/*
 * AVCodec public API
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVCODEC_CODEC_H
#define AVCODEC_CODEC_H

#include <stdint.h>

#include "libavutil/avutil.h"
#include "libavutil/hwcontext.h"
#include "libavutil/log.h"
#include "libavutil/pixfmt.h"
#include "libavutil/rational.h"
#include "libavutil/samplefmt.h"

#include "libavcodec/codec_id.h"
#include "libavcodec/version.h"

/**
 * @addtogroup lavc_core
 * @{
 */

/**
 * Decoder can use draw_horiz_band callback.
 */
#define AV_CODEC_CAP_DRAW_HORIZ_BAND (1 << 0)
/**
 * Codec uses get_buffer() or get_encode_buffer() for allocating buffers and
 * supports custom allocators.
 * If not set, it might not use get_buffer() or get_encode_buffer() at all, or
 * use operations that assume the buffer was allocated by
 * avcodec_default_get_buffer2 or avcodec_default_get_encode_buffer.
 */
#define AV_CODEC_CAP_DR1 (1 << 1)
#if FF_API_FLAG_TRUNCATED
/**
 * @deprecated Use parsers to always send proper frames.
 */
#  define AV_CODEC_CAP_TRUNCATED (1 << 3)
#endif
/**
 * Encoder or decoder requires flushing with NULL input at the end in order to
 * give the complete and correct output.
 *
 * NOTE: If this flag is not set, the codec is guaranteed to never be fed with
 *       with NULL data. The user can still send NULL data to the public encode
 *       or decode function, but libavcodec will not pass it along to the codec
 *       unless this flag is set.
 *
 * Decoders:
 * The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL,
 * avpkt->size=0 at the end to get the delayed data until the decoder no longer
 * returns frames.
 *
 * Encoders:
 * The encoder needs to be fed with NULL data at the end of encoding until the
 * encoder no longer returns data.
 *
 * NOTE: For encoders implementing the AVCodec.encode2() function, setting this
 *       flag also means that the encoder must set the pts and duration for
 *       each output packet. If this flag is not set, the pts and duration will
 *       be determined by libavcodec from the input frame.
 */
#define AV_CODEC_CAP_DELAY (1 << 5)
/**
 * Codec can be fed a final frame with a smaller size.
 * This can be used to prevent truncation of the last audio samples.
 */
#define AV_CODEC_CAP_SMALL_LAST_FRAME (1 << 6)

/**
 * Codec can output multiple frames per AVPacket
 * Normally demuxers return one frame at a time, demuxers which do not do
 * are connected to a parser to split what they return into proper frames.
 * This flag is reserved to the very rare category of codecs which have a
 * bitstream that cannot be split into frames without timeconsuming
 * operations like full decoding. Demuxers carrying such bitstreams thus
 * may return multiple frames in a packet. This has many disadvantages like
 * prohibiting stream copy in many cases thus it should only be considered
 * as a last resort.
 */
#define AV_CODEC_CAP_SUBFRAMES (1 << 8)
/**
 * Codec is experimental and is thus avoided in favor of non experimental
 * encoders
 */
#define AV_CODEC_CAP_EXPERIMENTAL (1 << 9)
/**
 * Codec should fill in channel configuration and samplerate instead of
 * container
 */
#define AV_CODEC_CAP_CHANNEL_CONF (1 << 10)
/**
 * Codec supports frame-level multithreading.
 */
#define AV_CODEC_CAP_FRAME_THREADS (1 << 12)
/**
 * Codec supports slice-based (or partition-based) multithreading.
 */
#define AV_CODEC_CAP_SLICE_THREADS (1 << 13)
/**
 * Codec supports changed parameters at any point.
 */
#define AV_CODEC_CAP_PARAM_CHANGE (1 << 14)
/**
 * Codec supports multithreading through a method other than slice- or
 * frame-level multithreading. Typically this marks wrappers around
 * multithreading-capable external libraries.
 */
#define AV_CODEC_CAP_OTHER_THREADS (1 << 15)
#if FF_API_AUTO_THREADS
#  define AV_CODEC_CAP_AUTO_THREADS AV_CODEC_CAP_OTHER_THREADS
#endif
/**
 * Audio encoder supports receiving a different number of samples in each call.
 */
#define AV_CODEC_CAP_VARIABLE_FRAME_SIZE (1 << 16)
/**
 * Decoder is not a preferred choice for probing.
 * This indicates that the decoder is not a good choice for probing.
 * It could for example be an expensive to spin up hardware decoder,
 * or it could simply not provide a lot of useful information about
 * the stream.
 * A decoder marked with this flag should only be used as last resort
 * choice for probing.
 */
#define AV_CODEC_CAP_AVOID_PROBING (1 << 17)

