// Copyright 2019 The MediaPipe Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <algorithm>
#include <functional>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <type_traits>
#include <utility>
#include "mediapipe/framework/calculator_framework.h"
#include "mediapipe/framework/collection_item_id.h"
#include "mediapipe/framework/input_stream_shard.h"
#include "mediapipe/framework/output_stream_shard.h"
#include "mediapipe/framework/port/logging.h"
#include "mediapipe/framework/port/ret_check.h"
#include "mediapipe/framework/port/status.h"
#include "mediapipe/framework/port/status_macros.h"
#include "mediapipe/framework/tool/container_util.h"
#include "mediapipe/framework/tool/switch_container.pb.h"
namespace mediapipe {
// A calculator to join several sets of input streams into one
// output channel, consisting of corresponding output streams.
// Each channel is distinguished by a tag-prefix such as "C1__".
// For example:
//
// node {
// calculator: "SwitchMuxCalculator"
// input_stream: "ENABLE:enable"
// input_stream: "C0__FUNC_INPUT:foo_0"
// input_stream: "C0__FUNC_INPUT:bar_0"
// input_stream: "C1__FUNC_INPUT:foo_1"
// input_stream: "C1__FUNC_INPUT:bar_1"
// output_stream: "FUNC_INPUT:foo"
// output_stream: "FUNC_INPUT:bar"
// }
//
// Input stream "ENABLE" specifies routing of packets from either channel 0
// or channel 1, given "ENABLE:false" or "ENABLE:true" respectively.
// Input-side-packet "ENABLE" and input-stream "SELECT" can also be used
// similarly to specify the active channel.
//
// SwitchMuxCalculator is used by SwitchContainer to enable one of several
// contained subgraph or calculator nodes.
//
class SwitchMuxCalculator : public CalculatorBase {
static constexpr char kSelectTag[] = "SELECT";
static constexpr char kEnableTag[] = "ENABLE";
public:
static absl::Status GetContract(CalculatorContract* cc);
absl::Status Open(CalculatorContext* cc) override;
absl::Status Process(CalculatorContext* cc) override;
private:
// Stores any new input channel history.
void RecordChannel(CalculatorContext* cc);
// Temporarily enqueues every new packet or timestamp bounds.
void RecordPackets(CalculatorContext* cc);
// Immediately sends any packets or timestamp bounds for settled timestamps.
void SendActivePackets(CalculatorContext* cc);
private:
int channel_index_;
std::set<std::string> channel_tags_;
mediapipe::SwitchContainerOptions options_;
// This is used to keep around packets that we've received but not
// relayed yet (because we may not know which channel we should yet be using).
std::map<CollectionItemId, std::queue<Packet>> packet_queue_;
// Historical channel index values for timestamps where we don't have all
// packets available yet.
std::map<Timestamp, int> channel_history_;
};
REGISTER_CALCULATOR(SwitchMuxCalculator);
absl::Status SwitchMuxCalculator::GetContract(CalculatorContract* cc) {
// Allow any one of kSelectTag, kEnableTag.
cc->Inputs().Tag(kSelectTag).Set<int>().Optional();
cc->Inputs().Tag(kEnableTag).Set<bool>().Optional();
// Allow any one of kSelectTag, kEnableTag.
cc->InputSidePackets().Tag(kSelectTag).Set<int>().Optional();
cc->InputSidePackets().Tag(kEnableTag).Set<bool>().Optional();
// Set the types for all input channels to corresponding output types.
std::set<std::string> channel_tags = ChannelTags(cc->Inputs().TagMap());
int channel_count = ChannelCount(cc->Inputs().TagMap());
for (const std::string& tag : channel_tags) {
for (int index = 0; index < cc->Outputs().NumEntries(tag); ++index) {
cc->Outputs().Get(tag, index).SetAny();
auto output_id = cc->Outputs().GetId(tag, index);
if (output_id.IsValid()) {
for (int channel = 0; channel < channel_count; ++channel) {
auto input_id =
cc->Inputs().GetId(tool::ChannelTag(tag, channel), index);
if (input_id.IsValid()) {
cc->Inputs().Get(input_id).SetSameAs(&cc->Outputs().Get(output_id));
}
}
}
}
}
channel_tags = ChannelTags(cc->InputSidePackets().TagMap());
channel_count = ChannelCount(cc->InputSidePackets().TagMap());
for (const std::string& tag : channel_tags) {
int num_entries = cc->OutputSidePackets().NumEntries(tag);
for (int index = 0; index < num_entries; ++index) {
cc->OutputSidePackets().Get(tag, index).SetAny();
auto output_id = cc->OutputSidePackets().GetId(tag, index);
if (output_id.IsValid()) {
for (int channel = 0; channel < channel_count; ++channel) {
auto input_id = cc->InputSidePackets().GetId(
tool::ChannelTag(tag, channel), index);
if (input_id.IsValid()) {
cc->InputSidePackets().Get(input_id).SetSameAs(
&cc->OutputSidePackets().Get(output_id));
}
}
}
}
}
cc->SetInputStreamHandler("ImmediateInputStreamHandler");
cc->SetProcessTimestampBounds(true);
return absl::OkStatus();
}
// Returns the last delivered timestamp for an input stream.
