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diff --git a/third_party/aom/examples/scalable_decoder.c b/third_party/aom/examples/scalable_decoder.c
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+/*
+ * Copyright (c) 2018, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+// Scalable Decoder
+// ==============
+//
+// This is an example of a scalable decoder loop. It takes a 2-spatial-layer
+// input file
+// containing the compressed data (in OBU format), passes it through the
+// decoder, and writes the decompressed frames to disk. The base layer and
+// enhancement layers are stored as separate files, out_lyr0.yuv and
+// out_lyr1.yuv, respectively.
+//
+// Standard Includes
+// -----------------
+// For decoders, you only have to include `aom_decoder.h` and then any
+// header files for the specific codecs you use. In this case, we're using
+// av1.
+//
+// Initializing The Codec
+// ----------------------
+// The libaom decoder is initialized by the call to aom_codec_dec_init().
+// Determining the codec interface to use is handled by AvxVideoReader and the
+// functions prefixed with aom_video_reader_. Discussion of those functions is
+// beyond the scope of this example, but the main gist is to open the input file
+// and parse just enough of it to determine if it's a AVx file and which AVx
+// codec is contained within the file.
+// Note the NULL pointer passed to aom_codec_dec_init(). We do that in this
+// example because we want the algorithm to determine the stream configuration
+// (width/height) and allocate memory automatically.
+//
+// Decoding A Frame
+// ----------------
+// Once the frame has been read into memory, it is decoded using the
+// `aom_codec_decode` function. The call takes a pointer to the data
+// (`frame`) and the length of the data (`frame_size`). No application data
+// is associated with the frame in this example, so the `user_priv`
+// parameter is NULL. The `deadline` parameter is left at zero for this
+// example. This parameter is generally only used when doing adaptive post
+// processing.
+//
+// Codecs may produce a variable number of output frames for every call to
+// `aom_codec_decode`. These frames are retrieved by the
+// `aom_codec_get_frame` iterator function. The iterator variable `iter` is
+// initialized to NULL each time `aom_codec_decode` is called.
+// `aom_codec_get_frame` is called in a loop, returning a pointer to a
+// decoded image or NULL to indicate the end of list.
+//
+// Processing The Decoded Data
+// ---------------------------
+// In this example, we simply write the encoded data to disk. It is
+// important to honor the image's `stride` values.
+//
+// Cleanup
+// -------
+// The `aom_codec_destroy` call frees any memory allocated by the codec.
+//
+// Error Handling
+// --------------
+// This example does not special case any error return codes. If there was
+// an error, a descriptive message is printed and the program exits. With
+// few exceptions, aom_codec functions return an enumerated error status,
+// with the value `0` indicating success.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "aom/aom_decoder.h"
+#include "aom/aomdx.h"
+#include "common/obudec.h"
+#include "common/tools_common.h"
+#include "common/video_reader.h"
+
+static const char *exec_name;
+
+#define MAX_LAYERS 5
+
+void usage_exit(void) {
+  fprintf(stderr, "Usage: %s <infile>\n", exec_name);
+  exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv) {
+  int frame_cnt = 0;
+  FILE *outfile[MAX_LAYERS];
+  char filename[80];
+  aom_codec_ctx_t codec;
+  const AvxInterface *decoder = NULL;
+  FILE *inputfile = NULL;
+  uint8_t *buf = NULL;
+  size_t bytes_in_buffer = 0;
+  size_t buffer_size = 0;
+  struct AvxInputContext aom_input_ctx;
+  struct ObuDecInputContext obu_ctx = { &aom_input_ctx, NULL, 0, 0, 0 };
+  aom_codec_stream_info_t si;
+  uint8_t tmpbuf[32];
+  unsigned int i;
+
+  exec_name = argv[0];
+
+  if (argc != 2) die("Invalid number of arguments.");
+
+  if (!(inputfile = fopen(argv[1], "rb")))
+    die("Failed to open %s for read.", argv[1]);
+  obu_ctx.avx_ctx->file = inputfile;
+  obu_ctx.avx_ctx->filename = argv[1];
+
+  decoder = get_aom_decoder_by_index(0);
+  printf("Using %s\n", aom_codec_iface_name(decoder->codec_interface()));
+
+  if (aom_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0))
+    die_codec(&codec, "Failed to initialize decoder.");
+
+  if (aom_codec_control(&codec, AV1D_SET_OUTPUT_ALL_LAYERS, 1)) {
+    die_codec(&codec, "Failed to set output_all_layers control.");
+  }
+
+  // peak sequence header OBU to get number of spatial layers
+  const size_t ret = fread(tmpbuf, 1, 32, inputfile);
+  if (ret != 32) die_codec(&codec, "Input is not a valid obu file");
+  si.is_annexb = 0;
+  if (aom_codec_peek_stream_info(decoder->codec_interface(), tmpbuf, 32, &si)) {
+    die_codec(&codec, "Input is not a valid obu file");
+  }
+  fseek(inputfile, -32, SEEK_CUR);
+
+  if (!file_is_obu(&obu_ctx))
+    die_codec(&codec, "Input is not a valid obu file");
+
+  // open base layer output yuv file
+  snprintf(filename, sizeof(filename), "out_lyr%d.yuv", 0);
+  if (!(outfile[0] = fopen(filename, "wb")))
+    die("Failed top open output for writing.");
+
+  // open any enhancement layer output yuv files
+  for (i = 1; i < si.number_spatial_layers; i++) {
+    snprintf(filename, sizeof(filename), "out_lyr%d.yuv", i);
+    if (!(outfile[i] = fopen(filename, "wb")))
+      die("Failed to open output for writing.");
+  }
+
+  while (!obudec_read_temporal_unit(&obu_ctx, &buf, &bytes_in_buffer,
+                                    &buffer_size)) {
+    aom_codec_iter_t iter = NULL;
+    aom_image_t *img = NULL;
+    if (aom_codec_decode(&codec, buf, bytes_in_buffer, NULL))
+      die_codec(&codec, "Failed to decode frame.");
+
+    while ((img = aom_codec_get_frame(&codec, &iter)) != NULL) {
+      aom_image_t *img_shifted =
+          aom_img_alloc(NULL, AOM_IMG_FMT_I420, img->d_w, img->d_h, 16);
+      img_shifted->bit_depth = 8;
+      aom_img_downshift(img_shifted, img,
+                        img->bit_depth - img_shifted->bit_depth);
+      if (img->spatial_id == 0) {
+        printf("Writing        base layer 0 %d\n", frame_cnt);
+        aom_img_write(img_shifted, outfile[0]);
+      } else if (img->spatial_id <= (int)(si.number_spatial_layers - 1)) {
+        printf("Writing enhancement layer %d %d\n", img->spatial_id, frame_cnt);
+        aom_img_write(img_shifted, outfile[img->spatial_id]);
+      } else {
+        die_codec(&codec, "Invalid bitstream. Layer id exceeds layer count");
+      }
+      if (img->spatial_id == (int)(si.number_spatial_layers - 1)) ++frame_cnt;
+    }
+  }
+
+  printf("Processed %d frames.\n", frame_cnt);
+  if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec");
+
+  for (i = 0; i < si.number_spatial_layers; i++) fclose(outfile[i]);
+
+  fclose(inputfile);
+
+  return EXIT_SUCCESS;
+}