#if FF_API_UNUSED_CODEC_CAPS
/**
 * Deprecated and unused. Use AVCodecDescriptor.props instead
 */
#  define AV_CODEC_CAP_INTRA_ONLY 0x40000000
/**
 * Deprecated and unused. Use AVCodecDescriptor.props instead
 */
#  define AV_CODEC_CAP_LOSSLESS 0x80000000
#endif

/**
 * Codec is backed by a hardware implementation. Typically used to
 * identify a non-hwaccel hardware decoder. For information about hwaccels, use
 * avcodec_get_hw_config() instead.
 */
#define AV_CODEC_CAP_HARDWARE (1 << 18)

/**
 * Codec is potentially backed by a hardware implementation, but not
 * necessarily. This is used instead of AV_CODEC_CAP_HARDWARE, if the
 * implementation provides some sort of internal fallback.
 */
#define AV_CODEC_CAP_HYBRID (1 << 19)

/**
 * This codec takes the reordered_opaque field from input AVFrames
 * and returns it in the corresponding field in AVCodecContext after
 * encoding.
 */
#define AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE (1 << 20)

/**
 * This encoder can be flushed using avcodec_flush_buffers(). If this flag is
 * not set, the encoder must be closed and reopened to ensure that no frames
 * remain pending.
 */
#define AV_CODEC_CAP_ENCODER_FLUSH (1 << 21)

/**
 * AVProfile.
 */
typedef struct AVProfile {
  int profile;
  const char* name;  ///< short name for the profile
} AVProfile;

typedef struct AVCodecDefault AVCodecDefault;

struct AVCodecContext;
struct AVSubtitle;
struct AVPacket;

/**
 * AVCodec.
 */
typedef struct AVCodec {
  /**
   * Name of the codec implementation.
   * The name is globally unique among encoders and among decoders (but an
   * encoder and a decoder can share the same name).
   * This is the primary way to find a codec from the user perspective.
   */
  const char* name;
  /**
   * Descriptive name for the codec, meant to be more human readable than name.
   * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
   */
  const char* long_name;
  enum AVMediaType type;
  enum AVCodecID id;
  /**
   * Codec capabilities.
   * see AV_CODEC_CAP_*
   */
  int capabilities;
  uint8_t max_lowres;  ///< maximum value for lowres supported by the decoder
  const AVRational*
      supported_framerates;  ///< array of supported framerates, or NULL if any,
                             ///< array is terminated by {0,0}
  const enum AVPixelFormat*
      pix_fmts;  ///< array of supported pixel formats, or NULL if unknown,
                 ///< array is terminated by -1
  const int*
      supported_samplerates;  ///< array of supported audio samplerates, or NULL
                              ///< if unknown, array is terminated by 0
  const enum AVSampleFormat*
      sample_fmts;  ///< array of supported sample formats, or NULL if unknown,
                    ///< array is terminated by -1
  const uint64_t*
      channel_layouts;        ///< array of support channel layouts, or NULL if
                              ///< unknown. array is terminated by 0
  const AVClass* priv_class;  ///< AVClass for the private context
  const AVProfile*
      profiles;  ///< array of recognized profiles, or NULL if unknown, array is
                 ///< terminated by {FF_PROFILE_UNKNOWN}

  /**
   * Group name of the codec implementation.
   * This is a short symbolic name of the wrapper backing this codec. A
   * wrapper uses some kind of external implementation for the codec, such
   * as an external library, or a codec implementation provided by the OS or
   * the hardware.
   * If this field is NULL, this is a builtin, libavcodec native codec.
   * If non-NULL, this will be the suffix in AVCodec.name in most cases
   * (usually AVCodec.name will be of the form "<codec_name>_<wrapper_name>").
   */
  const char* wrapper_name;

  /*****************************************************************
   * No fields below this line are part of the public API. They
   * may not be used outside of libavcodec and can be changed and
   * removed at will.
   * New public fields should be added right above.
   *****************************************************************
   */
  /**
   * Internal codec capabilities.
   * See FF_CODEC_CAP_* in internal.h
   */
  int caps_internal;

  int priv_data_size;
  /**
   * @name Frame-level threading support functions
   * @{
   */
  /**
   * Copy necessary context variables from a previous thread context to the
   * current one. If not defined, the next thread will start automatically;
   * otherwise, the codec must call ff_thread_finish_setup().
   *
   * dst and src will (rarely) point to the same context, in which case memcpy
   * should be skipped.
   */
  int (*update_thread_context)(struct AVCodecContext* dst,
                               const struct AVCodecContext* src);

  /**
   * Copy variables back to the user-facing context
   */
  int (*update_thread_context_for_user)(struct AVCodecContext* dst,
                                        const struct AVCodecContext* src);
  /** @} */

  /**
   * Private codec-specific defaults.
   */
  const AVCodecDefault* defaults;

  /**
   * Initialize codec static data, called from av_codec_iterate().
   *
   * This is not intended for time consuming operations as it is
   * run for every codec regardless of that codec being used.
   */
  void (*init_static_data)(struct AVCodec* codec);

  int (*init)(struct AVCodecContext*);
  int (*encode_sub)(struct AVCodecContext*, uint8_t* buf, int buf_size,
                    const struct AVSubtitle* sub);
  /**
   * Encode data to an AVPacket.
   *
   * @param      avctx          codec context
   * @param      avpkt          output AVPacket
   * @param[in]  frame          AVFrame containing the raw data to be encoded
   * @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a
   *                            non-empty packet was returned in avpkt.
   * @return 0 on success, negative error code on failure
   */
  int (*encode2)(struct AVCodecContext* avctx, struct AVPacket* avpkt,
                 const struct AVFrame* frame, int* got_packet_ptr);
  /**
   * Decode picture or subtitle data.
   *
   * @param      avctx          codec context
   * @param      outdata        codec type dependent output struct
   * @param[out] got_frame_ptr  decoder sets to 0 or 1 to indicate that a
   *                            non-empty frame or subtitle was returned in
   *                            outdata.
   * @param[in]  avpkt          AVPacket containing the data to be decoded
   * @return amount of bytes read from the packet on success, negative error
   *         code on failure
   */
  int (*decode)(struct AVCodecContext* avctx, void* outdata, int* got_frame_ptr,
                struct AVPacket* avpkt);
  int (*close)(struct AVCodecContext*);
  /**
   * Encode API with decoupled frame/packet dataflow. This function is called
   * to get one output packet. It should call ff_encode_get_frame() to obtain
   * input data.
   */
  int (*receive_packet)(struct AVCodecContext* avctx, struct AVPacket* avpkt);

  /**
   * Decode API with decoupled packet/frame dataflow. This function is called
   * to get one output frame. It should call ff_decode_get_packet() to obtain
   * input data.
   */
  int (*receive_frame)(struct AVCodecContext* avctx, struct AVFrame* frame);
  /**
   * Flush buffers.
   * Will be called when seeking
   */
  void (*flush)(struct AVCodecContext*);

  /**
   * Decoding only, a comma-separated list of bitstream filters to apply to
   * packets before decoding.
   */
  const char* bsfs;

  /**
   * Array of pointers to hardware configurations supported by the codec,
   * or NULL if no hardware supported.  The array is terminated by a NULL
   * pointer.
   *
   * The user can only access this field via avcodec_get_hw_config().
   */
  const struct AVCodecHWConfigInternal* const* hw_configs;

  /**
   * List of supported codec_tags, terminated by FF_CODEC_TAGS_END.
   */
  const uint32_t* codec_tags;
} AVCodec;

