Add support to pass in external frame buffers.

VP9 decoder can now use frame buffers passed in by the application.

Change-Id: I599527ec85c577f3f5552831d79a693884fafb73

21 files changed, 690 insertions, 39 deletions

diff --git a/libs.mk b/libs.mk
index 40628338f..8340eeebe 100644
--- a/libs.mk
+++ b/libs.mk
@@ -183,6 +183,7 @@ CODEC_EXPORTS-$(CONFIG_DECODERS) += vpx/exports_dec
 
 INSTALL-LIBS-yes += include/vpx/vpx_codec.h
 INSTALL-LIBS-yes += include/vpx/vpx_image.h
+INSTALL-LIBS-yes += include/vpx/vpx_external_frame_buffer.h
 INSTALL-LIBS-yes += include/vpx/vpx_integer.h
 INSTALL-LIBS-$(CONFIG_DECODERS) += include/vpx/vpx_decoder.h
 INSTALL-LIBS-$(CONFIG_ENCODERS) += include/vpx/vpx_encoder.h
diff --git a/test/codec_factory.h b/test/codec_factory.h
index cc7b53f06..2ca6ff086 100644
--- a/test/codec_factory.h
+++ b/test/codec_factory.h
@@ -26,6 +26,8 @@ extern "C" {
 #include "test/encode_test_driver.h"
 namespace libvpx_test {
 
+const int kCodecFactoryParam = 0;
+
 class CodecFactory {
  public:
   CodecFactory() {}
diff --git a/test/decode_test_driver.h b/test/decode_test_driver.h
index ddaed9fa0..79db6e1bc 100644
--- a/test/decode_test_driver.h
+++ b/test/decode_test_driver.h
@@ -76,6 +76,16 @@ class Decoder {
     return detail ? detail : vpx_codec_error(&decoder_);
   }
 
+  // Passes the external frame buffer information to libvpx.
+  vpx_codec_err_t SetExternalFrameBuffers(
+      vpx_codec_frame_buffer_t *fb_list, int fb_count,
+      vpx_realloc_frame_buffer_cb_fn_t cb, void *user_priv) {
+    InitOnce();
+    return vpx_codec_set_frame_buffers(&decoder_,
+                                       fb_list, fb_count,
+                                       cb, user_priv);
+  }
+
  protected:
   virtual const vpx_codec_iface_t* CodecInterface() const = 0;
 
