diff --git a/lib/libmixer/mixer.3 b/lib/libmixer/mixer.3 index 4008867ef2fb..04aa3bd1dca7 100644 --- a/lib/libmixer/mixer.3 +++ b/lib/libmixer/mixer.3 @@ -1,593 +1,590 @@ .\"- .\" Copyright (c) 2021-2022 Christos Margiolis .\" .\" Permission is hereby granted, free of charge, to any person obtaining a copy .\" of this software and associated documentation files (the "Software"), to deal .\" in the Software without restriction, including without limitation the rights .\" to use, copy, modify, merge, publish, distribute, sublicense, and/or sell .\" copies of the Software, and to permit persons to whom the Software is .\" furnished to do so, subject to the following conditions: .\" .\" The above copyright notice and this permission notice shall be included in .\" all copies or substantial portions of the Software. .\" .\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR .\" IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, .\" FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE .\" AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER .\" LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, .\" OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN .\" THE SOFTWARE. .\" -.Dd May 22, 2024 +.Dd August 4, 2024 .Dt MIXER 3 .Os .Sh NAME .Nm mixer_open , .Nm mixer_close , .Nm mixer_get_dev , .Nm mixer_get_dev_byname , .Nm mixer_add_ctl , .Nm mixer_add_ctl_s , .Nm mixer_remove_ctl , .Nm mixer_get_ctl , .Nm mixer_get_ctl_byname , .Nm mixer_set_vol , .Nm mixer_set_mute , .Nm mixer_mod_recsrc , .Nm mixer_get_dunit , .Nm mixer_set_dunit , .Nm mixer_get_mode , .Nm mixer_get_nmixers , .Nm mixer_get_path , .Nm MIX_ISDEV , .Nm MIX_ISMUTE , .Nm MIX_ISREC , .Nm MIX_ISRECSRC , .Nm MIX_VOLNORM , .Nm MIX_VOLDENORM .Nd interface to OSS mixers .Sh LIBRARY Mixer library (libmixer, -lmixer) .Sh SYNOPSIS .In mixer.h .Ft struct mixer * .Fn mixer_open "const char *name" .Ft int .Fn mixer_close "struct mixer *m" .Ft struct mix_dev * .Fn mixer_get_dev "struct mixer *m" "int devno" .Ft struct mix_dev * .Fn mixer_get_dev_byname "struct mixer *m" "name" .Ft int .Fn mixer_add_ctl "struct mix_dev *parent" "int id" "const char *name" \ "int (*mod)(struct mix_dev *d, void *p)" \ "int (*print)(struct mix_dev *d, void *p)" .Ft int .Fn mixer_add_ctl_s "mix_ctl_t *ctl" .Ft int .Fn mixer_remove_ctl "mix_ctl_t *ctl" .Ft mix_ctl_t * .Fn mixer_get_ctl "struct mix_dev *d" "int id" .Ft mix_ctl_t * .Fn mixer_get_ctl_byname "struct mix_dev *d" "const char *name" .Ft int .Fn mixer_set_vol "struct mixer *m" "mix_volume_t vol" .Ft int .Fn mixer_set_mute "struct mixer *m" "int opt" .Ft int .Fn mixer_mod_recsrc "struct mixer *m" "int opt" .Ft int .Fn mixer_get_dunit "void" .Ft int .Fn mixer_set_dunit "struct mixer *m" "int unit" .Ft int .Fn mixer_get_mode "int unit" .Ft int .Fn mixer_get_nmixers "void" .Ft int .Fn mixer_get_path "char * buf" "size_t size" "int unit" .Ft int .Fn MIX_ISDEV "struct mixer *m" "int devno" .Ft int .Fn MIX_ISMUTE "struct mixer *m" "int devno" .Ft int .Fn MIX_ISREC "struct mixer *m" "int devno" .Ft int .Fn MIX_ISRECSRC "struct mixer *m" "int devno" .Ft float .Fn MIX_VOLNORM "int v" .Ft int .Fn MIX_VOLDENORM "float v" .Sh DESCRIPTION The .Nm mixer library allows userspace programs to access and manipulate OSS sound mixers in a simple way. .Ss Mixer A mixer is described by the following structure: .Bd -literal struct mixer { TAILQ_HEAD(mix_devhead, mix_dev) devs; /* device list */ struct mix_dev *dev; /* selected device */ oss_mixerinfo mi; /* mixer info */ oss_card_info ci; /* audio card info */ char name[NAME_MAX]; /* mixer name (e.g /dev/mixer0) */ int fd; /* file descriptor */ int unit; /* audio card unit */ int ndev; /* number of devices */ int devmask; /* supported devices */ #define MIX_MUTE 0x01 #define MIX_UNMUTE 0x02 #define MIX_TOGGLEMUTE 0x04 int mutemask; /* muted devices */ int recmask; /* recording devices */ #define MIX_ADDRECSRC 0x01 #define MIX_REMOVERECSRC 0x02 #define MIX_SETRECSRC 0x04 #define MIX_TOGGLERECSRC 0x08 int recsrc; /* recording