examples/lightfield_bitstream_parsing.c - aom - Git at Google

 /*
  * 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.
  */

 // Lightfield Bitstream Parsing
 // ============================
 //
 // This is a lightfield bitstream parsing example. It takes an input file
 // containing the whole compressed lightfield bitstream(ivf file) and a text
 // file containing a stream of tiles to decode and then constructs and outputs
 // a new bitstream that can be decoded by an AV1 decoder. The output bitstream
 // contains reference frames(i.e. anchor frames), camera frame header, and
 // tile list OBUs. num_references is the number of anchor frames coded at the
 // beginning of the light field file.  After running the lightfield encoder,
 // run lightfield bitstream parsing:
 // examples/lightfield_bitstream_parsing vase10x10.ivf vase_tile_list.ivf 4
 //   tile_list.txt
 //
 // The tile_list.txt is expected to be of the form:
 // Frame <frame_index0>
 // <image_index0> <anchor_index0> <tile_col0> <tile_row0>
 // <image_index1> <anchor_index1> <tile_col1> <tile_row1>
 // ...
 // Frame <frame_index1)
 // ...
 //
 // The "Frame" markers indicate a new render frame and thus a new tile list
 // will be started and the old one flushed.  The image_indexN, anchor_indexN,
 // tile_colN, and tile_rowN identify an individual tile to be decoded and
 // to use anchor_indexN anchor image for MCP.

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include "aom/aom_codec.h"
 #include "aom/aom_decoder.h"
 #include "aom/aom_encoder.h"
 #include "aom/aom_integer.h"
 #include "aom/aomdx.h"
 #include "common/tools_common.h"
 #include "common/video_reader.h"
 #include "common/video_writer.h"

 #define MAX_TILES 512

 static const char *exec_name;

 void usage_exit(void) {
   fprintf(stderr, "Usage: %s <infile> <outfile> <num_references> <tile_list>\n",
           exec_name);
   exit(EXIT_FAILURE);
 }

 #define ALIGN_POWER_OF_TWO(value, n) \
   (((value) + ((1 << (n)) - 1)) & ~((1 << (n)) - 1))

 const int output_frame_width = 512;
 const int output_frame_height = 512;

 // Spec:
 // typedef struct {
 //   uint8_t anchor_frame_idx;
 //   uint8_t tile_row;
 //   uint8_t tile_col;
 //   uint16_t coded_tile_data_size_minus_1;
 //   uint8_t *coded_tile_data;
 // } TILE_LIST_ENTRY;

 // Tile list entry provided by the application
 typedef struct {
   int image_idx;
   int reference_idx;
   int tile_col;
   int tile_row;
 } TILE_LIST_INFO;

 static int get_image_bps(aom_img_fmt_t fmt) {
   switch (fmt) {
     case AOM_IMG_FMT_I420: return 12;
     case AOM_IMG_FMT_I422: return 16;
     case AOM_IMG_FMT_I444: return 24;
     case AOM_IMG_FMT_I42016: return 24;
     case AOM_IMG_FMT_I42216: return 32;
     case AOM_IMG_FMT_I44416: return 48;
     default: die("Invalid image format");
   }
 }

 static void process_tile_list(const TILE_LIST_INFO *tiles, int num_tiles,
                               aom_codec_pts_t tl_pts, unsigned char **frames,
                               const size_t *frame_sizes, aom_codec_ctx_t *codec,
                               unsigned char *tl_buf, AvxVideoWriter *writer,
                               uint8_t output_frame_width_in_tiles_minus_1,
                               uint8_t output_frame_height_in_tiles_minus_1) {
   unsigned char *tl = tl_buf;
   unsigned char *saved_obu_size_loc = NULL;
   uint32_t tile_list_obu_header_size = 0;
   uint32_t tile_list_obu_size = 0;
   int num_tiles_minus_1 = num_tiles - 1;
   int i;

   // Write the tile list OBU header that is 1 byte long.
   int obu_type = OBU_TILE_LIST;
   int obu_has_size_field = 1;
   *tl++ = (obu_type << 3) | (obu_has_size_field << 1);
   tile_list_obu_header_size++;

