ts-demux.h File Reference

MPEG-TS demuxer: PAT/PMT tables, per PID stats and reassembly of the PES packets of one PID. More...

#include "caption-common.h"
#include "ts-reader.h"

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Data Structures
struct	TsPidInfo_t

Macros
#define	TS_PID_PAT   0x0000
#define	TS_PID_NULL   0x1fff
#define	TS_PID_MAX   0x2000
#define	TS_PID_NONE   0xffff

Typedefs
typedef void(*	TsDemuxPesCallback_t) (const uint8_t *pes, size_t len, void *userdata)
typedef struct TsDemux_s	TsDemux_t

Functions
TsDemux_t *	ts_demux_new (void)
void	ts_demux_free (TsDemux_t *demux)
void	ts_demux_set_pes_callback (TsDemux_t *demux, uint16_t pid, TsDemuxPesCallback_t callback, void *userdata)
void	ts_demux_push (TsDemux_t *demux, const uint8_t *packet)
void	ts_demux_flush (TsDemux_t *demux)
const TsPidInfo_t *	ts_demux_get_pid_info (const TsDemux_t *demux, uint16_t pid)
uint16_t	ts_demux_get_caption_pid (const TsDemux_t *demux)
const char *	ts_demux_describe_pid (const TsDemux_t *demux, uint16_t pid, char *buf, size_t len)
const char *	ts_stream_type_name (uint8_t stream_type)
const char *	ts_component_tag_name (int16_t component_tag)
const char *	ts_system_pid_name (uint16_t pid)

Detailed Description

MPEG-TS demuxer: PAT/PMT tables, per PID stats and reassembly of the PES packets of one PID.

Author

Jorge Pereira jpere.nosp@m.iran.nosp@m.@gmai.nosp@m.l.co.nosp@m.m

The demuxer takes the 188 byte TS packets (see ts-reader.h) and:

• counts the packets of each PID;
• reads the PAT and the PMTs of all programs, finding out the type of each PID (video, audio, caption, PCR, etc.);
• suggests the caption PID, from the PMT component_tag;
• reassembles the PES packets of a chosen PID and hands each whole PES to a callback (for example, caption_screen_push_pes()).

Example:

static void
on_pes (const uint8_t *pes, size_t len, void *userdata)
{
  caption_screen_push_pes (userdata, pes, len);
}
 
TsDemux_t *demux = ts_demux_new ();
 
ts_demux_set_pes_callback (demux, 0x3ed, on_pes, screen);
 
while ((packet = ts_reader_next (reader)) != NULL)
  ts_demux_push (demux, packet);
 
ts_demux_flush (demux);
ts_demux_free (demux);

Definition in file ts-demux.h.

Macro Definition Documentation

TS_PID_PAT

#define TS_PID_PAT   0x0000

PAT PID (Program Association Table).

Definition at line 42 of file ts-demux.h.

TS_PID_NULL

#define TS_PID_NULL   0x1fff

PID of the null packets (stuffing).

Definition at line 45 of file ts-demux.h.

TS_PID_MAX

#define TS_PID_MAX   0x2000

Number of possible PIDs (13 bits).

Definition at line 48 of file ts-demux.h.

TS_PID_NONE

#define TS_PID_NONE   0xffff

Value used to say "no PID".

Definition at line 51 of file ts-demux.h.

Typedef Documentation

TsDemuxPesCallback_t

typedef void(* TsDemuxPesCallback_t) (const uint8_t *pes, size_t len, void *userdata)

Callback called for each whole PES of the PID chosen in ts_demux_set_pes_callback().

Parameters

pes	Whole PES packet, starting at the packet_start_code_prefix (00 00 01). Only valid during the call.
len	Size of pes in bytes.
userdata	Pointer given to ts_demux_set_pes_callback().

Definition at line 75 of file ts-demux.h.

TsDemux_t

typedef struct TsDemux_s TsDemux_t

MPEG-TS demuxer. Opaque struct, created by ts_demux_new().

Definition at line 82 of file ts-demux.h.

Function Documentation

ts_demux_new()

TsDemux_t * ts_demux_new

(

void

)

Creates a demuxer.

Returns

The demuxer, or NULL if out of memory. Free with ts_demux_free().

ts_demux_free()

void ts_demux_free

(

TsDemux_t *

demux

)

Frees the demuxer. Does not call ts_demux_flush().

Parameters

demux

Demuxer created by ts_demux_new(). NULL is fine.

ts_demux_set_pes_callback()

void ts_demux_set_pes_callback	(	TsDemux_t *	demux,
		uint16_t	pid,
		TsDemuxPesCallback_t	callback,
		void *	userdata
	)

Chooses the PID whose PES packets will be reassembled and handed to the callback.

Only one PID is reassembled at a time. A new call replaces the previous one and drops the PES that was incomplete.

Parameters

demux	Demuxer created by ts_demux_new().
pid	PID to be reassembled, or TS_PID_NONE to turn it off.
callback	Function called for each whole PES.
userdata	Passed on to the callback.

ts_demux_push()

void ts_demux_push	(	TsDemux_t *	demux,
		const uint8_t *	packet
	)

Processes a TS packet.

Packets with the transport_error_indicator set are ignored. Lost packets (continuity_counter failure) drop the incomplete PES.

Parameters

demux	Demuxer created by ts_demux_new().
packet	Packet of TS_PACKET_SIZE bytes, starting with TS_SYNC_BYTE.

ts_demux_flush()

void ts_demux_flush

(

TsDemux_t *

demux

)

Delivers the last PES, if it is still pending.

A PES is only considered complete when the next one starts or when it reaches the PES_packet_length; so call this function at the end of the file.

Parameters

demux

Demuxer created by ts_demux_new().

ts_demux_get_pid_info()

const TsPidInfo_t * ts_demux_get_pid_info	(	const TsDemux_t *	demux,
		uint16_t	pid
	)

Returns the info collected about a PID.

Parameters

demux	Demuxer created by ts_demux_new().
pid	PID between 0 and TS_PID_MAX - 1.

Returns

The PID info, or NULL if pid is invalid.

ts_demux_get_caption_pid()

uint16_t ts_demux_get_caption_pid

(

const TsDemux_t *

demux

)

Returns the caption PID suggested by the PMT.

It picks the private stream (stream_type 0x06) with a caption component_tag: 0x30 to 0x37 (full-seg) or 0x87 (one-seg), preferring the lowest component_tag, that is, the main full-seg caption.

Parameters

demux

Demuxer created by ts_demux_new().

Returns

The caption PID, or TS_PID_NONE if none was found.

ts_demux_describe_pid()

const char * ts_demux_describe_pid	(	const TsDemux_t *	demux,
		uint16_t	pid,
		char *	buf,
		size_t	len
	)

Builds a readable description of the PID, for example "0x06 PES privado (component_tag 0x30, legenda)".

Parameters

demux	Demuxer created by ts_demux_new().
pid	PID between 0 and TS_PID_MAX - 1.
buf	Buffer that receives the description.
len	Size of buf (128 bytes is enough).

Returns

buf itself.

ts_stream_type_name()

const char * ts_stream_type_name

(

uint8_t

stream_type

)

Name of the PMT stream_type (ISO/IEC 13818-1, Table 2-34).

Parameters

stream_type

stream_type value.

Returns

The name, for example "H.264 video", or "desconhecido" (unknown).

ts_component_tag_name()

const char * ts_component_tag_name

(

int16_t

component_tag

)

Name of the component_tag in ISDB-T (ARIB TR-B14 / ABNT NBR 15608).

Parameters

component_tag

component_tag value.

Returns

"legenda", "legenda one-seg", "superimpose", or NULL for the other values.

ts_system_pid_name()

const char * ts_system_pid_name

(

uint16_t

pid

)

Name of the PIDs reserved for system tables (PAT, NIT, SDT, EIT, etc.).

Parameters

pid	PID to look up.

Returns

The table name, or NULL if the PID is not reserved.