text: /*
   * 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
   */
  
  /**
   * @file
   * common internal api header.
   */
  
  #ifndef AVCODEC_INTERNAL_H
  #define AVCODEC_INTERNAL_H
  
  #include <stdint.h>
  
  #include "libavutil/buffer.h"
  #include "libavutil/channel_layout.h"
  #include "libavutil/mathematics.h"
  #include "libavutil/pixfmt.h"
  #include "avcodec.h"
  #include "config.h"
  
  /**
   * The codec does not modify any global variables in the init function,
   * allowing to call the init function without locking any global mutexes.
   */
  #define FF_CODEC_CAP_INIT_THREADSAFE        (1 << 0)
  /**
   * The codec allows calling the close function for deallocation even if
   * the init function returned a failure. Without this capability flag, a
   * codec does such cleanup internally when returning failures from the
   * init function and does not expect the close function to be called at
   * all.
   */
  #define FF_CODEC_CAP_INIT_CLEANUP           (1 << 1)
  /**
   * Decoders marked with FF_CODEC_CAP_SETS_PKT_DTS want to set
   * AVFrame.pkt_dts manually. If the flag is set, decode.c won't overwrite
   * this field. If it's unset, decode.c tries to guess the pkt_dts field
   * from the input AVPacket.
   */
  #define FF_CODEC_CAP_SETS_PKT_DTS           (1 << 2)
  /**
   * The decoder extracts and fills its parameters even if the frame is
   * skipped due to the skip_frame setting.
   */
  #define FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM  (1 << 3)
  /**
   * The decoder sets the cropping fields in the output frames manually.
   * If this cap is set, the generic code will initialize output frame
   * dimensions to coded rather than display values.
   */
  #define FF_CODEC_CAP_EXPORTS_CROPPING       (1 << 4)
  /**
   * Codec initializes slice-based threading with a main function
   */
  #define FF_CODEC_CAP_SLICE_THREAD_HAS_MF    (1 << 5)
  /*
   * The codec supports frame threading and has inter-frame dependencies, so it
   * uses ff_thread_report/await_progress().
   */
  #define FF_CODEC_CAP_ALLOCATE_PROGRESS      (1 << 6)
  
  /**
   * AVCodec.codec_tags termination value
   */
  #define FF_CODEC_TAGS_END -1
  
  
  #ifdef TRACE
  #   define ff_tlog(ctx, ...) av_log(ctx, AV_LOG_TRACE, __VA_ARGS__)
  #else
  #   define ff_tlog(ctx, ...) do { } while(0)
  #endif
  
  
  #define FF_DEFAULT_QUANT_BIAS 999999
  
  #define FF_QSCALE_TYPE_MPEG1 0
  #define FF_QSCALE_TYPE_MPEG2 1
  #define FF_QSCALE_TYPE_H264  2
  #define FF_QSCALE_TYPE_VP56  3
  
  #define FF_SANE_NB_CHANNELS 512U
  
  #define FF_SIGNBIT(x) ((x) >> CHAR_BIT * sizeof(x) - 1)
  
  #if HAVE_SIMD_ALIGN_64
  #   define STRIDE_ALIGN 64 /* AVX-512 */
  #elif HAVE_SIMD_ALIGN_32
  #   define STRIDE_ALIGN 32
  #elif HAVE_SIMD_ALIGN_16
  #   define STRIDE_ALIGN 16
  #else
  #   define STRIDE_ALIGN 8
  #endif
  
  typedef struct DecodeSimpleContext {
      AVPacket *in_pkt;
  } DecodeSimpleContext;
  
  typedef struct EncodeSimpleContext {
      AVFrame *in_frame;
  } EncodeSimpleContext;
  
  typedef struct AVCodecInternal {
      /**
       * Whether the parent AVCodecContext is a copy of the context which had
       * init() called on it.
       * This is used by multithreading - shared tables and picture pointers
       * should be freed from the original context only.
       */
      int is_copy;
  
      /**
       * An audio frame with less than required samples has been submitted and
       * padded with silence. Reject all subsequent frames.
       */
      int last_audio_frame;
  
      AVFrame *to_free;
  
      AVBufferRef *pool;
  
      void *thread_ctx;
  
      DecodeSimpleContext ds;
      AVBSFContext *bsf;
  
      /**
       * Properties (timestamps+side data) extracted from the last packet passed
       * for decoding.
       */
      AVPacket *last_pkt_props;
  
      /**
       * temporary buffer used for encoders to store their bitstream
       */
      uint8_t *byte_buffer;
      unsigned int byte_buffer_size;
  
      void *frame_thread_encoder;
  
      EncodeSimpleContext es;
  
      /**
       * Number of audio samples to skip at the start of the next decoded frame
       */
      int skip_samples;
  
      /**
       * hwaccel-specific private data
       */
      void *hwaccel_priv_data;
  
      /**
       * checks API usage: after codec draining, flush is required to resume operation
       */
      int draining;
  
      /**
       * buffers for using new encode/decode API through legacy API
       */
      AVPacket *buffer_pkt;
      AVFrame *buffer_frame;
      int draining_done;
      int compat_decode_warned;
      /* this variable is set by the decoder internals to signal to the old
       * API compat wrappers the amount of data consumed from the last packet */
      size_t compat_decode_consumed;
      /* when a partial packet has been consumed, this stores the remaining size
       * of the packet (that should be submitted in the next decode call */
      size_t compat_decode_partial_size;
      AVFrame *compat_decode_frame;
      AVPacket *compat_encode_packet;
  
      int showed_multi_packet_warning;
  
      int skip_samples_multiplier;
  
      /* to prevent infinite loop on errors when draining */
      int nb_draining_errors;
  
      /* used when avctx flag AV_CODEC_FLAG_DROPCHANGED is set */
      int changed_frames_dropped;
      int initial_format;
      int initial_width, initial_height;
      int initial_sample_rate;
      int initial_channels;
      uint64_t initial_channel_layout;
  } AVCodecInternal;
  
  struct AVCodecDefault {
      const uint8_t *key;
      const uint8_t *value;
  };
  
  extern const uint8_t ff_log2_run[41];
  
  /**
   * Return the index into tab at which {a,b} match elements {[0],[1]} of tab.
   * If there is no such matching pair then size is returned.
   */
  int ff_match_2uint16(const uint16_t (*tab)[2], int size, int a, int b);
  
  unsigned int avpriv_toupper4(unsigned int x);
  
  void ff_color_frame(AVFrame *frame, const int color[4]);
  
  /**
   * Maximum size in bytes of extradata.
   * This value was chosen such that every bit of the buffer is
   * addressable by a 32-bit signed integer as used by get_bits.
   */
  #define FF_MAX_EXTRADATA_SIZE ((1 << 28) - AV_INPUT_BUFFER_PADDING_SIZE)
  
  /**
   * Check AVPacket size and/or allocate data.
   *
   * Encoders supporting AVCodec.encode2() can use this as a convenience to
   * ensure the output packet data is large enough, whether provided by the user
   * or allocated in this function.
   *
   * @param avctx   the AVCodecContext of the encoder
   * @param avpkt   the AVPacket
   *                If avpkt->data is already set, avpkt->size is checked
   *                to ensure it is large enough.
   *                If avpkt->data is NULL, a new buffer is allocated.
   *                avpkt->size is set to the specified size.
   *                All other AVPacket fields will be reset with av_init_packet().
   * @param size    the minimum required packet size
   * @param min_size This is a hint to the allocation algorithm, which indicates
   *                to what minimal size the caller might later shrink the packet
   *                to. Encoders often allocate packets which are larger than the
   *                amount of data that is written into them as the exact amount is
   *                not known at the time of allocation. min_size represents the
   *                size a packet might be shrunk to by the caller. Can be set to
   *                0. setting this roughly correctly allows the allocation code
   *                to choose between several allocation strategies to improve
   *                speed slightly.
   * @return        non negative on success, negative error code on failure
   */
  int ff_alloc_packet2(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int64_t min_size);
  
  /**
   * Rescale from sample rate to AVCodecContext.time_base.
   */
  static av_always_inline int64_t ff_samples_to_time_base(AVCodecContext *avctx,
                                                          int64_t samples)
  {
      if(samples == AV_NOPTS_VALUE)
          return AV_NOPTS_VALUE;
      // ==> Start patch MPC
      AVRational cq = { 1, avctx->sample_rate };
      return av_rescale_q(samples, cq,
                          avctx->time_base);
      // ==> End patch MPC
  }
  
  /**
   * 2^(x) for integer x
   * @return correctly rounded float
   */
  static av_always_inline float ff_exp2fi(int x) {
      /* Normal range */
      if (-126 <= x && x <= 128)
          return av_int2float((x+127) << 23);
      /* Too large */
      else if (x > 128)
          return INFINITY;
      /* Subnormal numbers */
      else if (x > -150)
          return av_int2float(1 << (x+149));
      /* Negligibly small */
      else
          return 0;
  }
  
  /**
   * Get a buffer for a frame. This is a wrapper around
   * AVCodecContext.get_buffer() and should be used instead calling get_buffer()
   * directly.
   */
  int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags);
  