   // Write the OBU size using a fixed length_field_size of 4 bytes.
   saved_obu_size_loc = tl;
   for (i = 0; i < 4; i++) {
     *tl++ = 0;
   }
   tile_list_obu_header_size += 4;

   // write_tile_list_obu()
   *tl++ = output_frame_width_in_tiles_minus_1;
   *tl++ = output_frame_height_in_tiles_minus_1;
   *tl++ = (num_tiles_minus_1 >> 8) & 0xff;
   *tl++ = num_tiles_minus_1 & 0xff;
   tile_list_obu_size += 4;

   // Write each tile's data
   for (i = 0; i <= num_tiles_minus_1; i++) {
     aom_tile_data tile_data = { 0, NULL, 0 };

     int image_idx = tiles[i].image_idx;
     int ref_idx = tiles[i].reference_idx;
     int tc = tiles[i].tile_col;
     int tr = tiles[i].tile_row;

     size_t frame_size = frame_sizes[image_idx];
     const unsigned char *frame = frames[image_idx];

     AOM_CODEC_CONTROL_TYPECHECKED(codec, AV1_SET_DECODE_TILE_ROW, tr);
     AOM_CODEC_CONTROL_TYPECHECKED(codec, AV1_SET_DECODE_TILE_COL, tc);

     aom_codec_err_t aom_status =
         aom_codec_decode(codec, frame, frame_size, NULL);
     if (aom_status) die_codec(codec, "Failed to decode tile.");

     AOM_CODEC_CONTROL_TYPECHECKED(codec, AV1D_GET_TILE_DATA, &tile_data);

     // Copy over tile info.
     //  uint8_t anchor_frame_idx;
     //  uint8_t tile_row;
     //  uint8_t tile_col;
     //  uint16_t coded_tile_data_size_minus_1;
     //  uint8_t *coded_tile_data;
     uint32_t tile_info_bytes = 5;
     *tl++ = ref_idx;
     *tl++ = tr;
     *tl++ = tc;
     int coded_tile_data_size_minus_1 = (int)tile_data.coded_tile_data_size - 1;
     *tl++ = (coded_tile_data_size_minus_1 >> 8) & 0xff;
     *tl++ = coded_tile_data_size_minus_1 & 0xff;

     memcpy(tl, (uint8_t *)tile_data.coded_tile_data,
            tile_data.coded_tile_data_size);
     tl += tile_data.coded_tile_data_size;

     tile_list_obu_size +=
         tile_info_bytes + (uint32_t)tile_data.coded_tile_data_size;
   }

   // Write tile list OBU size.
   size_t bytes_written = 0;
   if (aom_uleb_encode_fixed_size(tile_list_obu_size, 4, 4, saved_obu_size_loc,
                                  &bytes_written))
     die_codec(codec, "Failed to encode the tile list obu size.");

   // Copy the tile list.
   if (!aom_video_writer_write_frame(
           writer, tl_buf, tile_list_obu_header_size + tile_list_obu_size,
           tl_pts))
     die_codec(codec, "Failed to copy compressed tile list.");
 }

 int main(int argc, char **argv) {
   AvxVideoReader *reader = NULL;
   AvxVideoWriter *writer = NULL;
   const AvxVideoInfo *info = NULL;
   int num_references;
   int i;
   aom_codec_pts_t pts;
   const char *tile_list_file = NULL;

   exec_name = argv[0];
   if (argc != 5) die("Invalid number of arguments.");

   reader = aom_video_reader_open(argv[1]);
   if (!reader) die("Failed to open %s for reading.", argv[1]);

   num_references = (int)strtol(argv[3], NULL, 0);
   info = aom_video_reader_get_info(reader);

   aom_video_reader_set_fourcc(reader, AV1_FOURCC);

   // The writer to write out ivf file in tile list OBU, which can be decoded by
   // AV1 decoder.
   writer = aom_video_writer_open(argv[2], kContainerIVF, info);
   if (!writer) die("Failed to open %s for writing", argv[2]);

   tile_list_file = argv[4];

   aom_codec_iface_t *decoder = get_aom_decoder_by_fourcc(info->codec_fourcc);
   if (!decoder) die("Unknown input codec.");
   printf("Using %s\n", aom_codec_iface_name(decoder));

   aom_codec_ctx_t codec;
   if (aom_codec_dec_init(&codec, decoder, NULL, 0))
     die("Failed to initialize decoder.");

