vpx/vpx_decoder.h

/*
 *  Copyright (c) 2010 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 VPX_VPX_DECODER_H_
#define VPX_VPX_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 "./vpx_codec.h"
#include "./vpx_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 VPX_DECODER_ABI_VERSION (3 + VPX_CODEC_ABI_VERSION) /**<\hideinitializer*/

  /*! \brief Decoder capabilities bitfield
   *
   *  Each decoder advertises the capabilities it supports as part of its
   *  ::vpx_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 VPX_CODEC_CAP_* defines.
   */
#define VPX_CODEC_CAP_PUT_SLICE  0x10000 /**< Will issue put_slice callbacks */
#define VPX_CODEC_CAP_PUT_FRAME  0x20000 /**< Will issue put_frame callbacks */
#define VPX_CODEC_CAP_POSTPROC   0x40000 /**< Can postprocess decoded frame */
#define VPX_CODEC_CAP_ERROR_CONCEALMENT   0x80000 /**< Can conceal errors due to
  packet loss */
#define VPX_CODEC_CAP_INPUT_FRAGMENTS   0x100000 /**< Can receive encoded frames
  one fragment at a time */

  /*! \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 VPX_CODEC_USE_* defines.
   */
#define VPX_CODEC_CAP_FRAME_THREADING   0x200000 /**< Can support frame-based
                                                      multi-threading */
#define VPX_CODEC_CAP_EXTERNAL_FRAME_BUFFER 0x400000 /**< Can support external
                                                          frame buffers */

#define VPX_CODEC_USE_POSTPROC   0x10000 /**< Postprocess decoded frame */
#define VPX_CODEC_USE_ERROR_CONCEALMENT 0x20000 /**< Conceal errors in decoded
  frames */
#define VPX_CODEC_USE_INPUT_FRAGMENTS   0x40000 /**< The input frame should be
  passed to the decoder one
  fragment at a time */
#define VPX_CODEC_USE_FRAME_THREADING   0x80000 /**< Enable frame-based
                                                     multi-threading */

  /*!\brief Stream properties
   *
   * This structure is used to query or set properties of the decoded
   * stream. Algorithms may extend this structure with data specific
   * to their bitstream by setting the sz member appropriately.
   */
  typedef struct vpx_codec_stream_info {
    unsigned int sz;     /**< Size of this structure */
    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 */
  } vpx_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 vpx_codec_dec_cfg {
    unsigned int threads; /**< Maximum number of threads to use, default 1 */
    unsigned int w;      /**< Width */
    unsigned int h;      /**< Height */
  } vpx_codec_dec_cfg_t; /**< alias for struct vpx_codec_dec_cfg */


  /*!\brief Initialize a decoder instance
   *
   * Initializes a decoder context using the given interface. Applications
   * should call the vpx_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 --disable-multithread, this call
   * is not thread safe and should be guarded with a lock if being used
   * in a multithreaded context.
   *
   * In XMA mode (activated by setting VPX_CODEC_USE_XMA in the flags
   * parameter), the storage pointed to by the cfg parameter must be
   * kept readable and stable until all memory maps have been set.
   *
   * \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 VPX_CODEC_USE_* flags
   * \param[in]    ver     ABI version number. Must be set to
   *                       VPX_DECODER_ABI_VERSION
   * \retval #VPX_CODEC_OK
   *     The decoder algorithm initialized.
   * \retval #VPX_CODEC_MEM_ERROR
   *     Memory allocation failed.
   */
  vpx_codec_err_t vpx_codec_dec_init_ver(vpx_codec_ctx_t      *ctx,
                                         vpx_codec_iface_t    *iface,
                                         vpx_codec_dec_cfg_t  *cfg,
                                         vpx_codec_flags_t     flags,
                                         int                   ver);

  /*!\brief Convenience macro for vpx_codec_dec_init_ver()
   *
   * Ensures the ABI version parameter is properly set.
   */
#define vpx_codec_dec_init(ctx, iface, cfg, flags) \
  vpx_codec_dec_init_ver(ctx, iface, cfg, flags, VPX_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 size member
   *                         \ref MUST be properly initialized, but \ref MAY be
   *                         clobbered by the algorithm. This parameter \ref MAY
   *                         be NULL.
   *
   * \retval #VPX_CODEC_OK
   *     Bitstream is parsable and stream information updated
   */
  vpx_codec_err_t vpx_codec_peek_stream_info(vpx_codec_iface_t       *iface,
                                             const uint8_t           *data,
                                             unsigned int             data_sz,
                                             vpx_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. The size member
   *                         \ref MUST be properly initialized, but \ref MAY be
   *                         clobbered by the algorithm. This parameter \ref MAY
   *                         be NULL.
   *
   * \retval #VPX_CODEC_OK
   *     Bitstream is parsable and stream information updated
   */
  vpx_codec_err_t vpx_codec_get_stream_info(vpx_codec_ctx_t         *ctx,
                                            vpx_codec_stream_info_t *si);