  #define FF_REGET_BUFFER_FLAG_READONLY 1 ///< the returned buffer does not need to be writable
  /**
   * Identical in function to ff_get_buffer(), except it reuses the existing buffer
   * if available.
   */
  int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags);
  
  int ff_thread_can_start_frame(AVCodecContext *avctx);
  
  int avpriv_h264_has_num_reorder_frames(AVCodecContext *avctx);
  
  /**
   * Call avcodec_open2 recursively by decrementing counter, unlocking mutex,
   * calling the function and then restoring again. Assumes the mutex is
   * already locked
   */
  int ff_codec_open2_recursive(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
  
  /**
   * Finalize buf into extradata and set its size appropriately.
   */
  int avpriv_bprint_to_extradata(AVCodecContext *avctx, struct AVBPrint *buf);
  
  const uint8_t *avpriv_find_start_code(const uint8_t *p,
                                        const uint8_t *end,
                                        uint32_t *state);
  
  int avpriv_codec_get_cap_skip_frame_fill_param(const AVCodec *codec);
  
  /**
   * Check that the provided frame dimensions are valid and set them on the codec
   * context.
   */
  int ff_set_dimensions(AVCodecContext *s, int width, int height);
  
  /**
   * Check that the provided sample aspect ratio is valid and set it on the codec
   * context.
   */
  int ff_set_sar(AVCodecContext *avctx, AVRational sar);
  
  /**
   * Add or update AV_FRAME_DATA_MATRIXENCODING side data.
   */
  int ff_side_data_update_matrix_encoding(AVFrame *frame,
                                          enum AVMatrixEncoding matrix_encoding);
  
  /**
   * Select the (possibly hardware accelerated) pixel format.
   * This is a wrapper around AVCodecContext.get_format() and should be used
   * instead of calling get_format() directly.
   *
   * The list of pixel formats must contain at least one valid entry, and is
   * terminated with AV_PIX_FMT_NONE.  If it is possible to decode to software,
   * the last entry in the list must be the most accurate software format.
   * If it is not possible to decode to software, AVCodecContext.sw_pix_fmt
   * must be set before calling this function.
   */
  int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt);
  
  /**
   * Set various frame properties from the codec context / packet data.
   */
  int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame);
  
  /**
   * Add a CPB properties side data to an encoding context.
   */
  AVCPBProperties *ff_add_cpb_side_data(AVCodecContext *avctx);
  
  /**
   * Check AVFrame for A53 side data and allocate and fill SEI message with A53 info
   *
   * @param frame      Raw frame to get A53 side data from
   * @param prefix_len Number of bytes to allocate before SEI message
   * @param data       Pointer to a variable to store allocated memory
   *                   Upon return the variable will hold NULL on error or if frame has no A53 info.
   *                   Otherwise it will point to prefix_len uninitialized bytes followed by
   *                   *sei_size SEI message
   * @param sei_size   Pointer to a variable to store generated SEI message length
   * @return           Zero on success, negative error code on failure
   */
  int ff_alloc_a53_sei(const AVFrame *frame, size_t prefix_len,
                       void **data, size_t *sei_size);
  
  /**
   * Check AVFrame for S12M timecode side data and allocate and fill TC SEI message with timecode info
   *
   * @param frame      Raw frame to get S12M timecode side data from
   * @param prefix_len Number of bytes to allocate before SEI message
   * @param data       Pointer to a variable to store allocated memory
   *                   Upon return the variable will hold NULL on error or if frame has no S12M timecode info.
   *                   Otherwise it will point to prefix_len uninitialized bytes followed by
   *                   *sei_size SEI message
   * @param sei_size   Pointer to a variable to store generated SEI message length
   * @return           Zero on success, negative error code on failure
   */
  int ff_alloc_timecode_sei(const AVFrame *frame, size_t prefix_len,
                       void **data, size_t *sei_size);
  
  /**
   * Get an estimated video bitrate based on frame size, frame rate and coded
   * bits per pixel.
   */
  int64_t ff_guess_coded_bitrate(AVCodecContext *avctx);
  
  /**
   * Check if a value is in the list. If not, return the default value
   *
   * @param ctx                Context for the log msg
   * @param val_name           Name of the checked value, for log msg
   * @param array_valid_values Array of valid int, ended with INT_MAX
   * @param default_value      Value return if checked value is not in the array
   * @return                   Value or default_value.
   */
  int ff_int_from_list_or_default(void *ctx, const char * val_name, int val,
                                  const int * array_valid_values, int default_value);
  
  void ff_dvdsub_parse_palette(uint32_t *palette, const char *p);
  
  #if defined(_WIN32) && CONFIG_SHARED && !defined(BUILDING_avcodec)
  #    define av_export_avcodec __declspec(dllimport)
  #else
  #    define av_export_avcodec
  #endif
  
  #endif /* AVCODEC_INTERNAL_H */
  