die_on_error("snd_pcm_nonblock()", snd_pcm_nonblock(pcm_handle, 1));
die_on_error("snd_pcm_prepare()", snd_pcm_prepare(pcm_handle));
-
}
ALSAInput::~ALSAInput()
}
}
+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);
+
+ // 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);
+ unsigned num_channels = 0;
+ 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) {
+ 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;
+}
void start_capture_thread();
void stop_capture_thread();
+ // TODO: Worry about hotplug.
+ struct Device {
+ std::string address; // E.g. “hw:0,0”.
+ std::string name, info;
+ unsigned num_channels;
+ };
+ static std::vector<Device> enumerate_devices();
+
private:
void capture_thread_func();
int64_t frames_to_pts(uint64_t n) const;