mirror of https://git.ffmpeg.org/ffmpeg.git
426 lines
15 KiB
C
426 lines
15 KiB
C
/*
|
|
* 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 {
|
|
/**
|
|
* 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;
|
|
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 */
|
|
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 */
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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.
|
|
* @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 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 */
|