diff --git a/test/external_frame_buffer_test.cc b/test/external_frame_buffer_test.cc
new file mode 100644
index 000000000..874d1997c
--- /dev/null
+++ b/test/external_frame_buffer_test.cc
@@ -0,0 +1,309 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#include <string>
+
+#include "test/codec_factory.h"
+#include "test/decode_test_driver.h"
+#include "test/ivf_video_source.h"
+#include "test/md5_helper.h"
+#include "test/test_vectors.h"
+#include "test/util.h"
+#include "test/webm_video_source.h"
+
+namespace {
+
+const int kVideoNameParam = 1;
+const char kVP9TestFile[] = "vp90-2-02-size-lf-1920x1080.webm";
+
+// Callback used by libvpx to request the application to allocate a frame
+// buffer of at least |new_size| in bytes.
+int realloc_vp9_frame_buffer(void *user_priv, size_t new_size,
+                             vpx_codec_frame_buffer_t *fb) {
+  (void)user_priv;
+  if (fb == NULL)
+    return -1;
+
+  delete [] fb->data;
+  fb->data = new uint8_t[new_size];
+  fb->size = new_size;
+  return 0;
+}
+
+// Callback will not allocate data for frame buffer.
+int zero_realloc_vp9_frame_buffer(void *user_priv, size_t new_size,
+                                  vpx_codec_frame_buffer_t *fb) {
+  (void)user_priv;
+  if (fb == NULL)
+    return -1;
+
+  delete [] fb->data;
+  fb->data = NULL;
+  fb->size = new_size;
+  return 0;
+}
+
+// Callback will allocate one less byte.
+int one_less_byte_realloc_vp9_frame_buffer(void *user_priv, size_t new_size,
+                                           vpx_codec_frame_buffer_t *fb) {
+  (void)user_priv;
+  if (fb == NULL)
+    return -1;
+
+  delete [] fb->data;
+
+  const size_t error_size = new_size - 1;
+  fb->data = new uint8_t[error_size];
+  fb->size = error_size;
+  return 0;
+}
+
+// Class for testing passing in external frame buffers to libvpx.
+class ExternalFrameBufferMD5Test
+    : public ::libvpx_test::DecoderTest,
+      public ::libvpx_test::CodecTestWithParam<const char*> {
+ protected:
+  ExternalFrameBufferMD5Test()
+      : DecoderTest(GET_PARAM(::libvpx_test::kCodecFactoryParam)),
+        md5_file_(NULL),
+        num_buffers_(0),
+        frame_buffers_(NULL) {}
+
+  virtual ~ExternalFrameBufferMD5Test() {
+    for (int i = 0; i < num_buffers_; ++i) {
+      delete [] frame_buffers_[i].data;
+    }
+    delete [] frame_buffers_;
+
+    if (md5_file_ != NULL)
+      fclose(md5_file_);
+  }
+
+  virtual void PreDecodeFrameHook(
+      const libvpx_test::CompressedVideoSource &video,
+      libvpx_test::Decoder *decoder) {
+    if (num_buffers_ > 0 && video.frame_number() == 0) {
+      // Have libvpx use frame buffers we create.
+      frame_buffers_ = new vpx_codec_frame_buffer_t[num_buffers_];
+      memset(frame_buffers_, 0, sizeof(frame_buffers_[0]) * num_buffers_);
+
+      ASSERT_EQ(VPX_CODEC_OK,
+                decoder->SetExternalFrameBuffers(
+                    frame_buffers_, num_buffers_,
+                    realloc_vp9_frame_buffer, NULL));
+    }
+  }
+
+  void OpenMD5File(const std::string &md5_file_name_) {
+    md5_file_ = libvpx_test::OpenTestDataFile(md5_file_name_);
+    ASSERT_TRUE(md5_file_ != NULL) << "Md5 file open failed. Filename: "
+        << md5_file_name_;
+  }
+
+  virtual void DecompressedFrameHook(const vpx_image_t &img,
+                                     const unsigned int frame_number) {
+    ASSERT_TRUE(md5_file_ != NULL);
+    char expected_md5[33];
+    char junk[128];
+
+    // Read correct md5 checksums.
+    const int res = fscanf(md5_file_, "%s  %s", expected_md5, junk);
+    ASSERT_NE(EOF, res) << "Read md5 data failed";
+    expected_md5[32] = '\0';
+
+    ::libvpx_test::MD5 md5_res;
+    md5_res.Add(&img);
+    const char *const actual_md5 = md5_res.Get();
+
+    // Check md5 match.
+    ASSERT_STREQ(expected_md5, actual_md5)
+        << "Md5 checksums don't match: frame number = " << frame_number;
+  }
+
+  void set_num_buffers(int num_buffers) { num_buffers_ = num_buffers; }
+  int num_buffers() const { return num_buffers_; }
+
+ private:
+  FILE *md5_file_;
+  int num_buffers_;
+  vpx_codec_frame_buffer_t *frame_buffers_;
+};
+
+class ExternalFrameBufferTest : public ::testing::Test {
+ protected:
+  ExternalFrameBufferTest()
+      : video_(NULL),
+        decoder_(NULL),
+        num_buffers_(0),
+        frame_buffers_(NULL) {}
+
+  virtual void SetUp() {
+    video_ = new libvpx_test::WebMVideoSource(kVP9TestFile);
+    video_->Init();
+    video_->Begin();
+
+    vpx_codec_dec_cfg_t cfg = {0};
+    decoder_ = new libvpx_test::VP9Decoder(cfg, 0);
+  }
+
+  virtual void TearDown() {
+    for (int i = 0; i < num_buffers_; ++i) {
+      delete [] frame_buffers_[i].data;
+    }
+    delete [] frame_buffers_;
+    delete decoder_;
+    delete video_;
+  }
+
+  // Passes the external frame buffer information to libvpx.
+  vpx_codec_err_t SetExternalFrameBuffers(
+      int num_buffers,
+      vpx_realloc_frame_buffer_cb_fn_t cb) {
+    if (num_buffers > 0) {
+      num_buffers_ = num_buffers;
+
+      // Have libvpx use frame buffers we create.
+      frame_buffers_ = new vpx_codec_frame_buffer_t[num_buffers_];
+      memset(frame_buffers_, 0, sizeof(frame_buffers_[0]) * num_buffers_);
+    }
+
+    return decoder_->SetExternalFrameBuffers(frame_buffers_, num_buffers_,
+                                             cb, NULL);
+  }
+
+  // Pass Null frame buffer list to libvpx.
+  vpx_codec_err_t SetNullFrameBuffers(
+      int num_buffers,
+      vpx_realloc_frame_buffer_cb_fn_t cb) {
+    return decoder_->SetExternalFrameBuffers(NULL, num_buffers,
+                                             cb, NULL);
+  }
+
+  vpx_codec_err_t DecodeOneFrame() {
+    const vpx_codec_err_t res =
+        decoder_->DecodeFrame(video_->cxdata(), video_->frame_size());
+    if (res == VPX_CODEC_OK)
+      video_->Next();
+    return res;
+  }
+
+  vpx_codec_err_t DecodeRemainingFrames() {
+    for (; video_->cxdata(); video_->Next()) {
+      const vpx_codec_err_t res =
+          decoder_->DecodeFrame(video_->cxdata(), video_->frame_size());
+      if (res != VPX_CODEC_OK)
+        return res;
+
+      libvpx_test::DxDataIterator dec_iter = decoder_->GetDxData();
+      const vpx_image_t *img = NULL;
+
+      // Get decompressed data
+      while ((img = dec_iter.Next())) {
+      }
+    }
+    return VPX_CODEC_OK;
+  }
+
+  libvpx_test::WebMVideoSource *video_;
+  libvpx_test::VP9Decoder *decoder_;
+  int num_buffers_;
+  vpx_codec_frame_buffer_t *frame_buffers_;
+};
+
+
+// This test runs through the set of test vectors, and decodes them.
+// Libvpx will call into the application to allocate a frame buffer when
+// needed. The md5 checksums are computed for each frame in the video file.
+// If md5 checksums match the correct md5 data, then the test is passed.
+// Otherwise, the test failed.
+TEST_P(ExternalFrameBufferMD5Test, ExtFBMD5Match) {
+  const std::string filename = GET_PARAM(kVideoNameParam);
+  libvpx_test::CompressedVideoSource *video = NULL;
+
+  // Number of buffers equals number of possible reference buffers(8), plus
+  // one working buffer, plus four jitter buffers.
+  const int num_buffers = 13;
+  set_num_buffers(num_buffers);
+
+  // Tell compiler we are not using kVP8TestVectors.
+  (void)libvpx_test::kVP8TestVectors;
+
+  // Open compressed video file.
+  if (filename.substr(filename.length() - 3, 3) == "ivf") {
+    video = new libvpx_test::IVFVideoSource(filename);
+  } else if (filename.substr(filename.length() - 4, 4) == "webm") {
+    video = new libvpx_test::WebMVideoSource(filename);
+  }
+  video->Init();
+
+  // Construct md5 file name.
+  const std::string md5_filename = filename + ".md5";
+  OpenMD5File(md5_filename);
+
+  // Decode frame, and check the md5 matching.
+  ASSERT_NO_FATAL_FAILURE(RunLoop(video));
+  delete video;
+}
+
+TEST_F(ExternalFrameBufferTest, EightFrameBuffers) {
+  // Minimum number of reference buffers for VP9 is 8.
+  const int num_buffers = 8;
+  ASSERT_EQ(VPX_CODEC_OK,
+            SetExternalFrameBuffers(num_buffers, realloc_vp9_frame_buffer));
+  ASSERT_EQ(VPX_CODEC_OK, DecodeRemainingFrames());
+}
+
+TEST_F(ExternalFrameBufferTest, EightJitterBuffers) {
+  // Number of buffers equals number of possible reference buffers(8), plus
+  // one working buffer, plus eight jitter buffers.
+  const int num_buffers = 17;
+  ASSERT_EQ(VPX_CODEC_OK,
+            SetExternalFrameBuffers(num_buffers, realloc_vp9_frame_buffer));
+  ASSERT_EQ(VPX_CODEC_OK, DecodeRemainingFrames());
+}
+
+TEST_F(ExternalFrameBufferTest, NotEnoughBuffers) {
+  // Minimum number of reference buffers for VP9 is 8.
+  const int num_buffers = 7;
+  ASSERT_EQ(VPX_CODEC_INVALID_PARAM,
+            SetExternalFrameBuffers(num_buffers, realloc_vp9_frame_buffer));
+}
+
+TEST_F(ExternalFrameBufferTest, NullFrameBufferList) {
+  // Number of buffers equals number of possible reference buffers(8), plus
+  // one working buffer, plus four jitter buffers.
+  const int num_buffers = 13;
+  ASSERT_EQ(VPX_CODEC_INVALID_PARAM,
+            SetNullFrameBuffers(num_buffers, realloc_vp9_frame_buffer));
+}
+
+TEST_F(ExternalFrameBufferTest, NullRealloc) {
+  // Number of buffers equals number of possible reference buffers(8), plus
+  // one working buffer, plus four jitter buffers.
+  const int num_buffers = 13;
+  ASSERT_EQ(VPX_CODEC_OK,
+            SetExternalFrameBuffers(num_buffers,
+                                    zero_realloc_vp9_frame_buffer));
+  ASSERT_EQ(VPX_CODEC_MEM_ERROR, DecodeOneFrame());
+}
+
+TEST_F(ExternalFrameBufferTest, ReallocOneLessByte) {
+  // Number of buffers equals number of possible reference buffers(8), plus
+  // one working buffer, plus four jitter buffers.
+  const int num_buffers = 13;
+  ASSERT_EQ(VPX_CODEC_OK,
+            SetExternalFrameBuffers(num_buffers,
+                                    one_less_byte_realloc_vp9_frame_buffer));
+  ASSERT_EQ(VPX_CODEC_MEM_ERROR, DecodeOneFrame());
+}
+
+VP9_INSTANTIATE_TEST_CASE(ExternalFrameBufferMD5Test,
+                          ::testing::ValuesIn(libvpx_test::kVP9TestVectors));
+}  // namespace
diff --git a/test/test.mk b/test/test.mk
index 743d0a431..63df488f9 100644
--- a/test/test.mk
+++ b/test/test.mk
@@ -34,6 +34,7 @@ LIBVPX_TEST_SRCS-$(CONFIG_DECODERS)    += ../md5_utils.h ../md5_utils.c
 LIBVPX_TEST_SRCS-yes                   += decode_test_driver.cc
 LIBVPX_TEST_SRCS-yes                   += decode_test_driver.h
 LIBVPX_TEST_SRCS-$(CONFIG_DECODERS)    += ivf_video_source.h
+LIBVPX_TEST_SRCS-$(CONFIG_VP9_DECODER) += external_frame_buffer_test.cc
 
