mux.c File Reference

muxing functions for use within libavformat More...

#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include "libavcodec/internal.h"
#include "libavcodec/bytestream.h"
#include "libavutil/opt.h"
#include "libavutil/dict.h"
#include "libavutil/pixdesc.h"
#include "libavutil/timestamp.h"
#include "metadata.h"
#include "id3v2.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/parseutils.h"
#include "libavutil/time.h"
#include "riff.h"
#include "audiointerleave.h"
#include "url.h"
#include <stdarg.h>
#include <assert.h>

Go to the source code of this file.

Macros
#define	CHUNK_START   0x1000

Functions
static void	frac_init (AVFrac *f, int64_t val, int64_t num, int64_t den)
	f = val + (num / den) + 0.5.
static void	frac_add (AVFrac *f, int64_t incr)
	Fractional addition to f: f = f + (incr / f->den).
AVRational	ff_choose_timebase (AVFormatContext *s, AVStream *st, int min_precission)
	Chooses a timebase for muxing the specified stream.
int	avformat_alloc_output_context2 (AVFormatContext **avctx, AVOutputFormat *oformat, const char *format, const char *filename)
	Allocate an AVFormatContext for an output format.
static int	validate_codec_tag (AVFormatContext *s, AVStream *st)
static int	init_muxer (AVFormatContext *s, AVDictionary **options)
static int	init_pts (AVFormatContext *s)
int	avformat_write_header (AVFormatContext *s, AVDictionary **options)
	Allocate the stream private data and write the stream header to an output media file.
static int	compute_pkt_fields2 (AVFormatContext *s, AVStream *st, AVPacket *pkt)
static int	write_packet (AVFormatContext *s, AVPacket *pkt)
	Make timestamps non negative, move side data from payload to internal struct, call muxer, and restore sidedata.
int	av_write_frame (AVFormatContext *s, AVPacket *pkt)
	Write a packet to an output media file.
int	ff_interleave_add_packet (AVFormatContext *s, AVPacket *pkt, int(*compare)(AVFormatContext *, AVPacket *, AVPacket *))
	Add packet to AVFormatContext->packet_buffer list, determining its interleaved position using compare() function argument.
static int	interleave_compare_dts (AVFormatContext *s, AVPacket *next, AVPacket *pkt)
int	ff_interleave_packet_per_dts (AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush)
	Interleave a packet per dts in an output media file.
static int	interleave_packet (AVFormatContext *s, AVPacket *out, AVPacket *in, int flush)
	Interleave an AVPacket correctly so it can be muxed.
int	av_interleaved_write_frame (AVFormatContext *s, AVPacket *pkt)
	Write a packet to an output media file ensuring correct interleaving.
int	av_write_trailer (AVFormatContext *s)
	Write the stream trailer to an output media file and free the file private data.
int	av_get_output_timestamp (struct AVFormatContext *s, int stream, int64_t *dts, int64_t *wall)
	Get timing information for the data currently output.
int	ff_write_chained (AVFormatContext *dst, int dst_stream, AVPacket *pkt, AVFormatContext *src)
	Write a packet to another muxer than the one the user originally intended.

Detailed Description

muxing functions for use within libavformat

Definition in file mux.c.

Macro Definition Documentation

#define CHUNK_START   0x1000

Definition at line 578 of file mux.c.

Referenced by ff_interleave_add_packet().

Function Documentation

static void frac_init ( AVFrac *  f, int64_t  val, int64_t  num, int64_t  den  )

static

f = val + (num / den) + 0.5.

'num' is normalized so that it is such as 0 <= num < den.

Parameters

f	fractional number
val	integer value
num	must be >= 0
den	must be >= 1

Definition at line 67 of file mux.c.

Referenced by init_pts().

static void frac_add ( AVFrac *  f, int64_t  incr  )

static

Fractional addition to f: f = f + (incr / f->den).

Parameters

f	fractional number
incr	increment, can be positive or negative

Definition at line 85 of file mux.c.

Referenced by compute_pkt_fields2().

AVRational ff_choose_timebase	(	AVFormatContext *	s,
		AVStream *	st,
		int	min_precission
	)

Chooses a timebase for muxing the specified stream.

The choosen timebase allows sample accurate timestamps based on the framerate or sample rate for audio streams. It also is at least as precisse as 1/min_precission would be.

Definition at line 105 of file mux.c.

