOTIFY)
-            status = send_offload_cmd_l(out, OFFLOAD_CMD_PARTIAL_DRAIN);
-        else
-            status = send_offload_cmd_l(out, OFFLOAD_CMD_DRAIN);
-        pthread_mutex_unlock(&out->lock);
-    }
+    if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD)
+        status = out_drain_offload(out, type);
     return status;
 }
 
@@ -3316,18 +3034,7 @@
     struct stream_out *out = (struct stream_out *)stream;
     ALOGV("%s", __func__);
     if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
-        lock_output_stream(out);
-        if (out->offload_state == OFFLOAD_STATE_PLAYING) {
-            ALOGE("out_flush() called in wrong state %d", out->offload_state);
-            pthread_mutex_unlock(&out->lock);
-            return -ENOSYS;
-        }
-        if (out->offload_state == OFFLOAD_STATE_PAUSED) {
-            stop_compressed_output_l(out);
-            out->offload_state = OFFLOAD_STATE_PAUSED_FLUSHED;
-        }
-        pthread_mutex_unlock(&out->lock);
-        return 0;
+        return out_flush_offload(out);
     }
     return -ENOSYS;
 }
diff --git a/audio/compress_offload.c b/audio/compress_offload.c
new file mode 100644
index 0000000..bdf3b0a
--- /dev/null
+++ b/audio/compress_offload.c
@@ -0,0 +1,429 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * Copyright (C) 2017 Christopher N. Hesse <raymanfx@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "audio_hw_primary"
+/*#define LOG_NDEBUG 0*/
+/*#define VERY_VERY_VERBOSE_LOGGING*/
+#ifdef VERY_VERY_VERBOSE_LOGGING
+#define ALOGVV ALOGV
+#else
+#define ALOGVV(a...) do { } while(0)
+#endif
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/resource.h>
+#include <sys/prctl.h>
+
+#include <cutils/log.h>
+#include <cutils/str_parms.h>
+#include <cutils/sched_policy.h>
+
+#include <system/thread_defs.h>
+#include "audio_hw.h"
+
+#include "sound/compress_params.h"
+
+#define MIXER_CTL_COMPRESS_PLAYBACK_VOLUME "Compress Playback Volume"
+
+
+/* Prototypes */
+void lock_input_stream(struct stream_in *in);
+void lock_output_stream(struct stream_out *out);
+int disable_snd_device(struct audio_device *adev,
+                              struct audio_usecase *uc_info,
+                              snd_device_t snd_device,
+                              bool update_mixer);
+void enable_output_path_l(struct stream_out *out);
+int disable_output_path_l(struct stream_out *out);
+
+/* must be called with out->lock locked */
+static int send_offload_cmd_l(struct stream_out* out, int command)
+{
+    struct offload_cmd *cmd = (struct offload_cmd *)calloc(1, sizeof(struct offload_cmd));
+
+    ALOGVV("%s %d", __func__, command);
+
+    cmd->cmd = command;
+    list_add_tail(&out->offload_cmd_list, &cmd->node);
+    pthread_cond_signal(&out->offload_cond);
+    return 0;
+}
+
+/* must be called iwth out->lock locked */
+void stop_compressed_output_l(struct stream_out *out)
+{
+    out->send_new_metadata = 1;
+    if (out->compr != NULL) {
+        compress_stop(out->compr);
+        while (out->offload_thread_blocked) {
+            pthread_cond_wait(&out->cond, &out->lock);
+        }
+    }
+}
+
+static void *offload_thread_loop(void *context)
+{
+    struct stream_out *out = (struct stream_out *) context;
+    struct listnode *item;
+
+    setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_AUDIO);
+    set_sched_policy(0, SP_FOREGROUND);
+    prctl(PR_SET_NAME, (unsigned long)"Offload Callback", 0, 0, 0);
+
+    ALOGV("%s", __func__);
+    lock_output_stream(out);
+    for (;;) {
+        struct offload_cmd *cmd = NULL;
+        stream_callback_event_t event;
+        bool send_callback = false;
+
+        ALOGVV("%s offload_cmd_list %d out->offload_state %d",
+              __func__, list_empty(&out->offload_cmd_list),
+              out->offload_state);
+        if (list_empty(&out->offload_cmd_list)) {
+            ALOGV("%s SLEEPING", __func__);
+            pthread_cond_wait(&out->offload_cond, &out->lock);
+            ALOGV("%s RUNNING", __func__);
+            continue;
+        }
+
+        item = list_head(&out->offload_cmd_list);
+        cmd = node_to_item(item, struct offload_cmd, node);
+        list_remove(item);
+
+        ALOGVV("%s STATE %d CMD %d out->compr %p",
+               __func__, out->offload_state, cmd->cmd, out->compr);
+
+        if (cmd->cmd == OFFLOAD_CMD_EXIT) {
+            free(cmd);
+            break;
+        }
+
+        if (out->compr == NULL) {
+            ALOGE("%s: Compress handle is NULL", __func__);
+            pthread_cond_signal(&out->cond);
+            continue;
+        }
+        out->offload_thread_blocked = true;
+        pthread_mutex_unlock(&out->lock);
+        send_callback = false;
+        switch(cmd->cmd) {
+        case OFFLOAD_CMD_WAIT_FOR_BUFFER:
+            compress_wait(out->compr, -1);
+            send_callback = true;
+            event = STREAM_CBK_EVENT_WRITE_READY;
+            break;
+        case OFFLOAD_CMD_PARTIAL_DRAIN:
+            compress_next_track(out->compr);
+            compress_partial_drain(out->compr);
+            send_callback = true;
+            event = STREAM_CBK_EVENT_DRAIN_READY;
+            break;
+        case OFFLOAD_CMD_DRAIN:
+            compress_drain(out->compr);
+            send_callback = true;
+            event = STREAM_CBK_EVENT_DRAIN_READY;
+            break;
+        default:
+            ALOGE("%s unknown command received: %d", __func__, cmd->cmd);
+            break;
+        }
+        lock_output_stream(out);
+        out->offload_thread_blocked = false;
+        pthread_cond_signal(&out->cond);
+        if (send_callback) {
+            out->offload_callback(event, NULL, out->offload_cookie);
+        }
+        free(cmd);
+    }
+
+    pthread_cond_signal(&out->cond);
+    while (!list_empty(&out->offload_cmd_list)) {
+        item = list_head(&out->offload_cmd_list);
+        list_remove(item);
+        free(node_to_item(item, struct offload_cmd, node));
+    }
+    pthread_mutex_unlock(&out->lock);
+
+    return NULL;
+}
+
+int create_offload_callback_thread(struct stream_out *out)
+{
+    pthread_cond_init(&out->offload_cond, (const pthread_condattr_t *) NULL);
+    list_init(&out->offload_cmd_list);
+    pthread_create(&out->offload_thread, (const pthread_attr_t *) NULL,
+                    offload_thread_loop, out);
+    return 0;
+}
+
+int destroy_offload_callback_thread(struct stream_out *out)
+{
+    lock_output_stream(out);
+    send_offload_cmd_l(out, OFFLOAD_CMD_EXIT);
+
+    pthread_mutex_unlock(&out->lock);
+    pthread_join(out->offload_thread, (void **) NULL);
+    pthread_cond_destroy(&out->offload_cond);
+
+    return 0;
+}
+
+int parse_compress_metadata(struct stream_out *out, struct str_parms *parms)
+{
+    int ret = 0;
+    char value[32];
+    struct compr_gapless_mdata tmp_mdata;
+
+    if (!out || !parms) {
+        return -EINVAL;
+    }
+
+    ret = str_parms_get_str(parms, AUDIO_OFFLOAD_CODEC_DELAY_SAMPLES, value, sizeof(value));
+    if (ret >= 0) {
+        tmp_mdata.encoder_delay = atoi(value); /* what is a good limit check? */
+    } else {
+        return -EINVAL;
+    }
+
+    ret = str_parms_get_str(parms, AUDIO_OFFLOAD_CODEC_PADDING_SAMPLES, value, sizeof(value));
+    if (ret >= 0) {
+        tmp_mdata.encoder_padding = atoi(value);
+    } else {
+        return -EINVAL;
+    }
+
+    out->gapless_mdata = tmp_mdata;
+    out->send_new_metadata = 1;
+    ALOGV("%s new encoder delay %u and padding %u", __func__,
+          out->gapless_mdata.encoder_delay, out->gapless_mdata.encoder_padding);
+
+    return 0;
+}
+
+int stop_output_offload_stream(struct stream_out *out, bool *disable)
+{
+    int ret = 0;
+    struct audio_device *adev = out->dev;
+
+    if (adev->offload_fx_stop_output != NULL) {
+        adev->offload_fx_stop_output(out->handle);
+
+        if (out->offload_state == OFFLOAD_STATE_PAUSED ||
