ts-reader.h File Reference

Reading MPEG-TS files, packet by packet. More...

#include "caption-common.h"

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Macros
#define	TS_PACKET_SIZE   188
#define	TS_SYNC_BYTE   0x47

Typedefs
typedef struct TsReader_s	TsReader_t

Enumerations
enum	TsReaderError_t { TS_READER_OK = 0 , TS_READER_ERROR_OPEN , TS_READER_ERROR_FORMAT , TS_READER_ERROR_MEMORY }

Functions
bool	ts_detect_packet_format (const uint8_t *buf, size_t len, size_t *packet_size, size_t *offset)
TsReader_t *	ts_reader_open (const char *filename, TsReaderError_t *error)
const uint8_t *	ts_reader_next (TsReader_t *reader)
size_t	ts_reader_get_packet_size (const TsReader_t *reader)
void	ts_reader_close (TsReader_t *reader)

Detailed Description

Reading MPEG-TS files, packet by packet.

Author

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

The reader detects the file format by itself and always hands over packets of TS_PACKET_SIZE bytes, ready for ts_demux_push().

Accepted formats:

• 188 bytes: standard MPEG-TS;
• 192 bytes: M2TS (4 bytes of timecode before each packet);
• 204 bytes: MPEG-TS with 16 bytes of Reed-Solomon at the end of each packet, common in ISDB-T captures.

When sync is lost (the TS_SYNC_BYTE byte is out of place), the reader looks for the next TS_SYNC_BYTE and keeps going from there.

Example:

TsReaderError_t error;
TsReader_t *reader = ts_reader_open ("video.ts", &error);
const uint8_t *packet;
 
if (reader == NULL)
  return;
 
while ((packet = ts_reader_next (reader)) != NULL)
  ts_demux_push (demux, packet);
 
ts_reader_close (reader);

Definition in file ts-reader.h.

Macro Definition Documentation

TS_PACKET_SIZE

#define TS_PACKET_SIZE   188

Size of an MPEG-TS packet, without the extra timecode or Reed-Solomon bytes.

Definition at line 39 of file ts-reader.h.

TS_SYNC_BYTE

#define TS_SYNC_BYTE   0x47

Sync byte that starts every MPEG-TS packet.

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

Typedef Documentation

TsReader_t

typedef struct TsReader_s TsReader_t

MPEG-TS file reader. Opaque struct, created by ts_reader_open().

Definition at line 57 of file ts-reader.h.

Enumeration Type Documentation

TsReaderError_t

enum TsReaderError_t

Errors returned by ts_reader_open().

Enumerator
TS_READER_OK	File opened fine.
TS_READER_ERROR_OPEN	Could not open the file; the reason is in errno.
TS_READER_ERROR_FORMAT	The file doesn't look like an MPEG-TS (188, 192 or 204 bytes).
TS_READER_ERROR_MEMORY	Failed to allocate memory.

Definition at line 47 of file ts-reader.h.

Function Documentation

ts_detect_packet_format()

bool ts_detect_packet_format	(	const uint8_t *	buf,
		size_t	len,
		size_t *	packet_size,
		size_t *	offset
	)

Detects the packet format from the start of a buffer.

It needs at least 3 consecutive packets with the sync byte in the right place for the format to be recognized.

Parameters

buf	Start of the file content.
len	Number of bytes in buf (recommended: 1024 or more).
packet_size	Receives the packet size: 188, 192 or 204.
offset	Receives the position of the TS_SYNC_BYTE inside the packet (4 for M2TS, 0 for the others).

Returns

TRUE if the format was recognized.

ts_reader_open()

TsReader_t * ts_reader_open	(	const char *	filename,
		TsReaderError_t *	error
	)

Opens an MPEG-TS file for reading.

Parameters

filename	File path.
error	Optional (can be NULL). Receives the reason of the failure.

Returns

The reader, or NULL on error. Free with ts_reader_close().

ts_reader_next()

const uint8_t * ts_reader_next

(

TsReader_t *

reader

)

Reads the next packet of the file.

Parameters

reader

Reader created by ts_reader_open().

Returns

Pointer to the TS_PACKET_SIZE bytes of the packet (already without the M2TS timecode and without the Reed-Solomon), or NULL at the end of the file. The pointer is only valid until the next call.

ts_reader_get_packet_size()

size_t ts_reader_get_packet_size

(

const TsReader_t *

reader

)

Tells the packet size in the file.

Parameters

reader

Reader created by ts_reader_open().

Returns

188, 192 or 204 bytes.

ts_reader_close()

void ts_reader_close

(

TsReader_t *

reader

)

Closes the file and frees the reader.

Parameters

reader

Reader created by ts_reader_open(). NULL is fine.