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FFmpeg/libavformat/avio.h
Michael Niedermayer 47572323f2 lavf: add internal AVIOContext.maxsize 
This allows simple and generic limiting of allocations used for packets.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2011-12-16 05:59:43 +01:00

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/*
* 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_AVIO_H
#define AVFORMAT_AVIO_H
/**
* @file
* @ingroup lavf_io
* Buffered I/O operations
*/
#include <stdint.h>
#include "libavutil/common.h"
#include "libavutil/dict.h"
#include "libavutil/log.h"
#include "libavformat/version.h"
#define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
/**
* Callback for checking whether to abort blocking functions.
* AVERROR_EXIT is returned in this case by the interrupted
* function. During blocking operations, callback is called with
* opaque as parameter. If the callback returns 1, the
* blocking operation will be aborted.
*
* No members can be added to this struct without a major bump, if
* new elements have been added after this struct in AVFormatContext
* or AVIOContext.
*/
typedef struct {
int (*callback)(void*);
void *opaque;
} AVIOInterruptCB;
/**
* Bytestream IO Context.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(AVIOContext) must not be used outside libav*.
*
* @note None of the function pointers in AVIOContext should be called
* directly, they should only be set by the client application
* when implementing custom I/O. Normally these are set to the
* function pointers specified in avio_alloc_context()
*/
typedef struct {
#if !FF_API_OLD_AVIO
/**
* A class for private options.
*
* If this AVIOContext is created by avio_open2(), av_class is set and
* passes the options down to protocols.
*
* If this AVIOContext is manually allocated, then av_class may be set by
* the caller.
*
* warning -- this field can be NULL, be sure to not pass this AVIOContext
* to any av_opt_* functions in that case.
*/
AVClass *av_class;
#endif
unsigned char *buffer; /**< Start of the buffer. */
int buffer_size; /**< Maximum buffer size */
unsigned char *buf_ptr; /**< Current position in the buffer */
unsigned char *buf_end; /**< End of the data, may be less than
buffer+buffer_size if the read function returned
less data than requested, e.g. for streams where
no more data has been received yet. */
void *opaque; /**< A private pointer, passed to the read/write/seek/...
functions. */
int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
int64_t (*seek)(void *opaque, int64_t offset, int whence);
int64_t pos; /**< position in the file of the current buffer */
int must_flush; /**< true if the next seek should flush */
int eof_reached; /**< true if eof reached */
int write_flag; /**< true if open for writing */
#if FF_API_OLD_AVIO
attribute_deprecated int is_streamed;
#endif
int max_packet_size;
unsigned long checksum;
unsigned char *checksum_ptr;
unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
int error; /**< contains the error code or 0 if no error happened */
/**
* Pause or resume playback for network streaming protocols - e.g. MMS.
*/
int (*read_pause)(void *opaque, int pause);
/**
* Seek to a given timestamp in stream with the specified stream_index.
* Needed for some network streaming protocols which don't support seeking
* to byte position.
*/
int64_t (*read_seek)(void *opaque, int stream_index,
int64_t timestamp, int flags);
/**
* A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
*/
int seekable;
/**
* max filesize, used to limit allocations
* This field is internal to libavformat and access from outside is not allowed.
*/
int64_t maxsize;
} AVIOContext;
/* unbuffered I/O */
#if FF_API_OLD_AVIO
/**
* URL Context.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(URLContext) must not be used outside libav*.
* @deprecated This struct will be made private
*/
typedef struct URLContext {
const AVClass *av_class; ///< information for av_log(). Set by url_open().
struct URLProtocol *prot;
int flags;
int is_streamed; /**< true if streamed (no seek possible), default = false */
int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
void *priv_data;
char *filename; /**< specified URL */
int is_connected;
AVIOInterruptCB interrupt_callback;
} URLContext;
#define URL_PROTOCOL_FLAG_NESTED_SCHEME 1 /*< The protocol name can be the first part of a nested protocol scheme */
/**
* @deprecated This struct is to be made private. Use the higher-level
* AVIOContext-based API instead.
*/
typedef struct URLProtocol {
const char *name;
int (*url_open)(URLContext *h, const char *url, int flags);
int (*url_read)(URLContext *h, unsigned char *buf, int size);
int (*url_write)(URLContext *h, const unsigned char *buf, int size);
int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
int (*url_close)(URLContext *h);
struct URLProtocol *next;
int (*url_read_pause)(URLContext *h, int pause);
int64_t (*url_read_seek)(URLContext *h, int stream_index,
int64_t timestamp, int flags);
int (*url_get_file_handle)(URLContext *h);
int priv_data_size;
const AVClass *priv_data_class;
int flags;
int (*url_check)(URLContext *h, int mask);
} URLProtocol;
typedef struct URLPollEntry {
URLContext *handle;
int events;
int revents;
} URLPollEntry;
/* not implemented */
attribute_deprecated int url_poll(URLPollEntry *poll_table, int n, int timeout);
/**
* @name URL open modes
* The flags argument to url_open and cosins must be one of the following
* constants, optionally ORed with other flags.
* @{
*/
#define URL_RDONLY 1 /**< read-only */
#define URL_WRONLY 2 /**< write-only */
#define URL_RDWR (URL_RDONLY|URL_WRONLY) /**< read-write */
/**
* @}
*/
/**
* Use non-blocking mode.
* If this flag is set, operations on the context will return
* AVERROR(EAGAIN) if they can not be performed immediately.
* If this flag is not set, operations on the context will never return
* AVERROR(EAGAIN).
* Note that this flag does not affect the opening/connecting of the
* context. Connecting a protocol will always block if necessary (e.g. on
* network protocols) but never hang (e.g. on busy devices).
* Warning: non-blocking protocols is work-in-progress; this flag may be
* silently ignored.
*/
#define URL_FLAG_NONBLOCK 4
typedef int URLInterruptCB(void);
extern URLInterruptCB *url_interrupt_cb;
/**
* @defgroup old_url_funcs Old url_* functions
* The following functions are deprecated. Use the buffered API based on #AVIOContext instead.
* @{
* @ingroup lavf_io
*/
attribute_deprecated int url_open_protocol (URLContext **puc, struct URLProtocol *up,
const char *url, int flags);
attribute_deprecated int url_alloc(URLContext **h, const char *url, int flags);
attribute_deprecated int url_connect(URLContext *h);
attribute_deprecated int url_open(URLContext **h, const char *url, int flags);
attribute_deprecated int url_read(URLContext *h, unsigned char *buf, int size);
attribute_deprecated int url_read_complete(URLContext *h, unsigned char *buf, int size);
attribute_deprecated int url_write(URLContext *h, const unsigned char *buf, int size);
attribute_deprecated int64_t url_seek(URLContext *h, int64_t pos, int whence);
attribute_deprecated int url_close(URLContext *h);
attribute_deprecated int64_t url_filesize(URLContext *h);
attribute_deprecated int url_get_file_handle(URLContext *h);
attribute_deprecated int url_get_max_packet_size(URLContext *h);
attribute_deprecated void url_get_filename(URLContext *h, char *buf, int buf_size);
attribute_deprecated int av_url_read_pause(URLContext *h, int pause);
attribute_deprecated int64_t av_url_read_seek(URLContext *h, int stream_index,
int64_t timestamp, int flags);
attribute_deprecated void url_set_interrupt_cb(int (*interrupt_cb)(void));
/**
* returns the next registered protocol after the given protocol (the first if
* NULL is given), or NULL if protocol is the last one.
*/
URLProtocol *av_protocol_next(URLProtocol *p);
/**
* Register the URLProtocol protocol.
*
* @param size the size of the URLProtocol struct referenced
*/
attribute_deprecated int av_register_protocol2(URLProtocol *protocol, int size);
/**
* @}
*/
typedef attribute_deprecated AVIOContext ByteIOContext;
attribute_deprecated int init_put_byte(AVIOContext *s,
unsigned char *buffer,
int buffer_size,
int write_flag,
void *opaque,
int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
int64_t (*seek)(void *opaque, int64_t offset, int whence));
attribute_deprecated AVIOContext *av_alloc_put_byte(
unsigned char *buffer,
int buffer_size,
int write_flag,
void *opaque,
int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
int64_t (*seek)(void *opaque, int64_t offset, int whence));
/**
* @defgroup old_avio_funcs Old put_/get_*() functions
* The following functions are deprecated. Use the "avio_"-prefixed functions instead.
* @{
* @ingroup lavf_io
*/
attribute_deprecated int get_buffer(AVIOContext *s, unsigned char *buf, int size);
attribute_deprecated int get_partial_buffer(AVIOContext *s, unsigned char *buf, int size);
attribute_deprecated int get_byte(AVIOContext *s);
attribute_deprecated unsigned int get_le16(AVIOContext *s);
attribute_deprecated unsigned int get_le24(AVIOContext *s);
attribute_deprecated unsigned int get_le32(AVIOContext *s);
attribute_deprecated uint64_t get_le64(AVIOContext *s);
attribute_deprecated unsigned int get_be16(AVIOContext *s);
attribute_deprecated unsigned int get_be24(AVIOContext *s);
attribute_deprecated unsigned int get_be32(AVIOContext *s);
attribute_deprecated uint64_t get_be64(AVIOContext *s);
attribute_deprecated void put_byte(AVIOContext *s, int b);
attribute_deprecated void put_nbyte(AVIOContext *s, int b, int count);
attribute_deprecated void put_buffer(AVIOContext *s, const unsigned char *buf, int size);
attribute_deprecated void put_le64(AVIOContext *s, uint64_t val);
attribute_deprecated void put_be64(AVIOContext *s, uint64_t val);
attribute_deprecated void put_le32(AVIOContext *s, unsigned int val);
attribute_deprecated void put_be32(AVIOContext *s, unsigned int val);
attribute_deprecated void put_le24(AVIOContext *s, unsigned int val);
attribute_deprecated void put_be24(AVIOContext *s, unsigned int val);
attribute_deprecated void put_le16(AVIOContext *s, unsigned int val);
attribute_deprecated void put_be16(AVIOContext *s, unsigned int val);
attribute_deprecated void put_tag(AVIOContext *s, const char *tag);
/**
* @}
*/
attribute_deprecated int av_url_read_fpause(AVIOContext *h, int pause);
attribute_deprecated int64_t av_url_read_fseek (AVIOContext *h, int stream_index,
int64_t timestamp, int flags);
/**
* @defgroup old_url_f_funcs Old url_f* functions
* The following functions are deprecated, use the "avio_"-prefixed functions instead.
* @{
* @ingroup lavf_io
*/
attribute_deprecated int url_fopen( AVIOContext **s, const char *url, int flags);
attribute_deprecated int url_fclose(AVIOContext *s);
attribute_deprecated int64_t url_fseek(AVIOContext *s, int64_t offset, int whence);
attribute_deprecated int url_fskip(AVIOContext *s, int64_t offset);
attribute_deprecated int64_t url_ftell(AVIOContext *s);
attribute_deprecated int64_t url_fsize(AVIOContext *s);
#define URL_EOF (-1)
attribute_deprecated int url_fgetc(AVIOContext *s);
attribute_deprecated int url_setbufsize(AVIOContext *s, int buf_size);
attribute_deprecated int url_fprintf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
attribute_deprecated void put_flush_packet(AVIOContext *s);
attribute_deprecated int url_open_dyn_buf(AVIOContext **s);
attribute_deprecated int url_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
attribute_deprecated int url_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
attribute_deprecated int url_fdopen(AVIOContext **s, URLContext *h);
/**
* @}
*/
attribute_deprecated int url_ferror(AVIOContext *s);
attribute_deprecated int udp_set_remote_url(URLContext *h, const char *uri);
attribute_deprecated int udp_get_local_port(URLContext *h);
attribute_deprecated void init_checksum(AVIOContext *s,
unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
unsigned long checksum);
attribute_deprecated unsigned long get_checksum(AVIOContext *s);
attribute_deprecated void put_strz(AVIOContext *s, const char *buf);
/** @note unlike fgets, the EOL character is not returned and a whole
line is parsed. return NULL if first char read was EOF */
attribute_deprecated char *url_fgets(AVIOContext *s, char *buf, int buf_size);
/**
* @deprecated use avio_get_str instead
*/
attribute_deprecated char *get_strz(AVIOContext *s, char *buf, int maxlen);
/**
* @deprecated Use AVIOContext.seekable field directly.
*/
attribute_deprecated static inline int url_is_streamed(AVIOContext *s)
{
return !s->seekable;
}
attribute_deprecated URLContext *url_fileno(AVIOContext *s);
/**
* @deprecated use AVIOContext.max_packet_size directly.
*/
attribute_deprecated int url_fget_max_packet_size(AVIOContext *s);
attribute_deprecated int url_open_buf(AVIOContext **s, uint8_t *buf, int buf_size, int flags);
/** return the written or read size */
attribute_deprecated int url_close_buf(AVIOContext *s);
/**
* Return a non-zero value if the resource indicated by url
* exists, 0 otherwise.
* @deprecated Use avio_check instead.
*/
attribute_deprecated int url_exist(const char *url);
#endif // FF_API_OLD_AVIO
/**
* Return AVIO_FLAG_* access flags corresponding to the access permissions
* of the resource in url, or a negative value corresponding to an
* AVERROR code in case of failure. The returned access flags are
* masked by the value in flags.
*
* @note This function is intrinsically unsafe, in the sense that the
* checked resource may change its existence or permission status from
* one call to another. Thus you should not trust the returned value,
* unless you are sure that no other processes are accessing the
* checked resource.
*/
int avio_check(const char *url, int flags);
#if FF_API_OLD_INTERRUPT_CB
/**
* The callback is called in blocking functions to test regulary if
* asynchronous interruption is needed. AVERROR_EXIT is returned
* in this case by the interrupted function. 'NULL' means no interrupt
* callback is given.
* @deprecated Use interrupt_callback in AVFormatContext/avio_open2
* instead.
*/
attribute_deprecated void avio_set_interrupt_cb(int (*interrupt_cb)(void));
#endif
/**
* Allocate and initialize an AVIOContext for buffered I/O. It must be later
* freed with av_free().
*
* @param buffer Memory block for input/output operations via AVIOContext.
* The buffer must be allocated with av_malloc() and friends.
* @param buffer_size The buffer size is very important for performance.
* For protocols with fixed blocksize it should be set to this blocksize.
* For others a typical size is a cache page, e.g. 4kb.
* @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
* @param opaque An opaque pointer to user-specific data.
* @param read_packet A function for refilling the buffer, may be NULL.
* @param write_packet A function for writing the buffer contents, may be NULL.
* @param seek A function for seeking to specified byte position, may be NULL.
*
* @return Allocated AVIOContext or NULL on failure.
*/
AVIOContext *avio_alloc_context(
unsigned char *buffer,
int buffer_size,
int write_flag,
void *opaque,
int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
int64_t (*seek)(void *opaque, int64_t offset, int whence));
void avio_w8(AVIOContext *s, int b);
void avio_write(AVIOContext *s, const unsigned char *buf, int size);
void avio_wl64(AVIOContext *s, uint64_t val);
void avio_wb64(AVIOContext *s, uint64_t val);
void avio_wl32(AVIOContext *s, unsigned int val);
void avio_wb32(AVIOContext *s, unsigned int val);
void avio_wl24(AVIOContext *s, unsigned int val);
void avio_wb24(AVIOContext *s, unsigned int val);
void avio_wl16(AVIOContext *s, unsigned int val);
void avio_wb16(AVIOContext *s, unsigned int val);
/**
* Write a NULL-terminated string.
* @return number of bytes written.
*/
int avio_put_str(AVIOContext *s, const char *str);
/**
* Convert an UTF-8 string to UTF-16LE and write it.
* @return number of bytes written.
*/
int avio_put_str16le(AVIOContext *s, const char *str);
/**
* Passing this as the "whence" parameter to a seek function causes it to
* return the filesize without seeking anywhere. Supporting this is optional.
* If it is not supported then the seek function will return <0.
*/
#define AVSEEK_SIZE 0x10000
/**
* Oring this flag as into the "whence" parameter to a seek function causes it to
* seek by any means (like reopening and linear reading) or other normally unreasonble
* means that can be extreemly slow.
* This may be ignored by the seek code.
*/
#define AVSEEK_FORCE 0x20000
/**
* fseek() equivalent for AVIOContext.
* @return new position or AVERROR.
*/
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
/**
* Skip given number of bytes forward
* @return new position or AVERROR.
*/
int64_t avio_skip(AVIOContext *s, int64_t offset);
/**
* ftell() equivalent for AVIOContext.
* @return position or AVERROR.
*/
static av_always_inline int64_t avio_tell(AVIOContext *s)
{
return avio_seek(s, 0, SEEK_CUR);
}
/**
* Get the filesize.
* @return filesize or AVERROR
*/
int64_t avio_size(AVIOContext *s);
/**
* feof() equivalent for AVIOContext.
* @return non zero if and only if end of file
*/
int url_feof(AVIOContext *s);
/** @warning currently size is limited */
int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
void avio_flush(AVIOContext *s);
/**
* Read size bytes from AVIOContext into buf.
* @return number of bytes read or AVERROR
*/
int avio_read(AVIOContext *s, unsigned char *buf, int size);
/**
* @name Functions for reading from AVIOContext
* @{
*
* @note return 0 if EOF, so you cannot use it if EOF handling is
* necessary
*/
int avio_r8 (AVIOContext *s);
unsigned int avio_rl16(AVIOContext *s);
unsigned int avio_rl24(AVIOContext *s);
unsigned int avio_rl32(AVIOContext *s);
uint64_t avio_rl64(AVIOContext *s);
unsigned int avio_rb16(AVIOContext *s);
unsigned int avio_rb24(AVIOContext *s);
unsigned int avio_rb32(AVIOContext *s);
uint64_t avio_rb64(AVIOContext *s);
/**
* @}
*/
/**
* Read a string from pb into buf. The reading will terminate when either
* a NULL character was encountered, maxlen bytes have been read, or nothing
* more can be read from pb. The result is guaranteed to be NULL-terminated, it
* will be truncated if buf is too small.
* Note that the string is not interpreted or validated in any way, it
* might get truncated in the middle of a sequence for multi-byte encodings.
*
* @return number of bytes read (is always <= maxlen).
* If reading ends on EOF or error, the return value will be one more than
* bytes actually read.
*/
int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
/**
* Read a UTF-16 string from pb and convert it to UTF-8.
* The reading will terminate when either a null or invalid character was
* encountered or maxlen bytes have been read.
* @return number of bytes read (is always <= maxlen)
*/
int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
/**
* @name URL open modes
* The flags argument to avio_open must be one of the following
* constants, optionally ORed with other flags.
* @{
*/
#define AVIO_FLAG_READ 1 /**< read-only */
#define AVIO_FLAG_WRITE 2 /**< write-only */
#define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
/**
* @}
*/
/**
* Use non-blocking mode.
