vp9: remove FrameWorkerData & vp9_dthread.h

the file was empty after the struct removal. the only remaining use was
within vp9_dx_iface, but the wrapper became unnecessary after the
removal of frame_parallel_decode.

BUG=webm:1395

Change-Id: I515ab585d701e77d388d12b2802d844c424f9bcd

8 files changed, 81 insertions, 280 deletions

diff --git a/test/vp9_encoder_parms_get_to_decoder.cc b/test/vp9_encoder_parms_get_to_decoder.cc
index 53dc8c9fe..62e8dcb9b 100644
--- a/test/vp9_encoder_parms_get_to_decoder.cc
+++ b/test/vp9_encoder_parms_get_to_decoder.cc
@@ -99,9 +99,7 @@ class VpxEncoderParmsGetToDecoder
     vpx_codec_ctx_t *const vp9_decoder = decoder->GetDecoder();
     vpx_codec_alg_priv_t *const priv =
         reinterpret_cast<vpx_codec_alg_priv_t *>(vp9_decoder->priv);
-    FrameWorkerData *const worker_data =
-        reinterpret_cast<FrameWorkerData *>(priv->frame_workers[0].data1);
-    VP9_COMMON *const common = &worker_data->pbi->common;
+    VP9_COMMON *const common = &priv->pbi->common;
 
     if (encode_parms.lossless) {
       EXPECT_EQ(0, common->base_qindex);
diff --git a/vp9/common/vp9_alloccommon.c b/vp9/common/vp9_alloccommon.c
index fa430b677..c9aca89d1 100644
--- a/vp9/common/vp9_alloccommon.c
+++ b/vp9/common/vp9_alloccommon.c
@@ -154,6 +154,9 @@ fail:
 }
 
 void vp9_remove_common(VP9_COMMON *cm) {
+#if CONFIG_VP9_POSTPROC
+  vp9_free_postproc_buffers(cm);
+#endif
   vp9_free_context_buffers(cm);
 
   vpx_free(cm->fc);
diff --git a/vp9/decoder/vp9_decoder.c b/vp9/decoder/vp9_decoder.c
index b47abe9fe..6adbee78f 100644
--- a/vp9/decoder/vp9_decoder.c
+++ b/vp9/decoder/vp9_decoder.c
@@ -139,6 +139,7 @@ void vp9_decoder_remove(VP9Decoder *pbi) {
     vp9_loop_filter_dealloc(&pbi->lf_row_sync);
   }
 
+  vp9_remove_common(&pbi->common);
   vpx_free(pbi);
 }
 
diff --git a/vp9/decoder/vp9_decoder.h b/vp9/decoder/vp9_decoder.h
index ed0fd82dc..2040cee81 100644
--- a/vp9/decoder/vp9_decoder.h
+++ b/vp9/decoder/vp9_decoder.h
@@ -21,7 +21,6 @@
 #include "vp9/common/vp9_thread_common.h"
 #include "vp9/common/vp9_onyxc_int.h"
 #include "vp9/common/vp9_ppflags.h"
-#include "vp9/decoder/vp9_dthread.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/vp9/decoder/vp9_dthread.h b/vp9/decoder/vp9_dthread.h
deleted file mode 100644
index 9e944f973..000000000
--- a/vp9/decoder/vp9_dthread.h
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef VP9_DECODER_VP9_DTHREAD_H_
-#define VP9_DECODER_VP9_DTHREAD_H_
-
-#include "./vpx_config.h"
-#include "vpx_util/vpx_thread.h"
-#include "vpx/internal/vpx_codec_internal.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-struct VP9Common;
-struct VP9Decoder;
-
-// WorkerData for the FrameWorker thread. It contains all the information of
-// the worker and decode structures for decoding a frame.
-typedef struct FrameWorkerData {
-  struct VP9Decoder *pbi;
-  const uint8_t *data;
-  const uint8_t *data_end;
-  size_t data_size;
-  void *user_priv;
-  int result;
-  int worker_id;
-  int received_frame;
-
-  // scratch_buffer is used in frame parallel mode only.
-  // It is used to make a copy of the compressed data.
-  uint8_t *scratch_buffer;
-  size_t scratch_buffer_size;
-
-#if CONFIG_MULTITHREAD
-  pthread_mutex_t stats_mutex;
-  pthread_cond_t stats_cond;
-#endif
-
-  int frame_context_ready;  // Current frame's context is ready to read.
-  int frame_decoded;        // Finished decoding current frame.
-} FrameWorkerData;
-
-#ifdef __cplusplus
-}  // extern "C"
-#endif
-
-#endif  // VP9_DECODER_VP9_DTHREAD_H_
diff --git a/vp9/vp9_dx_iface.c b/vp9/vp9_dx_iface.c
index cf3f6df44..b7dc14e4b 100644
--- a/vp9/vp9_dx_iface.c
+++ b/vp9/vp9_dx_iface.c
@@ -57,30 +57,8 @@ static vpx_codec_err_t decoder_init(vpx_codec_ctx_t *ctx,
 }
 
