From: Takashi Iwai Date: Tue, 4 Jan 2005 11:37:29 +0000 (+0000) Subject: Support stereo volume control X-Git-Tag: v1.0.8~8 X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=c7feb066b10ea5007e215dde7a75843eee334a64;p=alsa-lib.git Support stereo volume control softvol supports stereo volume controls. Fixed the dB calculation, too. --- diff --git a/src/pcm/pcm_softvol.c b/src/pcm/pcm_softvol.c index 8cfd9cb7..18019ffc 100644 --- a/src/pcm/pcm_softvol.c +++ b/src/pcm/pcm_softvol.c @@ -42,8 +42,10 @@ typedef struct { /* This field need to be the first */ snd_pcm_plugin_t plug; snd_pcm_format_t sformat; + unsigned int cchannels; snd_ctl_t *ctl; snd_ctl_elem_value_t elem; + unsigned int cur_vol[2]; unsigned int max_val; double min_dB; unsigned short *dB_value; @@ -55,38 +57,38 @@ typedef struct { #define PRESET_MIN_DB -48.0 static unsigned short preset_dB_value[PRESET_RESOLUTION] = { - 0x0000, 0x0930, 0x094f, 0x096e, 0x098e, 0x09af, 0x09cf, 0x09f0, - 0x0a12, 0x0a34, 0x0a56, 0x0a79, 0x0a9d, 0x0ac0, 0x0ae5, 0x0b0a, - 0x0b2f, 0x0b55, 0x0b7b, 0x0ba2, 0x0bc9, 0x0bf1, 0x0c19, 0x0c42, - 0x0c6b, 0x0c95, 0x0cc0, 0x0ceb, 0x0d16, 0x0d42, 0x0d6f, 0x0d9c, - 0x0dca, 0x0df9, 0x0e28, 0x0e58, 0x0e88, 0x0eb9, 0x0eeb, 0x0f1d, - 0x0f51, 0x0f84, 0x0fb9, 0x0fee, 0x1023, 0x105a, 0x1091, 0x10c9, - 0x1102, 0x113b, 0x1175, 0x11b0, 0x11ec, 0x1228, 0x1266, 0x12a4, - 0x12e3, 0x1322, 0x1363, 0x13a5, 0x13e7, 0x142a, 0x146e, 0x14b3, - 0x14f9, 0x1540, 0x1587, 0x15d0, 0x161a, 0x1664, 0x16b0, 0x16fd, - 0x174a, 0x1799, 0x17e8, 0x1839, 0x188b, 0x18de, 0x1932, 0x1987, - 0x19dd, 0x1a34, 0x1a8d, 0x1ae6, 0x1b41, 0x1b9d, 0x1bfa, 0x1c59, - 0x1cb8, 0x1d19, 0x1d7c, 0x1ddf, 0x1e44, 0x1eaa, 0x1f12, 0x1f7a, - 0x1fe5, 0x2050, 0x20bd, 0x212c, 0x219c, 0x220d, 0x2280, 0x22f5, - 0x236b, 0x23e2, 0x245b, 0x24d6, 0x2553, 0x25d1, 0x2650, 0x26d2, - 0x2755, 0x27d9, 0x2860, 0x28e8, 0x2972, 0x29fe, 0x2a8c, 0x2b1b, - 0x2bad, 0x2c40, 0x2cd6, 0x2d6d, 0x2e06, 0x2ea2, 0x2f3f, 0x2fdf, - 0x3080, 0x3124, 0x31ca, 0x3272, 0x331c, 0x33c9, 0x3477, 0x3529, - 0x35dc, 0x3692, 0x374a, 0x3805, 0x38c2, 0x3981, 0x3a43, 0x3b08, - 0x3bcf, 0x3c99, 0x3d66, 0x3e35, 0x3f07, 0x3fdc, 0x40b3, 0x418e, - 0x426b, 0x434b, 0x442e, 0x4514, 0x45fe, 0x46ea, 0x47d9, 0x48cc, - 0x49c2, 0x4aba, 0x4bb7, 0x4cb6, 0x4db9, 0x4ec0, 0x4fc9, 0x50d7, - 0x51e8, 0x52fc, 0x5414, 0x5530, 0x564f, 0x5773, 0x589a, 0x59c5, - 0x5af4, 0x5c27, 0x5d5e, 0x5e99, 0x5fd9, 0x611c, 0x6264, 0x63b0, - 0x6501, 0x6655, 0x67af, 0x690d, 0x6a6f, 0x6bd7, 0x6d43, 0x6eb3, - 0x7029, 0x71a4, 0x7323, 0x74a8, 0x7632, 0x77c1, 0x7955, 0x7aee, - 0x7c8d, 0x7e32, 0x7fdc, 0x818b, 0x8341, 0x84fc, 0x86bc, 0x8883, - 0x8a50, 0x8c23, 0x8dfc, 0x8fdb, 0x91c1, 0x93ad, 0x959f, 0x9798, - 0x9998, 0x9b9e, 0x9dac, 0x9fc0, 0xa1db, 0xa3fd, 0xa627, 0xa858, - 0xaa90, 0xacd0, 0xaf17, 0xb166, 0xb3bd, 0xb61c, 0xb882, 0xbaf1, - 0xbd68, 0xbfe7, 0xc26f, 0xc4ff, 0xc798, 0xca3a, 0xcce5, 0xcf98, - 0xd255, 0xd51b, 0xd7ea, 0xdac3, 0xdda5, 0xe092, 0xe388, 0xe688, - 0xe992, 0xeca6, 0xefc5, 0xf2ee, 0xf622, 0xf961, 0xfcab, 0xffff, + 0x0000, 0x0104, 0x010a, 0x0110, 0x0116, 0x011c, 0x0122, 0x0129, + 0x012f, 0x0136, 0x013d, 0x0144, 0x014b, 0x0152, 0x015a, 0x0161, + 