 ## WebM Parsing
 NESTEGG_SRCS                           += ../nestegg/halloc/halloc.h
diff --git a/vp8/vp8_dx_iface.c b/vp8/vp8_dx_iface.c
index 871b8d385..0b4c4cbbf 100644
--- a/vp8/vp8_dx_iface.c
+++ b/vp8/vp8_dx_iface.c
@@ -929,6 +929,7 @@ CODEC_INTERFACE(vpx_codec_vp8_dx) =
         vp8_get_si,       /* vpx_codec_get_si_fn_t     get_si; */
         vp8_decode,       /* vpx_codec_decode_fn_t     decode; */
         vp8_get_frame,    /* vpx_codec_frame_get_fn_t  frame_get; */
+        NOT_IMPLEMENTED,
     },
     { /* encoder functions */
         NOT_IMPLEMENTED,
diff --git a/vp9/common/vp9_alloccommon.c b/vp9/common/vp9_alloccommon.c
index f56784071..6c333c5ef 100644
--- a/vp9/common/vp9_alloccommon.c
+++ b/vp9/common/vp9_alloccommon.c
@@ -34,7 +34,7 @@ void vp9_update_mode_info_border(VP9_COMMON *cm, MODE_INFO *mi) {
 void vp9_free_frame_buffers(VP9_COMMON *cm) {
   int i;
 
-  for (i = 0; i < FRAME_BUFFERS; i++)
+  for (i = 0; i < cm->fb_count; i++)
     vp9_free_frame_buffer(&cm->yv12_fb[i]);
 
   vp9_free_frame_buffer(&cm->post_proc_buffer);
@@ -86,7 +86,7 @@ int vp9_resize_frame_buffers(VP9_COMMON *cm, int width, int height) {
   int mi_size;
 
   if (vp9_realloc_frame_buffer(&cm->post_proc_buffer, width, height, ss_x, ss_y,
-                             VP9BORDERINPIXELS) < 0)
+                               VP9BORDERINPIXELS, NULL, NULL, NULL) < 0)
     goto fail;
 
   set_mb_mi(cm, aligned_width, aligned_height);
@@ -138,16 +138,24 @@ int vp9_alloc_frame_buffers(VP9_COMMON *cm, int width, int height) {
   const int ss_y = cm->subsampling_y;
   int mi_size;
 
+  if (cm->fb_count == 0) {
+    cm->fb_count = FRAME_BUFFERS;
+    CHECK_MEM_ERROR(cm, cm->yv12_fb,
+                    vpx_calloc(cm->fb_count, sizeof(*cm->yv12_fb)));
+    CHECK_MEM_ERROR(cm, cm->fb_idx_ref_cnt,
+                    vpx_calloc(cm->fb_count, sizeof(*cm->fb_idx_ref_cnt)));
+  }
+
   vp9_free_frame_buffers(cm);
 
-  for (i = 0; i < FRAME_BUFFERS; i++) {
+  for (i = 0; i < cm->fb_count; i++) {
     cm->fb_idx_ref_cnt[i] = 0;
     if (vp9_alloc_frame_buffer(&cm->yv12_fb[i], width, height, ss_x, ss_y,
                                VP9BORDERINPIXELS) < 0)
       goto fail;
   }
 
-  cm->new_fb_idx = FRAME_BUFFERS - 1;
+  cm->new_fb_idx = cm->fb_count - 1;
   cm->fb_idx_ref_cnt[cm->new_fb_idx] = 1;
 
   for (i = 0; i < REFS_PER_FRAME; i++)
@@ -203,6 +211,12 @@ void vp9_create_common(VP9_COMMON *cm) {
 
 void vp9_remove_common(VP9_COMMON *cm) {
   vp9_free_frame_buffers(cm);
+
+  vpx_free(cm->yv12_fb);
+  vpx_free(cm->fb_idx_ref_cnt);
+
+  cm->yv12_fb = NULL;
+  cm->fb_idx_ref_cnt = NULL;
 }
 
 void vp9_initialize_common() {
diff --git a/vp9/common/vp9_onyxc_int.h b/vp9/common/vp9_onyxc_int.h
index 975a1d52a..db1ca3db3 100644
--- a/vp9/common/vp9_onyxc_int.h
+++ b/vp9/common/vp9_onyxc_int.h
@@ -113,8 +113,8 @@ typedef struct VP9Common {
 
   YV12_BUFFER_CONFIG *frame_to_show;
 
-  YV12_BUFFER_CONFIG yv12_fb[FRAME_BUFFERS];
-  int fb_idx_ref_cnt[FRAME_BUFFERS]; /* reference counts */
+  YV12_BUFFER_CONFIG *yv12_fb;
+  int *fb_idx_ref_cnt; /* reference counts */
   int ref_frame_map[REF_FRAMES]; /* maps fb_idx to reference slot */
 
   // TODO(jkoleszar): could expand active_ref_idx to 4, with 0 as intra, and
@@ -213,6 +213,11 @@ typedef struct VP9Common {
   int frame_parallel_decoding_mode;
 
   int log2_tile_cols, log2_tile_rows;
+
+  vpx_codec_frame_buffer_t *fb_list;  // External frame buffers
+  int fb_count;  // Total number of frame buffers
+  vpx_realloc_frame_buffer_cb_fn_t realloc_fb_cb;
+  void *user_priv;  // Private data associated with the external frame buffers.
 } VP9_COMMON;
 
