avformat.h

包裝ffmpeg中的codecs成為DirectShow中的transform filter

 * then it contains one frame.
 *
 * pkt->pts, pkt->dts and pkt->duration are always set to correct
 * values in AVStream.timebase units (and guessed if the format cannot
 * provided them). pkt->pts can be AV_NOPTS_VALUE if the video format
 * has B frames, so it is better to rely on pkt->dts if you do not
 * decompress the payload.
 *
 * @return 0 if OK, < 0 if error or end of file.
 */
int av_read_frame(AVFormatContext *s, AVPacket *pkt);

/**
 * Seek to the key frame at timestamp.
 * 'timestamp' in 'stream_index'.
 * @param stream_index If stream_index is (-1), a default
 * stream is selected, and timestamp is automatically converted
 * from AV_TIME_BASE units to the stream specific time_base.
 * @param timestamp timestamp in AVStream.time_base units
 *        or if there is no stream specified then in AV_TIME_BASE units
 * @param flags flags which select direction and seeking mode
 * @return >= 0 on success
 */
int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags);

/**
 * start playing a network based stream (e.g. RTSP stream) at the
 * current position
 */
int av_read_play(AVFormatContext *s);

/**
 * Pause a network based stream (e.g. RTSP stream).
 *
 * Use av_read_play() to resume it.
 */
int av_read_pause(AVFormatContext *s);

/**
 * Free a AVFormatContext allocated by av_open_input_stream.
 * @param s context to free
 */
void av_close_input_stream(AVFormatContext *s);

/**
 * Close a media file (but not its codecs).
 *
 * @param s media file handle
 */
void av_close_input_file(AVFormatContext *s);

/**
 * Add a new stream to a media file.
 *
 * Can only be called in the read_header() function. If the flag
 * AVFMTCTX_NOHEADER is in the format context, then new streams
 * can be added in read_packet too.
 *
 * @param s media file handle
 * @param id file format dependent stream id
 */
AVStream *av_new_stream(AVFormatContext *s, int id);
AVProgram *av_new_program(AVFormatContext *s, int id);

/**
 * Set the pts for a given stream.
 *
 * @param s stream
 * @param pts_wrap_bits number of bits effectively used by the pts
 *        (used for wrap control, 33 is the value for MPEG)
 * @param pts_num numerator to convert to seconds (MPEG: 1)
 * @param pts_den denominator to convert to seconds (MPEG: 90000)
 */
void av_set_pts_info(AVStream *s, int pts_wrap_bits,
                     int pts_num, int pts_den);

#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
#define AVSEEK_FLAG_BYTE     2 ///< seeking based on position in bytes
#define AVSEEK_FLAG_ANY      4 ///< seek to any frame, even non keyframes

int av_find_default_stream_index(AVFormatContext *s);

/**
 * Gets the index for a specific timestamp.
 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond to
 *                 the timestamp which is <= the requested one, if backward is 0
 *                 then it will be >=
 *              if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
 * @return < 0 if no such timestamp could be found
 */
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);

/**
 * Ensures the index uses less memory than the maximum specified in
 * AVFormatContext.max_index_size, by discarding entries if it grows
 * too large.
 * This function is not part of the public API and should only be called
 * by demuxers.
 */
void ff_reduce_index(AVFormatContext *s, int stream_index);

/**
 * Add a index entry into a sorted list updateing if it is already there.
 *
 * @param timestamp timestamp in the timebase of the given stream
 */
int av_add_index_entry(AVStream *st,
                       int64_t pos, int64_t timestamp, int size, int distance, int flags);

/**
 * Does a binary search using av_index_search_timestamp() and AVCodec.read_timestamp().
 * This is not supposed to be called directly by a user application, but by demuxers.
 * @param target_ts target timestamp in the time base of the given stream
 * @param stream_index stream number
 */
int av_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags);

/**
 * Updates cur_dts of all streams based on given timestamp and AVStream.
 *
 * Stream ref_st unchanged, others set cur_dts in their native timebase
 * 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 av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp);

/**
 * Does a binary search using read_timestamp().
 * This is not supposed to be called directly by a user application, but by demuxers.
 * @param target_ts target timestamp in the time base of the given stream
 * @param stream_index stream number
 */
int64_t av_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 ));

/** media file output */
int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap);

/**
 * Allocate the stream private data and write the stream header to an
 * output media file.
 *
 * @param s media file handle
 * @return 0 if OK. AVERROR_xxx if error.
 */
int av_write_header(AVFormatContext *s);

/**
 * Write a packet to an output media file.
 *
 * The packet shall contain one audio or video frame.
 * The packet must be correctly interleaved according to the container specification,
 * if not then av_interleaved_write_frame must be used
 *
 * @param s media file handle
 * @param pkt the packet, which contains the stream_index, buf/buf_size, dts/pts, ...
 * @return < 0 if error, = 0 if OK, 1 if end of stream wanted.
 */
int av_write_frame(AVFormatContext *s, AVPacket *pkt);

