vpx_temporal_scalable_patterns.c

/*
 *  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 temporal scalability for video applications
//  that benefit from a scalable bitstream.

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

#define VPX_CODEC_DISABLE_COMPAT 1
#include "vpx/vp8cx.h"
#include "vpx/vpx_encoder.h"

#include "./tools_common.h"
#include "./video_writer.h"

static const char *exec_name;

void usage_exit() {
  exit(EXIT_FAILURE);
}

static int mode_to_num_layers[12] = {1, 2, 2, 3, 3, 3, 3, 5, 2, 3, 3, 3};

// For rate control encoding stats.
struct RateControlMetrics {
  // Number of input frames per layer.
  int layer_input_frames[VPX_TS_MAX_LAYERS];
  // Total (cumulative) number of encoded frames per layer.
  int layer_tot_enc_frames[VPX_TS_MAX_LAYERS];
  // Number of encoded non-key frames per layer.
  int layer_enc_frames[VPX_TS_MAX_LAYERS];
  // Framerate per layer layer (cumulative).
  double layer_framerate[VPX_TS_MAX_LAYERS];
  // Target average frame size per layer (per-frame-bandwidth per layer).
  double layer_pfb[VPX_TS_MAX_LAYERS];
  // Actual average frame size per layer.
  double layer_avg_frame_size[VPX_TS_MAX_LAYERS];
  // Average rate mismatch per layer (|target - actual| / target).
  double layer_avg_rate_mismatch[VPX_TS_MAX_LAYERS];
  // Actual encoding bitrate per layer (cumulative).
  double layer_encoding_bitrate[VPX_TS_MAX_LAYERS];
};

// Note: these rate control metrics assume only 1 key frame in the
// sequence (i.e., first frame only). So for temporal pattern# 7
// (which has key frame for every frame on base layer), the metrics
// computation will be off/wrong.
// TODO(marpan): Update these metrics to account for multiple key frames
// in the stream.
static void set_rate_control_metrics(struct RateControlMetrics *rc,
                                     vpx_codec_enc_cfg_t *cfg) {
  unsigned int i = 0;
  // Set the layer (cumulative) framerate and the target layer (non-cumulative)
  // per-frame-bandwidth, for the rate control encoding stats below.
  const double framerate = cfg->g_timebase.den / cfg->g_timebase.num;
  rc->layer_framerate[0] = framerate / cfg->ts_rate_decimator[0];
  rc->layer_pfb[0] = 1000.0 * cfg->ts_target_bitrate[0] /
      rc->layer_framerate[0];
  for (i = 0; i < cfg->ts_number_layers; ++i) {