gecko-dev/media/libvpx/vp8/encoder/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 LOOKAHEAD_H
#define 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* vp8_lookahead_init(unsigned int width,
                                         unsigned int height,
                                         unsigned int depth
                                         );


/**\brief Destroys the lookahead stage
 *
 */
void vp8_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
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);


/**\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*
vp8_lookahead_pop(struct lookahead_ctx *ctx,
                  int                   drain);


#define PEEK_FORWARD   1
#define PEEK_BACKWARD -1
/**\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*
vp8_lookahead_peek(struct lookahead_ctx *ctx,
                   unsigned int          index,
                   int                   direction);


/**\brief Get the number of frames currently in the lookahead queue
 *
 * \param[in] ctx       Pointer to the lookahead context
 */
unsigned int
vp8_lookahead_depth(struct lookahead_ctx *ctx);


#endif