Timestamp SettledTimestamp(const InputStreamShard& input) {
return input.Value().Timestamp();
}
// Returns the last delivered timestamp for channel selection.
Timestamp ChannelSettledTimestamp(CalculatorContext* cc) {
Timestamp result = Timestamp::Done();
if (cc->Inputs().HasTag("ENABLE")) {
result = SettledTimestamp(cc->Inputs().Tag("ENABLE"));
} else if (cc->Inputs().HasTag("SELECT")) {
result = SettledTimestamp(cc->Inputs().Tag("SELECT"));
}
return result;
}
absl::Status SwitchMuxCalculator::Open(CalculatorContext* cc) {
// Initialize channel_index_ and channel_history_.
options_ = cc->Options<mediapipe::SwitchContainerOptions>();
channel_index_ = tool::GetChannelIndex(*cc, channel_index_);
channel_tags_ = ChannelTags(cc->Inputs().TagMap());
channel_history_[Timestamp::Unstarted()] = channel_index_;
// Relay side packets only from channel_index_.
for (const std::string& tag : ChannelTags(cc->InputSidePackets().TagMap())) {
int num_outputs = cc->OutputSidePackets().NumEntries(tag);
for (int index = 0; index < num_outputs; ++index) {
std::string input_tag = tool::ChannelTag(tag, channel_index_);
Packet input = cc->InputSidePackets().Get(input_tag, index);
cc->OutputSidePackets().Get(tag, index).Set(input);
}
}
return absl::OkStatus();
}
void SwitchMuxCalculator::RecordChannel(CalculatorContext* cc) {
Timestamp channel_settled = ChannelSettledTimestamp(cc);
int new_channel_index = tool::GetChannelIndex(*cc, channel_index_);
// Enque any new input channel and its activation timestamp.
if (channel_settled == cc->InputTimestamp() &&
new_channel_index != channel_index_) {
channel_index_ = new_channel_index;
channel_history_[channel_settled] = channel_index_;
}
}
void SwitchMuxCalculator::RecordPackets(CalculatorContext* cc) {
auto select_id = cc->Inputs().GetId("SELECT", 0);
auto enable_id = cc->Inputs().GetId("ENABLE", 0);
for (auto id = cc->Inputs().BeginId(); id < cc->Inputs().EndId(); ++id) {
if (id == select_id || id == enable_id) continue;
Packet packet = cc->Inputs().Get(id).Value();
// Enque any new packet or timestamp bound.
if (packet.Timestamp() == cc->InputTimestamp()) {
packet_queue_[id].push(packet);
}
}
}
void SwitchMuxCalculator::SendActivePackets(CalculatorContext* cc) {
Timestamp expired_history;
// Iterate through the recent active input channels.
for (auto it = channel_history_.begin(); it != channel_history_.end(); ++it) {
int channel = it->second;
Timestamp channel_start = it->first;
Timestamp channel_end =
(std::next(it) == channel_history_.end())
? ChannelSettledTimestamp(cc).NextAllowedInStream()
: std::next(it)->first;
Timestamp stream_settled = Timestamp::Done();
for (const std::string& tag : channel_tags_) {
std::string input_tag = tool::ChannelTag(tag, channel);
for (int index = 0; index < cc->Inputs().NumEntries(input_tag); ++index) {
CollectionItemId input_id = cc->Inputs().GetId(input_tag, index);
OutputStreamShard& output = cc->Outputs().Get(tag, index);
std::queue<Packet>& q = packet_queue_[input_id];
// Send any packets or bounds from a recent active input channel.
while (!q.empty() && q.front().Timestamp() < channel_end) {
if (q.front().Timestamp() >= channel_start) {
output.AddPacket(q.front());
}
q.pop();
}
stream_settled = std::min(stream_settled,
SettledTimestamp(cc->Inputs().Get(input_id)));
}
}
// A history entry is expired only if all streams have advanced past it.
if (stream_settled.NextAllowedInStream() < channel_end ||
std::next(it) == channel_history_.end()) {
break;
}
expired_history = channel_start;
// Discard any packets or bounds from recent inactive input channels.
for (auto id = cc->Inputs().BeginId(); id < cc->Inputs().EndId(); ++id) {
std::queue<Packet>& q = packet_queue_[id];
while (!q.empty() && q.front().Timestamp() < channel_end) {
q.pop();
}
}
}
// Discard any expired channel history entries.
if (expired_history != Timestamp::Unset()) {
channel_history_.erase(channel_history_.begin(),
std::next(channel_history_.find(expired_history)));
}
}
absl::Status SwitchMuxCalculator::Process(CalculatorContext* cc) {
// Normally packets will arrive on the active channel and will be passed
// through immediately. In the less common case in which the active input
// channel is not known for an input packet timestamp, the input packet is
// queued until the active channel becomes known.
RecordChannel(cc);
RecordPackets(cc);
SendActivePackets(cc);
return absl::OkStatus();
}
} // namespace mediapipe
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