Functions to decode data transmissions in Teletext Independent Data Line packets (EN 300 708 section 6).
More...
Detailed Description
Functions to decode data transmissions in Teletext Independent Data Line packets (EN 300 708 section 6).
Typedef Documentation
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
- Parameters:
-
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
- 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
- Parameters:
-
Frees all resources associated with dx.
- Since:
- 0.2.14
- 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