   // Decode anchor frames.
   AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_TILE_MODE, 0);

   printf("Reading %d reference images.\n", num_references);
   for (i = 0; i < num_references; ++i) {
     aom_video_reader_read_frame(reader);

     size_t frame_size = 0;
     const unsigned char *frame =
         aom_video_reader_get_frame(reader, &frame_size);
     pts = (aom_codec_pts_t)aom_video_reader_get_frame_pts(reader);

     // Copy references bitstream directly.
     if (!aom_video_writer_write_frame(writer, frame, frame_size, pts))
       die_codec(&codec, "Failed to copy compressed anchor frame.");

     if (aom_codec_decode(&codec, frame, frame_size, NULL))
       die_codec(&codec, "Failed to decode frame.");
   }

   // Decode camera frames.
   AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_TILE_MODE, 1);
   AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_EXT_TILE_DEBUG, 1);

   FILE *infile = aom_video_reader_get_file(reader);
   // Record the offset of the first camera image.
   const FileOffset camera_frame_pos = ftello(infile);

   printf("Loading compressed frames into memory.\n");

   // Count the frames in the lightfield.
   int num_frames = 0;
   while (aom_video_reader_read_frame(reader)) {
     ++num_frames;
   }
   if (num_frames < 1) die("Input light field has no frames.");

   // Read all of the lightfield frames into memory.
   unsigned char **frames =
       (unsigned char **)malloc(num_frames * sizeof(unsigned char *));
   size_t *frame_sizes = (size_t *)malloc(num_frames * sizeof(size_t));
   if (!(frames && frame_sizes)) die("Failed to allocate frame data.");

   // Seek to the first camera image.
   fseeko(infile, camera_frame_pos, SEEK_SET);
   for (int f = 0; f < num_frames; ++f) {
     aom_video_reader_read_frame(reader);
     size_t frame_size = 0;
     const unsigned char *frame =
         aom_video_reader_get_frame(reader, &frame_size);
     frames[f] = (unsigned char *)malloc(frame_size * sizeof(unsigned char));
     if (!frames[f]) die("Failed to allocate frame data.");
     memcpy(frames[f], frame, frame_size);
     frame_sizes[f] = frame_size;
   }
   printf("Read %d frames.\n", num_frames);

   // Copy first camera frame for getting camera frame header. This is done
   // only once.
   {
     size_t frame_size = frame_sizes[0];
     const unsigned char *frame = frames[0];
     pts = num_references;
     aom_tile_data frame_header_info = { 0, NULL, 0 };

     // Need to decode frame header to get camera frame header info. So, here
     // decoding 1 tile is enough.
     AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_DECODE_TILE_ROW, 0);
     AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_DECODE_TILE_COL, 0);

     aom_codec_err_t aom_status =
         aom_codec_decode(&codec, frame, frame_size, NULL);
     if (aom_status) die_codec(&codec, "Failed to decode tile.");

     AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_GET_FRAME_HEADER_INFO,
                                   &frame_header_info);

     size_t obu_size_offset =
         (uint8_t *)frame_header_info.coded_tile_data - frame;
     size_t length_field_size = frame_header_info.coded_tile_data_size;
     // Remove ext-tile tile info.
     uint32_t frame_header_size = (uint32_t)frame_header_info.extra_size - 1;
     size_t bytes_to_copy =
         obu_size_offset + length_field_size + frame_header_size;

     unsigned char *frame_hdr_buf = (unsigned char *)malloc(bytes_to_copy);
     if (frame_hdr_buf == NULL)
       die_codec(&codec, "Failed to allocate frame header buffer.");

     memcpy(frame_hdr_buf, frame, bytes_to_copy);

     // Update frame header OBU size.
     size_t bytes_written = 0;
     if (aom_uleb_encode_fixed_size(
             frame_header_size, length_field_size, length_field_size,
             frame_hdr_buf + obu_size_offset, &bytes_written))
       die_codec(&codec, "Failed to encode the tile list obu size.");

