visualisation_stream Class Reference
#include <vis.h>
Public Types | |
| typedef visualisation_stream | t_interface |
| typedef service_base | t_interface_parent |
Public Member Functions | |
| virtual bool | get_absolute_time (double &p_value)=0 |
| Retrieves absolute playback time since last playback start or seek. You typically pass value retrieved by this function - optionally with offset added - to other visualisation_stream methods. | |
| virtual bool | get_chunk_absolute (audio_chunk &p_chunk, double p_offset, double p_requested_length)=0 |
| virtual bool | get_spectrum_absolute (audio_chunk &p_chunk, double p_offset, unsigned p_fft_size)=0 |
| virtual void | make_fake_chunk_absolute (audio_chunk &p_chunk, double p_offset, double p_requested_length)=0 |
| virtual void | make_fake_spectrum_absolute (audio_chunk &p_chunk, double p_offset, unsigned p_fft_size)=0 |
Static Public Attributes | |
| static const GUID | class_guid |
Detailed Description
This class provides abstraction for receiving visualisation data. Instances of visualisation_stream being created/released serve as an indication for visualisation backend to process currently played audio data or shut down when there are no visualisation clients active.Use visualisation_manager::create_stream to instantiate.
Member Typedef Documentation
Reimplemented from service_base.
Member Function Documentation
| virtual bool visualisation_stream::get_absolute_time | ( | double & | p_value | ) | [pure virtual] |
Retrieves absolute playback time since last playback start or seek. You typically pass value retrieved by this function - optionally with offset added - to other visualisation_stream methods.
| virtual bool visualisation_stream::get_chunk_absolute | ( | audio_chunk & | p_chunk, | |
| double | p_offset, | |||
| double | p_requested_length | |||
| ) | [pure virtual] |
Retrieves an audio chunk starting at specified offset (see get_absolute_time()), of specified length.
- Returns:
- False when requested timestamp is out of available range, true on success.
| virtual bool visualisation_stream::get_spectrum_absolute | ( | audio_chunk & | p_chunk, | |
| double | p_offset, | |||
| unsigned | p_fft_size | |||
| ) | [pure virtual] |
Retrieves spectrum for audio data at specified offset (see get_absolute_time()), with specified FFT size.
- Parameters:
-
p_chunk Receives spectrum data. audio_chunk type is used for consistency (since required functionality is identical to provided by audio_chunk), the data is *not* PCM. Returned sample count is equal to half of FFT size; channels and sample rate are as in audio stream the spectrum was generated from. p_offset Timestamp of spectrum to retrieve. See get_absolute_time(). p_fft_size FFT size to use for spectrum generation. Must be a power of 2.
- Returns:
- False when requested timestamp is out of available range, true on success.
| virtual void visualisation_stream::make_fake_chunk_absolute | ( | audio_chunk & | p_chunk, | |
| double | p_offset, | |||
| double | p_requested_length | |||
| ) | [pure virtual] |
Generates fake audio chunk to display when get_chunk_absolute() fails - e.g. shortly after visualisation_stream creation data for currently played audio might not be available yet. Throws std::exception derivatives on failure.
| virtual void visualisation_stream::make_fake_spectrum_absolute | ( | audio_chunk & | p_chunk, | |
| double | p_offset, | |||
| unsigned | p_fft_size | |||
| ) | [pure virtual] |
Generates fake spectrum to display when get_spectrum_absolute() fails - e.g. shortly after visualisation_stream creation data for currently played audio might not be available yet. Throws std::exception derivatives on failure.
Member Data Documentation
const GUID visualisation_stream::class_guid [static] |
Initial value:
{ 0x4a4b1dd8, 0x82ff, 0x4071, { 0xa6, 0xe2, 0xbd, 0x4, 0x3f, 0x4c, 0x25, 0x1c } }
The documentation for this class was generated from the following files:
