Buffered I/O operations. More...

#include <stdint.h>
#include <stdio.h>
#include "libavutil/attributes.h"
#include "libavutil/dict.h"
#include "libavutil/log.h"
#include "libavformat/version_major.h"

Data Structures
struct	AVIOInterruptCB
	Callback for checking whether to abort blocking functions. More...

struct	AVIODirEntry
	Describes single entry of the directory. More...

struct	AVIODirContext

struct	AVIOContext
	Bytestream IO Context. More...

Macros
#define	AVIO_SEEKABLE_NORMAL (1 << 0)
	Seeking works like for a local file. More...

#define	AVIO_SEEKABLE_TIME (1 << 1)
	Seeking by timestamp with avio_seek_time() is possible. More...

#define	AVSEEK_SIZE 0x10000
	ORing this as the "whence" parameter to a seek function causes it to return the filesize without seeking anywhere. More...

#define	AVSEEK_FORCE 0x20000
	Passing this flag as the "whence" parameter to a seek function causes it to seek by any means (like reopening and linear reading) or other normally unreasonable means that can be extremely slow. More...

#define	avio_print(s, ...) avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
	Write strings (const char *) to the context. More...

#define	AVIO_FLAG_NONBLOCK 8
	Use non-blocking mode. More...

#define	AVIO_FLAG_DIRECT 0x8000
	Use direct mode. More...

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 More...

#define	AVIO_FLAG_WRITE 2
	write-only More...

#define	AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ\|AVIO_FLAG_WRITE)
	read-write pseudo flag More...

Enumerations
enum	AVIODirEntryType { AVIO_ENTRY_UNKNOWN , AVIO_ENTRY_BLOCK_DEVICE , AVIO_ENTRY_CHARACTER_DEVICE , AVIO_ENTRY_DIRECTORY , AVIO_ENTRY_NAMED_PIPE , AVIO_ENTRY_SYMBOLIC_LINK , AVIO_ENTRY_SOCKET , AVIO_ENTRY_FILE , AVIO_ENTRY_SERVER , AVIO_ENTRY_SHARE , AVIO_ENTRY_WORKGROUP }
	Directory entry types. More...

enum	AVIODataMarkerType { AVIO_DATA_MARKER_HEADER , AVIO_DATA_MARKER_SYNC_POINT , AVIO_DATA_MARKER_BOUNDARY_POINT , AVIO_DATA_MARKER_UNKNOWN , AVIO_DATA_MARKER_TRAILER , AVIO_DATA_MARKER_FLUSH_POINT }
	Different data types that can be returned via the AVIO write_data_type callback. More...

Functions
const char *	avio_find_protocol_name (const char *url)
	Return the name of the protocol that will handle the passed URL. More...

int	avio_check (const char *url, int flags)
	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. More...

int	avio_open_dir (AVIODirContext *s, const char url, AVDictionary **options)
	Open directory for reading. More...

int	avio_read_dir (AVIODirContext s, AVIODirEntry *next)
	Get next directory entry. More...

int	avio_close_dir (AVIODirContext **s)
	Close directory. More...

void	avio_free_directory_entry (AVIODirEntry **entry)
	Free entry allocated by avio_read_dir(). More...

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))
	Allocate and initialize an AVIOContext for buffered I/O. More...

void	avio_context_free (AVIOContext **s)
	Free the supplied IO context and everything associated with it. More...

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)

int	avio_put_str (AVIOContext s, const char str)
	Write a NULL-terminated string. More...

int	avio_put_str16le (AVIOContext s, const char str)
	Convert an UTF-8 string to UTF-16LE and write it. More...

int	avio_put_str16be (AVIOContext s, const char str)
	Convert an UTF-8 string to UTF-16BE and write it. More...

void	avio_write_marker (AVIOContext *s, int64_t time, enum AVIODataMarkerType type)
	Mark the written bytestream as a specific type. More...

int64_t	avio_seek (AVIOContext *s, int64_t offset, int whence)
	fseek() equivalent for AVIOContext. More...

int64_t	avio_skip (AVIOContext *s, int64_t offset)
	Skip given number of bytes forward. More...

static av_always_inline int64_t	avio_tell (AVIOContext *s)
	ftell() equivalent for AVIOContext. More...

int64_t	avio_size (AVIOContext *s)
	Get the filesize. More...

int	avio_feof (AVIOContext *s)
	Similar to feof() but also returns nonzero on read errors. More...

int	avio_vprintf (AVIOContext s, const char fmt, va_list ap)
	Writes a formatted string to the context taking a va_list. More...

int	avio_printf (AVIOContext s, const char fmt,...) av_printf_format(2
	Writes a formatted string to the context. More...

int void	avio_print_string_array (AVIOContext s, const char strings[])
	Write a NULL terminated array of strings to the context. More...

void	avio_flush (AVIOContext *s)
	Force flushing of buffered data. More...

int	avio_read (AVIOContext s, unsigned char buf, int size)
	Read size bytes from AVIOContext into buf. More...

int	avio_read_partial (AVIOContext s, unsigned char buf, int size)
	Read size bytes from AVIOContext into buf. More...

int	avio_get_str (AVIOContext pb, int maxlen, char buf, int buflen)
	Read a string from pb into buf. More...

int	avio_get_str16le (AVIOContext pb, int maxlen, char buf, int buflen)
	Read a UTF-16 string from pb and convert it to UTF-8. More...

int	avio_get_str16be (AVIOContext pb, int maxlen, char buf, int buflen)

int	avio_open (AVIOContext *s, const char url, int flags)
	Create and initialize a AVIOContext for accessing the resource indicated by url. More...

int	avio_open2 (AVIOContext *s, const char url, int flags, const AVIOInterruptCB int_cb, AVDictionary *options)
	Create and initialize a AVIOContext for accessing the resource indicated by url. More...

int	avio_close (AVIOContext *s)
	Close the resource accessed by the AVIOContext s and free it. More...

int	avio_closep (AVIOContext **s)
	Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL. More...

int	avio_open_dyn_buf (AVIOContext **s)
	Open a write only memory stream. More...

int	avio_get_dyn_buf (AVIOContext s, uint8_t *pbuffer)
	Return the written size and a pointer to the buffer. More...

int	avio_close_dyn_buf (AVIOContext s, uint8_t *pbuffer)
	Return the written size and a pointer to the buffer. More...

const char *	avio_enum_protocols (void **opaque, int output)
	Iterate through names of available protocols. More...

const AVClass *	avio_protocol_get_class (const char *name)
	Get AVClass by names of available protocols. More...

int	avio_pause (AVIOContext *h, int pause)
	Pause and resume playing - only meaningful if using a network streaming protocol (e.g. More...

int64_t	avio_seek_time (AVIOContext *h, int stream_index, int64_t timestamp, int flags)
	Seek to a given timestamp relative to some component stream. More...

int	avio_read_to_bprint (AVIOContext h, struct AVBPrint pb, size_t max_size)
	Read contents of h into print buffer, up to max_size bytes, or up to EOF. More...

int	avio_accept (AVIOContext s, AVIOContext *c)
	Accept and allocate a client context on a server context. More...

int	avio_handshake (AVIOContext *c)
	Perform one step of the protocol handshake to accept a new client. More...

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)

Detailed Description

Buffered I/O operations.

Definition in file avio.h.

Macro Definition Documentation

◆ AVIO_SEEKABLE_NORMAL

#define AVIO_SEEKABLE_NORMAL (1 << 0)

Seeking works like for a local file.

Definition at line 41 of file avio.h.

◆ AVIO_SEEKABLE_TIME

#define AVIO_SEEKABLE_TIME (1 << 1)

Seeking by timestamp with avio_seek_time() is possible.

Definition at line 46 of file avio.h.

◆ AVSEEK_SIZE

#define AVSEEK_SIZE 0x10000

ORing 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.

Definition at line 479 of file avio.h.

◆ AVSEEK_FORCE

#define AVSEEK_FORCE 0x20000

Passing this flag as the "whence" parameter to a seek function causes it to seek by any means (like reopening and linear reading) or other normally unreasonable means that can be extremely slow.

This may be ignored by the seek code.

Definition at line 487 of file avio.h.

◆ avio_print

#define avio_print	(	s,
		...
	)	avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})

Write strings (const char *) to the context.

This is a convenience macro around avio_print_string_array and it automatically creates the string array from the variable argument list. For simple string concatenations this function is more performant than using avio_printf since it does not need a temporary buffer.

Definition at line 548 of file avio.h.

◆ AVIO_FLAG_READ

#define AVIO_FLAG_READ 1

read-only

Examples: http_multiclient.c.

Definition at line 628 of file avio.h.

◆ AVIO_FLAG_WRITE

#define AVIO_FLAG_WRITE 2

write-only

Examples: http_multiclient.c, muxing.c, qsvdec.c, remuxing.c, transcode_aac.c, transcoding.c, and vaapi_transcode.c.

Definition at line 629 of file avio.h.

◆ AVIO_FLAG_READ_WRITE

#define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE)

read-write pseudo flag

Definition at line 630 of file avio.h.

◆ AVIO_FLAG_NONBLOCK

#define AVIO_FLAG_NONBLOCK 8

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.

Definition at line 647 of file avio.h.

◆ AVIO_FLAG_DIRECT

#define AVIO_FLAG_DIRECT 0x8000

Use direct mode.

avio_read and avio_write should if possible be satisfied directly instead of going through a buffer, and avio_seek will always call the underlying seek function directly.

Definition at line 655 of file avio.h.

Enumeration Type Documentation

◆ AVIODirEntryType

enum AVIODirEntryType

Directory entry types.

Enumerator
AVIO_ENTRY_UNKNOWN
AVIO_ENTRY_BLOCK_DEVICE
AVIO_ENTRY_CHARACTER_DEVICE
AVIO_ENTRY_DIRECTORY
AVIO_ENTRY_NAMED_PIPE
AVIO_ENTRY_SYMBOLIC_LINK
AVIO_ENTRY_SOCKET
AVIO_ENTRY_FILE
AVIO_ENTRY_SERVER
AVIO_ENTRY_SHARE
AVIO_ENTRY_WORKGROUP

Definition at line 67 of file avio.h.

◆ AVIODataMarkerType

enum AVIODataMarkerType

Different data types that can be returned via the AVIO write_data_type callback.

Enumerator
AVIO_DATA_MARKER_HEADER	Header data; this needs to be present for the stream to be decodeable.
AVIO_DATA_MARKER_SYNC_POINT	A point in the output bytestream where a decoder can start decoding (i.e. a keyframe). A demuxer/decoder given the data flagged with AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT, should give decodeable results.
AVIO_DATA_MARKER_BOUNDARY_POINT	A point in the output bytestream where a demuxer can start parsing (for non self synchronizing bytestream formats). That is, any non-keyframe packet start point.
AVIO_DATA_MARKER_UNKNOWN	This is any, unlabelled data. It can either be a muxer not marking any positions at all, it can be an actual boundary/sync point that the muxer chooses not to mark, or a later part of a packet/fragment that is cut into multiple write callbacks due to limited IO buffer size.
AVIO_DATA_MARKER_TRAILER	Trailer data, which doesn't contain actual content, but only for finalizing the output file.
AVIO_DATA_MARKER_FLUSH_POINT	A point in the output bytestream where the underlying AVIOContext might flush the buffer depending on latency or buffering requirements. Typically means the end of a packet.

Definition at line 112 of file avio.h.

Function Documentation

◆ avio_find_protocol_name()

const char * avio_find_protocol_name ( const char * url )

Return the name of the protocol that will handle the passed URL.

NULL is returned if no protocol could be found for the given URL.

Returns: Name of the protocol or NULL.

◆ avio_check()

int avio_check	(	const char *	url,
		int	flags
	)

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.

◆ avio_open_dir()

int avio_open_dir	(	AVIODirContext **	s,
		const char *	url,
		AVDictionary **	options
	)

Open directory for reading.

Parameters

s	directory read context. Pointer to a NULL pointer must be passed.
url	directory to be listed.
options	A dictionary filled with protocol-private options. On return this parameter will be destroyed and replaced with a dictionary containing options that were not found. May be NULL.

Returns: >=0 on success or negative on error.

