libvpx: Add VP9 decoder.

source/libvpx/vp9/encoder/vp9_lookahead.h

+/*
+ *  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.
+ */
+#ifndef VP9_ENCODER_VP9_LOOKAHEAD_H_
+#define VP9_ENCODER_VP9_LOOKAHEAD_H_
+#include "vpx_scale/yv12config.h"
+#include "vpx/vpx_integer.h"
+
+struct lookahead_entry {
+  YV12_BUFFER_CONFIG  img;
+  int64_t             ts_start;
+  int64_t             ts_end;
+  unsigned int        flags;
+};
+
+
+struct lookahead_ctx;
+
+/**\brief Initializes the lookahead stage
+ *
+ * The lookahead stage is a queue of frame buffers on which some analysis
+ * may be done when buffers are enqueued.
+ *
+ *
+ */
+struct lookahead_ctx *vp9_lookahead_init(unsigned int width,
+                                         unsigned int height,
+                                         unsigned int depth
+                                        );
+
+
+/**\brief Destroys the lookahead stage
+ *
+ */
+void vp9_lookahead_destroy(struct lookahead_ctx *ctx);
+
+
+/**\brief Enqueue a source buffer
+ *
+ * This function will copy the source image into a new framebuffer with
+ * the expected stride/border.
+ *
+ * If active_map is non-NULL and there is only one frame in the queue, then copy
+ * only active macroblocks.
+ *
+ * \param[in] ctx         Pointer to the lookahead context
+ * \param[in] src         Pointer to the image to enqueue
+ * \param[in] ts_start    Timestamp for the start of this frame
+ * \param[in] ts_end      Timestamp for the end of this frame
+ * \param[in] flags       Flags set on this frame
+ * \param[in] active_map  Map that specifies which macroblock is active
+ */
+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);
+
+
+/**\brief Get the next source buffer to encode
+ *
+ *
+ * \param[in] ctx       Pointer to the lookahead context
+ * \param[in] drain     Flag indicating the buffer should be drained
+ *                      (return a buffer regardless of the current queue depth)
+ *
+ * \retval NULL, if drain set and queue is empty
+ * \retval NULL, if drain not set and queue not of the configured depth
+ *
+ */
+struct lookahead_entry *
+vp9_lookahead_pop(struct lookahead_ctx *ctx,
+                  int                   drain);
+
+
+/**\brief Get a future source buffer to encode
+ *
+ * \param[in] ctx       Pointer to the lookahead context
+ * \param[in] index     Index of the frame to be returned, 0 == next frame
+ *
+ * \retval NULL, if no buffer exists at the specified index
+ *
+ */
+struct lookahead_entry *
+vp9_lookahead_peek(struct lookahead_ctx *ctx,
+                   int                   index);
+
+
+/**\brief Get the number of frames currently in the lookahead queue
+ *
+ * \param[in] ctx       Pointer to the lookahead context
+ */
+unsigned int
+vp9_lookahead_depth(struct lookahead_ctx *ctx);
+
+
+#endif