 static vpx_codec_err_t decoder_destroy(vpx_codec_alg_priv_t *ctx) {
-  if (ctx->frame_workers != NULL) {
-    int i;
-    // Shutdown all threads before reclaiming any memory. The frame-level
-    // parallel decoder may access data from another worker.
-    for (i = 0; i < ctx->num_frame_workers; ++i) {
-      VPxWorker *const worker = &ctx->frame_workers[i];
-      vpx_get_worker_interface()->end(worker);
-    }
-    for (i = 0; i < ctx->num_frame_workers; ++i) {
-      VPxWorker *const worker = &ctx->frame_workers[i];
-      FrameWorkerData *const frame_worker_data =
-          (FrameWorkerData *)worker->data1;
-      vp9_remove_common(&frame_worker_data->pbi->common);
-#if CONFIG_VP9_POSTPROC
-      vp9_free_postproc_buffers(&frame_worker_data->pbi->common);
-#endif
-      vp9_decoder_remove(frame_worker_data->pbi);
-      vpx_free(frame_worker_data->scratch_buffer);
-#if CONFIG_MULTITHREAD
-      pthread_mutex_destroy(&frame_worker_data->stats_mutex);
-      pthread_cond_destroy(&frame_worker_data->stats_cond);
-#endif
-      vpx_free(frame_worker_data);
-    }
+  if (ctx->pbi != NULL) {
+    vp9_decoder_remove(ctx->pbi);
   }
 
   if (ctx->buffer_pool) {
@@ -88,7 +66,6 @@ static vpx_codec_err_t decoder_destroy(vpx_codec_alg_priv_t *ctx) {
     vp9_free_internal_frame_buffers(&ctx->buffer_pool->int_frame_buffers);
   }
 
-  vpx_free(ctx->frame_workers);
   vpx_free(ctx->buffer_pool);
   vpx_free(ctx);
   return VPX_CODEC_OK;
@@ -222,32 +199,26 @@ static vpx_codec_err_t update_error_state(
 }
 
 static void init_buffer_callbacks(vpx_codec_alg_priv_t *ctx) {
-  int i;
-
-  for (i = 0; i < ctx->num_frame_workers; ++i) {
-    VPxWorker *const worker = &ctx->frame_workers[i];
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
-    VP9_COMMON *const cm = &frame_worker_data->pbi->common;
-    BufferPool *const pool = cm->buffer_pool;
-
-    cm->new_fb_idx = INVALID_IDX;
-    cm->byte_alignment = ctx->byte_alignment;
-    cm->skip_loop_filter = ctx->skip_loop_filter;
-
-    if (ctx->get_ext_fb_cb != NULL && ctx->release_ext_fb_cb != NULL) {
-      pool->get_fb_cb = ctx->get_ext_fb_cb;
-      pool->release_fb_cb = ctx->release_ext_fb_cb;
-      pool->cb_priv = ctx->ext_priv;
-    } else {
-      pool->get_fb_cb = vp9_get_frame_buffer;
-      pool->release_fb_cb = vp9_release_frame_buffer;
+  VP9_COMMON *const cm = &ctx->pbi->common;
+  BufferPool *const pool = cm->buffer_pool;
 
