159 lines
4.4 KiB
Clojure
159 lines
4.4 KiB
Clojure
|
|
=== Objectif ===
|
|
:** Understand basis of river
|
|
:** Create a simple recording interface that print the average of sample absolute value.
|
|
|
|
=== sample source: ===
|
|
[[http://github.com/HeeroYui/river.git/sample/read/ | sample source]]
|
|
|
|
=== Bases: ===
|
|
|
|
When you will create an application based on the river audio interface you need :
|
|
|
|
==== Include: ====
|
|
|
|
Include manager and interface node
|
|
|
|
[code style=c++]
|
|
#include <river/river.h>
|
|
#include <river/Manager.h>
|
|
#include <river/Interface.h>
|
|
[/code]
|
|
|
|
==== Initilize the River library: ====
|
|
|
|
We first need to initialize etk sub library (needed to select the log level of sub-libraries and file access abstraction
|
|
[code style=c++]
|
|
// the only one init for etk:
|
|
etk::init(_argc, _argv);
|
|
[/code]
|
|
|
|
Now we will initilaize the river library.
|
|
To do this We have 2 posibilities:
|
|
:** With a file:
|
|
[code style=c++]
|
|
// initialize river interface
|
|
river::init("DATA:configFileName.json");
|
|
[/code]
|
|
:** With a json string:
|
|
[code style=c++]
|
|
static const std::string configurationRiver =
|
|
"{\n"
|
|
" microphone:{\n"
|
|
" io:'input',\n"
|
|
" map-on:{\n"
|
|
" interface:'auto',\n"
|
|
" name:'default',\n"
|
|
" },\n"
|
|
" frequency:0,\n"
|
|
" channel-map:['front-left', 'front-right'],\n"
|
|
" type:'auto',\n"
|
|
" nb-chunk:1024\n"
|
|
" }\n"
|
|
"}\n";
|
|
// initialize river interface
|
|
river::initString(configurationRiver);
|
|
[/code]
|
|
|
|
For the example we select the second solution (faster to implement example and resource at the same position.
|
|
|
|
river::init / river::initString must be called only one time for all the application, this represent the hardware configuration.
|
|
It is Nearly not dynamic
|
|
|
|
To understand the configuration file Please see [tutorial[004_ConfigurationFile | Configuration file]]
|
|
|
|
[note]
|
|
This json is parsed by the [lib[ejson | e-json library]] it containe some update like:
|
|
:** Optionnal " in the name of element.
|
|
:** The possibilities to remplace " with '.
|
|
[/note]
|
|
|
|
|
|
==== Get the river interface manager: ====
|
|
|
|
An application can have many interface and only one Manager, And a process can contain many application.
|
|
|
|
Then, we will get the first application manager handle.
|
|
|
|
[code style=c++]
|
|
// Create the River manager for tha application or part of the application.
|
|
std11::shared_ptr<river::Manager> manager = river::Manager::create("river_sample_read");
|
|
[/code]
|
|
|
|
[note]
|
|
You can get back the application handle when you create a new one with the same name.
|
|
[/note]
|
|
|
|
==== Create your read interface: ====
|
|
|
|
[code style=c++]
|
|
// create interface:
|
|
std11::shared_ptr<river::Interface> interface;
|
|
//Get the generic input:
|
|
interface = manager->createInput(48000,
|
|
std::vector<audio::channel>(),
|
|
audio::format_int16,
|
|
"microphone");
|
|
[/code]
|
|
|
|
Here we create an interface with:
|
|
:** The frequency of 48000 Hz.
|
|
:** The default Low level definition channel
|
|
:** A data interface of 16 bits samples coded in [-32768..32767]
|
|
:** Select input interaface name "microphone"
|
|
|
|
|
|
==== Get datas: ====
|
|
|
|
The best way to get data is to instanciate a simple callback.
|
|
The callback is called when sample arrive and you have the nbChunk/frequency
|
|
to process the data, otherwise you can generate error in data stream.
|
|
|
|
|
|
[code style=c++]
|
|
// set callback mode ...
|
|
interface->setInputCallback(std11::bind(&onDataReceived,
|
|
std11::placeholders::_1,
|
|
std11::placeholders::_2,
|
|
std11::placeholders::_3,
|
|
std11::placeholders::_4,
|
|
std11::placeholders::_5,
|
|
std11::placeholders::_6));
|
|
[/code]
|
|
|
|
==== Callback inplementation: ====
|
|
|
|
Simply declare your function and do what you want inside.
|
|
|
|
[code style=c++]
|
|
void onDataReceived(const void* _data,
|
|
const std11::chrono::system_clock::time_point& _time,
|
|
size_t _nbChunk,
|
|
enum audio::format _format,
|
|
uint32_t _frequency,
|
|
const std::vector<audio::channel>& _map) {
|
|
if (_format == audio::format_int16) {
|
|
// stuff here
|
|
}
|
|
}
|
|
[/code]
|
|
|
|
==== start and stop: ====
|
|
|
|
[code style=c++]
|
|
// start the stream
|
|
interface->start();
|
|
// wait 10 second ...
|
|
sleep(10);
|
|
// stop the stream
|
|
interface->stop();
|
|
[/code]
|
|
|
|
==== Remove interfaces: ====
|
|
|
|
[code style=c++]
|
|
// remove interface and manager.
|
|
interface.reset();
|
|
manager.reset();
|
|
[/code]
|