diff --git a/vp9_spatial_scalable_encoder.c b/vp9_spatial_scalable_encoder.c
new file mode 100644
index 0000000..8bb582f
--- /dev/null
+++ b/vp9_spatial_scalable_encoder.c
@@ -0,0 +1,487 @@
+/*
+ *  Copyright (c) 2012 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.
+ */
+
+/*
+ * This is an example demonstrating how to implement a multi-layer
+ * VP9 encoding scheme based on spatial scalability for video applications
+ * that benefit from a scalable bitstream.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <time.h>
+#include <string.h>
+#include <unistd.h>
+#include <libgen.h>
+#define VPX_CODEC_DISABLE_COMPAT 1
+#include "vpx/vpx_encoder.h"
+#include "vpx/vp8cx.h"
+#define interface (vpx_codec_vp9_cx())
+#define fourcc 0x30395056
+#define IVF_FILE_HDR_SZ (32)
+#define IVF_FRAME_HDR_SZ (12)
+#define NUM_BUFFERS 8
+
+char *input_filename;
+char *output_filename;
+unsigned int number_frames_to_code = 60 * 60;
+unsigned int number_frames_to_skip = 0;
+unsigned int number_spatial_layers = 5;
+unsigned int key_period = 100;
+
+typedef enum ENCODING_MODE {
+  INTER_LAYER_PREDICTION_I,
+  INTER_LAYER_PREDICTION_IP,
+  USE_GOLDEN_FRAME
+} ENCODING_MODE;
+
+static void mem_put_le16(char *mem, unsigned int val) {
+  mem[0] = val;
+  mem[1] = val >> 8;
+}
+
+static void mem_put_le32(char *mem, unsigned int val) {
+  mem[0] = val;
+  mem[1] = val >> 8;
+  mem[2] = val >> 16;
+  mem[3] = val >> 24;
+}
+
+static void usage(char *program_name) {
+  printf(
+      "Usage: %s [-f frames] [-s skip_frames] [-w width] [-h height] \n\t"
+      "[-n rate_num] [-d rate_den] [-b bitrate] [-l layers] "
+      "<input_filename> <output_filename>\n",
+      basename(program_name));
+  exit(EXIT_FAILURE);
+}
+
+static void die(const char *fmt, ...) {
+  va_list ap;
+
+  va_start(ap, fmt);
+  vprintf(fmt, ap);
+  if (fmt[strlen(fmt) - 1] != '\n') printf("\n");
+  exit(EXIT_FAILURE);
+}
+
+static void die_codec(vpx_codec_ctx_t *ctx, const char *s) {
+  const char *detail = vpx_codec_error_detail(ctx);
+
+  printf("%s: %s\n", s, vpx_codec_error(ctx));
+  if (detail) printf("    %s\n", detail);
+  exit(EXIT_FAILURE);
+}
+
+static int read_frame(FILE *f, vpx_image_t *img) {
+  size_t nbytes, to_read;
+  int res = 1;
+
+  to_read = img->w * img->h * 3 / 2;
+  nbytes = fread(img->planes[0], 1, to_read, f);
+  if (nbytes != to_read) {
+    res = 0;
+    if (nbytes > 0)
+      printf("Warning: Read partial frame. Check your width & height!\n");
+  }
+  return res;
+}
+
+static int read_dummy_frame(vpx_image_t *img) {
+  size_t to_read;
+
+  to_read = img->w * img->h * 3 / 2;
+  memset(img->planes[0], 129, to_read);
+  return 1;
+}
+
+static void write_ivf_file_header(FILE *outfile, const vpx_codec_enc_cfg_t *cfg,
+                                  int frame_cnt) {
+  char header[32];
+
+  if (cfg->g_pass != VPX_RC_ONE_PASS && cfg->g_pass != VPX_RC_LAST_PASS) return;
+  header[0] = 'D';
+  header[1] = 'K';
+  header[2] = 'I';
+  header[3] = 'F';
+  mem_put_le16(header + 4, 0);                    /* version */
+  mem_put_le16(header + 6, 32);                   /* headersize */
+  mem_put_le32(header + 8, fourcc);               /* headersize */
+  mem_put_le16(header + 12, cfg->g_w);            /* width */
+  mem_put_le16(header + 14, cfg->g_h);            /* height */
+  mem_put_le32(header + 16, cfg->g_timebase.den); /* rate */
+  mem_put_le32(header + 20, cfg->g_timebase.num); /* scale */
+  mem_put_le32(header + 24, frame_cnt);           /* length */
+  mem_put_le32(header + 28, 0);                   /* unused */
+
+  (void)fwrite(header, 1, 32, outfile);
+}
+
+static void write_ivf_frame_header(FILE *outfile,
+                                   const vpx_codec_cx_pkt_t *pkt) {
+  char header[12];
+  vpx_codec_pts_t pts;
+
+  if (pkt->kind != VPX_CODEC_CX_FRAME_PKT) return;
+
+  pts = pkt->data.frame.pts;
+  mem_put_le32(header, pkt->data.frame.sz);
+  mem_put_le32(header + 4, pts & 0xFFFFFFFF);
+  mem_put_le32(header + 8, pts >> 32);
+
+  (void)fwrite(header, 1, 12, outfile);
+}
+
+static void check_parameters() {
+  if (number_spatial_layers > 5) die("Cannot support more than 5 layers");
+}
+
+static void parse_command_line(int argc, char **argv,
+                               vpx_codec_enc_cfg_t *cfg) {
+  unsigned int width = 1920;
+  unsigned int height = 1080;
+  unsigned int timebase_num = 1;
+  unsigned int timebase_den = 60;
+  unsigned int bitrate = 1000;
+  int c;
+  vpx_codec_err_t res;
+
+  opterr = 0;
+  while ((c = getopt(argc, argv, "f:w:h:n:d:b:s:l:p:")) != -1) switch (c) {
+      case 'f':
+        number_frames_to_code = atoi(optarg);
+        break;
+      case 'w':
+        width = atoi(optarg);
+        break;
+      case 'h':
+        height = atoi(optarg);
+        break;
+      case 'n':
+        timebase_num = atoi(optarg);
+        break;
+      case 'd':
+        timebase_den = atoi(optarg);
+        break;
+      case 'b':
+        bitrate = atoi(optarg);
+        break;
+      case 's':
+        number_frames_to_skip = atoi(optarg);
+        break;
+      case 'l':
+        number_spatial_layers = atoi(optarg);
+        break;
+      case 'p':
+        key_period = atoi(optarg);
+        break;
+      case '?':
+        usage(argv[0]);
+    }
+
+  // Parse required parameters
+  if (argc - optind != 2) {
+    usage(argv[0]);
+  }
+
+  input_filename = argv[optind];
+  output_filename = argv[optind + 1];
+
+  if (width < 16 || width % 2 || height < 16 || height % 2)
+    die("Invalid resolution: %d x %d", width, height);
+
+  /* Populate encoder configuration */
+  res = vpx_codec_enc_config_default(interface, cfg, 0);
+  if (res) {
+    die("Failed to get config: %s\n", vpx_codec_err_to_string(res));
+  }
+  printf(
+      "Codec %s\nframes: %d, skip: %d, layers: %d\n"
+      "width %d, height: %d, \n"
+      "num: %d, den: %d, bitrate: %d, \n"
+      "key period: %d \n",
+      vpx_codec_iface_name(interface), number_frames_to_code,
+      number_frames_to_skip, number_spatial_layers, width, height, timebase_num,
+      timebase_den, bitrate, key_period);
+
+  // Do minimal check at the application level. Encoder parameters will be
+  // checked internally
+  check_parameters();
+
+  cfg->rc_target_bitrate = bitrate;
+  cfg->g_w = width;
+  cfg->g_h = height;
+  cfg->g_timebase.num = timebase_num;
+  cfg->g_timebase.den = timebase_den;
+  cfg->ss_number_layers = number_spatial_layers;
+}
+
+static void set_default_configuration(vpx_codec_enc_cfg_t *cfg) {
+  /* Real time parameters */
+  cfg->rc_dropframe_thresh = 0;
+  cfg->rc_end_usage = VPX_CBR;
+  cfg->rc_resize_allowed = 0;
+  cfg->rc_min_quantizer = 33;
+  cfg->rc_max_quantizer = 33;
+  cfg->rc_undershoot_pct = 100;
+  cfg->rc_overshoot_pct = 15;
+  cfg->rc_buf_initial_sz = 500;
+  cfg->rc_buf_optimal_sz = 600;
+  cfg->rc_buf_sz = 1000;
+
+  /* Enable error resilient mode */
+  cfg->g_error_resilient = 1;
+  cfg->g_lag_in_frames = 0;
+
+  /* Disable automatic keyframe placement */
+  cfg->kf_mode = VPX_KF_DISABLED;
+  cfg->kf_min_dist = cfg->kf_max_dist = 3000;
+}
+
+static void initialize_codec(vpx_codec_ctx_t *codec, vpx_codec_enc_cfg_t *cfg) {
+  int max_intra_size_pct;
+
+  /* Initialize codec */
+  if (vpx_codec_enc_init(codec, interface, cfg, VPX_CODEC_USE_PSNR))
+    die_codec(codec, "Failed to initialize encoder");
+
+  vpx_codec_control(codec, VP9E_SET_SVC, 1);
+  /* Cap CPU & first I-frame size */
+  vpx_codec_control(codec, VP8E_SET_CPUUSED, 1);
+  vpx_codec_control(codec, VP8E_SET_STATIC_THRESHOLD, 1);
+  vpx_codec_control(codec, VP8E_SET_NOISE_SENSITIVITY, 1);
+  vpx_codec_control(codec, VP8E_SET_TOKEN_PARTITIONS, 1);
+
+  max_intra_size_pct =
+      (int)(((double)cfg->rc_buf_optimal_sz * 0.5) *
+            ((double)cfg->g_timebase.den / cfg->g_timebase.num) / 10.0);
+  /* printf ("max_intra_size_pct=%d\n", max_intra_size_pct); */
+
+  vpx_codec_control(codec, VP8E_SET_MAX_INTRA_BITRATE_PCT, max_intra_size_pct);
+}
+