Referenced by list_op().

◆ avio_read_dir()

int avio_read_dir	(	AVIODirContext *	s,
		AVIODirEntry **	next
	)

Get next directory entry.

Returned entry must be freed with avio_free_directory_entry(). In particular it may outlive AVIODirContext.

Parameters

	s	directory read context.
[out]	next	next entry or NULL when no more entries.

Returns: >=0 on success or negative on error. End of list is not considered an error.

Referenced by list_op().

◆ avio_close_dir()

int avio_close_dir ( AVIODirContext ** s )

Close directory.

Note: Entries created using avio_read_dir() are not deleted and must be freeded with avio_free_directory_entry().

Parameters

s	directory read context.

Returns: >=0 on success or negative on error.

Referenced by list_op().

◆ avio_free_directory_entry()

void avio_free_directory_entry ( AVIODirEntry ** entry )

Free entry allocated by avio_read_dir().

Parameters

entry entry to be freed.

Referenced by list_op().

◆ avio_alloc_context()

AVIOContext * avio_alloc_context	(	unsigned char *	buffer,
		int	buffer_size,
		int	write_flag,
		void *	opaque,
		int()(void opaque, uint8_t *buf, int buf_size)	read_packet,
		int()(void opaque, uint8_t *buf, int buf_size)	write_packet,
		int64_t()(void opaque, int64_t offset, int whence)	seek
	)

Allocate and initialize an AVIOContext for buffered I/O.

It must be later freed with avio_context_free().

Parameters

buffer	Memory block for input/output operations via AVIOContext. The buffer must be allocated with av_malloc() and friends. It may be freed and replaced with a new buffer by libavformat. AVIOContext.buffer holds the buffer currently in use, which must be later freed with av_free().
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.
write_flag	Set to 1 if the buffer should be writable, 0 otherwise.
opaque	An opaque pointer to user-specific data.
read_packet	A function for refilling the buffer, may be NULL. For stream protocols, must never return 0 but rather a proper AVERROR code.
write_packet	A function for writing the buffer contents, may be NULL. The function may not change the input buffers content.
seek	A function for seeking to specified byte position, may be NULL.

Returns: Allocated AVIOContext or NULL on failure.

Examples: avio_reading.c.

Referenced by main().

◆ avio_context_free()

void avio_context_free ( AVIOContext ** s )

Free the supplied IO context and everything associated with it.

Parameters

s	Double pointer to the IO context. This function will write NULL into s.

Examples: avio_reading.c.

Referenced by main().

◆ avio_w8()

void avio_w8	(	AVIOContext *	s,
		int	b
	)

◆ avio_write()

void avio_write	(	AVIOContext *	s,
		const unsigned char *	buf,
		int	size
	)

Examples: http_multiclient.c, and qsvdec.c.

Referenced by decode_packet(), and process_client().

◆ avio_wl64()

void avio_wl64	(	AVIOContext *	s,
		uint64_t	val
	)

◆ avio_wb64()

void avio_wb64	(	AVIOContext *	s,
		uint64_t	val
	)

◆ avio_wl32()

void avio_wl32	(	AVIOContext *	s,
		unsigned int	val
	)

◆ avio_wb32()

void avio_wb32	(	AVIOContext *	s,
		unsigned int	val
	)

◆ avio_wl24()

void avio_wl24	(	AVIOContext *	s,
		unsigned int	val
	)

◆ avio_wb24()

void avio_wb24	(	AVIOContext *	s,
		unsigned int	val
	)

◆ avio_wl16()

void avio_wl16	(	AVIOContext *	s,
		unsigned int	val
	)

◆ avio_wb16()

void avio_wb16	(	AVIOContext *	s,
		unsigned int	val
	)

◆ avio_put_str()

int avio_put_str	(	AVIOContext *	s,
		const char *	str
	)

Write a NULL-terminated string.

Returns: number of bytes written.

◆ avio_put_str16le()

int avio_put_str16le	(	AVIOContext *	s,
		const char *	str
	)

Convert an UTF-8 string to UTF-16LE and write it.

Parameters

s	the AVIOContext
str	NULL-terminated UTF-8 string

Returns: number of bytes written.