0x0169, 0x0171, 0x0179, 0x0181, 0x018a, 0x0193, 0x019c, 0x01a5, + 0x01ae, 0x01b7, 0x01c1, 0x01cb, 0x01d5, 0x01df, 0x01ea, 0x01f5, + 0x0200, 0x020b, 0x0216, 0x0222, 0x022e, 0x023b, 0x0247, 0x0254, + 0x0261, 0x026e, 0x027c, 0x028a, 0x0298, 0x02a7, 0x02b6, 0x02c5, + 0x02d5, 0x02e5, 0x02f5, 0x0306, 0x0317, 0x0328, 0x033a, 0x034c, + 0x035f, 0x0372, 0x0385, 0x0399, 0x03ad, 0x03c2, 0x03d7, 0x03ed, + 0x0403, 0x041a, 0x0431, 0x0448, 0x0460, 0x0479, 0x0492, 0x04ac, + 0x04c6, 0x04e1, 0x04fd, 0x0519, 0x0535, 0x0553, 0x0571, 0x058f, + 0x05af, 0x05cf, 0x05ef, 0x0611, 0x0633, 0x0656, 0x067a, 0x069e, + 0x06c3, 0x06ea, 0x0710, 0x0738, 0x0761, 0x078a, 0x07b5, 0x07e0, + 0x080d, 0x083a, 0x0868, 0x0898, 0x08c8, 0x08fa, 0x092c, 0x0960, + 0x0995, 0x09cb, 0x0a02, 0x0a3a, 0x0a74, 0x0aae, 0x0aeb, 0x0b28, + 0x0b67, 0x0ba7, 0x0be9, 0x0c2c, 0x0c70, 0x0cb6, 0x0cfe, 0x0d47, + 0x0d92, 0x0dde, 0x0e2d, 0x0e7c, 0x0ece, 0x0f21, 0x0f76, 0x0fce, + 0x1027, 0x1081, 0x10de, 0x113d, 0x119f, 0x1202, 0x1267, 0x12cf, + 0x1339, 0x13a5, 0x1414, 0x1485, 0x14f8, 0x156e, 0x15e7, 0x1662, + 0x16e0, 0x1761, 0x17e5, 0x186b, 0x18f5, 0x1981, 0x1a11, 0x1aa4, + 0x1b3a, 0x1bd3, 0x1c70, 0x1d10, 0x1db4, 0x1e5b, 0x1f06, 0x1fb4, + 0x2067, 0x211d, 0x21d8, 0x2297, 0x2359, 0x2420, 0x24ec, 0x25bc, + 0x2690, 0x2769, 0x2847, 0x292a, 0x2a12, 0x2aff, 0x2bf1, 0x2ce8, + 0x2de5, 0x2ee8, 0x2ff0, 0x30fe, 0x3211, 0x332b, 0x344c, 0x3572, + 0x369f, 0x37d2, 0x390d, 0x3a4e, 0x3b96, 0x3ce6, 0x3e3d, 0x3f9b, + 0x4101, 0x426f, 0x43e6, 0x4564, 0x46eb, 0x487a, 0x4a12, 0x4bb3, + 0x4d5d, 0x4f11, 0x50ce, 0x5295, 0x5466, 0x5642, 0x5827, 0x5a18, + 0x5c13, 0x5e19, 0x602b, 0x6249, 0x6472, 0x66a8, 0x68ea, 0x6b39, + 0x6d94, 0x6ffd, 0x7274, 0x74f8, 0x778b, 0x7a2c, 0x7cdc, 0x7f9b, + 0x826a, 0x8548, 0x8836, 0x8b35, 0x8e45, 0x9166, 0x9499, 0x97de, + 0x9b35, 0x9e9f, 0xa21c, 0xa5ad, 0xa952, 0xad0b, 0xb0da, 0xb4bd, + 0xb8b7, 0xbcc7, 0xc0ee, 0xc52d, 0xc983, 0xcdf1, 0xd279, 0xd71a, + 0xdbd5, 0xe0ab, 0xe59c, 0xeaa9, 0xefd3, 0xf519, 0xfa7d, 0xffff, }; #endif /* DOC_HIDDEN */ @@ -96,7 +98,7 @@ typedef union { int i; short s[2]; } val_t; -static inline int MULTI_DIV(int a, unsigned short b) +static inline int MULTI_DIV_int(int a, unsigned short b) { val_t v, x, y; v.i = a; @@ -113,71 +115,135 @@ static inline int MULTI_DIV(int a, unsigned short b) return y.i; } +/* (16bit x 16bit) >> 16 */ +#define MULTI_DIV_short(src,scale) (((int)(src) * (scale)) >> VOL_SCALE_SHIFT) + + /* * apply volumue attenuation * * TODO: use SIMD operations */ -static void snd_pcm_softvol_convert(snd_pcm_softvol_t *svol, - const snd_pcm_channel_area_t *dst_areas, - snd_pcm_uframes_t dst_offset, - const snd_pcm_channel_area_t *src_areas, - snd_pcm_uframes_t src_offset, - unsigned int channels, - snd_pcm_uframes_t frames, - unsigned int cur_vol) + +#define CONVERT_AREA(TYPE) do { \ + unsigned int ch, fr; \ + TYPE *src, *dst; \ + for (ch = 0; ch < channels; ch++) { \ + src_area = &src_areas[ch]; \ + dst_area = &dst_areas[ch]; \ + src = snd_pcm_channel_area_addr(src_area, src_offset); \ + dst = snd_pcm_channel_area_addr(dst_area, dst_offset); \ + src_step = snd_pcm_channel_area_step(src_area) / sizeof(TYPE); \ + dst_step = snd_pcm_channel_area_step(dst_area) / sizeof(TYPE); \ + GET_VOL_SCALE; \ + fr = frames; \ + if (! vol_scale) { \ + while (fr--) { \ + *dst = 0; \ + dst += dst_step; \ + } \ + } else if (vol_scale == 0xffff) { \ + while (fr--) { \ + *dst = *src; \ + src += src_step; \ + dst += dst_step; \ + } \ + } else { \ + while (fr--) { \ + *dst = MULTI_DIV_##TYPE(*src, vol_scale);\ + src += src_step; \ + dst += dst_step; \ + } \ + } \ + } \ +} while (0) + + + +#define GET_VOL_SCALE \ + switch (ch) { \ + case 0: \ + case 2: \ + vol_scale = (channels == ch + 1) ? vol_c : vol[0]; \ + break; \ + case 4: \ + case 5: \ + vol_scale = vol_c; \ + break; \ + default: \ + vol_scale = vol[ch & 1]; \ + break; \ + } + +/* 2-channel stereo control */ +static void softvol_convert_stereo_vol(snd_pcm_softvol_t *svol, + const snd_pcm_channel_area_t *dst_areas, + snd_pcm_uframes_t dst_offset, + const snd_pcm_channel_area_t *src_areas, + snd_pcm_uframes_t src_offset, + unsigned int channels, + snd_pcm_uframes_t frames) +{ + const snd_pcm_channel_area_t *dst_area, *src_area; + unsigned int src_step, dst_step; + unsigned int vol_scale, vol[2], vol_c; + + if (svol->cur_vol[0] == 0 && svol->cur_vol[1] == 0) { + snd_pcm_areas_silence(dst_areas, dst_offset, channels, frames, + svol->sformat); + return; + } else if (svol->cur_vol[0] == svol->max_val && + svol->cur_vol[1] == svol->max_val) { + snd_pcm_areas_copy(dst_areas, dst_offset, src_areas, src_offset, + channels, frames, svol->sformat); + return; + } + + vol[0] = svol->dB_value[svol->cur_vol[0]]; + vol[1] = svol->dB_value[svol->cur_vol[1]]; + vol_c = svol->dB_value[(svol->cur_vol[0] + svol->cur_vol[1]) / 2]; + if (svol->sformat == SND_PCM_FORMAT_S16) { + /* 16bit samples */ + CONVERT_AREA(short); + } else { + /* 32bit samples */ + CONVERT_AREA(int); + } +} + +#undef GET_VOL_SCALE +#define GET_VOL_SCALE + +/* mono control */ +static void softvol_convert_mono_vol(snd_pcm_softvol_t *svol, + const snd_pcm_channel_area_t *dst_areas, + snd_pcm_uframes_t dst_offset, + const snd_pcm_channel_area_t *src_areas, + snd_pcm_uframes_t src_offset, + unsigned int channels, + snd_pcm_uframes_t frames) { const snd_pcm_channel_area_t *dst_area, *src_area; unsigned int src_step, dst_step; - unsigned int ch; - unsigned int fr; unsigned int vol_scale; - if (cur_vol == 0) { + if (svol->cur_vol[0] == 0) { snd_pcm_areas_silence(dst_areas, dst_offset, channels, frames, svol->sformat); return; - } else if (cur_vol == svol->max_val) { + } else if (svol->cur_vol[0] == svol->max_val) { snd_pcm_areas_copy(dst_areas, dst_offset, src_areas, src_offset, channels, frames, svol->sformat); return; } - vol_scale = svol->dB_value[cur_vol]; + vol_scale = svol->dB_value[svol->cur_vol[0]]; if (svol->sformat == SND_PCM_FORMAT_S16) { /* 16bit samples */ - short *src, *dst; - for (ch = 0; ch < channels; ch++) { - src_area = &src_areas[ch]; - dst_area = &dst_areas[ch]; - src = snd_pcm_channel_area_addr(src_area, src_offset); - dst = snd_pcm_channel_area_addr(dst_area, dst_offset); - src_step = snd_pcm_channel_area_step(src_area) / sizeof(short); - dst_step = snd_pcm_channel_area_step(dst_area) / sizeof(short); - fr = frames; - while (fr--) { - *dst = ((int)*src * vol_scale) >> VOL_SCALE_SHIFT; - src += src_step; - dst += dst_step; - } - } + CONVERT_AREA(short); } else { /* 32bit samples */ - int *src, *dst; - for (ch = 0; ch < channels; ch++) { - src_area = &src_areas[ch]; - dst_area = &dst_areas[ch]; - src = snd_pcm_channel_area_addr(src_area, src_offset); - dst = snd_pcm_channel_area_addr(dst_area, dst_offset); - src_step = snd_pcm_channel_area_step(src_area) / sizeof(int); - dst_step = snd_pcm_channel_area_step(dst_area) / sizeof(int); - fr = frames; - while (fr--) { - *dst = MULTI_DIV(*src, vol_scale); - src += src_step; - dst += dst_step; - } - } + CONVERT_AREA(int); } } @@ -186,16 +252,19 @@ static void snd_pcm_softvol_convert(snd_pcm_softvol_t *svol, * * TODO: mmap support? */ -static unsigned int get_current_volume(snd_pcm_softvol_t *svol) +static void get_current_volume(snd_pcm_softvol_t *svol) { unsigned int val; + unsigned int i; + if (snd_ctl_elem_read(svol->ctl, &svol->elem) < 0) - return 0; - /* set max vol as default */ - val = svol->elem.value.integer.value[0]; - if (val > svol->max_val) - val = svol->max_val; - return val; + return; + for (i = 0; i < svol->cchannels; i++) { + val = svol->elem.value.integer.value[i]; + if (val > svol->max_val) + val = svol->max_val; + svol->cur_vol[i] = val; + } } static void softvol_free(snd_pcm_softvol_t *svol) @@ -251,7 +320,6 @@ static int snd_pcm_softvol_hw_refine_sprepare(snd_pcm_t *pcm, snd_pcm_hw_params_ _snd_pcm_hw_params_set_format(sparams, svol->sformat); _snd_pcm_hw_params_set_subformat(sparams, SND_PCM_SUBFORMAT_STD); } - _snd_pcm_hw_params_set_subformat(sparams, SND_PCM_SUBFORMAT_STD); return 0; } @@ -345,10 +413,13 @@ snd_pcm_softvol_write_areas(snd_pcm_t *pcm, snd_pcm_softvol_t *svol = pcm->private_data; if (size > *slave_sizep) size = *slave_sizep; - snd_pcm_softvol_convert(svol, slave_areas, slave_offset, - areas, offset, - pcm->channels, - size, get_current_volume(svol)); + get_current_volume(svol); + if (svol->cchannels == 1) + softvol_convert_mono_vol(svol, slave_areas, slave_offset, + areas, offset, pcm->channels, size); + else + softvol_convert_stereo_vol(svol, slave_areas, slave_offset, + areas, offset, pcm->channels, size); *slave_sizep = size; return size; } @@ -365,10 +436,13 @@ snd_pcm_softvol_read_areas(snd_pcm_t *pcm, snd_pcm_softvol_t *svol = pcm->private_data; if (size > *slave_sizep) size = *slave_sizep; - snd_pcm_softvol_convert(svol, areas, offset, - slave_areas, slave_offset, - pcm->channels, - size, get_current_volume(svol)); + get_current_volume(svol); + if (svol->cchannels == 1) + softvol_convert_mono_vol(svol, areas, offset, slave_areas, + slave_offset, pcm->channels, size); + else + softvol_convert_stereo_vol(svol, areas, offset, slave_areas, + slave_offset, pcm->channels, size); *slave_sizep = size; return size; } @@ -388,14 +462,17 @@ static void snd_pcm_softvol_dump(snd_pcm_t *pcm, snd_output_t *out) snd_pcm_dump(svol->plug.slave, out); } -static int add_user_ctl(snd_pcm_softvol_t *svol, snd_ctl_elem_info_t *cinfo) +static int add_user_ctl(snd_pcm_softvol_t *svol, snd_ctl_elem_info_t *cinfo, int count) { int err; + unsigned int i; - err = snd_ctl_elem_add_integer(svol->ctl, &cinfo->id, 1, 0, svol->max_val, 0); + err = snd_ctl_elem_add_integer(svol->ctl, &cinfo->id, count, 0, svol->max_val, 0); if (err < 0) return err; - svol->elem.value.integer.value[0] = svol->max_val; + /* set max value as default */ + for (i = 0; i < count; i++) + svol->elem.value.integer.value[i] = svol->max_val; return snd_ctl_elem_write(svol->ctl, &svol->elem); } @@ -407,7 +484,7 @@ static int add_user_ctl(snd_pcm_softvol_t *svol, snd_ctl_elem_info_t *cinfo) */ static int softvol_load_control(snd_pcm_t *pcm, snd_pcm_softvol_t *svol, int ctl_card, snd_ctl_elem_id_t *ctl_id, - double min_dB, int resolution) + int cchannels, double min_dB, int resolution) { char tmp_name[32]; snd_pcm_info_t *info; @@ -444,7 +521,7 @@ static int softvol_load_control(snd_pcm_t *pcm, snd_pcm_softvol_t *svol, SNDERR("Cannot get info for CTL %s", tmp_name); return err; } - err = add_user_ctl(svol, cinfo); + err = add_user_ctl(svol, cinfo, cchannels); if (err < 0) { SNDERR("Cannot add a control"); return err; @@ -455,13 +532,16 @@ static int softvol_load_control(snd_pcm_t *pcm, snd_pcm_softvol_t *svol, return 1; /* notify */ } else if (cinfo->type != SND_CTL_ELEM_TYPE_INTEGER || - cinfo->count != 1 || - cinfo->value.integer.min != 0 || - cinfo->value.integer.max != resolution - 1) { - snd_ctl_elem_remove(svol->ctl, &cinfo->id); - err = add_user_ctl(svol, cinfo); - if (err < 0) { - SNDERR("Cannot replace a control"); + cinfo->count != (unsigned int)cchannels || + cinfo->value.integer.min != 0 || + cinfo->value.integer.max != resolution - 1) { + if ((err = snd_ctl_elem_remove(svol->ctl, &cinfo->id)) < 0) { + SNDERR("Control %s mismatch", tmp_name); + return err; + } + snd_ctl_elem_info_set_id(cinfo, ctl_id); /* reset numid */ + if ((err = add_user_ctl(svol, cinfo, cchannels)) < 0) { + SNDERR("Cannot add a control"); return err; } } @@ -479,7 +559,7 @@ static int softvol_load_control(snd_pcm_t *pcm, snd_pcm_softvol_t *svol, svol->min_dB = min_dB; for (i = 1; i < svol->max_val; i++) { double db = svol->min_dB - ((i - 1) * svol->min_dB) / (svol->max_val - 1); - double v = (pow(2.0, db / 10.0) * (double)(1 << VOL_SCALE_SHIFT)); + double v = (pow(10.0, db / 20.0) * (double)(1 << VOL_SCALE_SHIFT)); svol->dB_value[i] = (unsigned short)v; } svol->dB_value[svol->max_val] = 65535; @@ -525,6 +605,7 @@ static snd_pcm_ops_t snd_pcm_softvol_ops = { int snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sformat, int ctl_card, snd_ctl_elem_id_t *ctl_id, + int cchannels, double min_dB, int resolution, snd_pcm_t *slave, int close_slave) { @@ -539,7 +620,8 @@ int snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name, svol = calloc(1, sizeof(*svol)); if (! svol) return -ENOMEM; - err = softvol_load_control(slave, svol, ctl_card, ctl_id, min_dB, resolution); + err = softvol_load_control(slave, svol, ctl_card, ctl_id, cchannels, + min_dB, resolution); if (err < 0) { softvol_free(svol); return err; @@ -553,6 +635,7 @@ int snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name, /* do softvol */ snd_pcm_plugin_init(&svol->plug); svol->sformat = sformat; + svol->cchannels = cchannels; svol->plug.read = snd_pcm_softvol_read_areas; svol->plug.write = snd_pcm_softvol_write_areas; svol->plug.undo_read = snd_pcm_plugin_undo_read_generic; @@ -580,7 +663,8 @@ int snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name, /* * parse card index and id for the softvol control */ -static int parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int *cardp) +static int parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int *cardp, + int *cchannelsp) { snd_config_iterator_t i, next; int iface = SND_CTL_ELEM_IFACE_MIXER; @@ -591,6 +675,7 @@ static int parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int * int err; *cardp = -1; + *cchannelsp = 2; snd_config_for_each(i, next, conf) { snd_config_t *n = snd_config_iterator_entry(i); const char *id; @@ -648,6 +733,19 @@ static int parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int * } continue; } + if (strcmp(id, "count") == 0) { + long v; + if ((err = snd_config_get_integer(n, &v)) < 0) { + SNDERR("field %s is not an integer", id); + goto _err; + } + if (v < 1 || v > 2) { + SNDERR("Invalid count %ld", v); + goto _err; + } + *cchannelsp = v; + continue; + } SNDERR("Unknown field %s", id); return -EINVAL; } @@ -680,6 +778,9 @@ static int parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int * This plugin applies the software volume attenuation. The format, rate and channels must match for both of source and destination. +When the control is stereo (count=2), the channels are assumed to be either +mono, 2.0, 2.1, 4.0, 4.1, 5.1 or 7.1. + If the control already exists and it's a system control (i.e. no user-defined control), the plugin simply passes its slave without any changes. @@ -697,13 +798,14 @@ pcm.name { } control { name STR # control element id string - [card STR] # control name (e.g. hw:0) + [card INT] # control card index [iface STR] # interface of the element [index INT] # index of the element [device INT] # device number of the element [subdevice INT] # subdevice number of the element + [count INT] # control channels 1 or 2 (default: 2) } - [min_dB REAL] # minimal dB value (default: -48 dB) + [min_dB REAL] # minimal dB value (default: -48.0) [resolution INT] # resolution (default: 256) } \endcode @@ -743,7 +845,7 @@ int _snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name, snd_ctl_elem_id_t *ctl_id; int resolution = PRESET_RESOLUTION; double min_dB = PRESET_MIN_DB; - int card = -1; + int card = -1, cchannels = 2; snd_config_for_each(i, next, conf) { snd_config_t *n = snd_config_iterator_entry(i); @@ -813,11 +915,12 @@ int _snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name, if (err < 0) return err; snd_ctl_elem_id_alloca(&ctl_id); - if ((err = parse_control_id(control, ctl_id, &card)) < 0) { + if ((err = parse_control_id(control, ctl_id, &card, &cchannels)) < 0) { snd_pcm_close(spcm); return err; } - err = snd_pcm_softvol_open(pcmp, name, sformat, card, ctl_id, min_dB, resolution, spcm, 1); + err = snd_pcm_softvol_open(pcmp, name, sformat, card, ctl_id, cchannels, + min_dB, resolution, spcm, 1); if (err < 0) snd_pcm_close(spcm); return err;