// as a whole, since that's what AudioMixer::add_audio() wants.
#include <alsa/asoundlib.h>
-
+#include <stdint.h>
+#include <sys/types.h>
#include <atomic>
#include <functional>
+#include <memory>
#include <string>
#include <thread>
-#include <unordered_map>
-#include <vector>
#include "bmusb/bmusb.h"
-#include "timebase.h"
class ALSAPool;
ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback, ALSAPool *parent_pool, unsigned internal_dev_index);
~ALSAInput();
+ // If not called before start_capture_thread(), the capture thread
+ // will call it until it succeeds.
+ bool open_device();
+
+ // Not valid before the device has been successfully opened.
// NOTE: Might very well be different from the sample rate given to the
// constructor, since the card might not support the one you wanted.
unsigned get_sample_rate() const { return sample_rate; }
void start_capture_thread();
void stop_capture_thread();
+ // Set access, sample rate and format parameters on the given ALSA PCM handle.
+ // Returns the computed parameter set and the chosen sample rate. Note that
+ // sample_rate is an in/out parameter; you send in the desired rate,
+ // and ALSA picks one as close to that as possible.
+ static bool set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate);
+
private:
void capture_thread_func();
int64_t frames_to_pts(uint64_t n) const;
- void die_on_error(const char *func_name, int err);
+
+ enum class CaptureEndReason {
+ REQUESTED_QUIT,
+ DEVICE_GONE,
+ OTHER_ERROR
+ };
+ CaptureEndReason do_capture();
std::string device;
unsigned sample_rate, num_channels, num_periods;
bmusb::AudioFormat audio_format;
audio_callback_t audio_callback;
- snd_pcm_t *pcm_handle;
+ snd_pcm_t *pcm_handle = nullptr;
std::thread capture_thread;
std::atomic<bool> should_quit{false};
std::unique_ptr<uint8_t[]> buffer;
unsigned internal_dev_index;
};
-// The class dealing with the collective of all ALSA cards in the system.
-// In particular, it deals with enumeration of cards, and hotplug of new ones.
-class ALSAPool {
-public:
- ~ALSAPool();
-
- struct Device {
- enum class State {
- // There is no card here. (There probably used to be one,
- // but it got removed.) We don't insert a card before
- // we've actually probed it, ie., we know whether it
- // can be captured from at all, and what its name is.
- EMPTY,
-
- // This card is ready for capture, as far as we know.
- // (It could still be used by someone else; we don't know
- // until we try to open it.)
- READY,
-
- // We are trying to start capture from this card, but we are not
- // streaming yet. Note that this could in theory go on forever,
- // if the card is in use by some other process; in the UI,
- // we will show this state as “(busy)”.
- STARTING,
-
- // The card is capturing and sending data. If there's a fatal error,
- // it could go back to STARTING, or it could go to DEAD
- // (depending on the error).
- RUNNING,
-
- // The card is gone (e.g., unplugged). However, since there's
- // still a bus using it, we can't just remove the entry.
- // If the card comes back (ie., a new card is plugged in,
- // and we believe it has the same configuration), it could be
- // installed in place of this card, and then presumably be put
- // back into STARTING or RUNNING.
- DEAD
- } state = State::EMPTY;
-
- std::string address; // E.g. “hw:0,0”.
- std::string name, info;
- unsigned num_channels;
- ALSAInput *input = nullptr; // nullptr iff EMPTY or DEAD.
-
- // Whether the AudioMixer is interested in this card or not.
- // “Interested” could mean either of two things: Either it is part of
- // a bus mapping, or it is in the process of enumerating devices
- // (to show to the user). A card that is _not_ held can disappear
- // at any given time as a result of an error or hotplug event;
- // a card that is held will go to the DEAD state instead.
- bool held = false;
- };
-
- void init();
-
- // Get the list of all current devices. Note that this will implicitly mark
- // all of the returned devices as held, since the input mapping UI needs
- // some kind of stability when the user is to choose. Thus, when you are done
- // with the list and have set a new mapping, you must go through all the devices
- // you don't want and release them using release_device().
- std::vector<Device> get_devices();
-
- void hold_device(unsigned index);
- void release_device(unsigned index); // Note: index is allowed to go out of bounds.
-
- // If device is held, start or restart capture. If device is not held,
- // stop capture if it isn't already.
- void reset_device(unsigned index);
-
- // Note: The card must be held. Returns OUTPUT_FREQUENCY if the card is in EMPTY or DEAD.
- unsigned get_capture_frequency(unsigned index);
-
- // Note: The card must be held.
- Device::State get_card_state(unsigned index);
-
- // Only for ALSAInput.
- void set_card_state(unsigned index, Device::State state);
-
- // Just a short form for taking <mu> and then moving the card to
- // EMPTY or DEAD state. Only for ALSAInput and for internal use.
- void free_card(unsigned index);
-
- // TODO: Add accessors and/or callbacks about changed state, so that
- // the UI actually stands a chance in using that information.
-
-private:
- mutable std::mutex mu;
- std::vector<Device> devices; // Under mu.
- std::vector<std::unique_ptr<ALSAInput>> inputs; // Under mu, corresponds 1:1 to devices.
-
- // Keyed on device address (e.g. “hw:0,0”). If there's an entry here,
- // it means we already have a thread doing retries, so we shouldn't
- // start a new one.
- std::unordered_map<std::string, unsigned> add_device_tries_left; // Under add_device_mutex.
- std::mutex add_device_mutex;
-
- static constexpr int num_retries = 10;
-
- void inotify_thread_func();
- void enumerate_devices();
-
- // Try to add an input at the given card/device. If it succeeds, return
- // synchronously. If not, fire off a background thread to try up to
- // <num_retries> times.
- void probe_device_with_retry(unsigned card_index, unsigned dev_index);
- void probe_device_retry_thread_func(unsigned card_index, unsigned dev_index);
-
- enum class ProbeResult {
- SUCCESS,
- DEFER,
- FAILURE
- };
- ProbeResult probe_device_once(unsigned card_index, unsigned dev_index);
-
- // Must be called with <mu> held. Will allocate a new entry if needed.
- // The returned entry will be set to READY state.
- unsigned find_free_device_index();
-
- friend class ALSAInput;
-};
-
#endif // !defined(_ALSA_INPUT_H)