◆ avio_put_str16be()

int avio_put_str16be	(	AVIOContext *	s,
		const char *	str
	)

Convert an UTF-8 string to UTF-16BE and write it.

Parameters

s	the AVIOContext
str	NULL-terminated UTF-8 string

Returns: number of bytes written.

◆ avio_write_marker()

void avio_write_marker	(	AVIOContext *	s,
		int64_t	time,
		enum AVIODataMarkerType	type
	)

Mark the written bytestream as a specific type.

Zero-length ranges are omitted from the output.

Parameters

time	the stream time the current bytestream pos corresponds to (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not applicable
type	the kind of data written starting at the current pos

◆ avio_seek()

int64_t avio_seek	(	AVIOContext *	s,
		int64_t	offset,
		int	whence
	)

fseek() equivalent for AVIOContext.

Returns: new position or AVERROR.

Referenced by avio_tell().

◆ avio_skip()

int64_t avio_skip	(	AVIOContext *	s,
		int64_t	offset
	)

Skip given number of bytes forward.

Returns: new position or AVERROR.

◆ avio_tell()

static av_always_inline int64_t avio_tell ( AVIOContext * s )

static

ftell() equivalent for AVIOContext.

Returns: position or AVERROR.

Definition at line 505 of file avio.h.

◆ avio_size()

int64_t avio_size ( AVIOContext * s )

Get the filesize.

Returns: filesize or AVERROR

◆ avio_feof()

int avio_feof ( AVIOContext * s )

Similar to feof() but also returns nonzero on read errors.

Returns: non zero if and only if at end of file or a read error happened when reading.

◆ avio_vprintf()

int avio_vprintf	(	AVIOContext *	s,
		const char *	fmt,
		va_list	ap
	)

Writes a formatted string to the context taking a va_list.

Returns: number of bytes written, < 0 on error.

◆ avio_printf()

int avio_printf	(	AVIOContext *	s,
		const char *	fmt,
			...
	)

Writes a formatted string to the context.

Returns: number of bytes written, < 0 on error.

◆ avio_print_string_array()

int void avio_print_string_array	(	AVIOContext *	s,
		const char *	strings[]
	)

Write a NULL terminated array of strings to the context.

Usually you don't need to use this function directly but its macro wrapper, avio_print.

◆ avio_flush()

void avio_flush ( AVIOContext * s )

Force flushing of buffered data.

For write streams, force the buffered data to be immediately written to the output, without to wait to fill the internal buffer.

For read streams, discard all currently buffered data, and advance the reported file position to that of the underlying stream. This does not read new data, and does not perform any seeks.

Examples: http_multiclient.c.

Referenced by process_client().

◆ avio_read()

int avio_read	(	AVIOContext *	s,
		unsigned char *	buf,
		int	size
	)

Read size bytes from AVIOContext into buf.

Returns: number of bytes read or AVERROR

Examples: http_multiclient.c.

Referenced by process_client().

◆ avio_read_partial()

int avio_read_partial	(	AVIOContext *	s,
		unsigned char *	buf,
		int	size
	)

Read size bytes from AVIOContext into buf.

Unlike avio_read(), this is allowed to read fewer bytes than requested. The missing bytes can be read in the next call. This always tries to read at least 1 byte. Useful to reduce latency in certain cases.

Returns: number of bytes read or AVERROR

◆ avio_r8()

int avio_r8 ( AVIOContext * s )

◆ avio_rl16()

unsigned int avio_rl16 ( AVIOContext * s )

◆ avio_rl24()

unsigned int avio_rl24 ( AVIOContext * s )

◆ avio_rl32()

unsigned int avio_rl32 ( AVIOContext * s )

◆ avio_rl64()

uint64_t avio_rl64 ( AVIOContext * s )

◆ avio_rb16()

unsigned int avio_rb16 ( AVIOContext * s )

◆ avio_rb24()

unsigned int avio_rb24 ( AVIOContext * s )

◆ avio_rb32()

unsigned int avio_rb32 ( AVIOContext * s )

◆ avio_rb64()

uint64_t avio_rb64 ( AVIOContext * s )

◆ avio_get_str()

int avio_get_str	(	AVIOContext *	pb,
		int	maxlen,
		char *	buf,
		int	buflen
	)

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.

Returns: 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.

◆ avio_get_str16le()

int avio_get_str16le	(	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.

Returns: number of bytes read (is always <= maxlen)

◆ avio_get_str16be()

int avio_get_str16be	(	AVIOContext *	pb,
		int	maxlen,
		char *	buf,
		int	buflen
	)

◆ avio_open()

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.

Parameters

s	Used to return the pointer to the created AVIOContext. In case of failure the pointed to value is set to NULL.
url	resource to access
flags	flags which control how the resource indicated by url is to be opened

Returns: >= 0 in case of success, a negative value corresponding to an AVERROR code in case of failure

Examples: muxing.c, qsvdec.c, remuxing.c, transcode_aac.c, transcoding.c, and vaapi_transcode.c.

Referenced by main(), and open_output_file().

◆ avio_open2()

int avio_open2	(	AVIOContext **	s,
		const char *	url,
		int	flags,
		const AVIOInterruptCB *	int_cb,
		AVDictionary **	options
	)

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.

Parameters

s	Used to return the pointer to the created AVIOContext. In case of failure the pointed to value is set to NULL.
url	resource to access
flags	flags which control how the resource indicated by url is to be opened
int_cb	an interrupt callback to be used at the protocols level
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.

Returns: >= 0 in case of success, a negative value corresponding to an AVERROR code in case of failure

Examples: http_multiclient.c.

Referenced by main(), and process_client().

◆ avio_close()

int avio_close ( AVIOContext * s )

Close the resource accessed by the AVIOContext s and free it.

This function can only be used if s was opened by avio_open().

The internal buffer is automatically flushed before closing the resource.

Returns: 0 on success, an AVERROR < 0 on error.

See also: avio_closep

Examples: http_multiclient.c, and qsvdec.c.

Referenced by main(), and process_client().

◆ avio_closep()

int avio_closep ( AVIOContext ** s )

Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL.

This function can only be used if s was opened by avio_open().

The internal buffer is automatically flushed before closing the resource.

Returns: 0 on success, an AVERROR < 0 on error.

See also: avio_close

Examples: muxing.c, remuxing.c, transcode_aac.c, and transcoding.c.

Referenced by main(), and open_output_file().

◆ avio_open_dyn_buf()

int avio_open_dyn_buf ( AVIOContext ** s )

Open a write only memory stream.

Parameters

s	new IO context

Returns: zero if no error.

◆ avio_get_dyn_buf()

int avio_get_dyn_buf	(	AVIOContext *	s,
		uint8_t **	pbuffer
	)

Return the written size and a pointer to the buffer.

The AVIOContext stream is left intact. The buffer must NOT be freed. No padding is added to the buffer.

Parameters

s	IO context
pbuffer	pointer to a byte buffer

Returns: the length of the byte buffer

◆ avio_close_dyn_buf()

int avio_close_dyn_buf	(	AVIOContext *	s,
		uint8_t **	pbuffer
	)

Return the written size and a pointer to the buffer.

The buffer must be freed with av_free(). Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.

Parameters

s	IO context
pbuffer	pointer to a byte buffer

Returns: the length of the byte buffer

◆ avio_enum_protocols()

const char * avio_enum_protocols	(	void **	opaque,
		int	output
	)

Iterate through names of available protocols.

Parameters

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.
output	If set to 1, iterate over output protocols, otherwise over input protocols.

Returns: A static string containing the name of current protocol or NULL

◆ avio_protocol_get_class()

const AVClass * avio_protocol_get_class ( const char * name )

Get AVClass by names of available protocols.

Returns: A AVClass of input protocol name or NULL

◆ avio_pause()

int avio_pause	(	AVIOContext *	h,
		int	pause
	)

Pause and resume playing - only meaningful if using a network streaming protocol (e.g.

MMS).

Parameters

h	IO context from which to call the read_pause function pointer
pause	1 for pause, 0 for resume

◆ avio_seek_time()

int64_t avio_seek_time	(	AVIOContext *	h,
		int	stream_index,
		int64_t	timestamp,
		int	flags
	)

Seek to a given timestamp relative to some component stream.

