text: /*
   * copyright (c) 2001 Fabrice Bellard
   *
   * 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 AVFORMAT_INTERNAL_H
  #define AVFORMAT_INTERNAL_H
  
  #include <stdint.h>
  #include "avformat.h"
  
  #define MAX_URL_SIZE 4096
  
  /** size of probe buffer, for guessing file type from file contents */
  #define PROBE_BUF_MIN 2048
  #define PROBE_BUF_MAX (1 << 20)
  
  #ifdef DEBUG
  #    define hex_dump_debug(class, buf, size) av_hex_dump_log(class, AV_LOG_DEBUG, buf, size)
  #else
  #    define hex_dump_debug(class, buf, size)
  #endif
  
  typedef struct AVCodecTag {
      enum AVCodecID id;
      unsigned int tag;
  } AVCodecTag;
  
  typedef struct CodecMime{
      char str[32];
      enum AVCodecID id;
  } CodecMime;
  
  struct AVFormatInternal {
      /**
       * Number of streams relevant for interleaving.
       * Muxing only.
       */
      int nb_interleaved_streams;
  
      int inject_global_side_data;
  };
  
  #ifdef __GNUC__
  #define dynarray_add(tab, nb_ptr, elem)\
  do {\
      __typeof__(tab) _tab = (tab);\
      __typeof__(elem) _elem = (elem);\
      (void)sizeof(**_tab == _elem); /* check that types are compatible */\
      av_dynarray_add(_tab, nb_ptr, _elem);\
  } while(0)
  #else
  #define dynarray_add(tab, nb_ptr, elem)\
  do {\
      av_dynarray_add((tab), nb_ptr, (elem));\
  } while(0)
  #endif
  
  struct tm *ff_brktimegm(time_t secs, struct tm *tm);
  
  char *ff_data_to_hex(char *buf, const uint8_t *src, int size, int lowercase);
  
  /**
   * Parse a string of hexadecimal strings. Any space between the hexadecimal
   * digits is ignored.
   *
   * @param data if non-null, the parsed data is written to this pointer
   * @param p the string to parse
   * @return the number of bytes written (or to be written, if data is null)
   */
  int ff_hex_to_data(uint8_t *data, const char *p);
  
  void ff_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx);
  
  /**
   * Add packet to AVFormatContext->packet_buffer list, determining its
   * interleaved position using compare() function argument.
   * @return 0, or < 0 on error
   */
  int ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,
                                int (*compare)(AVFormatContext *, AVPacket *, AVPacket *));
  
  void ff_read_frame_flush(AVFormatContext *s);
  
  #define NTP_OFFSET 2208988800ULL
  #define NTP_OFFSET_US (NTP_OFFSET * 1000000ULL)
  
  /** Get the current time since NTP epoch in microseconds. */
  uint64_t ff_ntp_time(void);
  
  /**
   * Append the media-specific SDP fragment for the media stream c
   * to the buffer buff.
   *
   * Note, the buffer needs to be initialized, since it is appended to
   * existing content.
   *
   * @param buff the buffer to append the SDP fragment to
   * @param size the size of the buff buffer
   * @param st the AVStream of the media to describe
   * @param idx the global stream index
   * @param dest_addr the destination address of the media stream, may be NULL
   * @param dest_type the destination address type, may be NULL
   * @param port the destination port of the media stream, 0 if unknown
   * @param ttl the time to live of the stream, 0 if not multicast
   * @param fmt the AVFormatContext, which might contain options modifying
   *            the generated SDP
   */
  void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
                          const char *dest_addr, const char *dest_type,
                          int port, int ttl, AVFormatContext *fmt);
  
  /**
   * Write a packet to another muxer than the one the user originally
   * intended. Useful when chaining muxers, where one muxer internally
   * writes a received packet to another muxer.
   *
   * @param dst the muxer to write the packet to
   * @param dst_stream the stream index within dst to write the packet to
   * @param pkt the packet to be written
   * @param src the muxer the packet originally was intended for
   * @return the value av_write_frame returned
   */
  int ff_write_chained(AVFormatContext *dst, int dst_stream, AVPacket *pkt,
                       AVFormatContext *src);
  
  /**
   * Get the length in bytes which is needed to store val as v.
   */
  int ff_get_v_length(uint64_t val);
  
  /**
   * Put val using a variable number of bytes.
   */
  void ff_put_v(AVIOContext *bc, uint64_t val);
  
