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Mp3_audio_sink: add equalizer and volume control

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Thirty-two equalizer bands may be adjusted using positive and negative
real numbers. The volume may also be be adjusted linearly using a
positive real number relative to 1.0. The volume adjustment is made in
the processing chain and the output is floating-point, so it is not
recommended to adjust the volume here but at the mixer.

<config>
	<volume linear="0.5"/> <!-- default, half volume -->
	<eq band="14" value="-0.2"/>
	<eq band="15" value="-0.1"/>
	<eq band="16" value="0.0"/> <!-- default, no adjustment -->
	<eq band="17" value="0.1"/>
	<eq band="18" value="0.2"/>
</config>
This commit is contained in:
Emery Hemingway
2018-05-24 11:23:37 +02:00
parent 1f5a59a3f2
commit 739df3bdbb
3 changed files with 33 additions and 2 deletions
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2
recipes/src/libmpg123/hash
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@@ -1 +1 @@
2018-03-24 44b1460890c468d2aca6be56caf0faf075df29d4
2018-05-24 15d7bc2940af4abfbea3229d4e2fd84981ac9962

2
recipes/src/mp3_audio_sink/hash
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@@ -1 +1 @@
2018-03-24 fe37ac4217462df71d74721c1ac22f7158ef210d
2018-05-24 7f16584ef3bc7e7700adc9048f7c64efd0bf6a3e

31
src/app/mp3_audio_sink/component.cc
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@@ -24,6 +24,7 @@
#include <libc/component.h>
#include <audio_out_session/connection.h>
#include <terminal_session/connection.h>
#include <base/attached_rom_dataspace.h>
#include <base/attached_ram_dataspace.h>
#include <base/sleep.h>
@@ -65,6 +66,8 @@ struct Mp3_audio_sink::Decoder
Genode::Env &_env;
Attached_rom_dataspace _config_rom { _env, "config" };
Audio_out::Connection _out_left { _env, "left", true, true };
Audio_out::Connection _out_right { _env, "right", false, false };
Audio_out::Connection *_out[NUM_CHANNELS];
@@ -187,11 +190,39 @@ struct Mp3_audio_sink::Decoder
Io_signal_handler<Decoder> _progress_handler {
_env.ep(), *this, &Decoder::submit_audio };
Signal_handler<Decoder> _config_handler {
_env.ep(), *this, &Decoder::_handle_config };
void _handle_config()
{
_config_rom.update();
Xml_node const config = _config_rom.xml();
enum { EQ_COUNT = 32 };
mpg123_reset_eq(_mh);
config.for_each_sub_node("eq", [&] (Xml_node const &node) {
unsigned band = node.attribute_value("band", 32U);
double value = node.attribute_value("value", 0.0);
if (band < EQ_COUNT && value != 0.0) {
mpg123_eq(_mh, MPG123_LR , band, value);
log("EQ ", band, ": ", mpg123_geteq(_mh, MPG123_LR , band));
}
});
double volume = 0.5;
config.for_each_sub_node("volume", [&] (Xml_node const &node) {
volume = node.attribute_value("linear", volume); });
mpg123_volume(_mh, 0.5);
}
Decoder(Genode::Env &env) : _env(env)
{
_out[LEFT] = &_out_left;
_out[RIGHT] = &_out_right;
_out_left.progress_sigh(_progress_handler);
_config_rom.sigh(_config_handler);
_handle_config();
}
};