-      if (vp9_alloc_internal_frame_buffers(&pool->int_frame_buffers))
-        vpx_internal_error(&cm->error, VPX_CODEC_MEM_ERROR,
-                           "Failed to initialize internal frame buffers");
+  cm->new_fb_idx = INVALID_IDX;
+  cm->byte_alignment = ctx->byte_alignment;
+  cm->skip_loop_filter = ctx->skip_loop_filter;
 
-      pool->cb_priv = &pool->int_frame_buffers;
-    }
+  if (ctx->get_ext_fb_cb != NULL && ctx->release_ext_fb_cb != NULL) {
+    pool->get_fb_cb = ctx->get_ext_fb_cb;
+    pool->release_fb_cb = ctx->release_ext_fb_cb;
+    pool->cb_priv = ctx->ext_priv;
+  } else {
+    pool->get_fb_cb = vp9_get_frame_buffer;
+    pool->release_fb_cb = vp9_release_frame_buffer;
+
+    if (vp9_alloc_internal_frame_buffers(&pool->int_frame_buffers))
+      vpx_internal_error(&cm->error, VPX_CODEC_MEM_ERROR,
+                         "Failed to initialize internal frame buffers");
+
+    pool->cb_priv = &pool->int_frame_buffers;
   }
 }
 
@@ -264,80 +235,21 @@ static void set_ppflags(const vpx_codec_alg_priv_t *ctx, vp9_ppflags_t *flags) {
   flags->noise_level = ctx->postproc_cfg.noise_level;
 }
 
-static int frame_worker_hook(void *arg1, void *arg2) {
-  FrameWorkerData *const frame_worker_data = (FrameWorkerData *)arg1;
-  const uint8_t *data = frame_worker_data->data;
-  (void)arg2;
-
-  frame_worker_data->result = vp9_receive_compressed_data(
-      frame_worker_data->pbi, frame_worker_data->data_size, &data);
-  frame_worker_data->data_end = data;
-
-  if (frame_worker_data->result != 0) {
-    // Check decode result in serial decode.
-    frame_worker_data->pbi->cur_buf->buf.corrupted = 1;
-    frame_worker_data->pbi->need_resync = 1;
-  }
-  return !frame_worker_data->result;
-}
-
 static vpx_codec_err_t init_decoder(vpx_codec_alg_priv_t *ctx) {
-  int i;
-  const VPxWorkerInterface *const winterface = vpx_get_worker_interface();
-
   ctx->last_show_frame = -1;
   ctx->need_resync = 1;
-  ctx->num_frame_workers = 1;
   ctx->flushed = 0;
 
   ctx->buffer_pool = (BufferPool *)vpx_calloc(1, sizeof(BufferPool));
   if (ctx->buffer_pool == NULL) return VPX_CODEC_MEM_ERROR;
 
-  ctx->frame_workers = (VPxWorker *)vpx_malloc(ctx->num_frame_workers *
-                                               sizeof(*ctx->frame_workers));
-  if (ctx->frame_workers == NULL) {
-    set_error_detail(ctx, "Failed to allocate frame_workers");
+  ctx->pbi = vp9_decoder_create(ctx->buffer_pool);
+  if (ctx->pbi == NULL) {
+    set_error_detail(ctx, "Failed to allocate decoder");
     return VPX_CODEC_MEM_ERROR;
   }
-
-  for (i = 0; i < ctx->num_frame_workers; ++i) {
-    VPxWorker *const worker = &ctx->frame_workers[i];
-    FrameWorkerData *frame_worker_data = NULL;
-    winterface->init(worker);
-    worker->data1 = vpx_memalign(32, sizeof(FrameWorkerData));
-    if (worker->data1 == NULL) {
-      set_error_detail(ctx, "Failed to allocate frame_worker_data");
-      return VPX_CODEC_MEM_ERROR;
-    }
-    frame_worker_data = (FrameWorkerData *)worker->data1;
-    frame_worker_data->pbi = vp9_decoder_create(ctx->buffer_pool);
-    if (frame_worker_data->pbi == NULL) {
-      set_error_detail(ctx, "Failed to allocate frame_worker_data");
-      return VPX_CODEC_MEM_ERROR;
-    }
-    frame_worker_data->worker_id = i;
-    frame_worker_data->scratch_buffer = NULL;
-    frame_worker_data->scratch_buffer_size = 0;
-    frame_worker_data->frame_context_ready = 0;
-    frame_worker_data->received_frame = 0;
-#if CONFIG_MULTITHREAD
-    if (pthread_mutex_init(&frame_worker_data->stats_mutex, NULL)) {
-      set_error_detail(ctx, "Failed to allocate frame_worker_data mutex");
-      return VPX_CODEC_MEM_ERROR;
-    }
-
-    if (pthread_cond_init(&frame_worker_data->stats_cond, NULL)) {
-      set_error_detail(ctx, "Failed to allocate frame_worker_data cond");
-      return VPX_CODEC_MEM_ERROR;
-    }
-#endif
-    // If decoding in serial mode, FrameWorker thread could create tile worker
-    // thread or loopfilter thread.
-    frame_worker_data->pbi->max_threads = ctx->cfg.threads;
-
-    frame_worker_data->pbi->inv_tile_order = ctx->invert_tile_order;
-    worker->hook = (VPxWorkerHook)frame_worker_hook;
-  }
+  ctx->pbi->max_threads = ctx->cfg.threads;
+  ctx->pbi->inv_tile_order = ctx->invert_tile_order;
 
   // If postprocessing was enabled by the application and a
   // configuration has not been provided, default it.
@@ -351,7 +263,7 @@ static vpx_codec_err_t init_decoder(vpx_codec_alg_priv_t *ctx) {
 
 static INLINE void check_resync(vpx_codec_alg_priv_t *const ctx,
                                 const VP9Decoder *const pbi) {
-  // Clear resync flag if worker got a key frame or intra only frame.
+  // Clear resync flag if the decoder got a key frame or intra only frame.
   if (ctx->need_resync == 1 && pbi->need_resync == 0 &&
       (pbi->common.intra_only || pbi->common.frame_type == KEY_FRAME))
     ctx->need_resync = 0;
@@ -360,7 +272,6 @@ static INLINE void check_resync(vpx_codec_alg_priv_t *const ctx,
 static vpx_codec_err_t decode_one(vpx_codec_alg_priv_t *ctx,
                                   const uint8_t **data, unsigned int data_sz,
                                   void *user_priv, int64_t deadline) {
-  const VPxWorkerInterface *const winterface = vpx_get_worker_interface();
   (void)deadline;
 
   // Determine the stream parameters. Note that we rely on peek_si to
@@ -376,31 +287,22 @@ static vpx_codec_err_t decode_one(vpx_codec_alg_priv_t *ctx,
     if (!ctx->si.is_kf && !is_intra_only) return VPX_CODEC_ERROR;
   }
 
