libvpx: Pull from upstream

source/libvpx/rate_hist.c

Index: source/libvpx/rate_hist.c
===================================================================
--- source/libvpx/rate_hist.c	(revision 0)
+++ source/libvpx/rate_hist.c	(revision 0)
@@ -0,0 +1,282 @@
+/*
+ *  Copyright (c) 2014 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 <assert.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+#include <math.h>
+
+#include "./rate_hist.h"
+
+#define RATE_BINS 100
+#define HIST_BAR_MAX 40
+
+struct hist_bucket {
+  int low;
+  int high;
+  int count;
+};
+
+struct rate_hist {
+  int64_t *pts;
+  int *sz;
+  int samples;
+  int frames;
+  struct hist_bucket bucket[RATE_BINS];
+  int total;
+};
+
+struct rate_hist *init_rate_histogram(const vpx_codec_enc_cfg_t *cfg,
+                                      const vpx_rational_t *fps) {
+  int i;
+  struct rate_hist *hist = malloc(sizeof(*hist));
+
+  // Determine the number of samples in the buffer. Use the file's framerate
+  // to determine the number of frames in rc_buf_sz milliseconds, with an
+  // adjustment (5/4) to account for alt-refs
+  hist->samples = cfg->rc_buf_sz * 5 / 4 * fps->num / fps->den / 1000;
+
+  // prevent division by zero
+  if (hist->samples == 0)
+    hist->samples = 1;
+
+  hist->frames = 0;
+  hist->total = 0;
+
+  hist->pts = calloc(hist->samples, sizeof(*hist->pts));
+  hist->sz = calloc(hist->samples, sizeof(*hist->sz));
+  for (i = 0; i < RATE_BINS; i++) {
+    hist->bucket[i].low = INT_MAX;
+    hist->bucket[i].high = 0;
+    hist->bucket[i].count = 0;
+  }
+
+  return hist;
+}
+
+void destroy_rate_histogram(struct rate_hist *hist) {
+  if (hist) {
+    free(hist->pts);
+    free(hist->sz);
+    free(hist);
+  }
+}
+
+void update_rate_histogram(struct rate_hist *hist,
+                           const vpx_codec_enc_cfg_t *cfg,
+                           const vpx_codec_cx_pkt_t *pkt) {
+  int i;
+  int64_t then = 0;
+  int64_t avg_bitrate = 0;
+  int64_t sum_sz = 0;
+  const int64_t now = pkt->data.frame.pts * 1000 *
+                          (uint64_t)cfg->g_timebase.num /
+                              (uint64_t)cfg->g_timebase.den;
+
+  int idx = hist->frames++ % hist->samples;
+  hist->pts[idx] = now;
+  hist->sz[idx] = (int)pkt->data.frame.sz;
+
+  if (now < cfg->rc_buf_initial_sz)
+    return;
+
+  then = now;
+
+  /* Sum the size over the past rc_buf_sz ms */
+  for (i = hist->frames; i > 0 && hist->frames - i < hist->samples; i--) {
+    const int i_idx = (i - 1) % hist->samples;
+
+    then = hist->pts[i_idx];
+    if (now - then > cfg->rc_buf_sz)
+      break;
+    sum_sz += hist->sz[i_idx];
+  }
+
+  if (now == then)
+    return;
+
+  avg_bitrate = sum_sz * 8 * 1000 / (now - then);
+  idx = (int)(avg_bitrate * (RATE_BINS / 2) / (cfg->rc_target_bitrate * 1000));
+  if (idx < 0)
+    idx = 0;
+  if (idx > RATE_BINS - 1)
+    idx = RATE_BINS - 1;
+  if (hist->bucket[idx].low > avg_bitrate)
+    hist->bucket[idx].low = (int)avg_bitrate;
+  if (hist->bucket[idx].high < avg_bitrate)
+    hist->bucket[idx].high = (int)avg_bitrate;
+  hist->bucket[idx].count++;
+  hist->total++;
+}
+
+static int merge_hist_buckets(struct hist_bucket *bucket,
+                              int max_buckets, int *num_buckets) {
+  int small_bucket = 0, merge_bucket = INT_MAX, big_bucket = 0;
+  int buckets = *num_buckets;
+  int i;
+
+  /* Find the extrema for this list of buckets */
+  big_bucket = small_bucket = 0;
+  for (i = 0; i < buckets; i++) {
+    if (bucket[i].count < bucket[small_bucket].count)
+      small_bucket = i;
+    if (bucket[i].count > bucket[big_bucket].count)
+      big_bucket = i;
+  }
+
+  /* If we have too many buckets, merge the smallest with an adjacent
+   * bucket.
+   */
+  while (buckets > max_buckets) {
+    int last_bucket = buckets - 1;
+
+    /* merge the small bucket with an adjacent one. */
+    if (small_bucket == 0)
+      merge_bucket = 1;
+    else if (small_bucket == last_bucket)
+      merge_bucket = last_bucket - 1;
+    else if (bucket[small_bucket - 1].count < bucket[small_bucket + 1].count)
+      merge_bucket = small_bucket - 1;
+    else
+      merge_bucket = small_bucket + 1;
+
+    assert(abs(merge_bucket - small_bucket) <= 1);
+    assert(small_bucket < buckets);
+    assert(big_bucket < buckets);
+    assert(merge_bucket < buckets);
+
+    if (merge_bucket < small_bucket) {
+      bucket[merge_bucket].high = bucket[small_bucket].high;
+      bucket[merge_bucket].count += bucket[small_bucket].count;
+    } else {
+      bucket[small_bucket].high = bucket[merge_bucket].high;
+      bucket[small_bucket].count += bucket[merge_bucket].count;
+      merge_bucket = small_bucket;
+    }
+
+    assert(bucket[merge_bucket].low != bucket[merge_bucket].high);
+
+    buckets--;
+
+    /* Remove the merge_bucket from the list, and find the new small
+     * and big buckets while we're at it
+     */
+    big_bucket = small_bucket = 0;
+    for (i = 0; i < buckets; i++) {
+      if (i > merge_bucket)
+        bucket[i] = bucket[i + 1];
+
+      if (bucket[i].count < bucket[small_bucket].count)
+        small_bucket = i;
+      if (bucket[i].count > bucket[big_bucket].count)
+        big_bucket = i;
+    }
+  }
+
+  *num_buckets = buckets;
+  return bucket[big_bucket].count;
+}
+
+static void show_histogram(const struct hist_bucket *bucket,
+                           int buckets, int total, int scale) {
+  const char *pat1, *pat2;
+  int i;
+
+  switch ((int)(log(bucket[buckets - 1].high) / log(10)) + 1) {
+    case 1:
+    case 2:
+      pat1 = "%4d %2s: ";
+      pat2 = "%4d-%2d: ";
+      break;
+    case 3:
+      pat1 = "%5d %3s: ";
+      pat2 = "%5d-%3d: ";
+      break;
+    case 4:
+      pat1 = "%6d %4s: ";
+      pat2 = "%6d-%4d: ";
+      break;
+    case 5:
+      pat1 = "%7d %5s: ";
+      pat2 = "%7d-%5d: ";
+      break;
+    case 6:
+      pat1 = "%8d %6s: ";
+      pat2 = "%8d-%6d: ";
+      break;
+    case 7:
+      pat1 = "%9d %7s: ";
+      pat2 = "%9d-%7d: ";
+      break;
+    default:
+      pat1 = "%12d %10s: ";
+      pat2 = "%12d-%10d: ";
+      break;
+  }
+
+  for (i = 0; i < buckets; i++) {
+    int len;
+    int j;
+    float pct;
+
+    pct = (float)(100.0 * bucket[i].count / total);
+    len = HIST_BAR_MAX * bucket[i].count / scale;
+    if (len < 1)
+      len = 1;
+    assert(len <= HIST_BAR_MAX);
+
+    if (bucket[i].low == bucket[i].high)
+      fprintf(stderr, pat1, bucket[i].low, "");
+    else
+      fprintf(stderr, pat2, bucket[i].low, bucket[i].high);
+
+    for (j = 0; j < HIST_BAR_MAX; j++)
+      fprintf(stderr, j < len ? "=" : " ");
+    fprintf(stderr, "\t%5d (%6.2f%%)\n", bucket[i].count, pct);
+  }
+}
+
+void show_q_histogram(const int counts[64], int max_buckets) {
+  struct hist_bucket bucket[64];
+  int buckets = 0;
+  int total = 0;
+  int scale;
+  int i;
+
+  for (i = 0; i < 64; i++) {
+    if (counts[i]) {
+      bucket[buckets].low = bucket[buckets].high = i;
+      bucket[buckets].count = counts[i];
+      buckets++;
+      total += counts[i];
+    }
+  }
+
+  fprintf(stderr, "\nQuantizer Selection:\n");
+  scale = merge_hist_buckets(bucket, max_buckets, &buckets);
+  show_histogram(bucket, buckets, total, scale);
+}
+
+void show_rate_histogram(struct rate_hist *hist,
+                         const vpx_codec_enc_cfg_t *cfg, int max_buckets) {
+  int i, scale;
+  int buckets = 0;
+
+  for (i = 0; i < RATE_BINS; i++) {
+    if (hist->bucket[i].low == INT_MAX)
+      continue;
+    hist->bucket[buckets++] = hist->bucket[i];
+  }
+
+  fprintf(stderr, "\nRate (over %dms window):\n", cfg->rc_buf_sz);
+  scale = merge_hist_buckets(hist->bucket, max_buckets, &buckets);
+  show_histogram(hist->bucket, buckets, hist->total, scale);
+}