-void ALSAInput::die_on_error(const char *func_name, int err)
-{
- if (err < 0) {
- fprintf(stderr, "[%s] %s: %s\n", device.c_str(), func_name, snd_strerror(err));
- exit(1);
- }
-}
-
-bool ALSAInput::set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate)
-{
- int err;
- err = snd_pcm_hw_params_any(pcm_handle, hw_params);
- if (err < 0) {
- fprintf(stderr, "[%s] snd_pcm_hw_params_any(): %s\n", device_name, snd_strerror(err));
- return false;
- }
- err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
- if (err < 0) {
- fprintf(stderr, "[%s] snd_pcm_hw_params_set_access(): %s\n", device_name, snd_strerror(err));
- return false;
- }
- snd_pcm_format_mask_t *format_mask;
- snd_pcm_format_mask_alloca(&format_mask);
- snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S16_LE);
- snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S24_LE);
- snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S32_LE);
- err = snd_pcm_hw_params_set_format_mask(pcm_handle, hw_params, format_mask);
- if (err < 0) {
- fprintf(stderr, "[%s] snd_pcm_hw_params_set_format_mask(): %s\n", device_name, snd_strerror(err));
- return false;
- }
- err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, sample_rate, 0);
- if (err < 0) {
- fprintf(stderr, "[%s] snd_pcm_hw_params_set_rate_near(): %s\n", device_name, snd_strerror(err));
- return false;
- }
- return true;
-}
-
-vector<ALSAInput::Device> ALSAInput::enumerate_devices()
-{
- vector<Device> ret;
-
- // Enumerate all cards.
- for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
- char address[256];
- snprintf(address, sizeof(address), "hw:%d", card_index);
-
- snd_ctl_t *ctl;
- int err = snd_ctl_open(&ctl, address, 0);
- if (err < 0) {
- printf("%s: %s\n", address, snd_strerror(err));
- continue;
- }
- snd_ctl_card_info_t *card_info;
- snd_ctl_card_info_alloca(&card_info);
- snd_ctl_card_info(ctl, card_info);
-
- string card_name = snd_ctl_card_info_get_name(card_info);
-
- // Enumerate all devices on this card.
- for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
- snd_pcm_info_t *pcm_info;
- snd_pcm_info_alloca(&pcm_info);
- snd_pcm_info_set_device(pcm_info, dev_index);
- snd_pcm_info_set_subdevice(pcm_info, 0);
- snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
- if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
- // Not available for capture.
- continue;
- }
-
- snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
-
- unsigned num_channels = 0;
-
- // Find all channel maps for this device, and pick out the one
- // with the most channels.
- snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
- if (cmaps != nullptr) {
- for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
- num_channels = max(num_channels, (*ptr)->map.channels);
- }
- snd_pcm_free_chmaps(cmaps);
- }
- if (num_channels == 0) {
- // Device had no channel maps. We need to open it to query.
- snd_pcm_t *pcm_handle;
- int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
- if (err < 0) {
- // TODO: When we go to hotplug support, we should support some
- // retry here, as the device could legitimately be busy.
- printf("%s: %s\n", address, snd_strerror(err));
- continue;
- }
- snd_pcm_hw_params_t *hw_params;
- snd_pcm_hw_params_alloca(&hw_params);
- unsigned sample_rate;
- if (!set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
- snd_pcm_close(pcm_handle);
- continue;
- }
- err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
- if (err < 0) {
- fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
- address, snd_strerror(err));
- snd_pcm_close(pcm_handle);
- continue;
- }
- snd_pcm_close(pcm_handle);
- }
-
- if (num_channels == 0) {
- printf("%s: No channel maps with channels\n", address);
- continue;
- }
-
- Device dev;
- dev.address = address;
- dev.name = card_name;
- dev.info = snd_pcm_info_get_name(pcm_info);
- dev.num_channels = num_channels;
-
- ret.push_back(dev);
- }
- snd_ctl_close(ctl);
- }
-
- return ret;
-}