Functions to decode data transmissions in Teletext Page Function Clear packets (EN 300 708 section 4).
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Detailed Description
Functions to decode data transmissions in Teletext Page Function Clear packets (EN 300 708 section 4).
Typedef Documentation
PFC demultiplexer context.
The contents of this structure are private.
Call vbi_pfc_demux_new() to allocate a PFC demultiplexer context.
- Parameters:
-
dx | PFC demultiplexer context returned by vbi_pfx_demux_new() and given to vbi_pfc_demux_feed(). |
user_data | User pointer given to vbi_pfc_demux_new(). |
block | Structure describing the received data block. |
Function called by vbi_pfc_demux_feed() when a new data block is available.
- Returns:
- FALSE on error, will be returned by vbi_pfc_demux_feed().
- Bug:
- vbi_pfc_demux_feed() returns the user_data pointer as second parameter the block pointer as third parameter, but prior to version 0.2.26 this function incorrectly defined block as second and user_data as third parameter.
Function Documentation
- Parameters:
-
Resets the PFC demux context, useful for example after a channel change.
vbi_bool vbi_pfc_demux_feed |
( |
vbi_pfc_demux * |
dx, |
|
|
const uint8_t |
buffer[42] |
|
) |
| |
- Parameters:
-
dx | PFC demultiplexer context allocated with vbi_pfc_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 raw stream of Teletext packets, filters out the page and stream requested with vbi_pfc_demux_new() and assembles the data transmitted in this page in a buffer. When a data block is complete it calls the output function given to vbi_pfc_demux_new().
- Returns:
- FALSE if the packet contained incorrectable errors.
- Parameters:
-
dx | PFC demultiplexer context allocated with vbi_pfc_demux_new(). |
sliced | Sliced VBI data. |
n_lines | Number of lines in the sliced array. |
This function works like vbi_pfc_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.
- Parameters:
-
pgno | Page to take PFC data from. |
stream | PFC stream to be demultiplexed. |
callback | Function to be called by vbi_pfc_demux_feed() when a new data block is available. |
user_data | User pointer passed through to cb function. |
Allocates a new Page Function Clear (ETS 300 708 section 4) demultiplexer.
- Returns:
- Pointer to newly allocated PFC demux context which must be freed with vbi_pfc_demux_delete() when done.
NULL
on failure (out of memory).