+static int calculate_layer(int frame_cnt, int number_spatial_layers) {
+  if (frame_cnt == 0)
+    return 0;
+  else
+    return (frame_cnt + number_spatial_layers - 1) % number_spatial_layers;
+}
+
+static void switch_to_layer(int layer, unsigned int initial_width,
+                            unsigned int initial_height,
+                            vpx_codec_ctx_t *codec) {
+  // Set layer size
+  int scaling_factor_num[MAX_LAYERS] = {2, 1, 4, 2, 1};
+  int scaling_factor_den[MAX_LAYERS] = {9, 3, 9, 3, 1};
+
+  int quantizer[MAX_LAYERS] = {60, 53, 39, 33, 27};
+
+  unsigned int current_width;
+  unsigned int current_height;
+
+  current_width = initial_width *
+                  scaling_factor_num[layer + 5 - number_spatial_layers] /
+                  scaling_factor_den[layer + 5 - number_spatial_layers];
+  current_height = initial_height *
+                   scaling_factor_num[layer + 5 - number_spatial_layers] /
+                   scaling_factor_den[layer + 5 - number_spatial_layers];
+
+  current_width += current_width % 2;
+  current_height += current_height % 2;
+
+  vpx_codec_control(codec, VP9E_SET_WIDTH, &current_width);
+  vpx_codec_control(codec, VP9E_SET_HEIGHT, &current_height);
+
+  // Set layer context
+  vpx_codec_control(codec, VP9E_SET_LAYER, &layer);
+  vpx_codec_control(codec, VP9E_SET_MAX_Q,
+                    quantizer[layer + 5 - number_spatial_layers]);
+  vpx_codec_control(codec, VP9E_SET_MIN_Q,
+                    quantizer[layer + 5 - number_spatial_layers]);
+}
+
+static int get_flag(int is_I_frame_in_layer, int layer, ENCODING_MODE mode) {
+  // First layer
+  switch (mode) {
+    case INTER_LAYER_PREDICTION_I:
+      if (is_I_frame_in_layer && layer == 0) return VPX_EFLAG_FORCE_KF;
+      if (layer == 0)
+        return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+               VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF;
+      else if (is_I_frame_in_layer)
+        return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+               VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_LAST;
+      else
+        return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+               VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF;
+      break;
+
+    case INTER_LAYER_PREDICTION_IP:
+      if (is_I_frame_in_layer && layer == 0) return VPX_EFLAG_FORCE_KF;
+      if (layer == 0)
+        return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+               VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF;
+      else if (is_I_frame_in_layer)
+        return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+               VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_LAST;
+      else
+        return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF | VP8_EFLAG_NO_REF_GF;
+      break;
+
+    case USE_GOLDEN_FRAME:
+      if (is_I_frame_in_layer && layer == 0) return VPX_EFLAG_FORCE_KF;
+      if (2 * number_spatial_layers - NUM_BUFFERS <= layer) {
+        if (layer == 0)
+          return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+                 VP8_EFLAG_NO_REF_ARF;
+        else if (is_I_frame_in_layer)
+          return VP8_EFLAG_NO_UPD_ARF | VP8_EFLAG_NO_REF_GF |
+                 VP8_EFLAG_NO_REF_LAST;
+        else
+          return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF;
+      } else {
+        if (layer == 0)
+          return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+                 VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF;
+        else if (is_I_frame_in_layer)
+          return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+                 VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_LAST;
+        else
+          return VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+                 VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF;
+      }
+      break;
+    default:
+      return VPX_EFLAG_FORCE_KF;
+  }
+}
+