/**
 * Iterate over all registered codecs.
 *
 * @param opaque a pointer where libavcodec will store the iteration state. Must
 *               point to NULL to start the iteration.
 *
 * @return the next registered codec or NULL when the iteration is
 *         finished
 */
const AVCodec* av_codec_iterate(void** opaque);

/**
 * Find a registered decoder with a matching codec ID.
 *
 * @param id AVCodecID of the requested decoder
 * @return A decoder if one was found, NULL otherwise.
 */
const AVCodec* avcodec_find_decoder(enum AVCodecID id);

/**
 * Find a registered decoder with the specified name.
 *
 * @param name name of the requested decoder
 * @return A decoder if one was found, NULL otherwise.
 */
const AVCodec* avcodec_find_decoder_by_name(const char* name);

/**
 * Find a registered encoder with a matching codec ID.
 *
 * @param id AVCodecID of the requested encoder
 * @return An encoder if one was found, NULL otherwise.
 */
const AVCodec* avcodec_find_encoder(enum AVCodecID id);

/**
 * Find a registered encoder with the specified name.
 *
 * @param name name of the requested encoder
 * @return An encoder if one was found, NULL otherwise.
 */
const AVCodec* avcodec_find_encoder_by_name(const char* name);
/**
 * @return a non-zero number if codec is an encoder, zero otherwise
 */
int av_codec_is_encoder(const AVCodec* codec);

/**
 * @return a non-zero number if codec is a decoder, zero otherwise
 */
int av_codec_is_decoder(const AVCodec* codec);

/**
 * Return a name for the specified profile, if available.
 *
 * @param codec the codec that is searched for the given profile
 * @param profile the profile value for which a name is requested
 * @return A name for the profile if found, NULL otherwise.
 */
const char* av_get_profile_name(const AVCodec* codec, int profile);

enum {
  /**
   * The codec supports this format via the hw_device_ctx interface.
   *
   * When selecting this format, AVCodecContext.hw_device_ctx should
   * have been set to a device of the specified type before calling
   * avcodec_open2().
   */
  AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX = 0x01,
  /**
   * The codec supports this format via the hw_frames_ctx interface.
   *
   * When selecting this format for a decoder,
   * AVCodecContext.hw_frames_ctx should be set to a suitable frames
   * context inside the get_format() callback.  The frames context
   * must have been created on a device of the specified type.
   *
   * When selecting this format for an encoder,
   * AVCodecContext.hw_frames_ctx should be set to the context which
   * will be used for the input frames before calling avcodec_open2().
   */
  AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX = 0x02,
  /**
   * The codec supports this format by some internal method.
   *
   * This format can be selected without any additional configuration -
   * no device or frames context is required.
   */
  AV_CODEC_HW_CONFIG_METHOD_INTERNAL = 0x04,
  /**
   * The codec supports this format by some ad-hoc method.
   *
   * Additional settings and/or function calls are required.  See the
   * codec-specific documentation for details.  (Methods requiring
   * this sort of configuration are deprecated and others should be
   * used in preference.)
   */
  AV_CODEC_HW_CONFIG_METHOD_AD_HOC = 0x08,
};

typedef struct AVCodecHWConfig {
  /**
   * For decoders, a hardware pixel format which that decoder may be
   * able to decode to if suitable hardware is available.
   *
   * For encoders, a pixel format which the encoder may be able to
   * accept.  If set to AV_PIX_FMT_NONE, this applies to all pixel
   * formats supported by the codec.
   */
  enum AVPixelFormat pix_fmt;
  /**
   * Bit set of AV_CODEC_HW_CONFIG_METHOD_* flags, describing the possible
   * setup methods which can be used with this configuration.
   */
  int methods;
  /**
   * The device type associated with the configuration.
   *
   * Must be set for AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX and
   * AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX, otherwise unused.
   */
  enum AVHWDeviceType device_type;
} AVCodecHWConfig;

/**
 * Retrieve supported hardware configurations for a codec.
 *
 * Values of index from zero to some maximum return the indexed configuration
 * descriptor; all other values return NULL.  If the codec does not support
 * any hardware configurations then it will always return NULL.
 */
const AVCodecHWConfig* avcodec_get_hw_config(const AVCodec* codec, int index);

/**
 * @}
 */

#endif /* AVCODEC_CODEC_H */