     // Copy camera frame header bitstream.
     if (!aom_video_writer_write_frame(writer, frame_hdr_buf, bytes_to_copy,
                                       pts))
       die_codec(&codec, "Failed to copy compressed camera frame header.");
     free(frame_hdr_buf);
   }

   // Read out the image format.
   aom_img_fmt_t ref_fmt = 0;
   if (AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_GET_IMG_FORMAT, &ref_fmt))
     die_codec(&codec, "Failed to get the image format");
   const int bps = get_image_bps(ref_fmt);
   if (!bps) die_codec(&codec, "Invalid image format.");
   // read out the tile size.
   unsigned int tile_size = 0;
   if (AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_GET_TILE_SIZE, &tile_size))
     die_codec(&codec, "Failed to get the tile size");
   const unsigned int tile_width = tile_size >> 16;
   const unsigned int tile_height = tile_size & 65535;
   // Allocate a buffer to store tile list bitstream.
   const size_t data_sz = MAX_TILES * ALIGN_POWER_OF_TWO(tile_width, 5) *
                          ALIGN_POWER_OF_TWO(tile_height, 5) * bps / 8;

   unsigned char *tl_buf = (unsigned char *)malloc(data_sz);
   if (tl_buf == NULL) die_codec(&codec, "Failed to allocate tile list buffer.");

   aom_codec_pts_t tl_pts = num_references;
   const uint8_t output_frame_width_in_tiles_minus_1 =
       output_frame_width / tile_width - 1;
   const uint8_t output_frame_height_in_tiles_minus_1 =
       output_frame_height / tile_height - 1;

   printf("Reading tile list from file.\n");
   char line[1024];
   FILE *tile_list_fptr = fopen(tile_list_file, "r");
   if (!tile_list_fptr) die_codec(&codec, "Failed to open tile list file.");
   int num_tiles = 0;
   TILE_LIST_INFO tiles[MAX_TILES];
   while ((fgets(line, 1024, tile_list_fptr)) != NULL) {
     if (line[0] == 'F' || num_tiles >= MAX_TILES) {
       // Flush existing tile list and start another, either because we hit a
       // new render frame or because we've hit our max number of tiles per list.
       if (num_tiles > 0) {
         process_tile_list(tiles, num_tiles, tl_pts, frames, frame_sizes, &codec,
                           tl_buf, writer, output_frame_width_in_tiles_minus_1,
                           output_frame_height_in_tiles_minus_1);
         ++tl_pts;
       }
       num_tiles = 0;
     }
     if (line[0] == 'F') {
       continue;
     }
     if (sscanf(line, "%d %d %d %d", &tiles[num_tiles].image_idx,
                &tiles[num_tiles].reference_idx, &tiles[num_tiles].tile_col,
                &tiles[num_tiles].tile_row) == 4) {
       if (tiles[num_tiles].image_idx >= num_frames) {
         die("Tile list image_idx out of bounds: %d >= %d.",
             tiles[num_tiles].image_idx, num_frames);
       }
       if (tiles[num_tiles].reference_idx >= num_references) {
         die("Tile list reference_idx out of bounds: %d >= %d.",
             tiles[num_tiles].reference_idx, num_references);
       }
       ++num_tiles;
     }
   }
   if (num_tiles > 0) {
     // Flush out the last tile list.
     process_tile_list(tiles, num_tiles, tl_pts, frames, frame_sizes, &codec,
                       tl_buf, writer, output_frame_width_in_tiles_minus_1,
                       output_frame_height_in_tiles_minus_1);
     ++tl_pts;
   }

   const int num_tile_lists = (int)(tl_pts - pts);
   printf("Finished processing tile lists.  Num tile lists: %d.\n",
          num_tile_lists);
   free(tl_buf);
   for (int f = 0; f < num_frames; ++f) {
     free(frames[f]);
   }
   free(frame_sizes);
   free(frames);
   if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec");
   aom_video_writer_close(writer);
   aom_video_reader_close(reader);

   return EXIT_SUCCESS;
 }
	/*
	* 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.
	*/

