1 files changed, 184 insertions, 0 deletions
diff --git a/media/libvpx/libvpx/vp8/encoder/lookahead.c b/media/libvpx/libvpx/vp8/encoder/lookahead.c
new file mode 100644
index 0000000000..49f851d019
--- /dev/null
+++ b/media/libvpx/libvpx/vp8/encoder/lookahead.c
@@ -0,0 +1,184 @@
+/*
+ *  Copyright (c) 2011 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 "vpx_config.h"
+#include "lookahead.h"
+#include "vp8/common/extend.h"
+
+#define MAX_LAG_BUFFERS (CONFIG_REALTIME_ONLY ? 1 : 25)
+
+struct lookahead_ctx {
+  unsigned int max_sz;         /* Absolute size of the queue */
+  unsigned int sz;             /* Number of buffers currently in the queue */
+  unsigned int read_idx;       /* Read index */
+  unsigned int write_idx;      /* Write index */
+  struct lookahead_entry *buf; /* Buffer list */
+};
+
+/* Return the buffer at the given absolute index and increment the index */
+static struct lookahead_entry *pop(struct lookahead_ctx *ctx,
+                                   unsigned int *idx) {
+  unsigned int index = *idx;
+  struct lookahead_entry *buf = ctx->buf + index;
+
+  assert(index < ctx->max_sz);
+  if (++index >= ctx->max_sz) index -= ctx->max_sz;
+  *idx = index;
+  return buf;
+}
+
+void vp8_lookahead_destroy(struct lookahead_ctx *ctx) {
+  if (ctx) {
+    if (ctx->buf) {
+      unsigned int i;
+
+      for (i = 0; i < ctx->max_sz; ++i) {
+        vp8_yv12_de_alloc_frame_buffer(&ctx->buf[i].img);
+      }
+      free(ctx->buf);
+    }
+    free(ctx);
+  }
+}
+
+struct lookahead_ctx *vp8_lookahead_init(unsigned int width,
+                                         unsigned int height,
+                                         unsigned int depth) {
+  struct lookahead_ctx *ctx = NULL;
+  unsigned int i;
+
+  /* Clamp the lookahead queue depth */
+  if (depth < 1) {
+    depth = 1;
+  } else if (depth > MAX_LAG_BUFFERS) {
+    depth = MAX_LAG_BUFFERS;
+  }
+
+  /* Keep last frame in lookahead buffer by increasing depth by 1.*/
+  depth += 1;
+
+  /* Align the buffer dimensions */
+  width = (width + 15) & ~15u;
+  height = (height + 15) & ~15u;
+
+  /* Allocate the lookahead structures */
+  ctx = calloc(1, sizeof(*ctx));
+  if (ctx) {
+    ctx->max_sz = depth;
+    ctx->buf = calloc(depth, sizeof(*ctx->buf));
+    if (!ctx->buf) goto bail;
+    for (i = 0; i < depth; ++i) {
+      if (vp8_yv12_alloc_frame_buffer(&ctx->buf[i].img, width, height,
+                                      VP8BORDERINPIXELS)) {
+        goto bail;
+      }
+    }
+  }
+  return ctx;
+bail:
+  vp8_lookahead_destroy(ctx);
+  return NULL;
+}
+
+int vp8_lookahead_push(struct lookahead_ctx *ctx, YV12_BUFFER_CONFIG *src,
+                       int64_t ts_start, int64_t ts_end, unsigned int flags,
+                       unsigned char *active_map) {
+  struct lookahead_entry *buf;
+  int row, col, active_end;
+  int mb_rows = (src->y_height + 15) >> 4;
+  int mb_cols = (src->y_width + 15) >> 4;
+
+  if (ctx->sz + 2 > ctx->max_sz) return 1;
+  ctx->sz++;
+  buf = pop(ctx, &ctx->write_idx);
+
+  /* Only do this partial copy if the following conditions are all met:
+   * 1. Lookahead queue has has size of 1.
+   * 2. Active map is provided.
+   * 3. This is not a key frame, golden nor altref frame.
+   */
+  if (ctx->max_sz == 1 && active_map && !flags) {
+    for (row = 0; row < mb_rows; ++row) {
+      col = 0;
+
+      while (1) {
+        /* Find the first active macroblock in this row. */
+        for (; col < mb_cols; ++col) {
+          if (active_map[col]) break;
+        }
+
+        /* No more active macroblock in this row. */
+        if (col == mb_cols) break;
+
+        /* Find the end of active region in this row. */
+        active_end = col;
+
+        for (; active_end < mb_cols; ++active_end) {
+          if (!active_map[active_end]) break;
+        }
+
+        /* Only copy this active region. */
+        vp8_copy_and_extend_frame_with_rect(src, &buf->img, row << 4, col << 4,
+                                            16, (active_end - col) << 4);
+
+        /* Start again from the end of this active region. */
+        col = active_end;
+      }
+
+      active_map += mb_cols;
+    }
+  } else {
+    vp8_copy_and_extend_frame(src, &buf->img);
+  }
+  buf->ts_start = ts_start;
+  buf->ts_end = ts_end;
+  buf->flags = flags;
+  return 0;
+}
+
+struct lookahead_entry *vp8_lookahead_pop(struct lookahead_ctx *ctx,
+                                          int drain) {
+  struct lookahead_entry *buf = NULL;
+
+  assert(ctx != NULL);
+  if (ctx->sz && (drain || ctx->sz == ctx->max_sz - 1)) {
+    buf = pop(ctx, &ctx->read_idx);
+    ctx->sz--;
+  }
+  return buf;
+}
+
+struct lookahead_entry *vp8_lookahead_peek(struct lookahead_ctx *ctx,
+                                           unsigned int index, int direction) {
+  struct lookahead_entry *buf = NULL;
+
+  if (direction == PEEK_FORWARD) {
+    assert(index < ctx->max_sz - 1);
+    if (index < ctx->sz) {
+      index += ctx->read_idx;
+      if (index >= ctx->max_sz) index -= ctx->max_sz;
+      buf = ctx->buf + index;
+    }
+  } else if (direction == PEEK_BACKWARD) {
+    assert(index == 1);
+
+    if (ctx->read_idx == 0) {
+      index = ctx->max_sz - 1;
+    } else {
+      index = ctx->read_idx - index;
+    }
+    buf = ctx->buf + index;
+  }
+
+  return buf;
+}
+
+unsigned int vp8_lookahead_depth(struct lookahead_ctx *ctx) { return ctx->sz; }