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发表于 2006-10-21 21:16:34
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基于alsa的音量控制代码
[php]
//头文件
#include <alsa/asoundlib.h>
//类定义
class Sound {
public:
Sound();
~Sound();
int sound_read();
void sound_write(int);
private:
snd_mixer_t * mixer;
snd_mixer_elem_t *pcm_element;
};
//初始化-----------------------------------------------------
Sound::Sound()
{
snd_mixer_open(&mixer, 0);
snd_mixer_attach(mixer, "default");
snd_mixer_selem_register(mixer, NULL, NULL);
snd_mixer_load(mixer);
//找到Pcm对应的element,方法比较笨拙
pcm_element = snd_mixer_first_elem(mixer);
pcm_element = snd_mixer_elem_next(pcm_element);
pcm_element = snd_mixer_elem_next(pcm_element);
//
long int a, b;
long alsa_min_vol, alsa_max_vol;
///处理alsa1.0之前的bug,之后的可略去该部分代码
snd_mixer_selem_get_playback_volume(pcm_element,
SND_MIXER_SCHN_FRONT_LEFT, &a);
snd_mixer_selem_get_playback_volume(pcm_element,
SND_MIXER_SCHN_FRONT_RIGHT, &b);
snd_mixer_selem_get_playback_volume_range(pcm_element,
&alsa_min_vol,
&alsa_max_vol);
///设定音量范围
snd_mixer_selem_set_playback_volume_range(pcm_element, 0, 100);
}
//读音量值-----------------------------------------------------
int Sound::sound_read()
{
long ll, lr;
//处理事件
snd_mixer_handle_events(mixer);
//左声道
snd_mixer_selem_get_playback_volume(pcm_element,
SND_MIXER_SCHN_FRONT_LEFT, &ll);
//右声道
snd_mixer_selem_get_playback_volume(pcm_element,
SND_MIXER_SCHN_FRONT_RIGHT, &lr);
return (ll + lr) >> 1;
}
//写入音量-----------------------------------------------------
void Sound::sound_write(int leftright)
{
//左音量
snd_mixer_selem_set_playback_volume(pcm_element,
SND_MIXER_SCHN_FRONT_LEFT,
leftright);
//右音量
snd_mixer_selem_set_playback_volume(pcm_element,
SND_MIXER_SCHN_FRONT_RIGHT,
leftright);
}
//退出-----------------------------------------------------
Sound::~Sound()
{
snd_mixer_close(mixer);
}
[/php]
编译时要加库: -lasound
以上代码参考了xmms |
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