 // ref == 0 => LAST_FRAME
@@ -228,11 +233,11 @@ static YV12_BUFFER_CONFIG *get_frame_new_buffer(VP9_COMMON *cm) {
 
 static int get_free_fb(VP9_COMMON *cm) {
   int i;
-  for (i = 0; i < FRAME_BUFFERS; i++)
+  for (i = 0; i < cm->fb_count; i++)
     if (cm->fb_idx_ref_cnt[i] == 0)
       break;
 
-  assert(i < FRAME_BUFFERS);
+  assert(i < cm->fb_count);
   cm->fb_idx_ref_cnt[i] = 1;
   return i;
 }
diff --git a/vp9/common/vp9_reconinter.c b/vp9/common/vp9_reconinter.c
index e8247679c..24f7b597f 100644
--- a/vp9/common/vp9_reconinter.c
+++ b/vp9/common/vp9_reconinter.c
@@ -288,7 +288,7 @@ void vp9_setup_scale_factors(VP9_COMMON *cm, int i) {
   const int ref = cm->active_ref_idx[i];
   struct scale_factors *const sf = &cm->active_ref_scale[i];
   struct scale_factors_common *const sfc = &cm->active_ref_scale_comm[i];
-  if (ref >= FRAME_BUFFERS) {
+  if (ref >= cm->fb_count) {
     vp9_zero(*sf);
     vp9_zero(*sfc);
   } else {
diff --git a/vp9/decoder/vp9_decodeframe.c b/vp9/decoder/vp9_decodeframe.c
index 07c5401d6..9452b194a 100644
--- a/vp9/decoder/vp9_decodeframe.c
+++ b/vp9/decoder/vp9_decodeframe.c
@@ -700,9 +700,21 @@ static void apply_frame_size(VP9D_COMP *pbi, int width, int height) {
     vp9_update_frame_size(cm);
   }
 
-  vp9_realloc_frame_buffer(get_frame_new_buffer(cm), cm->width, cm->height,
-                           cm->subsampling_x, cm->subsampling_y,
-                           VP9BORDERINPIXELS);
+  if (cm->fb_list != NULL) {
+    vpx_codec_frame_buffer_t *const ext_fb = &cm->fb_list[cm->new_fb_idx];
+    if (vp9_realloc_frame_buffer(get_frame_new_buffer(cm),
+                                 cm->width, cm->height,
+                                 cm->subsampling_x, cm->subsampling_y,
+                                 VP9BORDERINPIXELS, ext_fb,
+                                 cm->realloc_fb_cb, cm->user_priv)) {
+      vpx_internal_error(&cm->error, VPX_CODEC_MEM_ERROR,
+                         "Failed to allocate external frame buffer");
+    }
+  } else {
+    vp9_realloc_frame_buffer(get_frame_new_buffer(cm), cm->width, cm->height,
+                             cm->subsampling_x, cm->subsampling_y,
+                             VP9BORDERINPIXELS, NULL, NULL, NULL);
+  }
 }
 
 static void setup_frame_size(VP9D_COMP *pbi,
diff --git a/vp9/encoder/vp9_onyx_if.c b/vp9/encoder/vp9_onyx_if.c
index ce12b4322..ce87a76cb 100644
--- a/vp9/encoder/vp9_onyx_if.c
+++ b/vp9/encoder/vp9_onyx_if.c
@@ -920,7 +920,7 @@ static void alloc_raw_frame_buffers(VP9_COMP *cpi) {
   if (vp9_realloc_frame_buffer(&cpi->alt_ref_buffer,
                                cpi->oxcf.width, cpi->oxcf.height,
                                cm->subsampling_x, cm->subsampling_y,
-                               VP9BORDERINPIXELS))
+                               VP9BORDERINPIXELS, NULL, NULL, NULL))
     vpx_internal_error(&cpi->common.error, VPX_CODEC_MEM_ERROR,
                        "Failed to allocate altref buffer");
 }
@@ -988,14 +988,14 @@ static void update_frame_size(VP9_COMP *cpi) {
   if (vp9_realloc_frame_buffer(&cpi->last_frame_uf,
                                cm->width, cm->height,
                                cm->subsampling_x, cm->subsampling_y,
-                               VP9BORDERINPIXELS))
+                               VP9BORDERINPIXELS, NULL, NULL, NULL))
     vpx_internal_error(&cpi->common.error, VPX_CODEC_MEM_ERROR,
                        "Failed to reallocate last frame buffer");
 
   if (vp9_realloc_frame_buffer(&cpi->scaled_source,
                                cm->width, cm->height,
                                cm->subsampling_x, cm->subsampling_y,
-                               VP9BORDERINPIXELS))
+                               VP9BORDERINPIXELS, NULL, NULL, NULL))
     vpx_internal_error(&cpi->common.error, VPX_CODEC_MEM_ERROR,
                        "Failed to reallocate scaled source buffer");
 
@@ -2563,7 +2563,7 @@ static void scale_references(VP9_COMP *cpi) {
       vp9_realloc_frame_buffer(&cm->yv12_fb[new_fb],
                                cm->width, cm->height,
                                cm->subsampling_x, cm->subsampling_y,
-                               VP9BORDERINPIXELS);
+                               VP9BORDERINPIXELS, NULL, NULL, NULL);
       scale_and_extend_frame(ref, &cm->yv12_fb[new_fb]);
       cpi->scaled_ref_idx[i] = new_fb;
     } else {
@@ -3554,7 +3554,7 @@ int vp9_get_compressed_data(VP9_PTR ptr, unsigned int *frame_flags,
   vp9_realloc_frame_buffer(get_frame_new_buffer(cm),
                            cm->width, cm->height,
                            cm->subsampling_x, cm->subsampling_y,
-                           VP9BORDERINPIXELS);
+                           VP9BORDERINPIXELS, NULL, NULL, NULL);
 
   // Calculate scaling factors for each of the 3 available references
   for (i = 0; i < REFS_PER_FRAME; ++i) {
diff --git a/vp9/vp9_dx_iface.c b/vp9/vp9_dx_iface.c
index fde73e4ab..7fdd5ef5c 100644
--- a/vp9/vp9_dx_iface.c
+++ b/vp9/vp9_dx_iface.c
@@ -59,6 +59,12 @@ struct vpx_codec_alg_priv {
   int                     img_setup;
   int                     img_avail;
   int                     invert_tile_order;
+
+  /* External buffer info to save for VP9 common. */
+  vpx_codec_frame_buffer_t *fb_list;  // External frame buffers
+  int fb_count;  // Total number of frame buffers
+  vpx_realloc_frame_buffer_cb_fn_t realloc_fb_cb;
+  void *user_priv;  // Private data associated with the external frame buffers.
 };
 
 static unsigned long priv_sz(const vpx_codec_dec_cfg_t *si,
@@ -307,10 +313,26 @@ static vpx_codec_err_t decode_one(vpx_codec_alg_priv_t  *ctx,
         ctx->postproc_cfg.noise_level = 0;
       }
 