sources */ #define MIX_MODE_MIXER 0x01 #define MIX_MODE_PLAY 0x02 #define MIX_MODE_REC 0x04 int mode; /* dev.pcm.X.mode sysctl */ int f_default; /* default mixer flag */ }; .Ed .Pp The fields are follows: .Bl -tag -width "f_default" .It Fa devs A tail queue structure containing all supported mixer devices. .It Fa dev A pointer to the currently selected device. The device is one of the elements in .Ar devs . .It Fa mi OSS information about the mixer. Look at the definition of the .Ft oss_mixerinfo structure in .In sys/soundcard.h to see its fields. .It Fa ci OSS audio card information. This structure is also defined in .In sys/soundcard.h . .It Fa name Path to the mixer (e.g /dev/mixer0). .It Fa fd File descriptor returned when the mixer is opened in .Fn mixer_open . .It Fa unit Audio card unit. Since each mixer device maps to a pcmX device, .Ar unit is always equal to the number of that pcmX device. For example, if the audio device's number is 0 (i.e pcm0), then .Ar unit is 0 as well. This number is useful when checking if the mixer's audio card is the default one. .It Fa ndev Number of devices in .Ar devs . .It Fa devmask Bit mask containing all supported devices for the mixer. For example, if device 10 is supported, then the 10th bit in the mask will be set. By default, .Fn mixer_open stores only the supported devices in devs, so it is very unlikely this mask will be needed. .It Fa mutemask Bit mask containing all muted devices. The logic is the same as with .Ar devmask . .It Fa recmask Bit mask containing all recording devices. Again, same logic as with the other masks. .It Fa recsrc Bit mask containing all recording sources. Yes, same logic again. .It Fa mode Bit mask containing the supported modes for this audio device. It holds the value of the .Ar dev.pcm.X.mode sysctl. .It Fa f_default Flag which tells whether the mixer's audio card is the default one. .El .Ss Mixer device Each mixer device stored in a mixer is described as follows: .Bd -literal struct mix_dev { struct mixer *parent_mixer; /* parent mixer */ char name[NAME_MAX]; /* device name (e.g "vol") */ int devno; /* device number */ struct mix_volume { #define MIX_VOLMIN 0.0f #define MIX_VOLMAX 1.0f #define MIX_VOLNORM(v) ((v) / 100.0f) #define MIX_VOLDENORM(v) ((int)((v) * 100.0f + 0.5f)) float left; /* left volume */ float right; /* right volume */ } vol; int nctl; /* number of controls */ TAILQ_HEAD(mix_ctlhead, mix_ctl) ctls; /* control list */ TAILQ_ENTRY(mix_dev) devs; }; .Ed .Pp The fields are follows: .Bl -tag -width "parent_mixer" .It Fa parent_mixer Pointer to the mixer the device is attached to. .It Fa name Device name given by the OSS API. Devices can have one of the following names: .Bd -ragged vol, bass, treble, synth, pcm, speaker, line, mic, cd, mix, pcm2, rec, igain, ogain, line1, line2, line3, dig1, dig2, dig3, phin, phout, video, radio, and monitor. .Ed .It Fa devno Device's index in the SOUND_MIXER_NRDEVICES macro defined in .In sys/soundcard.h . This number is used to check against the masks defined in the .Ar mixer structure. .It Fa left right Left and right-ear volumes. Although the OSS API stores volumes in integers from 0-100, \ we normalize them to 32-bit floating point numbers. However, the volumes can be denormalized using the .Ar MIX_VOLDENORM macro if needed. .It Fa nctl Number of user-defined mixer controls associated with the device. .It Fa ctls A tail queue containing user-defined mixer controls. .El .Ss User-defined mixer controls Each mixer device can have user-defined controls. The control structure is defined as follows: .Bd -literal struct mix_ctl { struct mix_dev *parent_dev; /* parent device */ int id; /* control id */ char name[NAME_MAX]; /* control name */ int (*mod)(struct mix_dev *, void *); /* modify control values */ int (*print)(struct mix_dev *, void *); /* print control */ TAILQ_ENTRY(mix_ctl) ctls; }; .Ed .Pp The fields are follows: .Bl -tag -width "parent_dev" .It Fa parent_dev Pointer to the device the control is attached to. .It Fa