audio_output_alsa.c

audio_output_apply_hwparams audio_output_close audio_output_open audio_output_play audio_output_volume_adjust audio_output_volume_down audio_output_volume_open audio_output_volume_up channels devhnd elem mixhnd srate

static int audio_output_volume_adjust ( int  n  )  [static] Adjust the audio output by a certain percentage and return the new value. Definition at line 214 of file audio_output_alsa.c. { int delta; long min, max; long right, left; if (mixhnd == NULL) return (-1); /* Allow other applications to change mixer */ snd_mixer_handle_events(mixhnd); /* Obtain volume range boundaries */ if (snd_mixer_selem_get_playback_volume_range(elem, &min, &max) != 0) return (-1); if (min >= max) return (-1); /* Convert delta from percent to steps */ delta = (n * (max - min)) / 100; if (delta == 0) delta = n > 0 ? 1 : -1; /* Obtain current volume */ if (snd_mixer_selem_get_playback_volume(elem, SND_MIXER_SCHN_FRONT_LEFT, &left) != 0) return (-1); if (snd_mixer_selem_get_playback_volume(elem, SND_MIXER_SCHN_FRONT_RIGHT, &right) != 0) return (-1); left = left + delta; left = CLAMP(left, min, max); right = right + delta; right = CLAMP(right, min, max); /* Set new volume */ if (snd_mixer_selem_set_playback_volume(elem, SND_MIXER_SCHN_FRONT_LEFT, left) != 0) return (-1); if (snd_mixer_selem_set_playback_volume(elem, SND_MIXER_SCHN_FRONT_RIGHT, right) != 0) return (-1); /* Convert volume back to a percentage */ return (((left + right) / 2 - min) * 100) / (max - min); } Here is the caller graph for this function: