diff options
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/dvb-core/demux.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/media/dvb-core/demux.h b/drivers/media/dvb-core/demux.h index 7405d6e2297d..39e644113350 100644 --- a/drivers/media/dvb-core/demux.h +++ b/drivers/media/dvb-core/demux.h @@ -195,6 +195,61 @@ struct dmx_section_feed { * Callback functions */ +/** + * typedef dmx_ts_cb - DVB demux TS filter callback function prototype + * + * @buffer1: Pointer to the start of the filtered TS packets. + * @buffer1_length: Length of the TS data in buffer1. + * @buffer2: Pointer to the tail of the filtered TS packets, or NULL. + * @buffer2_length: Length of the TS data in buffer2. + * @source: Indicates which TS feed is the source of the callback. + * + * This function callback prototype, provided by the client of the demux API, + * is called from the demux code. The function is only called when filtering + * on ae TS feed has been enabled using the start_filtering() function at + * the &dmx_demux. + * Any TS packets that match the filter settings are copied to a circular + * buffer. The filtered TS packets are delivered to the client using this + * callback function. The size of the circular buffer is controlled by the + * circular_buffer_size parameter of the &dmx_ts_feed.@set function. + * It is expected that the @buffer1 and @buffer2 callback parameters point to + * addresses within the circular buffer, but other implementations are also + * possible. Note that the called party should not try to free the memory + * the @buffer1 and @buffer2 parameters point to. + * + * When this function is called, the @buffer1 parameter typically points to + * the start of the first undelivered TS packet within a circular buffer. + * The @buffer2 buffer parameter is normally NULL, except when the received + * TS packets have crossed the last address of the circular buffer and + * ”wrapped” to the beginning of the buffer. In the latter case the @buffer1 + * parameter would contain an address within the circular buffer, while the + * @buffer2 parameter would contain the first address of the circular buffer. + * The number of bytes delivered with this function (i.e. @buffer1_length + + * @buffer2_length) is usually equal to the value of callback_length parameter + * given in the set() function, with one exception: if a timeout occurs before + * receiving callback_length bytes of TS data, any undelivered packets are + * immediately delivered to the client by calling this function. The timeout + * duration is controlled by the set() function in the TS Feed API. + * + * If a TS packet is received with errors that could not be fixed by the + * TS-level forward error correction (FEC), the Transport_error_indicator + * flag of the TS packet header should be set. The TS packet should not be + * discarded, as the error can possibly be corrected by a higher layer + * protocol. If the called party is slow in processing the callback, it + * is possible that the circular buffer eventually fills up. If this happens, + * the demux driver should discard any TS packets received while the buffer + * is full and return -EOVERFLOW. + * + * The type of data returned to the callback can be selected by the + * &dmx_ts_feed.@set function. The type parameter decides if the raw + * TS packet (TS_PACKET) or just the payload (TS_PACKET|TS_PAYLOAD_ONLY) + * should be returned. If additionally the TS_DECODER bit is set the stream + * will also be sent to the hardware MPEG decoder. + * + * Return: + * 0, on success; + * -EOVERFLOW, on buffer overflow. + */ typedef int (*dmx_ts_cb)(const u8 *buffer1, size_t buffer1_length, const u8 *buffer2, |