+int main(int argc, char **argv) {
+  FILE *infile, *outfile[MAX_LAYERS];
+  vpx_codec_ctx_t codec;
+  vpx_codec_enc_cfg_t cfg;
+  int frame_cnt = 0;
+  vpx_image_t raw;
+  int frame_avail = 1;
+  int got_data = 0;
+  int i;
+  int frames_in_layer[MAX_LAYERS] = {0};
+  clock_t before;
+  clock_t after;
+  int pts = 0;            /* PTS starts at 0 */
+  int frame_duration = 1; /* 1 timebase tick per frame */
+
+  parse_command_line(argc, argv, &cfg);
+
+  // Allocate image buffer
+  if (!vpx_img_alloc(&raw, VPX_IMG_FMT_I420, cfg.g_w, cfg.g_h, 32))
+    die("Failed to allocate image", cfg.g_w, cfg.g_h);
+
+  set_default_configuration(&cfg);
+
+  /* Open input file */
+  if (!(infile = fopen(input_filename, "rb")))
+    die("Failed to open %s for reading", argv[1]);
+
+  /* Open output file  */
+  for (i = 0; i < number_spatial_layers; i++) {
+    char file_name[512];
+    snprintf(file_name, sizeof(file_name), "%s_%d.ivf", output_filename, i);
+    if (!(outfile[i] = fopen(file_name, "wb")))
+      die("Failed to open %s for writing", file_name);
+    write_ivf_file_header(outfile[i], &cfg, 0);
+  }
+
+  initialize_codec(&codec, &cfg);
+
+  // skip initial frames
+  for (i = 0; i < number_frames_to_skip; i++) {
+    read_frame(infile, &raw);
+  }
+
+  before = clock();
+  // Encoding frames
+  while ((frame_avail || got_data) &&
+         frame_cnt <= number_frames_to_code * number_spatial_layers) {
+    int flags = 0;
+    vpx_codec_iter_t iter = NULL;
+    const vpx_codec_cx_pkt_t *pkt;
+
+    int layer = calculate_layer(frame_cnt, number_spatial_layers);
+    int is_I_frame_in_layer =
+        (((frame_cnt - 1) / number_spatial_layers % key_period) == 0);
+    int is_dummy = (frame_cnt == 0);
+
+    if (is_dummy) {  // Dummy frame
+      flags = VPX_EFLAG_FORCE_KF;
+      frame_avail = read_dummy_frame(&raw);
+
+    } else {  // Regular frame
+      // Read a new frame only at the base layer
+      if (layer == 0) frame_avail = read_frame(infile, &raw);
+      switch_to_layer(layer, cfg.g_w, cfg.g_h, &codec);
+      flags = get_flag(is_I_frame_in_layer, layer, INTER_LAYER_PREDICTION_I);
+    }
+
+    // Actual Encoding
+    if (vpx_codec_encode(&codec, frame_avail ? &raw : NULL, pts, 1, flags,
+                         VPX_DL_REALTIME))
+      die_codec(&codec, "Failed to encode frame");
+
+    got_data = 0;
+    // Process data / Get PSNR statistics
+    while ((pkt = vpx_codec_get_cx_data(&codec, &iter))) {
+      got_data = 1;
+      switch (pkt->kind) {
+        case VPX_CODEC_CX_FRAME_PKT:
+          for (i = layer; i < number_spatial_layers; i++) {
+            write_ivf_frame_header(outfile[i], pkt);
+            (void)fwrite(pkt->data.frame.buf, 1, pkt->data.frame.sz,
+                         outfile[i]);
+            frames_in_layer[i]++;
+          }
+          break;
+        case VPX_CODEC_PSNR_PKT:
+          if (frame_cnt != 0)
+            printf(
+                "Processed Frame %d, layer %d, PSNR(Total/Y/U/V): "
+                "%2.3f  %2.3f  %2.3f  %2.3f \n",
+                (frame_cnt - 1) / number_spatial_layers + 1, layer,
+                pkt->data.psnr.psnr[0], pkt->data.psnr.psnr[1],
+                pkt->data.psnr.psnr[2], pkt->data.psnr.psnr[3]);
+          break;
+        default:
+          break;
+      }
+    }
+    frame_cnt++;
+    // TODO(ivan): Modify ts later if(!layer)
+    pts += frame_duration;
+  }
+  // end while
+
+  after = clock();
+  printf("Processed %d frames in different resolutions in %ld ms.\n",
+         frame_cnt - 1, (int)(after - before) / (CLOCKS_PER_SEC / 1000));
+
+  fclose(infile);
+
+  if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec");
+
+  /* Try to rewrite the output file headers with the actual frame count */
+  for (i = 0; i < number_spatial_layers; i++) {
+    if (!fseek(outfile[i], 0, SEEK_SET)) {
+      write_ivf_file_header(outfile[i], &cfg, frames_in_layer[i]);
+    }
+    fclose(outfile[i]);
+  }
+
+  return EXIT_SUCCESS;
+}