  /*!\brief Decode data
   *
   * Processes a buffer of coded data. If the processing results in a new
   * decoded frame becoming available, PUT_SLICE and PUT_FRAME events may be
   * generated, as appropriate. Encoded data \ref MUST be passed in DTS (decode
   * time stamp) order. Frames produced will always be in PTS (presentation
   * time stamp) order.
   * If the decoder is configured with VPX_CODEC_USE_INPUT_FRAGMENTS enabled,
   * data and data_sz can contain a fragment of the encoded frame. Fragment
   * \#n must contain at least partition \#n, but can also contain subsequent
   * partitions (\#n+1 - \#n+i), and if so, fragments \#n+1, .., \#n+i must
   * be empty. When no more data is available, this function should be called
   * with NULL as data and 0 as data_sz. The memory passed to this function
   * must be available until the frame has been decoded.
   *
   * \param[in] ctx          Pointer to this instance's context
   * \param[in] data         Pointer to this block of new coded data. If
   *                         NULL, a VPX_CODEC_CB_PUT_FRAME event is posted
   *                         for the previously decoded frame.
   * \param[in] data_sz      Size of the coded data, in bytes.
   * \param[in] user_priv    Application specific data to associate with
   *                         this frame.
   * \param[in] deadline     Soft deadline the decoder should attempt to meet,
   *                         in us. Set to zero for unlimited.
   *
   * \return Returns #VPX_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 ::vpx_codec_err_t
   *         for recoverability capabilities.
   */
  vpx_codec_err_t vpx_codec_decode(vpx_codec_ctx_t    *ctx,
                                   const uint8_t        *data,
                                   unsigned int            data_sz,
                                   void               *user_priv,
                                   long                deadline);


  /*!\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
   * vpx_codec_decode call, and remains valid until the next call to vpx_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.
   */
  vpx_image_t *vpx_codec_get_frame(vpx_codec_ctx_t  *ctx,
                                   vpx_codec_iter_t *iter);


  /*!\defgroup cap_put_frame Frame-Based Decoding Functions
   *
   * The following functions are required to be implemented for all decoders
   * that advertise the VPX_CODEC_CAP_PUT_FRAME capability. Calling these functions
   * for codecs that don't advertise this capability will result in an error
   * code being returned, usually VPX_CODEC_ERROR
   * @{
   */

  /*!\brief put frame callback prototype
   *
   * This callback is invoked by the decoder to notify the application of
   * the availability of decoded image data.
   */
  typedef void (*vpx_codec_put_frame_cb_fn_t)(void        *user_priv,
                                              const vpx_image_t *img);


  /*!\brief Register for notification of frame completion.
   *
   * Registers a given function to be called when a decoded frame is
   * available.
   *
   * \param[in] ctx          Pointer to this instance's context
   * \param[in] cb           Pointer to the callback function
   * \param[in] user_priv    User's private data
   *
   * \retval #VPX_CODEC_OK
   *     Callback successfully registered.
   * \retval #VPX_CODEC_ERROR
   *     Decoder context not initialized, or algorithm not capable of
   *     posting slice completion.
   */
  vpx_codec_err_t vpx_codec_register_put_frame_cb(vpx_codec_ctx_t             *ctx,
                                                  vpx_codec_put_frame_cb_fn_t  cb,
                                                  void                        *user_priv);


  /*!@} - end defgroup cap_put_frame */

  /*!\defgroup cap_put_slice Slice-Based Decoding Functions
   *
   * The following functions are required to be implemented for all decoders
   * that advertise the VPX_CODEC_CAP_PUT_SLICE capability. Calling these functions
   * for codecs that don't advertise this capability will result in an error
   * code being returned, usually VPX_CODEC_ERROR
   * @{
   */

  /*!\brief put slice callback prototype
   *
   * This callback is invoked by the decoder to notify the application of
   * the availability of partially decoded image data. The
   */
  typedef void (*vpx_codec_put_slice_cb_fn_t)(void         *user_priv,
                                              const vpx_image_t      *img,
                                              const vpx_image_rect_t *valid,
                                              const vpx_image_rect_t *update);


  /*!\brief Register for notification of slice completion.
   *
   * Registers a given function to be called when a decoded slice is
   * available.
   *
   * \param[in] ctx          Pointer to this instance's context
   * \param[in] cb           Pointer to the callback function
   * \param[in] user_priv    User's private data
   *
   * \retval #VPX_CODEC_OK
   *     Callback successfully registered.
   * \retval #VPX_CODEC_ERROR
   *     Decoder context not initialized, or algorithm not capable of
   *     posting slice completion.
   */
  vpx_codec_err_t vpx_codec_register_put_slice_cb(vpx_codec_ctx_t             *ctx,
                                                  vpx_codec_put_slice_cb_fn_t  cb,
                                                  void                        *user_priv);


  /*!@} - end defgroup cap_put_slice*/

  /*!\defgroup cap_external_frame_buffer External Frame Buffer Functions
   *
   * The following section is required to be implemented for all decoders
   * that advertise the VPX_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 VPX_CODEC_ERROR.
   *
   * \note
   * Currently this only works with VP9.
   * @{
   */

  /*!\brief Pass in external frame buffers for the decoder to use.
   *
   * Registers functions to be called when libvpx needs a frame buffer
   * to decode the current frame and a function to be called when libvpx does
   * not internally reference the frame buffer. This set function must
   * be called before the first call to decode or libvpx 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 #VPX_CODEC_OK
   *     External frame buffers will be used by libvpx.
   * \retval #VPX_CODEC_INVALID_PARAM
   *     One or more of the callbacks were NULL.
   * \retval #VPX_CODEC_ERROR
   *     Decoder context not initialized, or algorithm not capable of
   *     using external frame buffers.
   *
   * \note
   * When decoding VP9, the application may be required to pass in at least
   * #VP9_MAXIMUM_REF_BUFFERS + #VPX_MAXIMUM_WORK_BUFFERS external frame
   * buffers.
   */
  vpx_codec_err_t vpx_codec_set_frame_buffer_functions(
      vpx_codec_ctx_t *ctx,
      vpx_get_frame_buffer_cb_fn_t cb_get,
      vpx_release_frame_buffer_cb_fn_t cb_release, void *cb_priv);

  /*!@} - end defgroup cap_external_frame_buffer */

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