  /**
   * Read a whole line of text from AVIOContext. Stop reading after reaching
   * either a \\n, a \\0 or EOF. The returned string is always \\0-terminated,
   * and may be truncated if the buffer is too small.
   *
   * @param s the read-only AVIOContext
   * @param buf buffer to store the read line
   * @param maxlen size of the buffer
   * @return the length of the string written in the buffer, not including the
   *         final \\0
   */
  int ff_get_line(AVIOContext *s, char *buf, int maxlen);
  
  #define SPACE_CHARS " \t\r\n"
  
  /**
   * Callback function type for ff_parse_key_value.
   *
   * @param key a pointer to the key
   * @param key_len the number of bytes that belong to the key, including the '='
   *                char
   * @param dest return the destination pointer for the value in *dest, may
   *             be null to ignore the value
   * @param dest_len the length of the *dest buffer
   */
  typedef void (*ff_parse_key_val_cb)(void *context, const char *key,
                                      int key_len, char **dest, int *dest_len);
  /**
   * Parse a string with comma-separated key=value pairs. The value strings
   * may be quoted and may contain escaped characters within quoted strings.
   *
   * @param str the string to parse
   * @param callback_get_buf function that returns where to store the
   *                         unescaped value string.
   * @param context the opaque context pointer to pass to callback_get_buf
   */
  void ff_parse_key_value(const char *str, ff_parse_key_val_cb callback_get_buf,
                          void *context);
  
  /**
   * Find stream index based on format-specific stream ID
   * @return stream index, or < 0 on error
   */
  int ff_find_stream_index(AVFormatContext *s, int id);
  
  /**
   * Internal version of av_index_search_timestamp
   */
  int ff_index_search_timestamp(const AVIndexEntry *entries, int nb_entries,
                                int64_t wanted_timestamp, int flags);
  
  /**
   * Internal version of av_add_index_entry
   */
  int ff_add_index_entry(AVIndexEntry **index_entries,
                         int *nb_index_entries,
                         unsigned int *index_entries_allocated_size,
                         int64_t pos, int64_t timestamp, int size, int distance, int flags);
  
  /**
   * Add a new chapter.
   *
   * @param s media file handle
   * @param id unique ID for this chapter
   * @param start chapter start time in time_base units
   * @param end chapter end time in time_base units
   * @param title chapter title
   *
   * @return AVChapter or NULL on error
   */
  AVChapter *avpriv_new_chapter(AVFormatContext *s, int id, AVRational time_base,
                                int64_t start, int64_t end, const char *title);
  
  /**
   * Ensure the index uses less memory than the maximum specified in
   * AVFormatContext.max_index_size by discarding entries if it grows
   * too large.
   */
  void ff_reduce_index(AVFormatContext *s, int stream_index);
  
  enum AVCodecID ff_guess_image2_codec(const char *filename);
  
  /**
   * Convert a date string in ISO8601 format to Unix timestamp.
   */
  int64_t ff_iso8601_to_unix_time(const char *datestr);
  
  /**
   * Perform a binary search using av_index_search_timestamp() and
   * AVInputFormat.read_timestamp().
   *
   * @param target_ts target timestamp in the time base of the given stream
   * @param stream_index stream number
   */
  int ff_seek_frame_binary(AVFormatContext *s, int stream_index,
                           int64_t target_ts, int flags);
  
  /**
   * Update cur_dts of all streams based on the given timestamp and AVStream.
   *
   * Stream ref_st unchanged, others set cur_dts in their native time base.
   * Only needed for timestamp wrapping or if (dts not set and pts!=dts).
   * @param timestamp new dts expressed in time_base of param ref_st
   * @param ref_st reference stream giving time_base of param timestamp
   */
  void ff_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp);
  
  int ff_find_last_ts(AVFormatContext *s, int stream_index, int64_t *ts, int64_t *pos,
                      int64_t (*read_timestamp)(struct AVFormatContext *, int , int64_t *, int64_t ));
  
  /**
   * Perform a binary search using read_timestamp().
   *
   * @param target_ts target timestamp in the time base of the given stream
   * @param stream_index stream number
   */
  int64_t ff_gen_search(AVFormatContext *s, int stream_index,
                        int64_t target_ts, int64_t pos_min,
                        int64_t pos_max, int64_t pos_limit,
                        int64_t ts_min, int64_t ts_max,
                        int flags, int64_t *ts_ret,
                        int64_t (*read_timestamp)(struct AVFormatContext *, int , int64_t *, int64_t ));
  
  /**
   * Set the time base and wrapping info for a given stream. This will be used
   * to interpret the stream's timestamps. If the new time base is invalid
   * (numerator or denominator are non-positive), it leaves the stream
   * unchanged.
   *
   * @param s stream
   * @param pts_wrap_bits number of bits effectively used by the pts
   *        (used for wrap control)
   * @param pts_num time base numerator
   * @param pts_den time base denominator
   */
  void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits,
                           unsigned int pts_num, unsigned int pts_den);
  