/**
 * Writes a packet to an output media file ensuring correct interleaving.
 *
 * The packet must contain one audio or video frame.
 * If the packets are already correctly interleaved the application should
 * call av_write_frame() instead as it is slightly faster. It is also important
 * to keep in mind that completely non-interleaved input will need huge amounts
 * of memory to interleave with this, so it is preferable to interleave at the
 * demuxer level.
 *
 * @param s media file handle
 * @param pkt the packet, which contains the stream_index, buf/buf_size, dts/pts, ...
 * @return < 0 if error, = 0 if OK, 1 if end of stream wanted.
 */
int av_interleaved_write_frame(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 calling av_free_packet() on them is still safe.
 *
 * @param s media file handle
 * @param out the interleaved packet will be output here
 * @param in 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 av_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush);

/**
 * @brief Write the stream trailer to an output media file and
 *        free the file private data.
 *
 * @param s media file handle
 * @return 0 if OK. AVERROR_xxx if error.
 */
int av_write_trailer(AVFormatContext *s);

void dump_format(AVFormatContext *ic,
                 int index,
                 const char *url,
                 int is_output);

/**
 * parses width and height out of string str.
 * @deprecated Use av_parse_video_frame_size instead.
 */
attribute_deprecated int parse_image_size(int *width_ptr, int *height_ptr, const char *str);

/**
 * Converts frame rate from string to a fraction.
 * @deprecated Use av_parse_video_frame_rate instead.
 */
attribute_deprecated int parse_frame_rate(int *frame_rate, int *frame_rate_base, const char *arg);

/**
 * Parses \p datestr and returns a corresponding number of microseconds.
 * @param datestr String representing a date or a duration.
 * - If a date the syntax is:
 * @code
 *  [{YYYY-MM-DD|YYYYMMDD}]{T| }{HH[:MM[:SS[.m...]]][Z]|HH[MM[SS[.m...]]][Z]}
 * @endcode
 * Time is localtime unless Z is appended, in which case it is
 * interpreted as UTC.
 * If the year-month-day part isn't specified it takes the current
 * year-month-day.
 * Returns the number of microseconds since 1st of January, 1970 up to
 * the time of the parsed date or INT64_MIN if \p datestr cannot be
 * successfully parsed.
 * - If a duration the syntax is:
 * @code
 *  [-]HH[:MM[:SS[.m...]]]
 *  [-]S+[.m...]
 * @endcode
 * Returns the number of microseconds contained in a time interval
 * with the specified duration or INT64_MIN if \p datestr cannot be
 * successfully parsed.
 * @param duration Flag which tells how to interpret \p datestr, if
 * not zero \p datestr is interpreted as a duration, otherwise as a
 * date.
 */
int64_t parse_date(const char *datestr, int duration);

int64_t av_gettime(void);

/* ffm specific for ffserver */
#define FFM_PACKET_SIZE 4096
offset_t ffm_read_write_index(int fd);
void ffm_write_write_index(int fd, offset_t pos);
void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size);

/**
 * Attempts to find a specific tag in a URL.
 *
 * syntax: '?tag1=val1&tag2=val2...'. Little URL decoding is done.
 * Return 1 if found.
 */
int find_info_tag(char *arg, int arg_size, const char *tag1, const char *info);

/**
 * Returns in 'buf' the path with '%d' replaced by number.

 * Also handles the '%0nd' format where 'n' is the total number
 * of digits and '%%'.
 *
 * @param buf destination buffer
 * @param buf_size destination buffer size
 * @param path numbered sequence string
 * @param number frame number
 * @return 0 if OK, -1 if format error.
 */
int av_get_frame_filename(char *buf, int buf_size,
                          const char *path, int number);

/**
 * Check whether filename actually is a numbered sequence generator.
 *
 * @param filename possible numbered sequence string
 * @return 1 if a valid numbered sequence string, 0 otherwise.
 */
int av_filename_number_test(const char *filename);

/**
 * Generate an SDP for an RTP session.
 *
 * @param ac array of AVFormatContexts describing the RTP streams. If the
 *           array is composed by only one context, such context can contain
 *           multiple AVStreams (one AVStream per RTP stream). Otherwise,
 *           all the contexts in the array (an AVCodecContext per RTP stream)
 *           must contain only one AVStream
 * @param n_files number of AVCodecContexts contained in ac
 * @param buff buffer where the SDP will be stored (must be allocated by
 *             the caller
 * @param size the size of the buffer
 * @return 0 if OK. AVERROR_xxx if error.
 */
int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size);

#ifdef HAVE_AV_CONFIG_H

void __dynarray_add(unsigned long **tab_ptr, int *nb_ptr, unsigned long elem);

#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 */\
    __dynarray_add((unsigned long **)_tab, nb_ptr, (unsigned long)_elem);\
} while(0)
#else
#define dynarray_add(tab, nb_ptr, elem)\
do {\
    __dynarray_add((unsigned long **)(tab), nb_ptr, (unsigned long)(elem));\
} while(0)
#endif

time_t mktimegm(struct tm *tm);
struct tm *brktimegm(time_t secs, struct tm *tm);
const char *small_strptime(const char *p, const char *fmt,
                           struct tm *dt);

struct in_addr;
int resolve_host(struct in_addr *sin_addr, const char *hostname);

void url_split(char *proto, int proto_size,
               char *authorization, int authorization_size,
               char *hostname, int hostname_size,
               int *port_ptr,
               char *path, int path_size,
               const char *url);

int match_ext(const char *filename, const char *extensions);

#endif /* HAVE_AV_CONFIG_H */

#endif /* FFMPEG_AVFORMAT_H */