-      if (!optr)
+      if (!optr) {
         res = VPX_CODEC_ERROR;
-      else
+      } else {
+        VP9D_COMP *const pbi = (VP9D_COMP*)optr;
+        VP9_COMMON *const cm = &pbi->common;
+        if (ctx->fb_list != NULL && ctx->realloc_fb_cb != NULL &&
+            ctx->fb_count > 0) {
+          cm->fb_list = ctx->fb_list;
+          cm->fb_count = ctx->fb_count;
+          cm->realloc_fb_cb = ctx->realloc_fb_cb;
+          cm->user_priv = ctx->user_priv;
+        } else {
+          cm->fb_count = FRAME_BUFFERS;
+        }
+        CHECK_MEM_ERROR(cm, cm->yv12_fb,
+                        vpx_calloc(cm->fb_count, sizeof(*cm->yv12_fb)));
+        CHECK_MEM_ERROR(cm, cm->fb_idx_ref_cnt,
+                        vpx_calloc(cm->fb_count, sizeof(*cm->fb_idx_ref_cnt)));
         ctx->pbi = optr;
+      }
     }
 
     ctx->decoder_init = 1;
@@ -347,7 +369,7 @@ static vpx_codec_err_t decode_one(vpx_codec_alg_priv_t  *ctx,
     }
 
     if (vp9_receive_compressed_data(ctx->pbi, data_sz, data, deadline)) {
-      VP9D_COMP *pbi = (VP9D_COMP *)ctx->pbi;
+      VP9D_COMP *pbi = (VP9D_COMP*)ctx->pbi;
       res = update_error_state(ctx, &pbi->common.error);
     }
 
@@ -475,6 +497,27 @@ static vpx_image_t *vp9_get_frame(vpx_codec_alg_priv_t  *ctx,
   return img;
 }
 
+static vpx_codec_err_t vp9_set_frame_buffers(
+    vpx_codec_alg_priv_t *ctx,
+    vpx_codec_frame_buffer_t *fb_list, int fb_count,
+    vpx_realloc_frame_buffer_cb_fn_t cb, void *user_priv) {
+  if (fb_count < REF_FRAMES) {
+    /* The application must pass in at least REF_FRAMES frame buffers. */
+    return VPX_CODEC_INVALID_PARAM;
+  } else if (!ctx->pbi) {
+    /* If the decoder has already been initialized, do not accept external
+     * frame buffers.
+     */
+    ctx->fb_list = fb_list;
+    ctx->fb_count = fb_count;
+    ctx->realloc_fb_cb = cb;
+    ctx->user_priv = user_priv;
+    return VPX_CODEC_OK;
+  }
+
+  return VPX_CODEC_ERROR;
+}
+
 static vpx_codec_err_t vp9_xma_get_mmap(const vpx_codec_ctx_t      *ctx,
                                         vpx_codec_mmap_t           *mmap,
                                         vpx_codec_iter_t           *iter) {
@@ -639,7 +682,7 @@ static vpx_codec_err_t get_last_ref_updates(vpx_codec_alg_priv_t *ctx,
                                             int ctrl_id,
                                             va_list args) {
   int *update_info = va_arg(args, int *);
-  VP9D_COMP *pbi = (VP9D_COMP *)ctx->pbi;
+  VP9D_COMP *pbi = (VP9D_COMP*)ctx->pbi;
 
   if (update_info) {
     *update_info = pbi->refresh_frame_flags;
@@ -657,7 +700,7 @@ static vpx_codec_err_t get_frame_corrupted(vpx_codec_alg_priv_t *ctx,
   int *corrupted = va_arg(args, int *);
 
   if (corrupted) {
-    VP9D_COMP *pbi = (VP9D_COMP *)ctx->pbi;
+    VP9D_COMP *pbi = (VP9D_COMP*)ctx->pbi;
     if (pbi)
       *corrupted = pbi->common.frame_to_show->corrupted;
     else
@@ -674,7 +717,7 @@ static vpx_codec_err_t get_display_size(vpx_codec_alg_priv_t *ctx,
   int *const display_size = va_arg(args, int *);
 
   if (display_size) {
-    const VP9D_COMP *const pbi = (VP9D_COMP *)ctx->pbi;
+    const VP9D_COMP *const pbi = (VP9D_COMP*)ctx->pbi;
     if (pbi) {
       display_size[0] = pbi->common.display_width;
       display_size[1] = pbi->common.display_height;
@@ -717,7 +760,8 @@ static vpx_codec_ctrl_fn_map_t ctf_maps[] = {
 CODEC_INTERFACE(vpx_codec_vp9_dx) = {
   "WebM Project VP9 Decoder" VERSION_STRING,
   VPX_CODEC_INTERNAL_ABI_VERSION,
-  VPX_CODEC_CAP_DECODER | VP9_CAP_POSTPROC,
+  VPX_CODEC_CAP_DECODER | VP9_CAP_POSTPROC |
+      VPX_CODEC_CAP_EXTERNAL_FRAME_BUFFER,
   /* vpx_codec_caps_t          caps; */
   vp9_init,         /* vpx_codec_init_fn_t       init; */
   vp9_destroy,      /* vpx_codec_destroy_fn_t    destroy; */
@@ -729,6 +773,7 @@ CODEC_INTERFACE(vpx_codec_vp9_dx) = {
     vp9_get_si,       /* vpx_codec_get_si_fn_t     get_si; */
     vp9_decode,       /* vpx_codec_decode_fn_t     decode; */
     vp9_get_frame,    /* vpx_codec_frame_get_fn_t  frame_get; */
+    vp9_set_frame_buffers,    /* vpx_codec_set_frame_buffers_fn_t  set_fb; */
   },
   { // NOLINT
     /* encoder functions */
diff --git a/vpx/exports_dec b/vpx/exports_dec
index ed121f7ec..d058c9bdb 100644
--- a/vpx/exports_dec
+++ b/vpx/exports_dec
@@ -7,3 +7,4 @@ text vpx_codec_peek_stream_info
 text vpx_codec_register_put_frame_cb
 text vpx_codec_register_put_slice_cb
 text vpx_codec_set_mem_map
+text vpx_codec_set_frame_buffers
diff --git a/vpx/internal/vpx_codec_internal.h b/vpx/internal/vpx_codec_internal.h
index 05fed977e..75b4a1877 100644
--- a/vpx/internal/vpx_codec_internal.h
+++ b/vpx/internal/vpx_codec_internal.h
@@ -56,7 +56,7 @@
  * types, removing or reassigning enums, adding/removing/rearranging
  * fields to structures
  */
-#define VPX_CODEC_INTERNAL_ABI_VERSION (4) /**<\hideinitializer*/
+#define VPX_CODEC_INTERNAL_ABI_VERSION (5) /**<\hideinitializer*/
 
 typedef struct vpx_codec_alg_priv  vpx_codec_alg_priv_t;
 typedef struct vpx_codec_priv_enc_mr_cfg vpx_codec_priv_enc_mr_cfg_t;
@@ -215,6 +215,36 @@ typedef vpx_codec_err_t (*vpx_codec_decode_fn_t)(vpx_codec_alg_priv_t  *ctx,
 typedef vpx_image_t *(*vpx_codec_get_frame_fn_t)(vpx_codec_alg_priv_t *ctx,
                                                  vpx_codec_iter_t     *iter);
 