	// Lightfield Bitstream Parsing
	// ============================
	//
	// This is a lightfield bitstream parsing example. It takes an input file
	// containing the whole compressed lightfield bitstream(ivf file) and a text
	// file containing a stream of tiles to decode and then constructs and outputs
	// a new bitstream that can be decoded by an AV1 decoder. The output bitstream
	// contains reference frames(i.e. anchor frames), camera frame header, and
	// tile list OBUs. num_references is the number of anchor frames coded at the
	// beginning of the light field file. After running the lightfield encoder,
	// run lightfield bitstream parsing:
	// examples/lightfield_bitstream_parsing vase10x10.ivf vase_tile_list.ivf 4
	// tile_list.txt
	//
	// The tile_list.txt is expected to be of the form:
	// Frame <frame_index0>
	// <image_index0> <anchor_index0> <tile_col0> <tile_row0>
	// <image_index1> <anchor_index1> <tile_col1> <tile_row1>
	// ...
	// Frame <frame_index1)
	// ...
	//
	// The "Frame" markers indicate a new render frame and thus a new tile list
	// will be started and the old one flushed. The image_indexN, anchor_indexN,
	// tile_colN, and tile_rowN identify an individual tile to be decoded and
	// to use anchor_indexN anchor image for MCP.

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "aom/aom_codec.h"
	#include "aom/aom_decoder.h"
	#include "aom/aom_encoder.h"
	#include "aom/aom_integer.h"
	#include "aom/aomdx.h"
	#include "common/tools_common.h"
	#include "common/video_reader.h"
	#include "common/video_writer.h"

	#define MAX_TILES 512

	static const char *exec_name;

	void usage_exit(void) {
	fprintf(stderr, "Usage: %s <infile> <outfile> <num_references> <tile_list>\n",
	exec_name);
	exit(EXIT_FAILURE);
	}

	#define ALIGN_POWER_OF_TWO(value, n) \
	(((value) + ((1 << (n)) - 1)) & ~((1 << (n)) - 1))

	const int output_frame_width = 512;
	const int output_frame_height = 512;

	// Spec:
	// typedef struct {
	// uint8_t anchor_frame_idx;
	// uint8_t tile_row;
	// uint8_t tile_col;
	// uint16_t coded_tile_data_size_minus_1;
	// uint8_t *coded_tile_data;
	// } TILE_LIST_ENTRY;

	// Tile list entry provided by the application
	typedef struct {
	int image_idx;
	int reference_idx;
	int tile_col;
	int tile_row;
	} TILE_LIST_INFO;

	static int get_image_bps(aom_img_fmt_t fmt) {
	switch (fmt) {
	case AOM_IMG_FMT_I420: return 12;
	case AOM_IMG_FMT_I422: return 16;
	case AOM_IMG_FMT_I444: return 24;
	case AOM_IMG_FMT_I42016: return 24;
	case AOM_IMG_FMT_I42216: return 32;
	case AOM_IMG_FMT_I44416: return 48;
	default: die("Invalid image format");
	}
	}

	static void process_tile_list(const TILE_LIST_INFO *tiles, int num_tiles,
	aom_codec_pts_t tl_pts, unsigned char **frames,
	const size_t frame_sizes, aom_codec_ctx_t codec,
	unsigned char tl_buf, AvxVideoWriter writer,
	uint8_t output_frame_width_in_tiles_minus_1,
	uint8_t output_frame_height_in_tiles_minus_1) {
	unsigned char *tl = tl_buf;
	unsigned char *saved_obu_size_loc = NULL;
	uint32_t tile_list_obu_header_size = 0;
	uint32_t tile_list_obu_size = 0;
	int num_tiles_minus_1 = num_tiles - 1;
	int i;

	// Write the tile list OBU header that is 1 byte long.
	int obu_type = OBU_TILE_LIST;
	int obu_has_size_field = 1;
	*tl++ = (obu_type << 3) \| (obu_has_size_field << 1);
	tile_list_obu_header_size++;

