alsa: Use more hints for opening default devices.

This commit is contained in:
Ryan C. Gordon
2024-12-15 16:20:32 -05:00
parent 576f13ac7c
commit 35360ec4d7
2 changed files with 57 additions and 14 deletions

View File

@@ -216,16 +216,58 @@ extern "C" {
* Specify the default ALSA audio device name.
*
* This variable is a specific audio device to open when the "default" audio
* device is used. By default if 4 channel audio is requested, the
* "plug:surround40" device will be opened and if 6 channel audio is requested
* the "plug:surround51" device will be opened.
* device is used.
*
* This hint will be ignored when opening the default playback device if
* SDL_HINT_AUDIO_ALSA_DEFAULT_PLAYBACK_DEVICE is set, or when opening the
* default recording device if SDL_HINT_AUDIO_ALSA_DEFAULT_RECORDING_DEVICE
* is set.
*
* This hint should be set before an audio device is opened.
*
* \since This hint is available since SDL 3.1.3.
*
* \sa SDL_HINT_AUDIO_ALSA_DEFAULT_PLAYBACK_DEVICE
* \sa SDL_HINT_AUDIO_ALSA_DEFAULT_RECORDING_DEVICE
*/
#define SDL_HINT_AUDIO_ALSA_DEFAULT_DEVICE "SDL_AUDIO_ALSA_DEFAULT_DEVICE"
/**
* Specify the default ALSA audio playback device name.
*
* This variable is a specific audio device to open for playback, when the
* "default" audio device is used.
*
* If this hint isn't set, SDL will check SDL_HINT_AUDIO_ALSA_DEFAULT_DEVICE
* before choosing a reasonable default.
*
* This hint should be set before an audio device is opened.
*
* \since This hint is available since SDL 3.1.7.
*
* \sa SDL_HINT_AUDIO_ALSA_DEFAULT_RECORDING_DEVICE
* \sa SDL_HINT_AUDIO_ALSA_DEFAULT_DEVICE
*/
#define SDL_HINT_AUDIO_ALSA_DEFAULT_PLAYBACK_DEVICE "SDL_AUDIO_ALSA_DEFAULT_PLAYBACK_DEVICE"
/**
* Specify the default ALSA audio recording device name.
*
* This variable is a specific audio device to open for recording, when the
* "default" audio device is used.
*
* If this hint isn't set, SDL will check SDL_HINT_AUDIO_ALSA_DEFAULT_DEVICE
* before choosing a reasonable default.
*
* This hint should be set before an audio device is opened.
*
* \since This hint is available since SDL 3.1.7.
*
* \sa SDL_HINT_AUDIO_ALSA_DEFAULT_PLAYBACK_DEVICE
* \sa SDL_HINT_AUDIO_ALSA_DEFAULT_DEVICE
*/
#define SDL_HINT_AUDIO_ALSA_DEFAULT_RECORDING_DEVICE "SDL_AUDIO_ALSA_DEFAULT_RECORDING_DEVICE"
/**
* A variable controlling the audio category on iOS and macOS.
*

View File

@@ -325,19 +325,20 @@ static char *get_pcm_str(void *handle)
{
SDL_assert(handle != NULL); // SDL2 used NULL to mean "default" but that's not true in SDL3.
ALSA_Device *dev = (ALSA_Device *)handle;
// If the user does not want to go thru the default PCM or the canonical default, the
// the configuration space being _massive_, give the user the ability to specify
// its own PCMs using environment variables. It will have to fit SDL constraints though.
// !!! FIXME: make these into SDL_Hints?
const char *env = SDL_getenv(dev->recording ? "SDL_AUDIO_ALSA_PCM_RECORDING" : "SDL_AUDIO_ALSA_PCM_PLAYBACK");
if (env) {
return SDL_strdup(env);
}
char *pcm_str = NULL;
if (SDL_strlen(dev->id) == 0) {
pcm_str = SDL_strdup("default");
// If the user does not want to go thru the default PCM or the canonical default, the
// the configuration space being _massive_, give the user the ability to specify
// its own PCMs using environment variables. It will have to fit SDL constraints though.
const char *devname = SDL_GetHint(dev->recording ? SDL_HINT_AUDIO_ALSA_DEFAULT_RECORDING_DEVICE : SDL_HINT_AUDIO_ALSA_DEFAULT_PLAYBACK_DEVICE);
if (!devname) {
devname = SDL_GetHint(SDL_HINT_AUDIO_ALSA_DEFAULT_DEVICE);
if (!devname) {
devname = "default";
}
}
pcm_str = SDL_strdup(devname);
} else {
SDL_asprintf(&pcm_str, "%sCARD=%s", ALSA_device_prefix, dev->id);
}