+/*!\brief Pass in external frame buffers for the decoder to use.
+ *
+ * Registers a given function to be called when the current frame to
+ * decode will be bigger than the external frame buffer size. This
+ * function must be called before the first call to decode or libvpx
+ * will assume the default behavior of allocating frame buffers internally.
+ * Frame buffers with a size of 0 are valid.
+ *
+ * \param[in] ctx          Pointer to this instance's context
+ * \param[in] fb_list      Pointer to array of frame buffers
+ * \param[in] fb_count     Number of elements in frame buffer array
+ * \param[in] cb           Pointer to the callback function
+ * \param[in] user_priv    User's private data
+ *
+ * \retval #VPX_CODEC_OK
+ *     External frame buffers will be used by libvpx.
+ * \retval #VPX_CODEC_INVALID_PARAM
+ *     fb_count was less than the value needed by the codec.
+ * \retval #VPX_CODEC_ERROR
+ *     Decoder context not initialized, or algorithm not capable of
+ *     using external frame buffers.
+ *
+ * \note
+ * When decoding VP9, the application must pass in at least 8 external
+ * frame buffers, as VP9 can have up to 8 reference frames.
+ */
+typedef vpx_codec_err_t (*vpx_codec_set_frame_buffers_fn_t)(
+    vpx_codec_alg_priv_t *ctx,
+    vpx_codec_frame_buffer_t *fb_list, int fb_count,
+    vpx_realloc_frame_buffer_cb_fn_t cb, void *user_priv);
 
 /*\brief eXternal Memory Allocation memory map get iterator
  *
@@ -305,6 +335,7 @@ struct vpx_codec_iface {
     vpx_codec_get_si_fn_t     get_si;      /**< \copydoc ::vpx_codec_get_si_fn_t */
     vpx_codec_decode_fn_t     decode;      /**< \copydoc ::vpx_codec_decode_fn_t */
     vpx_codec_get_frame_fn_t  get_frame;   /**< \copydoc ::vpx_codec_get_frame_fn_t */
+    vpx_codec_set_frame_buffers_fn_t set_fb; /**< \copydoc ::vpx_codec_set_frame_buffers_fn_t */
   } dec;
   struct vpx_codec_enc_iface {
     vpx_codec_enc_cfg_map_t           *cfg_maps;      /**< \copydoc ::vpx_codec_enc_cfg_map_t */
diff --git a/vpx/src/vpx_decoder.c b/vpx/src/vpx_decoder.c
index a99e48f88..39fd217ea 100644
--- a/vpx/src/vpx_decoder.c
+++ b/vpx/src/vpx_decoder.c
@@ -226,3 +226,22 @@ vpx_codec_err_t vpx_codec_set_mem_map(vpx_codec_ctx_t   *ctx,
 
   return SAVE_STATUS(ctx, res);
 }
+
+vpx_codec_err_t vpx_codec_set_frame_buffers(
+    vpx_codec_ctx_t *ctx,
+    vpx_codec_frame_buffer_t *fb_list, int fb_count,
+    vpx_realloc_frame_buffer_cb_fn_t cb, void *user_priv) {
+  vpx_codec_err_t res;
+
+  if (!ctx || !fb_list || fb_count <= 0 || !cb) {
+    res = VPX_CODEC_INVALID_PARAM;
+  } else if (!ctx->iface || !ctx->priv ||
+             !(ctx->iface->caps & VPX_CODEC_CAP_EXTERNAL_FRAME_BUFFER)) {
+    res = VPX_CODEC_ERROR;
+  } else {
+    res = ctx->iface->dec.set_fb(ctx->priv->alg_priv, fb_list, fb_count,
+                                 cb, user_priv);
+  }
+
+  return SAVE_STATUS(ctx, res);
+}
diff --git a/vpx/vpx_codec.mk b/vpx/vpx_codec.mk
index 549c24908..df3ff6ef1 100644
--- a/vpx/vpx_codec.mk
+++ b/vpx/vpx_codec.mk
@@ -27,6 +27,7 @@ API_DOC_SRCS-yes += vpx_codec.h
 API_DOC_SRCS-yes += vpx_decoder.h
 API_DOC_SRCS-yes += vpx_encoder.h
 API_DOC_SRCS-yes += vpx_image.h
+API_DOC_SRCS-yes += vpx_external_frame_buffer.h
 
 API_SRCS-yes                += src/vpx_decoder.c
 API_SRCS-yes                += vpx_decoder.h
@@ -38,4 +39,5 @@ API_SRCS-yes                += src/vpx_image.c
 API_SRCS-yes                += vpx_codec.h
 API_SRCS-yes                += vpx_codec.mk
 API_SRCS-yes                += vpx_image.h
+API_SRCS-yes                += vpx_external_frame_buffer.h
 API_SRCS-$(BUILD_LIBVPX)    += vpx_integer.h
diff --git a/vpx/vpx_decoder.h b/vpx/vpx_decoder.h
index 2dcd024cc..08f7f434e 100644
--- a/vpx/vpx_decoder.h
+++ b/vpx/vpx_decoder.h
@@ -30,6 +30,7 @@ extern "C" {
 #endif
 
 #include "vpx_codec.h"
+#include "vpx_external_frame_buffer.h"
 
   /*!\brief Current ABI version number
    *
@@ -39,7 +40,7 @@ extern "C" {
    * types, removing or reassigning enums, adding/removing/rearranging
    * fields to structures
    */
-#define VPX_DECODER_ABI_VERSION (2 + VPX_CODEC_ABI_VERSION) /**<\hideinitializer*/
+#define VPX_DECODER_ABI_VERSION (3 + VPX_CODEC_ABI_VERSION) /**<\hideinitializer*/
 
   /*! \brief Decoder capabilities bitfield
    *
@@ -66,6 +67,8 @@ extern "C" {
    */
 #define VPX_CODEC_CAP_FRAME_THREADING   0x200000 /**< Can support frame-based
                                                       multi-threading */
+#define VPX_CODEC_CAP_EXTERNAL_FRAME_BUFFER 0x400000 /**< Can support external
+                                                      frame buffers */
 
 #define VPX_CODEC_USE_POSTPROC   0x10000 /**< Postprocess decoded frame */
 #define VPX_CODEC_USE_ERROR_CONCEALMENT 0x20000 /**< Conceal errors in decoded
@@ -326,6 +329,49 @@ extern "C" {
 