Referenced by nut_write_header().

int avformat_alloc_output_context2	(	AVFormatContext **	ctx,
		AVOutputFormat *	oformat,
		const char *	format_name,
		const char *	filename
	)

Allocate an AVFormatContext for an output format.

avformat_free_context() can be used to free the context and everything allocated by the framework within it.

Parameters

*ctx	is set to the created format context, or to NULL in case of failure
oformat	format to use for allocating the context, if NULL format_name and filename are used instead
format_name	the name of output format to use for allocating the context, if NULL filename is used instead
filename	the name of the filename to use for allocating the context, may be NULL

Returns

>= 0 in case of success, a negative AVERROR code in case of failure

Definition at line 124 of file mux.c.

Referenced by main(), open_output_file(), open_slave(), and write_packet().

static int validate_codec_tag ( AVFormatContext *  s, AVStream *  st  )

static

Check that tag + id is in the table If neither is in the table -> OK If tag is in the table with another id -> FAIL If id is in the table with another tag -> FAIL unless strict < normal

Definition at line 187 of file mux.c.

Referenced by init_muxer().

static int init_muxer ( AVFormatContext *  s, AVDictionary **  options  )

static

Definition at line 221 of file mux.c.

Referenced by avformat_write_header().

static int init_pts ( AVFormatContext *  s )

static

Definition at line 356 of file mux.c.

Referenced by avformat_write_header().

static int compute_pkt_fields2 ( AVFormatContext *  s, AVStream *  st, AVPacket *  pkt  )

static

Definition at line 416 of file mux.c.

Referenced by av_interleaved_write_frame(), and av_write_frame().

static int write_packet ( AVFormatContext *  s, AVPacket *  pkt  )

static

Make timestamps non negative, move side data from payload to internal struct, call muxer, and restore sidedata.

FIXME: this function should NEVER get undefined pts/dts beside when the AVFMT_NOTIMESTAMPS is set. Those additional safety checks should be dropped once the correct checks are set in the callers.

Definition at line 507 of file mux.c.

Referenced by av_interleaved_write_frame(), av_write_frame(), and av_write_trailer().

int ff_interleave_add_packet	(	AVFormatContext *	s,
		AVPacket *	pkt,
		int(*)(AVFormatContext *, AVPacket *, AVPacket *)	compare
	)

Add packet to AVFormatContext->packet_buffer list, determining its interleaved position using compare() function argument.

Returns

0, or < 0 on error

Definition at line 580 of file mux.c.

Referenced by ff_audio_rechunk_interleave(), and ff_interleave_packet_per_dts().

static int interleave_compare_dts ( AVFormatContext *  s, AVPacket *  next, AVPacket *  pkt  )

static

Definition at line 650 of file mux.c.

Referenced by ff_interleave_packet_per_dts().

int ff_interleave_packet_per_dts	(	AVFormatContext *	s,
		AVPacket *	out,
		AVPacket *	pkt,
		int	flush
	)

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.

Parameters

s	media file handle
out	the interleaved packet will be output here
pkt	the input packet
flush	1 if no further packets are available as input and all remaining packets should be output

Returns

1 if a packet was output, 0 if no packet could be output, < 0 if an error occurred

Definition at line 673 of file mux.c.

Referenced by gxf_interleave_packet(), and interleave_packet().

static int interleave_packet ( AVFormatContext *  s, AVPacket *  out, AVPacket *  in, int  flush  )

static

Interleave an AVPacket correctly so it can be muxed.

Parameters

out	the interleaved packet will be output here
in	the input packet
flush	1 if no further packets are available as input and all remaining packets should be output

Returns

1 if a packet was output, 0 if no packet could be output, < 0 if an error occurred

Definition at line 746 of file mux.c.

Referenced by av_interleaved_write_frame(), and av_write_trailer().

int ff_write_chained	(	AVFormatContext *	dst,
		int	dst_stream,
		AVPacket *	pkt,
		AVFormatContext *	src
	)

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.

Parameters

dst	the muxer to write the packet to
dst_stream	the stream index within dst to write the packet to
pkt	the packet to be written
src	the muxer the packet originally was intended for

Returns

the value av_write_frame returned

Definition at line 851 of file mux.c.

Referenced by ff_mov_add_hinted_packet(), hls_write_packet(), ism_write_packet(), rtsp_write_packet(), sap_write_packet(), and seg_write_packet().