Only meaningful if using a network streaming protocol (e.g. MMS.).

Parameters

h	IO context from which to call the seek function pointers
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.
timestamp	timestamp in AVStream.time_base units or if there is no stream specified then in AV_TIME_BASE units.
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 if used and not supported.

Returns: >= 0 on success

See also: AVInputFormat::read_seek

◆ avio_read_to_bprint()

int avio_read_to_bprint	(	AVIOContext *	h,
		struct AVBPrint *	pb,
		size_t	max_size
	)

Read contents of h into print buffer, up to max_size bytes, or up to EOF.

Returns: 0 for success (max_size bytes read or EOF reached), negative error code otherwise

◆ avio_accept()

int avio_accept	(	AVIOContext *	s,
		AVIOContext **	c
	)

Accept and allocate a client context on a server context.

Parameters

s	the server context
c	the client context, must be unallocated

Returns: >= 0 on success or a negative value corresponding to an AVERROR on failure

Examples: http_multiclient.c.

Referenced by main().

◆ avio_handshake()

int avio_handshake ( AVIOContext * c )

Perform one step of the protocol handshake to accept a new client.

This function must be called on a client returned by avio_accept() before using it as a read/write context. It is separate from avio_accept() because it may block. A step of the handshake is defined by places where the application may decide to change the proceedings. For example, on a protocol with a request header and a reply header, each one can constitute a step because the application may use the parameters from the request to change parameters in the reply; or each individual chunk of the request can constitute a step. If the handshake is already finished, avio_handshake() does nothing and returns 0 immediately.

Parameters

c	the client context to perform the handshake on

Returns: 0 on a complete and successful handshake > 0 if the handshake progressed, but is not complete < 0 for an AVERROR code

Examples: http_multiclient.c.

Referenced by process_client().

Data Structures

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ AVIO_SEEKABLE_NORMAL

◆ AVIO_SEEKABLE_TIME

◆ AVSEEK_SIZE

◆ AVSEEK_FORCE

◆ avio_print

◆ AVIO_FLAG_READ

◆ AVIO_FLAG_WRITE

◆ AVIO_FLAG_READ_WRITE

◆ AVIO_FLAG_NONBLOCK

◆ AVIO_FLAG_DIRECT

Enumeration Type Documentation

◆ AVIODirEntryType

◆ AVIODataMarkerType

Function Documentation

◆ avio_find_protocol_name()

◆ avio_check()

◆ avio_open_dir()

◆ avio_read_dir()

◆ avio_close_dir()

◆ avio_free_directory_entry()

◆ avio_alloc_context()

◆ avio_context_free()

◆ avio_w8()

◆ avio_write()

◆ avio_wl64()

◆ avio_wb64()

◆ avio_wl32()

◆ avio_wb32()

◆ avio_wl24()

◆ avio_wb24()

◆ avio_wl16()

◆ avio_wb16()

◆ avio_put_str()

◆ avio_put_str16le()

◆ avio_put_str16be()

◆ avio_write_marker()

◆ avio_seek()

◆ avio_skip()

◆ avio_tell()

◆ avio_size()

◆ avio_feof()

◆ avio_vprintf()

◆ avio_printf()

◆ avio_print_string_array()

◆ avio_flush()

◆ avio_read()

◆ avio_read_partial()

◆ avio_r8()

◆ avio_rl16()

◆ avio_rl24()

◆ avio_rl32()

◆ avio_rl64()

◆ avio_rb16()

◆ avio_rb24()

◆ avio_rb32()

◆ avio_rb64()

◆ avio_get_str()

◆ avio_get_str16le()

◆ avio_get_str16be()

◆ avio_open()

◆ avio_open2()

◆ avio_close()

◆ avio_closep()

◆ avio_open_dyn_buf()

◆ avio_get_dyn_buf()

◆ avio_close_dyn_buf()

◆ avio_enum_protocols()

◆ avio_protocol_get_class()

◆ avio_pause()

◆ avio_seek_time()

◆ avio_read_to_bprint()

◆ avio_accept()

◆ avio_handshake()