-  {
-    VPxWorker *const worker = ctx->frame_workers;
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
-    frame_worker_data->data = *data;
-    frame_worker_data->data_size = data_sz;
-    frame_worker_data->user_priv = user_priv;
-    frame_worker_data->received_frame = 1;
-
-    // Set these even if already initialized.  The caller may have changed the
-    // decrypt config between frames.
-    frame_worker_data->pbi->decrypt_cb = ctx->decrypt_cb;
-    frame_worker_data->pbi->decrypt_state = ctx->decrypt_state;
-
-    worker->had_error = 0;
-    winterface->execute(worker);
-
-    // Update data pointer after decode.
-    *data = frame_worker_data->data_end;
+  ctx->user_priv = user_priv;
 
-    if (worker->had_error)
-      return update_error_state(ctx, &frame_worker_data->pbi->common.error);
+  // Set these even if already initialized.  The caller may have changed the
+  // decrypt config between frames.
+  ctx->pbi->decrypt_cb = ctx->decrypt_cb;
+  ctx->pbi->decrypt_state = ctx->decrypt_state;
 
-    check_resync(ctx, frame_worker_data->pbi);
+  if (vp9_receive_compressed_data(ctx->pbi, data_sz, data)) {
+    ctx->pbi->cur_buf->buf.corrupted = 1;
+    ctx->pbi->need_resync = 1;
+    ctx->need_resync = 1;
+    return update_error_state(ctx, &ctx->pbi->common.error);
   }
 
+  check_resync(ctx, ctx->pbi);
+
   return VPX_CODEC_OK;
 }
 
@@ -421,8 +323,8 @@ static vpx_codec_err_t decoder_decode(vpx_codec_alg_priv_t *ctx,
   // Reset flushed when receiving a valid frame.
   ctx->flushed = 0;
 
-  // Initialize the decoder workers on the first frame.
-  if (ctx->frame_workers == NULL) {
+  // Initialize the decoder on the first frame.
+  if (ctx->pbi == NULL) {
     const vpx_codec_err_t res = init_decoder(ctx);
     if (res != VPX_CODEC_OK) return res;
   }
@@ -478,35 +380,19 @@ static vpx_image_t *decoder_get_frame(vpx_codec_alg_priv_t *ctx,
 