id Control ID assigned by the caller. Even though the library will report it, care has to be taken to not give \ a control the same ID in case the caller has to choose controls using their ID. .It Fa name Control name. As with .Ar id , the caller has to make sure the same name is not used more than once. .It Fa mod Function pointer to a control modification function. As in .Xr mixer 8 , each mixer control's values can be modified. For example, if we have a volume control, the .Ar mod function will be responsible for handling volume changes. .It Fa print Function pointer to a control print function. .El .Ss Opening and closing the mixer The application must first call the .Fn mixer_open function to obtain a handle to the device, which is used as an argument \ in most other functions and macros. The parameter .Ar name specifies the path to the mixer. OSS mixers are stored under .Ar /dev/mixerN where .Ar N is the number of the mixer device. Each device maps to an actual .Ar pcm audio card, so .Ar /dev/mixer0 is the mixer for .Ar pcm0 , and so on. If .Ar name is .Ar NULL or .Ar /dev/mixer , .Fn mixer_open opens the default mixer (hw.snd.default_unit). .Pp The .Fn mixer_close function frees resources and closes the mixer device. It is a good practice to always call it when the application is done using the mixer. .Ss Manipulating the mixer The .Fn mixer_get_dev and .Fn mixer_get_dev_byname functions select a mixer device, either by its number or by its name respectively. The mixer structure keeps a list of all the devices, but only one can be manipulated at a time. Each time a new device is to be manipulated, one of the two functions has to be called. .Pp The .Fn mixer_set_vol function changes the volume of the selected mixer device. The .Ar vol parameter is a structure that stores the left and right volumes of a given device. The allowed volume values are between MIX_VOLMIN (0.0) and MIX_VOLMAX (1.0). .Pp The .Fn mixer_set_mute function modifies the mute of a selected device. The .Ar opt parameter has to be one of the following options: .Bl -tag -width MIX_TOGGLEMUTE -offset indent .It Dv MIX_MUTE Mute the device. .It Dv MIX_UNMUTE Unmute the device. .It Dv MIX_TOGGLEMUTE Toggle the device's mute (e.g mute if unmuted and unmute if muted). .El .Pp The .Fn mixer_mod_recsrc function modifies a recording device. The selected device has to be a recording device, otherwise the function will fail. The .Ar opt parameter has to be one of the following options: .Bl -tag -width MIX_REMOVERECSRC -offset indent .It Dv MIX_ADDRECSRC Add device to the recording sources. .It Dv MIX_REMOVERECSRC Remove device from the recording sources. .It Dv MIX_SETRECSRC Set device as the only recording source. .It Dv MIX_TOGGLERECSRC Toggle device from the recording sources. .El .Pp The .Fn mixer_get_dunit and .Fn mixer_set_dunit functions get and set the default audio card in the system. Although this is not really a mixer feature, it is useful to have instead of \ having to use the .Xr sysctl 3 controls. .Pp The .Fn mixer_get_mode -function returns the playback/recording mode of the audio device the mixer \ -belongs to. -The available values are the following: -.Bl -tag -width "MIX_STATUS_PLAY | MIX_STATUS_REC" -offset indent -.It Dv MIX_STATUS_NONE -Neither playback nor recording. -.It Dv MIX_STATUS_PLAY -Playback. -.It Dv MIX_STATUS_REC -Recording. -.It Dv MIX_STATUS_PLAY | MIX_STATUS_REC -Playback and recording. +function returns the operating mode of the audio device the mixer belongs to. +The following values can be OR'ed in case more than one mode is supported: +.Bl -tag -width "MIX_MODE_MIXER" -offset indent +.It Dv MIX_MODE_MIXER +The audio device has a mixer. +.It Dv MIX_MODE_PLAY +The audio device supports playback. +.It Dv MIX_MODE_REC +The audio device supports recording. .El .Pp The .Fn mixer_get_nmixers function returns the maximum mixer unit number. Although this might sound as incorrect behavior, given that one would expect "nmixers" to refer to the total number of