Teletext IDL packet demultiplexer
[Low Level Decoding]

Functions to decode data transmissions in Teletext Independent Data Line packets (EN 300 708 section 6). More...

Defines
#define	VBI_IDL_DATA_LOST   (1 << 0)
#define	VBI_IDL_DEPENDENT   (1 << 3)
Typedefs
typedef _vbi_idl_demux	vbi_idl_demux
	IDL demultiplexer context.
typedef vbi_bool	vbi_idl_demux_cb (vbi_idl_demux *dx, const uint8_t *buffer, unsigned int n_bytes, unsigned int flags, void *user_data)
Functions
void	vbi_idl_demux_reset (vbi_idl_demux *dx) _vbi_nonnull((1))
vbi_bool	vbi_idl_demux_feed (vbi_idl_demux *dx, const uint8_t buffer[42])
vbi_bool	vbi_idl_demux_feed_frame (vbi_idl_demux *dx, const vbi_sliced *sliced, unsigned int n_lines)
void	vbi_idl_demux_delete (vbi_idl_demux *dx)
vbi_idl_demux *	vbi_idl_a_demux_new (unsigned int channel, unsigned int address, vbi_idl_demux_cb *callback, void *user_data)

---

Detailed Description

Functions to decode data transmissions in Teletext Independent Data Line packets (EN 300 708 section 6).

vbi_idl_demux_cb flags

---

Define Documentation

#define VBI_IDL_DATA_LOST   (1 << 0)

Data was lost (not received or uncorrectable) between the current and previous vbi_idl_demux_feed() call.

#define VBI_IDL_DEPENDENT   (1 << 3)

IDL Format A flag (EN 300 708 section 6.5.2): The data may require the use of data in other channels or with other service packet addresses as defined by the application.

---

Typedef Documentation

typedef struct _vbi_idl_demux vbi_idl_demux

IDL demultiplexer context. The contents of this structure are private. Call vbi_idl_demux_new() to allocate an IDL demultiplexer context.

typedef vbi_bool vbi_idl_demux_cb(vbi_idl_demux *dx, const uint8_t *buffer, unsigned int n_bytes, unsigned int flags, void *user_data)

Parameters: dx  IDL demultiplexer returned by vbi_idl_a_demux_new() and given to vbi_idl_demux_feed(). buffer  Pointer to received user data. n_bytes  Number of bytes in the buffer. Can be 0 if the decoded packet did not contain user data. flags  VBI_IDL_DATA_LOST, VBI_IDL_DEPENDENT. user_data  User pointer passed to vbi_idl_demux_new(). The vbi_idl_demux_feed() function calls a function of this type after successfully decoding an IDL packet. Returns: FALSE to abort vbi_idl_demux_feed() and return FALSE.

---

Function Documentation

void vbi_idl_demux_reset (  vbi_idl_demux *  dx  )

Parameters: dx  IDL demultiplexer allocated with vbi_idl_a_demux_new(). Resets the IDL demux context, useful for example after a channel change. Since: 0.2.14

vbi_bool vbi_idl_demux_feed (  vbi_idl_demux *  dx, const uint8_t  buffer[42] )

Parameters: dx  IDL demultiplexer allocated with vbi_idl_a_demux_new(). buffer  Teletext packet (last 42 bytes, i. e. without clock run-in and framing code), as in struct vbi_sliced. This function takes a stream of Teletext packets, filters out packets of the desired data channel and address and calls the output function given to vbi_idl_a_demux_new() when new user data is available. Returns: FALSE if the packet contained incorrectable errors. Since: 0.2.14

vbi_bool vbi_idl_demux_feed_frame (  vbi_idl_demux *  dx, const vbi_sliced *  sliced, unsigned int  n_lines )

Parameters: dx  IDL demultiplexer allocated with vbi_idl_a_demux_new(). sliced  Sliced VBI data. n_lines  Number of lines in the sliced array. This function works like vbi_idl_demux_feed() but operates on sliced VBI data and filters out VBI_SLICED_TELETEXT_B_625. Returns: FALSE if any Teletext lines contained incorrectable errors. Since: 0.2.26

void vbi_idl_demux_delete (  vbi_idl_demux *  dx  )

Parameters: dx  IDL demultiplexer allocated with vbi_idl_a_demux_new(), can be NULL. Frees all resources associated with dx. Since: 0.2.14

vbi_idl_demux* vbi_idl_a_demux_new (  unsigned int  channel, unsigned int  address, vbi_idl_demux_cb *  callback, void *  user_data )

Parameters: channel  Filter out packets of this channel. address  Filter out packets with this service data address. callback  Function to be called by vbi_idl_demux_feed() when new data is available. user_data  User pointer passed through to callback function. Allocates a new Independent Data Line format A (EN 300 708 section 6.5) demultiplexer. Returns: Pointer to newly allocated IDL demultiplexer which must be freed with vbi_idl_demux_delete() when done. NULL on failure (out of memory). Since: 0.2.14

---