   // iter acts as a flip flop, so an image is only returned on the first
   // call to get_frame.
-  if (*iter == NULL && ctx->frame_workers != NULL) {
+  if (*iter == NULL && ctx->pbi != NULL) {
     YV12_BUFFER_CONFIG sd;
     vp9_ppflags_t flags = { 0, 0, 0 };
-    const VPxWorkerInterface *const winterface = vpx_get_worker_interface();
-    VPxWorker *const worker = &ctx->frame_workers[0];
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
     if (ctx->base.init_flags & VPX_CODEC_USE_POSTPROC) set_ppflags(ctx, &flags);
-    // Wait for the frame from worker thread.
-    if (winterface->sync(worker)) {
-      // Check if worker has received any frames.
-      if (frame_worker_data->received_frame == 1) {
-        frame_worker_data->received_frame = 0;
-        check_resync(ctx, frame_worker_data->pbi);
-      }
-      if (vp9_get_raw_frame(frame_worker_data->pbi, &sd, &flags) == 0) {
-        VP9_COMMON *const cm = &frame_worker_data->pbi->common;
-        RefCntBuffer *const frame_bufs = cm->buffer_pool->frame_bufs;
-        ctx->last_show_frame = frame_worker_data->pbi->common.new_fb_idx;
-        if (ctx->need_resync) return NULL;
-        yuvconfig2image(&ctx->img, &sd, frame_worker_data->user_priv);
-        ctx->img.fb_priv = frame_bufs[cm->new_fb_idx].raw_frame_buffer.priv;
-        img = &ctx->img;
-        return img;
-      }
-    } else {
-      // Decoding failed. Release the worker thread.
-      frame_worker_data->received_frame = 0;
-      ctx->need_resync = 1;
-      if (ctx->flushed != 1) return NULL;
+    if (vp9_get_raw_frame(ctx->pbi, &sd, &flags) == 0) {
+      VP9_COMMON *const cm = &ctx->pbi->common;
+      RefCntBuffer *const frame_bufs = cm->buffer_pool->frame_bufs;
+      ctx->last_show_frame = ctx->pbi->common.new_fb_idx;
+      if (ctx->need_resync) return NULL;
+      yuvconfig2image(&ctx->img, &sd, ctx->user_priv);
+      ctx->img.fb_priv = frame_bufs[cm->new_fb_idx].raw_frame_buffer.priv;
+      img = &ctx->img;
+      return img;
     }
   }
   return NULL;
@@ -517,7 +403,7 @@ static vpx_codec_err_t decoder_set_fb_fn(
     vpx_release_frame_buffer_cb_fn_t cb_release, void *cb_priv) {
   if (cb_get == NULL || cb_release == NULL) {
     return VPX_CODEC_INVALID_PARAM;
-  } else if (ctx->frame_workers == NULL) {
+  } else if (ctx->pbi == NULL) {
     // If the decoder has already been initialized, do not accept changes to
     // the frame buffer functions.
     ctx->get_ext_fb_cb = cb_get;
@@ -536,12 +422,9 @@ static vpx_codec_err_t ctrl_set_reference(vpx_codec_alg_priv_t *ctx,
   if (data) {
     vpx_ref_frame_t *const frame = (vpx_ref_frame_t *)data;
     YV12_BUFFER_CONFIG sd;
-    VPxWorker *const worker = ctx->frame_workers;
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
     image2yuvconfig(&frame->img, &sd);
-    return vp9_set_reference_dec(&frame_worker_data->pbi->common,
-                                 ref_frame_to_vp9_reframe(frame->frame_type),
-                                 &sd);
+    return vp9_set_reference_dec(
+        &ctx->pbi->common, ref_frame_to_vp9_reframe(frame->frame_type), &sd);
   } else {
     return VPX_CODEC_INVALID_PARAM;
   }
@@ -554,11 +437,9 @@ static vpx_codec_err_t ctrl_copy_reference(vpx_codec_alg_priv_t *ctx,
   if (data) {
     vpx_ref_frame_t *frame = (vpx_ref_frame_t *)data;
     YV12_BUFFER_CONFIG sd;
-    VPxWorker *const worker = ctx->frame_workers;
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
     image2yuvconfig(&frame->img, &sd);
-    return vp9_copy_reference_dec(frame_worker_data->pbi,
-                                  (VP9_REFFRAME)frame->frame_type, &sd);
+    return vp9_copy_reference_dec(ctx->pbi, (VP9_REFFRAME)frame->frame_type,
+                                  &sd);
   } else {
     return VPX_CODEC_INVALID_PARAM;
   }
@@ -570,9 +451,7 @@ static vpx_codec_err_t ctrl_get_reference(vpx_codec_alg_priv_t *ctx,
 
   if (data) {
     YV12_BUFFER_CONFIG *fb;
-    VPxWorker *const worker = ctx->frame_workers;
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
-    fb = get_ref_frame(&frame_worker_data->pbi->common, data->idx);
+    fb = get_ref_frame(&ctx->pbi->common, data->idx);
     if (fb == NULL) return VPX_CODEC_ERROR;
     yuvconfig2image(&data->img, fb, NULL);
     return VPX_CODEC_OK;
@@ -603,9 +482,8 @@ static vpx_codec_err_t ctrl_set_postproc(vpx_codec_alg_priv_t *ctx,
 static vpx_codec_err_t ctrl_get_quantizer(vpx_codec_alg_priv_t *ctx,
                                           va_list args) {
   int *const arg = va_arg(args, int *);
-  if (arg == NULL) return VPX_CODEC_INVALID_PARAM;
-  *arg =
-      ((FrameWorkerData *)ctx->frame_workers[0].data1)->pbi->common.base_qindex;
+  if (arg == NULL || ctx->pbi == NULL) return VPX_CODEC_INVALID_PARAM;
+  *arg = ctx->pbi->common.base_qindex;
   return VPX_CODEC_OK;
 }
 