  /**
   * Add side data to a packet for changing parameters to the given values.
   * Parameters set to 0 aren't included in the change.
   */
  int ff_add_param_change(AVPacket *pkt, int32_t channels,
                          uint64_t channel_layout, int32_t sample_rate,
                          int32_t width, int32_t height);
  
  /**
   * Set the timebase for each stream from the corresponding codec timebase and
   * print it.
   */
  int ff_framehash_write_header(AVFormatContext *s);
  
  /**
   * Read a transport packet from a media file.
   *
   * @param s media file handle
   * @param pkt is filled
   * @return 0 if OK, AVERROR_xxx on error
   */
  int ff_read_packet(AVFormatContext *s, AVPacket *pkt);
  
  /**
   * Interleave a packet per dts in an output media file.
   *
   * Packets with pkt->destruct == av_destruct_packet will be freed inside this
   * function, so they cannot be used after it. Note that calling av_free_packet()
   * on them is still safe.
   *
   * @param s media file handle
   * @param out the interleaved packet will be output here
   * @param pkt the input packet
   * @param flush 1 if no further packets are available as input and all
   *              remaining packets should be output
   * @return 1 if a packet was output, 0 if no packet could be output,
   *         < 0 if an error occurred
   */
  int ff_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,
                                   AVPacket *pkt, int flush);
  
  void ff_free_stream(AVFormatContext *s, AVStream *st);
  
  /**
   * Return the frame duration in seconds. Return 0 if not available.
   */
  void ff_compute_frame_duration(int *pnum, int *pden, AVStream *st,
                                 AVCodecParserContext *pc, AVPacket *pkt);
  
  int ff_get_audio_frame_size(AVCodecContext *enc, int size, int mux);
  
  unsigned int ff_codec_get_tag(const AVCodecTag *tags, enum AVCodecID id);
  
  enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag);
  
  /**
   * Select a PCM codec based on the given parameters.
   *
   * @param bps     bits-per-sample
   * @param flt     floating-point
   * @param be      big-endian
   * @param sflags  signed flags. each bit corresponds to one byte of bit depth.
   *                e.g. the 1st bit indicates if 8-bit should be signed or
   *                unsigned, the 2nd bit indicates if 16-bit should be signed or
   *                unsigned, etc... This is useful for formats such as WAVE where
   *                only 8-bit is unsigned and all other bit depths are signed.
   * @return        a PCM codec id or AV_CODEC_ID_NONE
   */
  enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags);
  
  /**
   * Chooses a timebase for muxing the specified stream.
   *
   * The chosen timebase allows sample accurate timestamps based
   * on the framerate or sample rate for audio streams. It also is
   * at least as precise as 1/min_precision would be.
   */
  AVRational ff_choose_timebase(AVFormatContext *s, AVStream *st, int min_precision);
  
  /**
   * Generate standard extradata for AVC-Intra based on width/height and field
   * order.
   */
  int ff_generate_avci_extradata(AVStream *st);
  
  /**
   * Allocate extradata with additional FF_INPUT_BUFFER_PADDING_SIZE at end
   * which is always set to 0.
   *
   * @param size size of extradata
   * @return 0 if OK, AVERROR_xxx on error
   */
  int ff_alloc_extradata(AVCodecContext *avctx, int size);
  
  /**
   * Allocate extradata with additional FF_INPUT_BUFFER_PADDING_SIZE at end
   * which is always set to 0 and fill it from pb.
   *
   * @param size size of extradata
   * @return >= 0 if OK, AVERROR_xxx on error
   */
  int ff_get_extradata(AVCodecContext *avctx, AVIOContext *pb, int size);
  
  /**
   * add frame for rfps calculation.
   *
   * @param dts timestamp of the i-th frame
   * @return 0 if OK, AVERROR_xxx on error
   */
  int ff_rfps_add_frame(AVFormatContext *ic, AVStream *st, int64_t dts);
  
  void ff_rfps_calculate(AVFormatContext *ic);
  
  /**
   * Flags for AVFormatContext.write_uncoded_frame()
   */
  enum AVWriteUncodedFrameFlags {
  
      /**
       * Query whether the feature is possible on this stream.
       * The frame argument is ignored.
       */
      AV_WRITE_UNCODED_FRAME_QUERY           = 0x0001,
  
  };
  
  
  #endif /* AVFORMAT_INTERNAL_H */
  