+                out->offload_state == OFFLOAD_STATE_PAUSED_FLUSHED)
+            *disable = false;
+        out->offload_state = OFFLOAD_STATE_IDLE;
+    }
+
+    return ret;
+}
+
+int out_set_offload_parameters(struct audio_device *adev, struct audio_usecase *uc_info)
+{
+    int ret = 0;
+
+    if (uc_info == NULL) {
+        ALOGE("%s: Could not find the usecase (%d) in the list",
+                __func__, USECASE_AUDIO_PLAYBACK);
+        ret = -1;
+    }
+    if (uc_info != NULL && uc_info->out_snd_device == SND_DEVICE_OUT_SPEAKER_AND_HEADPHONES) {
+        ALOGV("Out_set_param: spk+headset enabled\n");
+        uc_info->out_snd_device = SND_DEVICE_OUT_HEADPHONES;
+        disable_snd_device(adev, uc_info, SND_DEVICE_OUT_SPEAKER, true);
+    }
+
+    return ret;
+}
+
+ssize_t out_write_offload(struct audio_stream_out *stream, const void *buffer,
+                         size_t bytes)
+{
+    struct stream_out *out = (struct stream_out *)stream;
+    struct audio_device *adev = out->dev;
+    ssize_t ret = 0;
+
+    ALOGVV("%s: writing buffer (%d bytes) to compress device", __func__, bytes);
+
+    if (out->offload_state == OFFLOAD_STATE_PAUSED_FLUSHED) {
+        ALOGV("start offload write from pause state");
+        pthread_mutex_lock(&adev->lock);
+        enable_output_path_l(out);
+        pthread_mutex_unlock(&adev->lock);
+    }
+
+    if (out->send_new_metadata) {
+        ALOGVV("send new gapless metadata");
+        compress_set_gapless_metadata(out->compr, &out->gapless_mdata);
+        out->send_new_metadata = 0;
+    }
+
+    ret = compress_write(out->compr, buffer, bytes);
+    ALOGVV("%s: writing buffer (%d bytes) to compress device returned %d", __func__, bytes, ret);
+    if (ret >= 0 && ret < (ssize_t)bytes) {
+        send_offload_cmd_l(out, OFFLOAD_CMD_WAIT_FOR_BUFFER);
+    }
+    if (out->offload_state != OFFLOAD_STATE_PLAYING) {
+        compress_start(out->compr);
+        out->offload_state = OFFLOAD_STATE_PLAYING;
+    }
+    pthread_mutex_unlock(&out->lock);
+#ifdef PREPROCESSING_ENABLED
+    if (in) {
+        /* This mutex was left locked iff in != NULL */
+        pthread_mutex_unlock(&adev->lock_inputs);
+    }
+#endif
+
+    return ret;
+}
+
+int out_get_render_offload_position(struct stream_out *out,
+                                   uint32_t *dsp_frames)
+{
+    *dsp_frames = 0;
+    if (dsp_frames != NULL) {
+        lock_output_stream(out);
+        if (out->compr != NULL) {
+            compress_get_tstamp(out->compr, (unsigned long *)dsp_frames,
+                    &out->sample_rate);
+            ALOGVV("%s rendered frames %d sample_rate %d",
+                   __func__, *dsp_frames, out->sample_rate);
+        }
+        pthread_mutex_unlock(&out->lock);
+        return 0;
+    } else
+        return -EINVAL;
+}
+
+int out_get_presentation_offload_position(struct stream_out *out, uint64_t *frames,
+                                   struct timespec *timestamp)
+{
+    int ret = -1;
+    unsigned long dsp_frames;
+
+    if (out->compr != NULL) {
+        compress_get_tstamp(out->compr, &dsp_frames,
+                &out->sample_rate);
+        ALOGVV("%s rendered frames %ld sample_rate %d",
+                __func__, dsp_frames, out->sample_rate);
+        *frames = dsp_frames;
+        ret = 0;
+        /* this is the best we can do */
+        clock_gettime(CLOCK_MONOTONIC, timestamp);
+    }
+
+    return ret;
+}
+
+int out_pause_offload(struct stream_out *out)
+{
+    int status = -ENOSYS;
+
+    lock_output_stream(out);
+    if (out->compr != NULL && out->offload_state == OFFLOAD_STATE_PLAYING) {
+        status = compress_pause(out->compr);
+        out->offload_state = OFFLOAD_STATE_PAUSED;
+        pthread_mutex_lock(&out->dev->lock);
+        status = disable_output_path_l(out);
+        pthread_mutex_unlock(&out->dev->lock);
+    }
+    pthread_mutex_unlock(&out->lock);
+