@@ -614,11 +492,8 @@ static vpx_codec_err_t ctrl_get_last_ref_updates(vpx_codec_alg_priv_t *ctx,
   int *const update_info = va_arg(args, int *);
 
   if (update_info) {
-    if (ctx->frame_workers) {
-      VPxWorker *const worker = ctx->frame_workers;
-      FrameWorkerData *const frame_worker_data =
-          (FrameWorkerData *)worker->data1;
-      *update_info = frame_worker_data->pbi->refresh_frame_flags;
+    if (ctx->pbi != NULL) {
+      *update_info = ctx->pbi->refresh_frame_flags;
       return VPX_CODEC_OK;
     } else {
       return VPX_CODEC_ERROR;
@@ -633,14 +508,9 @@ static vpx_codec_err_t ctrl_get_frame_corrupted(vpx_codec_alg_priv_t *ctx,
   int *corrupted = va_arg(args, int *);
 
   if (corrupted) {
-    if (ctx->frame_workers) {
-      VPxWorker *const worker = ctx->frame_workers;
-      FrameWorkerData *const frame_worker_data =
-          (FrameWorkerData *)worker->data1;
-      RefCntBuffer *const frame_bufs =
-          frame_worker_data->pbi->common.buffer_pool->frame_bufs;
-      if (frame_worker_data->pbi->common.frame_to_show == NULL)
-        return VPX_CODEC_ERROR;
+    if (ctx->pbi != NULL) {
+      RefCntBuffer *const frame_bufs = ctx->pbi->common.buffer_pool->frame_bufs;
+      if (ctx->pbi->common.frame_to_show == NULL) return VPX_CODEC_ERROR;
       if (ctx->last_show_frame >= 0)
         *corrupted = frame_bufs[ctx->last_show_frame].buf.corrupted;
       return VPX_CODEC_OK;
@@ -657,11 +527,8 @@ static vpx_codec_err_t ctrl_get_frame_size(vpx_codec_alg_priv_t *ctx,
   int *const frame_size = va_arg(args, int *);
 
   if (frame_size) {
-    if (ctx->frame_workers) {
-      VPxWorker *const worker = ctx->frame_workers;
-      FrameWorkerData *const frame_worker_data =
-          (FrameWorkerData *)worker->data1;
-      const VP9_COMMON *const cm = &frame_worker_data->pbi->common;
+    if (ctx->pbi != NULL) {
+      const VP9_COMMON *const cm = &ctx->pbi->common;
       frame_size[0] = cm->width;
       frame_size[1] = cm->height;
       return VPX_CODEC_OK;
@@ -678,11 +545,8 @@ static vpx_codec_err_t ctrl_get_render_size(vpx_codec_alg_priv_t *ctx,
   int *const render_size = va_arg(args, int *);
 
   if (render_size) {
-    if (ctx->frame_workers) {
-      VPxWorker *const worker = ctx->frame_workers;
-      FrameWorkerData *const frame_worker_data =
-          (FrameWorkerData *)worker->data1;
-      const VP9_COMMON *const cm = &frame_worker_data->pbi->common;
+    if (ctx->pbi != NULL) {
+      const VP9_COMMON *const cm = &ctx->pbi->common;
       render_size[0] = cm->render_width;
       render_size[1] = cm->render_height;
       return VPX_CODEC_OK;
@@ -697,13 +561,10 @@ static vpx_codec_err_t ctrl_get_render_size(vpx_codec_alg_priv_t *ctx,
 static vpx_codec_err_t ctrl_get_bit_depth(vpx_codec_alg_priv_t *ctx,
                                           va_list args) {
   unsigned int *const bit_depth = va_arg(args, unsigned int *);
-  VPxWorker *const worker = &ctx->frame_workers[0];
 
