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 /*

  *  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 "vp9/common/vp9_common.h"

 #include "vp9/encoder/vp9_lookahead.h"

 #include "vp9/common/vp9_extend.h"

 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 vp9_lookahead_destroy(struct lookahead_ctx *ctx) {

   if (ctx) {

     if (ctx->buf) {

       unsigned int i;

       for (i = 0; i < ctx->max_sz; i++)

         vp9_free_frame_buffer(&ctx->buf[i].img);

       free(ctx->buf);

     }

     free(ctx);

   }

 }

 struct lookahead_ctx * vp9_lookahead_init(unsigned int width,

                                           unsigned int height,

                                           unsigned int subsampling_x,

                                           unsigned int subsampling_y,

                                           unsigned int depth) {

   struct lookahead_ctx *ctx = NULL;

   // Clamp the lookahead queue depth

   depth = clamp(depth, 1, MAX_LAG_BUFFERS);

   // Allocate the lookahead structures

   ctx = calloc(1, sizeof(*ctx));

   if (ctx) {

     unsigned int i;

     ctx->max_sz = depth;

     ctx->buf = calloc(depth, sizeof(*ctx->buf));

     if (!ctx->buf)

       goto bail;

     for (i = 0; i < depth; i++)

       if (vp9_alloc_frame_buffer(&ctx->buf[i].img,

                                  width, height, subsampling_x, subsampling_y,

                                  VP9BORDERINPIXELS))

         goto bail;

   }

   return ctx;

  bail:

   vp9_lookahead_destroy(ctx);

   return NULL;

 }

 #define USE_PARTIAL_COPY 0

 int vp9_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;

 #if USE_PARTIAL_COPY

   int row, col, active_end;

   int mb_rows = (src->y_height + 15) >> 4;

   int mb_cols = (src->y_width + 15) >> 4;

 #endif

   if (ctx->sz + 1 > ctx->max_sz)

     return 1;

   ctx->sz++;

   buf = pop(ctx, &ctx->write_idx);

 #if USE_PARTIAL_COPY

   // TODO(jkoleszar): This is disabled for now, as

   // vp9_copy_and_extend_frame_with_rect is not subsampling/alpha aware.

   // 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.

         vp9_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 {

     vp9_copy_and_extend_frame(src, &buf->img);

   }

 #else

   // Partial copy not implemented yet

   vp9_copy_and_extend_frame(src, &buf->img);

 #endif

   buf->ts_start = ts_start;

   buf->ts_end = ts_end;

   buf->flags = flags;

   return 0;

 }

 struct lookahead_entry * vp9_lookahead_pop(struct lookahead_ctx *ctx,

                                            int drain) {

   struct lookahead_entry *buf = NULL;

   if (ctx->sz && (drain || ctx->sz == ctx->max_sz)) {

     buf = pop(ctx, &ctx->read_idx);

     ctx->sz--;

   }

   return buf;

 }

 struct lookahead_entry * vp9_lookahead_peek(struct lookahead_ctx *ctx,

                                             int index) {

   struct lookahead_entry *buf = NULL;

   assert(index < (int)ctx->max_sz);

   if (index < (int)ctx->sz) {

     index += ctx->read_idx;

     if (index >= (int)ctx->max_sz)

       index -= ctx->max_sz;

     buf = ctx->buf + index;

   }

   return buf;

 }

 unsigned int vp9_lookahead_depth(struct lookahead_ctx *ctx) {

   return ctx->sz;

 }