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Filename : aom_decoder.h
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/*
 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */
#ifndef AOM_AOM_AOM_DECODER_H_
#define AOM_AOM_AOM_DECODER_H_

/*!\defgroup decoder Decoder Algorithm Interface
 * \ingroup codec
 * This abstraction allows applications using this decoder to easily support
 * multiple video formats with minimal code duplication. This section describes
 * the interface common to all decoders.
 * @{
 */

/*!\file
 * \brief Describes the decoder algorithm interface to applications.
 *
 * This file describes the interface between an application and a
 * video decoder algorithm.
 *
 */
#ifdef __cplusplus
extern "C" {
#endif

#include "aom/aom_codec.h"  // IWYU pragma: export
#include "aom/aom_frame_buffer.h"

/*!\brief Current ABI version number
 *
 * \internal
 * If this file is altered in any way that changes the ABI, this value
 * must be bumped.  Examples include, but are not limited to, changing
 * types, removing or reassigning enums, adding/removing/rearranging
 * fields to structures
 */
#define AOM_DECODER_ABI_VERSION \
  (6 + AOM_CODEC_ABI_VERSION) /**<\hideinitializer*/

/*! \brief Decoder capabilities bitfield
 *
 *  Each decoder advertises the capabilities it supports as part of its
 *  ::aom_codec_iface_t interface structure. Capabilities are extra interfaces
 *  or functionality, and are not required to be supported by a decoder.
 *
 *  The available flags are specified by AOM_CODEC_CAP_* defines.
 */
/*!brief Can support external frame buffers */
#define AOM_CODEC_CAP_EXTERNAL_FRAME_BUFFER 0x200000

/*! \brief Initialization-time Feature Enabling
 *
 *  Certain codec features must be known at initialization time, to allow for
 *  proper memory allocation.
 *
 *  The available flags are specified by AOM_CODEC_USE_* defines.
 */

/*!\brief Stream properties
 *
 * This structure is used to query or set properties of the decoded
 * stream.
 */
typedef struct aom_codec_stream_info {
  unsigned int w;                      /**< Width (or 0 for unknown/default) */
  unsigned int h;                      /**< Height (or 0 for unknown/default) */
  unsigned int is_kf;                  /**< Current frame is a keyframe */
  unsigned int number_spatial_layers;  /**< Number of spatial layers */
  unsigned int number_temporal_layers; /**< Number of temporal layers */
  unsigned int is_annexb;              /**< Is Bitstream in Annex-B format */
} aom_codec_stream_info_t;

/* REQUIRED FUNCTIONS
 *
 * The following functions are required to be implemented for all decoders.
 * They represent the base case functionality expected of all decoders.
 */

/*!\brief Initialization Configurations
 *
 * This structure is used to pass init time configuration options to the
 * decoder.
 */
typedef struct aom_codec_dec_cfg {
  unsigned int threads; /**< Maximum number of threads to use, default 1 */
  unsigned int w;       /**< Width */
  unsigned int h;       /**< Height */
  unsigned int allow_lowbitdepth; /**< Allow use of low-bitdepth coding path */
} aom_codec_dec_cfg_t;            /**< alias for struct aom_codec_dec_cfg */

/*!\brief Initialize a decoder instance
 *
 * Initializes a decoder context using the given interface. Applications
 * should call the aom_codec_dec_init convenience macro instead of this
 * function directly, to ensure that the ABI version number parameter
 * is properly initialized.
 *
 * If the library was configured with cmake -DCONFIG_MULTITHREAD=0, this
 * call is not thread safe and should be guarded with a lock if being used
 * in a multithreaded context.
 *
 * \param[in]    ctx     Pointer to this instance's context.
 * \param[in]    iface   Pointer to the algorithm interface to use.
 * \param[in]    cfg     Configuration to use, if known. May be NULL.
 * \param[in]    flags   Bitfield of AOM_CODEC_USE_* flags
 * \param[in]    ver     ABI version number. Must be set to
 *                       AOM_DECODER_ABI_VERSION
 * \retval #AOM_CODEC_OK
 *     The decoder algorithm has been initialized.
 * \retval #AOM_CODEC_MEM_ERROR
 *     Memory allocation failed.
 */
aom_codec_err_t aom_codec_dec_init_ver(aom_codec_ctx_t *ctx,
                                       aom_codec_iface_t *iface,
                                       const aom_codec_dec_cfg_t *cfg,
                                       aom_codec_flags_t flags, int ver);

/*!\brief Convenience macro for aom_codec_dec_init_ver()
 *
 * Ensures the ABI version parameter is properly set.
 */
#define aom_codec_dec_init(ctx, iface, cfg, flags) \
  aom_codec_dec_init_ver(ctx, iface, cfg, flags, AOM_DECODER_ABI_VERSION)