   if (bit_depth) {
-    if (worker) {
-      FrameWorkerData *const frame_worker_data =
-          (FrameWorkerData *)worker->data1;
-      const VP9_COMMON *const cm = &frame_worker_data->pbi->common;
+    if (ctx->pbi != NULL) {
+      const VP9_COMMON *const cm = &ctx->pbi->common;
       *bit_depth = cm->bit_depth;
       return VPX_CODEC_OK;
     } else {
@@ -742,10 +603,8 @@ static vpx_codec_err_t ctrl_set_byte_alignment(vpx_codec_alg_priv_t *ctx,
     return VPX_CODEC_INVALID_PARAM;
 
   ctx->byte_alignment = byte_alignment;
-  if (ctx->frame_workers) {
-    VPxWorker *const worker = ctx->frame_workers;
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
-    frame_worker_data->pbi->common.byte_alignment = byte_alignment;
+  if (ctx->pbi != NULL) {
+    ctx->pbi->common.byte_alignment = byte_alignment;
   }
   return VPX_CODEC_OK;
 }
@@ -754,10 +613,8 @@ static vpx_codec_err_t ctrl_set_skip_loop_filter(vpx_codec_alg_priv_t *ctx,
                                                  va_list args) {
   ctx->skip_loop_filter = va_arg(args, int);
 
-  if (ctx->frame_workers) {
-    VPxWorker *const worker = ctx->frame_workers;
-    FrameWorkerData *const frame_worker_data = (FrameWorkerData *)worker->data1;
-    frame_worker_data->pbi->common.skip_loop_filter = ctx->skip_loop_filter;
+  if (ctx->pbi != NULL) {
+    ctx->pbi->common.skip_loop_filter = ctx->skip_loop_filter;
   }
 
   return VPX_CODEC_OK;
diff --git a/vp9/vp9_dx_iface.h b/vp9/vp9_dx_iface.h
index f0a934073..18bc7ab0d 100644
--- a/vp9/vp9_dx_iface.h
+++ b/vp9/vp9_dx_iface.h
@@ -19,6 +19,8 @@ struct vpx_codec_alg_priv {
   vpx_codec_priv_t base;
   vpx_codec_dec_cfg_t cfg;
   vp9_stream_info_t si;
+  VP9Decoder *pbi;
+  void *user_priv;
   int postproc_cfg_set;
   vp8_postproc_cfg_t postproc_cfg;
   vpx_decrypt_cb decrypt_cb;
@@ -31,11 +33,8 @@ struct vpx_codec_alg_priv {
   int byte_alignment;
   int skip_loop_filter;
 
-  // Frame parallel related.
-  VPxWorker *frame_workers;
-  int num_frame_workers;
   int need_resync;  // wait for key/intra-only frame
-  // BufferPool that holds all reference frames. Shared by all the FrameWorkers.
+  // BufferPool that holds all reference frames.
   BufferPool *buffer_pool;
 
   // External frame buffer info to save for VP9 common.
diff --git a/vp9/vp9dx.mk b/vp9/vp9dx.mk
index 5d6858e86..59f612b94 100644
--- a/vp9/vp9dx.mk
+++ b/vp9/vp9dx.mk
@@ -24,7 +24,6 @@ VP9_DX_SRCS-yes += decoder/vp9_decodeframe.h
 VP9_DX_SRCS-yes += decoder/vp9_detokenize.c
 VP9_DX_SRCS-yes += decoder/vp9_decodemv.h
 VP9_DX_SRCS-yes += decoder/vp9_detokenize.h
-VP9_DX_SRCS-yes += decoder/vp9_dthread.h
 VP9_DX_SRCS-yes += decoder/vp9_decoder.c
 VP9_DX_SRCS-yes += decoder/vp9_decoder.h
 VP9_DX_SRCS-yes += decoder/vp9_dsubexp.c