+    return status;
+}
+
+int out_resume_offload(struct stream_out *out)
+{
+    int status = -ENOSYS;
+
+    status = 0;
+    lock_output_stream(out);
+    if (out->compr != NULL && out->offload_state == OFFLOAD_STATE_PAUSED) {
+        pthread_mutex_lock(&out->dev->lock);
+        enable_output_path_l(out);
+        pthread_mutex_unlock(&out->dev->lock);
+        status = compress_resume(out->compr);
+        out->offload_state = OFFLOAD_STATE_PLAYING;
+    }
+    pthread_mutex_unlock(&out->lock);
+
+    return status;
+}
+
+int out_drain_offload(struct stream_out *out, audio_drain_type_t type)
+{
+    int status = -ENOSYS;
+
+    lock_output_stream(out);
+    if (type == AUDIO_DRAIN_EARLY_NOTIFY)
+        status = send_offload_cmd_l(out, OFFLOAD_CMD_PARTIAL_DRAIN);
+    else
+        status = send_offload_cmd_l(out, OFFLOAD_CMD_DRAIN);
+    pthread_mutex_unlock(&out->lock);
+
+    return status;
+}
+
+int out_flush_offload(struct stream_out *out)
+{
+    lock_output_stream(out);
+    if (out->offload_state == OFFLOAD_STATE_PLAYING) {
+        ALOGE("out_flush() called in wrong state %d", out->offload_state);
+        pthread_mutex_unlock(&out->lock);
+        return -ENOSYS;
+    }
+    if (out->offload_state == OFFLOAD_STATE_PAUSED) {
+        stop_compressed_output_l(out);
+        out->offload_state = OFFLOAD_STATE_PAUSED_FLUSHED;
+    }
+    pthread_mutex_unlock(&out->lock);
+    return 0;
+}
+
+int out_set_offload_volume(float left, float right)
+{
+    int offload_volume[2];//For stereo
+    struct mixer_ctl *ctl;
+    struct mixer *mixer = NULL;
+
+    offload_volume[0] = (int)(left * COMPRESS_PLAYBACK_VOLUME_MAX);
+    offload_volume[1] = (int)(right * COMPRESS_PLAYBACK_VOLUME_MAX);
+
+    mixer = mixer_open(MIXER_CARD);
+    if (!mixer) {
+        ALOGE("%s unable to open the mixer for card %d, aborting.",
+                __func__, MIXER_CARD);
+        return -EINVAL;
+    }
+    ctl = mixer_get_ctl_by_name(mixer, MIXER_CTL_COMPRESS_PLAYBACK_VOLUME);
+    if (!ctl) {
+        ALOGE("%s: Could not get ctl for mixer cmd - %s",
+                __func__, MIXER_CTL_COMPRESS_PLAYBACK_VOLUME);
+        mixer_close(mixer);
+        return -EINVAL;
+    }
+    ALOGV("out_set_volume set offload volume (%f, %f)", left, right);
+    mixer_ctl_set_array(ctl, offload_volume,
+                        sizeof(offload_volume)/sizeof(offload_volume[0]));
+    mixer_close(mixer);
+    return 0;
+}
diff --git a/audio/compress_offload.h b/audio/compress_offload.h
new file mode 100644
index 0000000..601445f
--- /dev/null
+++ b/audio/compress_offload.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * Copyright (C) 2017 Christopher N. Hesse <raymanfx@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef COMPRESS_OFFLOAD_H
+#define COMPRESS_OFFLOAD_H
+
+void stop_compressed_output_l(struct stream_out *out);
+
+int create_offload_callback_thread(struct stream_out *out);
+
+int destroy_offload_callback_thread(struct stream_out *out);
+
+int parse_compress_metadata(struct stream_out *out, struct str_parms *parms);
+
+int stop_output_offload_stream(struct stream_out *out, bool *disable);
+
+int out_set_offload_parameters(struct audio_device *adev, struct audio_usecase *uc_info);
+
+ssize_t out_write_offload(struct audio_stream_out *stream, const void *buffer,
+                         size_t bytes);
+
+int out_get_render_offload_position(struct stream_out *out,
+                                   uint32_t *dsp_frames);
+
+int out_get_presentation_offload_position(struct stream_out *out, uint64_t *frames,
+                                   struct timespec *timestamp);
+
+int out_pause_offload(struct stream_out *out);
+
+int out_resume_offload(struct stream_out *out);
+
+int out_drain_offload(struct stream_out *out, audio_drain_type_t type);
+
+int out_flush_offload(struct stream_out *out);
+
+int out_set_offload_volume(float left, float right);
+
+#endif // COMPRESS_OFFLOAD_H