* If this flag is set, operations on the context will return
* AVERROR(EAGAIN) if they can not be performed immediately.
* If this flag is not set, operations on the context will never return
* AVERROR(EAGAIN).
* Note that this flag does not affect the opening/connecting of the
* context. Connecting a protocol will always block if necessary (e.g. on
* network protocols) but never hang (e.g. on busy devices).
* Warning: non-blocking protocols is work-in-progress; this flag may be
* silently ignored.
*/
#define AVIO_FLAG_NONBLOCK 8
/**
* Create and initialize a AVIOContext for accessing the
* resource indicated by url.
* @note When the resource indicated by url has been opened in
* read+write mode, the AVIOContext can be used only for writing.
*
* @param s Used to return the pointer to the created AVIOContext.
* In case of failure the pointed to value is set to NULL.
* @param flags flags which control how the resource indicated by url
* is to be opened
* @return 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int avio_open(AVIOContext **s, const char *url, int flags);
/**
* Create and initialize a AVIOContext for accessing the
* resource indicated by url.
* @note When the resource indicated by url has been opened in
* read+write mode, the AVIOContext can be used only for writing.
*
* @param s Used to return the pointer to the created AVIOContext.
* In case of failure the pointed to value is set to NULL.
* @param flags flags which control how the resource indicated by url
* is to be opened
* @param int_cb an interrupt callback to be used at the protocols level
* @param options A dictionary filled with protocol-private options. On return
* this parameter will be destroyed and replaced with a dict containing options
* that were not found. May be NULL.
* @return 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int avio_open2(AVIOContext **s, const char *url, int flags,
const AVIOInterruptCB *int_cb, AVDictionary **options);
/**
* Close the resource accessed by the AVIOContext s and free it.
* This function can only be used if s was opened by avio_open().
*
* @return 0 on success, an AVERROR < 0 on error.
*/
int avio_close(AVIOContext *s);
/**
* Open a write only memory stream.
*
* @param s new IO context
* @return zero if no error.
*/
int avio_open_dyn_buf(AVIOContext **s);
/**
* Return the written size and a pointer to the buffer. The buffer
* must be freed with av_free().
* Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
*
* @param s IO context
* @param pbuffer pointer to a byte buffer
* @return the length of the byte buffer
*/
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
/**
* Iterate through names of available protocols.
* @note it is recommanded to use av_protocol_next() instead of this
*
* @param opaque A private pointer representing current protocol.
* It must be a pointer to NULL on first iteration and will
* be updated by successive calls to avio_enum_protocols.
* @param output If set to 1, iterate over output protocols,
* otherwise over input protocols.
*
* @return A static string containing the name of current protocol or NULL
*/
const char *avio_enum_protocols(void **opaque, int output);
/**
* Pause and resume playing - only meaningful if using a network streaming
* protocol (e.g. MMS).
* @param pause 1 for pause, 0 for resume
*/
int avio_pause(AVIOContext *h, int pause);
/**
* Seek to a given timestamp relative to some component stream.
* Only meaningful if using a network streaming protocol (e.g. MMS.).
* @param stream_index The stream index that the timestamp is relative to.
* If stream_index is (-1) the timestamp should be in AV_TIME_BASE
* units from the beginning of the presentation.
* If a stream_index >= 0 is used and the protocol does not support
* seeking based on component streams, the call will fail with ENOTSUP.
* @param timestamp timestamp in AVStream.time_base units
* or if there is no stream specified then in AV_TIME_BASE units.
* @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
* and AVSEEK_FLAG_ANY. The protocol may silently ignore
* AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
* fail with ENOTSUP if used and not supported.
* @return >= 0 on success
* @see AVInputFormat::read_seek
*/
int64_t avio_seek_time(AVIOContext *h, int stream_index,
int64_t timestamp, int flags);
#endif /* AVFORMAT_AVIO_H */
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