MessageGroup¶

The MessageGroup message type is a versatile container used in DepthAI pipelines to group together a map of arbitrary DepthAI messages. It serves as the primary output of the Sync node, effectively synchronizing various input streams, and acts as the input to the MessageDemux node for subsequent disaggregation and processing.

Creating MessageGroup¶

MessageGroup can be created automatically by the Sync node as it aligns and groups messages from different sources based on their timestamps. Alternatively, it can be manually constructed in a host application or within a Script node to create custom groupings of DepthAI messages.

Reference¶

class depthai.MessageGroup

MessageGroup message. Carries multiple messages in one.

getData(self: object) → numpy.ndarray[numpy.uint8]

Get non-owning reference to internal buffer

Returns: Reference to internal buffer

getIntervalNs(self: depthai.MessageGroup) → int: Retrieves interval between the first and the last message in the group.

getMessageNames(self: depthai.MessageGroup) → List[str]: Gets the names of messages in the group

getNumMessages(self: depthai.MessageGroup) → int

getRaw(self: depthai.ADatatype) → depthai.RawBuffer

getSequenceNum(self: depthai.MessageGroup) → int: Retrieves sequence number

getTimestamp(self: depthai.MessageGroup) → datetime.timedelta: Retrieves timestamp related to dai::Clock::now()

getTimestampDevice(self: depthai.MessageGroup) → datetime.timedelta: Retrieves timestamp directly captured from device’s monotonic clock, not synchronized to host time. Used mostly for debugging

isSynced(self: depthai.MessageGroup, arg0: int) → bool

True if all messages in the group are in the interval

Parameter thresholdNs:: Maximal interval between messages

setData(*args, **kwargs)

Overloaded function.

setData(self: depthai.Buffer, arg0: List[int]) -> None

Parameter data:: Copies data to internal buffer

setData(self: depthai.Buffer, arg0: numpy.ndarray[numpy.uint8]) -> None

Parameter data:: Copies data to internal buffer

setSequenceNum(self: depthai.MessageGroup, arg0: int) → depthai.MessageGroup: Retrieves image sequence number

setTimestamp(self: depthai.MessageGroup, arg0: datetime.timedelta) → depthai.MessageGroup: Sets image timestamp related to dai::Clock::now()

setTimestampDevice(self: depthai.MessageGroup, arg0: datetime.timedelta) → depthai.MessageGroup: Sets image timestamp related to dai::Clock::now()

class dai::MessageGroup : public dai::Buffer ¶

MessageGroup message. Carries multiple messages in one.

Public Functions

MessageGroup()¶: Construct MessageGroup message.

MessageGroup(std::shared_ptr<RawMessageGroup> ptr)¶

~MessageGroup() = default¶

std::shared_ptr<ADatatype> operator[](const std::string &name)¶: Group.

template<typename T> std::shared_ptr<T> get(const std::string &name)¶

void add(const std::string &name, const std::shared_ptr<ADatatype> &value)¶

template<typename T> void add(const std::string &name, const T &value)¶

std::unordered_map<std::string, std::shared_ptr<ADatatype>>::iterator begin()¶

std::unordered_map<std::string, std::shared_ptr<ADatatype>>::iterator end()¶

bool isSynced(int64_t thresholdNs) const¶

True if all messages in the group are in the interval

Parameters

thresholdNs: Maximal interval between messages

int64_t getIntervalNs() const¶: Retrieves interval between the first and the last message in the group.

int64_t getNumMessages() const¶

std::vector<std::string> getMessageNames() const¶: Gets the names of messages in the group

MessageGroup &setTimestamp(std::chrono::time_point<std::chrono::steady_clock, std::chrono::steady_clock::duration> timestamp)¶: Sets image timestamp related to dai::Clock::now()

MessageGroup &setTimestampDevice(std::chrono::time_point<std::chrono::steady_clock, std::chrono::steady_clock::duration> timestamp)¶: Sets image timestamp related to dai::Clock::now()

MessageGroup &setSequenceNum(int64_t sequenceNum)¶: Retrieves image sequence number

Private Functions

std::shared_ptr<RawBuffer> serialize() const override¶

Private Members

RawMessageGroup &rawGrp¶

std::unordered_map<std::string, std::shared_ptr<ADatatype>> group¶

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