	// Write the OBU size using a fixed length_field_size of 4 bytes.
	saved_obu_size_loc = tl;
	for (i = 0; i < 4; i++) {
	*tl++ = 0;
	}
	tile_list_obu_header_size += 4;

	// write_tile_list_obu()
	*tl++ = output_frame_width_in_tiles_minus_1;
	*tl++ = output_frame_height_in_tiles_minus_1;
	*tl++ = (num_tiles_minus_1 >> 8) & 0xff;
	*tl++ = num_tiles_minus_1 & 0xff;
	tile_list_obu_size += 4;

	// Write each tile's data
	for (i = 0; i <= num_tiles_minus_1; i++) {
	aom_tile_data tile_data = { 0, NULL, 0 };

	int image_idx = tiles[i].image_idx;
	int ref_idx = tiles[i].reference_idx;
	int tc = tiles[i].tile_col;
	int tr = tiles[i].tile_row;

	size_t frame_size = frame_sizes[image_idx];
	const unsigned char *frame = frames[image_idx];

	AOM_CODEC_CONTROL_TYPECHECKED(codec, AV1_SET_DECODE_TILE_ROW, tr);
	AOM_CODEC_CONTROL_TYPECHECKED(codec, AV1_SET_DECODE_TILE_COL, tc);

	aom_codec_err_t aom_status =
	aom_codec_decode(codec, frame, frame_size, NULL);
	if (aom_status) die_codec(codec, "Failed to decode tile.");

	AOM_CODEC_CONTROL_TYPECHECKED(codec, AV1D_GET_TILE_DATA, &tile_data);

	// Copy over tile info.
	// uint8_t anchor_frame_idx;
	// uint8_t tile_row;
	// uint8_t tile_col;
	// uint16_t coded_tile_data_size_minus_1;
	// uint8_t *coded_tile_data;
	uint32_t tile_info_bytes = 5;
	*tl++ = ref_idx;
	*tl++ = tr;
	*tl++ = tc;
	int coded_tile_data_size_minus_1 = (int)tile_data.coded_tile_data_size - 1;
	*tl++ = (coded_tile_data_size_minus_1 >> 8) & 0xff;
	*tl++ = coded_tile_data_size_minus_1 & 0xff;

	memcpy(tl, (uint8_t *)tile_data.coded_tile_data,
	tile_data.coded_tile_data_size);
	tl += tile_data.coded_tile_data_size;

	tile_list_obu_size +=
	tile_info_bytes + (uint32_t)tile_data.coded_tile_data_size;
	}

	// Write tile list OBU size.
	size_t bytes_written = 0;
	if (aom_uleb_encode_fixed_size(tile_list_obu_size, 4, 4, saved_obu_size_loc,
	&bytes_written))
	die_codec(codec, "Failed to encode the tile list obu size.");

	// Copy the tile list.
	if (!aom_video_writer_write_frame(
	writer, tl_buf, tile_list_obu_header_size + tile_list_obu_size,
	tl_pts))
	die_codec(codec, "Failed to copy compressed tile list.");
	}

	int main(int argc, char **argv) {
	AvxVideoReader *reader = NULL;
	AvxVideoWriter *writer = NULL;
	const AvxVideoInfo *info = NULL;
	int num_references;
	int i;
	aom_codec_pts_t pts;
	const char *tile_list_file = NULL;

	exec_name = argv[0];
	if (argc != 5) die("Invalid number of arguments.");

	reader = aom_video_reader_open(argv[1]);
	if (!reader) die("Failed to open %s for reading.", argv[1]);

	num_references = (int)strtol(argv[3], NULL, 0);
	info = aom_video_reader_get_info(reader);

	aom_video_reader_set_fourcc(reader, AV1_FOURCC);

	// The writer to write out ivf file in tile list OBU, which can be decoded by
	// AV1 decoder.
	writer = aom_video_writer_open(argv[2], kContainerIVF, info);
	if (!writer) die("Failed to open %s for writing", argv[2]);

	tile_list_file = argv[4];

	aom_codec_iface_t *decoder = get_aom_decoder_by_fourcc(info->codec_fourcc);
	if (!decoder) die("Unknown input codec.");
	printf("Using %s\n", aom_codec_iface_name(decoder));

	aom_codec_ctx_t codec;
	if (aom_codec_dec_init(&codec, decoder, NULL, 0))
	die("Failed to initialize decoder.");

	// Decode anchor frames.
	AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_TILE_MODE, 0);

	printf("Reading %d reference images.\n", num_references);
	for (i = 0; i < num_references; ++i) {
	aom_video_reader_read_frame(reader);

	size_t frame_size = 0;
	const unsigned char *frame =
	aom_video_reader_get_frame(reader, &frame_size);
	pts = (aom_codec_pts_t)aom_video_reader_get_frame_pts(reader);

	// Copy references bitstream directly.
	if (!aom_video_writer_write_frame(writer, frame, frame_size, pts))
	die_codec(&codec, "Failed to copy compressed anchor frame.");

	if (aom_codec_decode(&codec, frame, frame_size, NULL))
	die_codec(&codec, "Failed to decode frame.");
	}

	// Decode camera frames.
	AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_TILE_MODE, 1);
	AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_EXT_TILE_DEBUG, 1);

	FILE *infile = aom_video_reader_get_file(reader);
	// Record the offset of the first camera image.
	const FileOffset camera_frame_pos = ftello(infile);

	printf("Loading compressed frames into memory.\n");

	// Count the frames in the lightfield.
	int num_frames = 0;
	while (aom_video_reader_read_frame(reader)) {
	++num_frames;
	}
	if (num_frames < 1) die("Input light field has no frames.");

	// Read all of the lightfield frames into memory.
	unsigned char **frames =
	(unsigned char *)malloc(num_frames sizeof(unsigned char *));
	size_t frame_sizes = (size_t )malloc(num_frames * sizeof(size_t));
	if (!(frames && frame_sizes)) die("Failed to allocate frame data.");

	// Seek to the first camera image.
	fseeko(infile, camera_frame_pos, SEEK_SET);
	for (int f = 0; f < num_frames; ++f) {
	aom_video_reader_read_frame(reader);
	size_t frame_size = 0;
	const unsigned char *frame =
	aom_video_reader_get_frame(reader, &frame_size);
	frames[f] = (unsigned char )malloc(frame_size sizeof(unsigned char));
	if (!frames[f]) die("Failed to allocate frame data.");
	memcpy(frames[f], frame, frame_size);
	frame_sizes[f] = frame_size;
	}
	printf("Read %d frames.\n", num_frames);

	// Copy first camera frame for getting camera frame header. This is done
	// only once.
	{
	size_t frame_size = frame_sizes[0];
	const unsigned char *frame = frames[0];
	pts = num_references;
	aom_tile_data frame_header_info = { 0, NULL, 0 };

	// Need to decode frame header to get camera frame header info. So, here
	// decoding 1 tile is enough.
	AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_DECODE_TILE_ROW, 0);
	AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1_SET_DECODE_TILE_COL, 0);

	aom_codec_err_t aom_status =
	aom_codec_decode(&codec, frame, frame_size, NULL);
	if (aom_status) die_codec(&codec, "Failed to decode tile.");

	AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_GET_FRAME_HEADER_INFO,
	&frame_header_info);

	size_t obu_size_offset =
	(uint8_t *)frame_header_info.coded_tile_data - frame;
	size_t length_field_size = frame_header_info.coded_tile_data_size;
	// Remove ext-tile tile info.
	uint32_t frame_header_size = (uint32_t)frame_header_info.extra_size - 1;
	size_t bytes_to_copy =
	obu_size_offset + length_field_size + frame_header_size;

	unsigned char frame_hdr_buf = (unsigned char )malloc(bytes_to_copy);
	if (frame_hdr_buf == NULL)
	die_codec(&codec, "Failed to allocate frame header buffer.");

	memcpy(frame_hdr_buf, frame, bytes_to_copy);

	// Update frame header OBU size.
	size_t bytes_written = 0;
	if (aom_uleb_encode_fixed_size(
	frame_header_size, length_field_size, length_field_size,
	frame_hdr_buf + obu_size_offset, &bytes_written))
	die_codec(&codec, "Failed to encode the tile list obu size.");