   /*!@} - end defgroup cap_put_slice*/
 
+  /*!\defgroup cap_external_frame_buffer External Frame Buffer Functions
+   *
+   * The following section is required to be implemented for all decoders
+   * that advertise the VPX_CODEC_CAP_EXTERNAL_FRAME_BUFFER capability.
+   * Calling this function for codecs that don't advertise this capability
+   * will result in an error code being returned, usually VPX_CODEC_ERROR.
+   *
+   * \note
+   * Currently this only works with VP9.
+   * @{
+   */
+
+  /*!\brief Pass in external frame buffers for the decoder to use.
+   *
+   * Registers a given function to be called when the current frame to
+   * decode will be bigger than the external frame buffer size. This
+   * function must be called before the first call to decode or libvpx
+   * will assume the default behavior of allocating frame buffers internally.
+   * Frame buffers with a size of 0 are valid.
+   *
+   * \param[in] ctx          Pointer to this instance's context
+   * \param[in] fb_list      Pointer to array of frame buffers
+   * \param[in] fb_count     Number of elements in frame buffer array
+   * \param[in] cb           Pointer to the callback function
+   * \param[in] user_priv    User's private data
+   *
+   * \retval #VPX_CODEC_OK
+   *     External frame buffers passed into the decoder.
+   * \retval #VPX_CODEC_ERROR
+   *     Decoder context not initialized, or algorithm not capable of
+   *     using external frame buffers.
+   *
+   * \note
+   * When decoding VP9, the application must pass in at least 8 external
+   * frame buffers, as VP9 can have up to 8 reference frames.
+   */
+  vpx_codec_err_t vpx_codec_set_frame_buffers(
+      vpx_codec_ctx_t *ctx,
+      vpx_codec_frame_buffer_t *fb_list, int fb_count,
+      vpx_realloc_frame_buffer_cb_fn_t cb, void *user_priv);
+
+  /*!@} - end defgroup cap_external_frame_buffer */
+
   /*!@} - end defgroup decoder*/
 #ifdef __cplusplus
 }
diff --git a/vpx/vpx_external_frame_buffer.h b/vpx/vpx_external_frame_buffer.h
new file mode 100644
index 000000000..adf133042
--- /dev/null
+++ b/vpx/vpx_external_frame_buffer.h
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2013 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 VPX_VPX_EXTERNAL_FRAME_BUFFER_H_
+#define VPX_VPX_EXTERNAL_FRAME_BUFFER_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "vpx/vpx_integer.h"
+
+/*!\brief External frame buffer
+ *
+ * This structure is used to hold external frame buffers passed into the
+ * decoder by the application.
+ */
+typedef struct vpx_codec_frame_buffer {
+  uint8_t *data;    /**< Pointer to the data buffer */
+  size_t size;      /**< Size of data in bytes */
+  void *frame_priv;  /**< Frame's private data */
+} vpx_codec_frame_buffer_t;
+
+/*!\brief realloc frame buffer callback prototype
+ *
+ * This callback is invoked by the decoder to notify the application one
+ * of the external frame buffers must increase in size, in order for the
+ * decode call to complete. The callback must allocate at least new_size in
+ * bytes and assign it to fb->data. Then the callback must set fb->size to
+ * the allocated size. The application does not need to align the allocated
+ * data. The callback is usually triggered by a frame size change. On success
+ * the callback must return 0. Any failure the callback must return a value
+ * less than 0.
+ *
+ * \param[in] user_priv    User's private data
+ * \param[in] new_size     Size in bytes needed by the buffer.
+ * \param[in/out] fb       Pointer to frame buffer to increase size.
+ */
+typedef int (*vpx_realloc_frame_buffer_cb_fn_t)(
+    void *user_priv, size_t new_size, vpx_codec_frame_buffer_t *fb);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // VPX_VPX_EXTERNAL_FRAME_BUFFER_H_
diff --git a/vpx_scale/generic/yv12config.c b/vpx_scale/generic/yv12config.c
index 7c3f7ece9..a020e19b7 100644
--- a/vpx_scale/generic/yv12config.c
+++ b/vpx_scale/generic/yv12config.c
@@ -19,10 +19,18 @@
 /****************************************************************************
  *
  ****************************************************************************/
+
+#define yv12_align_addr(addr, align) \
+  (void*)(((size_t)(addr) + ((align) - 1)) & (size_t)-(align))
+
 int
 vp8_yv12_de_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf) {
   if (ybf) {
-    vpx_free(ybf->buffer_alloc);
+    // If libvpx is using external frame buffers then buffer_alloc_sz must
+    // not be set.
+    if (ybf->buffer_alloc_sz > 0) {
+      vpx_free(ybf->buffer_alloc);
+    }
 
     /* buffer_alloc isn't accessed by most functions.  Rather y_buffer,
       u_buffer and v_buffer point to buffer_alloc and are used.  Clear out
@@ -108,7 +116,9 @@ int vp8_yv12_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
 
 int vp9_free_frame_buffer(YV12_BUFFER_CONFIG *ybf) {
   if (ybf) {
-    vpx_free(ybf->buffer_alloc);
+    if (ybf->buffer_alloc_sz > 0) {
+      vpx_free(ybf->buffer_alloc);
+    }
 
     /* buffer_alloc isn't accessed by most functions.  Rather y_buffer,
       u_buffer and v_buffer point to buffer_alloc and are used.  Clear out
@@ -123,7 +133,10 @@ int vp9_free_frame_buffer(YV12_BUFFER_CONFIG *ybf) {
 
 int vp9_realloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
                              int width, int height,
-                             int ss_x, int ss_y, int border) {
+                             int ss_x, int ss_y, int border,
+                             vpx_codec_frame_buffer_t *ext_fb,
+                             vpx_realloc_frame_buffer_cb_fn_t cb,
+                             void *user_priv) {
   if (ybf) {
     const int aligned_width = (width + 7) & ~7;
     const int aligned_height = (height + 7) & ~7;
@@ -148,15 +161,36 @@ int vp9_realloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
 #else
     const int frame_size = yplane_size + 2 * uvplane_size;
 #endif
-    if (frame_size > ybf->buffer_alloc_sz) {
-      // Allocation to hold larger frame, or first allocation.
-      if (ybf->buffer_alloc)
-        vpx_free(ybf->buffer_alloc);
-      ybf->buffer_alloc = vpx_memalign(32, frame_size);
-      ybf->buffer_alloc_sz = frame_size;
+
+    if (ext_fb != NULL) {
+      const int align_addr_extra_size = 31;
+      const int external_frame_size = frame_size + align_addr_extra_size;
+      if (external_frame_size > ext_fb->size) {
+        // Allocation to hold larger frame, or first allocation.
+        if (cb(user_priv, external_frame_size, ext_fb) < 0) {
+          return -1;
+        }
+
+        if (ext_fb->data == NULL || ext_fb->size < external_frame_size) {
+          return -1;
+        }
+
+        ybf->buffer_alloc = yv12_align_addr(ext_fb->data, 32);
+      }
+    } else {
+      if (frame_size > ybf->buffer_alloc_sz) {
+        // Allocation to hold larger frame, or first allocation.
+        if (ybf->buffer_alloc)
+          vpx_free(ybf->buffer_alloc);
+        ybf->buffer_alloc = vpx_memalign(32, frame_size);
+        ybf->buffer_alloc_sz = frame_size;
+      }
+
+      if (ybf->buffer_alloc_sz < frame_size)
+        return -1;
     }
 
-    if (!ybf->buffer_alloc || ybf->buffer_alloc_sz < frame_size)
+    if (!ybf->buffer_alloc)
       return -1;
 
     /* Only support allocating buffers that have a border that's a multiple
@@ -206,7 +240,8 @@ int vp9_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
                            int ss_x, int ss_y, int border) {
   if (ybf) {
     vp9_free_frame_buffer(ybf);
-    return vp9_realloc_frame_buffer(ybf, width, height, ss_x, ss_y, border);
+    return vp9_realloc_frame_buffer(ybf, width, height, ss_x, ss_y, border,
+                                    NULL, NULL, NULL);
   }
   return -2;
 }
diff --git a/vpx_scale/yv12config.h b/vpx_scale/yv12config.h
index 0e950fb14..f23e1163c 100644
--- a/vpx_scale/yv12config.h
+++ b/vpx_scale/yv12config.h
@@ -15,6 +15,7 @@
 extern "C" {
 #endif
 
+#include "vpx/vpx_external_frame_buffer.h"
 #include "vpx/vpx_integer.h"
 
 #define VP8BORDERINPIXELS       32
@@ -64,9 +65,20 @@ extern "C" {
   int vp9_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
                              int width, int height, int ss_x, int ss_y,
                              int border);
+
+  // Updates the yv12 buffer config with the frame buffer. If ext_fb is not
+  // NULL then libvpx is using external frame buffers. The function will
+  // check if the frame buffer is big enough to fit the decoded frame and
+  // try to reallocate the frame buffer. If ext_fb is not NULL and the frame
+  // buffer is not big enough libvpx will call cb with minimum size in bytes.
+  //
+  // Returns 0 on success. Returns < 0 on failure.
   int vp9_realloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
                                int width, int height, int ss_x, int ss_y,
-                               int border);
+                               int border,
+                               vpx_codec_frame_buffer_t *ext_fb,
+                               vpx_realloc_frame_buffer_cb_fn_t cb,
+                               void *user_priv);
   int vp9_free_frame_buffer(YV12_BUFFER_CONFIG *ybf);
 
 #ifdef __cplusplus
diff --git a/vpxdec.c b/vpxdec.c
index 1b9bfd302..01e0da2ca 100644
--- a/vpxdec.c
+++ b/vpxdec.c
@@ -89,6 +89,8 @@ static const arg_def_t error_concealment = ARG_DEF(NULL, "error-concealment", 0,
                                                    "Enable decoder error-concealment");
 static const arg_def_t scalearg = ARG_DEF("S", "scale", 0,
                                             "Scale output frames uniformly");
+static const arg_def_t fb_arg =
+    ARG_DEF(NULL, "frame-buffers", 1, "Number of frame buffers to use");
 
 
 #if CONFIG_MD5
@@ -98,7 +100,7 @@ static const arg_def_t md5arg = ARG_DEF(NULL, "md5", 0,
 static const arg_def_t *all_args[] = {
   &codecarg, &use_yv12, &use_i420, &flipuvarg, &noblitarg,
   &progressarg, &limitarg, &skiparg, &postprocarg, &summaryarg, &outputfile,
-  &threadsarg, &verbosearg, &scalearg,
+  &threadsarg, &verbosearg, &scalearg, &fb_arg,
 #if CONFIG_MD5
   &md5arg,
 #endif
@@ -314,6 +316,31 @@ void show_progress(int frame_in, int frame_out, unsigned long dx_time) {
           (float)frame_out * 1000000.0 / (float)dx_time);
 }
 
+// Called by libvpx if the frame buffer size needs to increase.
+//
+// Parameters:
+// user_priv    Data passed into libvpx.
+// new_size     Minimum size needed by libvpx to decompress the next frame.
+// fb           Pointer to the frame buffer to update.
+//
+// Returns 0 on success. Returns < 0 on failure.
+int realloc_vp9_frame_buffer(void *user_priv, size_t new_size,
+                             vpx_codec_frame_buffer_t *fb) {
+  (void)user_priv;
+  if (!fb)
+    return -1;
+
+  free(fb->data);
+  fb->data = (uint8_t*)malloc(new_size);
+  if (!fb->data) {
+    fb->size = 0;
+    return -1;
+  }
+
+  fb->size = new_size;
+  return 0;
+}
+
 void generate_filename(const char *pattern, char *out, size_t q_len,
                        unsigned int d_w, unsigned int d_h,
                        unsigned int frame_in) {
@@ -428,6 +455,8 @@ int main_loop(int argc, const char **argv_) {
   int                     do_scale = 0;
   vpx_image_t             *scaled_img = NULL;
   int                     frame_avail, got_data;
+  int                     num_external_frame_buffers = 0;
+  vpx_codec_frame_buffer_t *frame_buffers = NULL;
 
   struct VpxDecInputContext input = {0};
   struct VpxInputContext vpx_input_ctx = {0};
@@ -487,6 +516,9 @@ int main_loop(int argc, const char **argv_) {
       quiet = 0;
     else if (arg_match(&arg, &scalearg, argi))
       do_scale = 1;
+    else if (arg_match(&arg, &fb_arg, argi))
+      num_external_frame_buffers = arg_parse_uint(&arg);
+
 
 #if CONFIG_VP8_DECODER
     else if (arg_match(&arg, &addnoise_level, argi)) {
@@ -704,6 +736,22 @@ int main_loop(int argc, const char **argv_) {
     arg_skip--;
   }
 
+  if (num_external_frame_buffers > 0) {
+    // Allocate the frame buffer list, setting all of the values to 0.
+    // Including the size of frame buffers. Libvpx will request the
+    // application to realloc the frame buffer data if the size is too small.
+    frame_buffers = (vpx_codec_frame_buffer_t*)calloc(
+        num_external_frame_buffers, sizeof(*frame_buffers));
+    if (vpx_codec_set_frame_buffers(&decoder, frame_buffers,
+                                    num_external_frame_buffers,
+                                    realloc_vp9_frame_buffer,
+                                    NULL)) {
+      fprintf(stderr, "Failed to configure external frame buffers: %s\n",
+              vpx_codec_error(&decoder));
+      return EXIT_FAILURE;
+    }
+  }
+
   frame_avail = 1;
   got_data = 0;
 
@@ -878,6 +926,10 @@ fail:
     free(buf);
 
   if (scaled_img) vpx_img_free(scaled_img);
+  for (i = 0; i < num_external_frame_buffers; ++i) {
+    free(frame_buffers[i].data);
+  }
+  free(frame_buffers);
 
   fclose(infile);
   free(argv);