active mixers, it is more intuitive for applications that want to loop through all mixer devices (see the .Sx EXAMPLES section). .Pp The .Fn mixer_get_path function writes the path of the mixer device specified in the .Ar unit argument to the buffer specified in .Ar buf . .Ar unit can be either -1, in which case .Fn mixer_get_path will fetch the path of the default mixer, or between 0 and the maximum mixer unit. .Pp The .Fn MIX_ISDEV macro checks if a device is actually a valid device for a given mixer. It is very unlikely that this macro will ever be needed since the library \ stores only valid devices by default. .Pp The .Fn MIX_ISMUTE macro checks if a device is muted. .Pp The .Fn MIX_ISREC macro checks if a device is a recording device. .Pp The .Fn MIX_ISRECSRC macro checks if a device is a recording source. .Pp The .Fn MIX_VOLNORM macro normalizes a value to 32-bit floating point number. It is used to normalize the volumes read from the OSS API. .Pp The .Fn MIX_VOLDENORM macro denormalizes the left and right volumes stores in the .Ft mix_dev structure. .Ss Defining and using mixer controls The .Fn mix_add_ctl function creates a control and attaches it to the device specified in the .Ar parent argument. .Pp The .Fn mix_add_ctl_s function does the same thing as with .Fn mix_add_ctl but the caller passes a .Ft mix_ctl_t * structure instead of each field as a separate argument. .Pp The .Fn mixer_remove_ctl functions removes a control from the device its attached to. .Pp The .Fn mixer_get_ctl function searches for a control in the device specified in the .Ar d argument and returns a pointer to it. The search is done using the control's ID. .Pp The .Fn mixer_get_ctl_byname function is the same as with .Fn mixer_get_ctl but the search is done using the control's name. .Sh RETURN VALUES The .Fn mixer_open function returns the newly created handle on success and NULL on failure. .Pp The .Fn mixer_close , .Fn mixer_set_vol , .Fn mixer_set_mute , .Fn mixer_mod_recsrc , .Fn mixer_get_dunut , .Fn mixer_set_dunit , .Fn mixer_get_nmixers , and .Fn mixer_get_path functions return 0 or positive values on success and -1 on failure. .Pp The .Fn mixer_get_dev and .Fn mixer_get_dev_byname functions return the selected device on success and NULL on failure. .Pp All functions set the value of .Ar errno on failure. .Sh EXAMPLES .Ss Change the volume of a device .Bd -literal struct mixer *m; mix_volume_t vol; char *mix_name, *dev_name; mix_name = ...; if ((m = mixer_open(mix_name)) == NULL) err(1, "mixer_open: %s", mix_name); dev_name = ...; if ((m->dev = mixer_get_dev_byname(m, dev_name)) < 0) err(1, "unknown device: %s", dev_name); vol.left = ...; vol.right = ....; if (mixer_set_vol(m, vol) < 0) warn("cannot change volume"); (void)mixer_close(m); .Ed .Ss Mute all unmuted devices .Bd -literal struct mixer *m; struct mix_dev *dp; if ((m = mixer_open(NULL)) == NULL) /* Open the default mixer. */ err(1, "mixer_open"); TAILQ_FOREACH(dp, &m->devs, devs) { m->dev = dp; /* Select device. */ if (M_ISMUTE(m, dp->devno)) continue; if (mixer_set_mute(m, MIX_MUTE) < 0) warn("cannot mute device: %s", dp->name); } (void)mixer_close(m); .Ed .Ss Print all recording sources' names and volumes .Bd -literal struct mixer *m; struct mix_dev *dp; char *mix_name, *dev_name; mix_name = ...; if ((m = mixer_open(mix_name)) == NULL) err(1, "mixer_open: %s", mix_name); TAILQ_FOREACH(dp, &m->devs, devs) { if (M_ISRECSRC(m, dp->devno)) printf("%s\\t%.2f:%.2f\\n", dp->name, dp->vol.left, dp->vol.right); } (void)mixer_close(m); .Ed .Ss Loop through all mixer devices in the system .Bd -literal struct mixer *m; char buf[NAME_MAX]; int n; if ((n = mixer_get_nmixers()) < 0) errx(1, "no mixers present in the system"); for (i = 0; i < n; i++) { (void)mixer_get_path(buf, sizeof(buf), i); if ((m = mixer_open(buf)) == NULL) continue; ... (void)mixer_close(m); } .Ed .Sh SEE ALSO .Xr queue 3 , .Xr sysctl 3 , .Xr sound 4 , .Xr mixer 8 and .Xr errno 2 .Sh AUTHORS .An Christos Margiolis Aq Mt christos@FreeBSD.org