	// Copy camera frame header bitstream.
	if (!aom_video_writer_write_frame(writer, frame_hdr_buf, bytes_to_copy,
	pts))
	die_codec(&codec, "Failed to copy compressed camera frame header.");
	free(frame_hdr_buf);
	}

	// Read out the image format.
	aom_img_fmt_t ref_fmt = 0;
	if (AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_GET_IMG_FORMAT, &ref_fmt))
	die_codec(&codec, "Failed to get the image format");
	const int bps = get_image_bps(ref_fmt);
	if (!bps) die_codec(&codec, "Invalid image format.");
	// read out the tile size.
	unsigned int tile_size = 0;
	if (AOM_CODEC_CONTROL_TYPECHECKED(&codec, AV1D_GET_TILE_SIZE, &tile_size))
	die_codec(&codec, "Failed to get the tile size");
	const unsigned int tile_width = tile_size >> 16;
	const unsigned int tile_height = tile_size & 65535;
	// Allocate a buffer to store tile list bitstream.
	const size_t data_sz = MAX_TILES * ALIGN_POWER_OF_TWO(tile_width, 5) *
	ALIGN_POWER_OF_TWO(tile_height, 5) * bps / 8;

	unsigned char tl_buf = (unsigned char )malloc(data_sz);
	if (tl_buf == NULL) die_codec(&codec, "Failed to allocate tile list buffer.");

	aom_codec_pts_t tl_pts = num_references;
	const uint8_t output_frame_width_in_tiles_minus_1 =
	output_frame_width / tile_width - 1;
	const uint8_t output_frame_height_in_tiles_minus_1 =
	output_frame_height / tile_height - 1;

	printf("Reading tile list from file.\n");
	char line[1024];
	FILE *tile_list_fptr = fopen(tile_list_file, "r");
	if (!tile_list_fptr) die_codec(&codec, "Failed to open tile list file.");
	int num_tiles = 0;
	TILE_LIST_INFO tiles[MAX_TILES];
	while ((fgets(line, 1024, tile_list_fptr)) != NULL) {
	if (line[0] == 'F' \|\| num_tiles >= MAX_TILES) {
	// Flush existing tile list and start another, either because we hit a
	// new render frame or because we've hit our max number of tiles per list.
	if (num_tiles > 0) {
	process_tile_list(tiles, num_tiles, tl_pts, frames, frame_sizes, &codec,
	tl_buf, writer, output_frame_width_in_tiles_minus_1,
	output_frame_height_in_tiles_minus_1);
	++tl_pts;
	}
	num_tiles = 0;
	}
	if (line[0] == 'F') {
	continue;
	}
	if (sscanf(line, "%d %d %d %d", &tiles[num_tiles].image_idx,
	&tiles[num_tiles].reference_idx, &tiles[num_tiles].tile_col,
	&tiles[num_tiles].tile_row) == 4) {
	if (tiles[num_tiles].image_idx >= num_frames) {
	die("Tile list image_idx out of bounds: %d >= %d.",
	tiles[num_tiles].image_idx, num_frames);
	}
	if (tiles[num_tiles].reference_idx >= num_references) {
	die("Tile list reference_idx out of bounds: %d >= %d.",
	tiles[num_tiles].reference_idx, num_references);
	}
	++num_tiles;
	}
	}
	if (num_tiles > 0) {
	// Flush out the last tile list.
	process_tile_list(tiles, num_tiles, tl_pts, frames, frame_sizes, &codec,
	tl_buf, writer, output_frame_width_in_tiles_minus_1,
	output_frame_height_in_tiles_minus_1);
	++tl_pts;
	}

	const int num_tile_lists = (int)(tl_pts - pts);
	printf("Finished processing tile lists. Num tile lists: %d.\n",
	num_tile_lists);
	free(tl_buf);
	for (int f = 0; f < num_frames; ++f) {
	free(frames[f]);
	}
	free(frame_sizes);
	free(frames);
	if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec");
	aom_video_writer_close(writer);
	aom_video_reader_close(reader);

	return EXIT_SUCCESS;
	}