/*!\brief Parse stream info from a buffer
 *
 * Performs high level parsing of the bitstream. Construction of a decoder
 * context is not necessary. Can be used to determine if the bitstream is
 * of the proper format, and to extract information from the stream.
 *
 * \param[in]      iface   Pointer to the algorithm interface
 * \param[in]      data    Pointer to a block of data to parse
 * \param[in]      data_sz Size of the data buffer
 * \param[in,out]  si      Pointer to stream info to update. The is_annexb
 *                         member \ref MUST be properly initialized. This
 *                         function sets the rest of the members.
 *
 * \retval #AOM_CODEC_OK
 *     Bitstream is parsable and stream information updated.
 * \retval #AOM_CODEC_INVALID_PARAM
 *     One of the arguments is invalid, for example a NULL pointer.
 * \retval #AOM_CODEC_UNSUP_BITSTREAM
 *     The decoder didn't recognize the coded data, or the
 *     buffer was too short.
 */
aom_codec_err_t aom_codec_peek_stream_info(aom_codec_iface_t *iface,
                                           const uint8_t *data, size_t data_sz,
                                           aom_codec_stream_info_t *si);

/*!\brief Return information about the current stream.
 *
 * Returns information about the stream that has been parsed during decoding.
 *
 * \param[in]      ctx     Pointer to this instance's context
 * \param[in,out]  si      Pointer to stream info to update.
 *
 * \retval #AOM_CODEC_OK
 *     Bitstream is parsable and stream information updated.
 * \retval #AOM_CODEC_INVALID_PARAM
 *     One of the arguments is invalid, for example a NULL pointer.
 * \retval #AOM_CODEC_UNSUP_BITSTREAM
 *     The decoder couldn't parse the submitted data.
 */
aom_codec_err_t aom_codec_get_stream_info(aom_codec_ctx_t *ctx,
                                          aom_codec_stream_info_t *si);

/*!\brief Decode data
 *
 * Processes a buffer of coded data. Encoded data \ref MUST be passed in DTS
 * (decode time stamp) order. Frames produced will always be in PTS
 * (presentation time stamp) order.
 *
 * \param[in] ctx          Pointer to this instance's context
 * \param[in] data         Pointer to this block of new coded data.
 * \param[in] data_sz      Size of the coded data, in bytes.
 * \param[in] user_priv    Application specific data to associate with
 *                         this frame.
 *
 * \return Returns #AOM_CODEC_OK if the coded data was processed completely
 *         and future pictures can be decoded without error. Otherwise,
 *         see the descriptions of the other error codes in ::aom_codec_err_t
 *         for recoverability capabilities.
 */
aom_codec_err_t aom_codec_decode(aom_codec_ctx_t *ctx, const uint8_t *data,
                                 size_t data_sz, void *user_priv);

/*!\brief Decoded frames iterator
 *
 * Iterates over a list of the frames available for display. The iterator
 * storage should be initialized to NULL to start the iteration. Iteration is
 * complete when this function returns NULL.
 *
 * The list of available frames becomes valid upon completion of the
 * aom_codec_decode call, and remains valid until the next call to
 * aom_codec_decode.
 *
 * \param[in]     ctx      Pointer to this instance's context
 * \param[in,out] iter     Iterator storage, initialized to NULL
 *
 * \return Returns a pointer to an image, if one is ready for display. Frames
 *         produced will always be in PTS (presentation time stamp) order.
 */
aom_image_t *aom_codec_get_frame(aom_codec_ctx_t *ctx, aom_codec_iter_t *iter);

/*!\defgroup cap_external_frame_buffer External Frame Buffer Functions
 *
 * The following function is required to be implemented for all decoders
 * that advertise the AOM_CODEC_CAP_EXTERNAL_FRAME_BUFFER capability.
 * Calling this function for codecs that don't advertise this capability
 * will result in an error code being returned, usually AOM_CODEC_INCAPABLE.
 * @{
 */

/*!\brief Pass in external frame buffers for the decoder to use.
 *
 * Registers functions to be called when libaom needs a frame buffer
 * to decode the current frame and a function to be called when libaom does
 * not internally reference the frame buffer. This set function must
 * be called before the first call to decode or libaom will assume the
 * default behavior of allocating frame buffers internally.
 *
 * \param[in] ctx          Pointer to this instance's context
 * \param[in] cb_get       Pointer to the get callback function
 * \param[in] cb_release   Pointer to the release callback function
 * \param[in] cb_priv      Callback's private data
 *
 * \retval #AOM_CODEC_OK
 *     External frame buffers will be used by libaom.
 * \retval #AOM_CODEC_INVALID_PARAM
 *     One or more of the callbacks were NULL.
 * \retval #AOM_CODEC_ERROR
 *     Decoder context not initialized.
 * \retval #AOM_CODEC_INCAPABLE
 *     Algorithm not capable of using external frame buffers.
 *
 * \note
 * When decoding AV1, the application may be required to pass in at least
 * #AOM_MAXIMUM_WORK_BUFFERS external frame buffers.
 */
aom_codec_err_t aom_codec_set_frame_buffer_functions(
    aom_codec_ctx_t *ctx, aom_get_frame_buffer_cb_fn_t cb_get,
    aom_release_frame_buffer_cb_fn_t cb_release, void *cb_priv);

/*!@} - end defgroup cap_external_frame_buffer */

/*!@} - end defgroup decoder*/
#ifdef __cplusplus
}
#endif
#endif  // AOM_AOM_AOM_DECODER_H_