brew install bufbuild/buf/buf

gen
├── ... other languages ...
└── go
   ├── cobaltspeech
   │ ├── ...
   │   └── voicebio
   │      └── v1
   │        ├── voicebio_grpc.pb.go
   │        └── voicebio.pb.go
   └── gw
     └── cobaltspeech
       ├── ...
       └── voicebio
         └── v1
            └── voicebio.pb.gw.go

go get google.golang.org/protobuf
go get google.golang.org/grpc
go get google.golang.org/genproto

# More details on grpc installation can be found at:

# https://grpc.io/docs/languages/cpp/quickstart/

COBALT="${HOME}/cobalt"
mkdir -p "${COBALT}/git"

# Latest version as of 14th March, 2023.

VERSION="v1.52.0"
GRPC_REPO="${COBALT}/git/grpc-${VERSION}"

git clone \
 --recurse-submodules --depth 1 --shallow-submodules \
 -b "${VERSION}" \
 https://github.com/grpc/grpc ${GRPC_REPO}

cd "${GRPC_REPO}"
mkdir -p cmake/build

# Change this to where you want to install libprotobuf and libgrpc.

# It is encouraged to install gRPC locally as there is no easy way to

# uninstall gRPC after you’ve installed it globally.

INSTALL_DIR="${COBALT}"

cd cmake/build
cmake \
 -DgRPC_INSTALL=ON \
 -DgRPC_BUILD_TESTS=OFF \
 -DCMAKE_INSTALL_PREFIX=${INSTALL_DIR} \
 ../..

make -j
make install

package main

import (
	"context"
	"fmt"
	"os"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	voicebiopb "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {
	const (
		serverAddress  = "localhost:2727"
	)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	opts := []grpc.DialOption{
		grpc.WithTransportCredentials(insecure.NewCredentials()), // Using a channel without TLS enabled.
		grpc.WithBlock(),
		grpc.WithReturnConnectionError(),
		grpc.FailOnNonTempDialError(true),
	}

	conn, err := grpc.DialContext(ctx, serverAddress, opts...)
	if err != nil {
		fmt.Printf("failed to dial gRPC connection: %v\n", err)
		os.Exit(1)
	}

	client := voicebiopb.NewVoiceBioServiceClient(conn)

	// Get server version.
	versionResp, err := client.Version(ctx, &voicebiopb.VersionRequest{})
	if err != nil {
		fmt.Printf("failed to get server version: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("%v\n", versionResp)
}

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"os"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"

	voicebiopb "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {
	const (
		serverAddress  = "demo.cobaltspeech.com:2727"
		connectTimeout = 10 * time.Second
	)

	// Setup a gRPC connection with TLS. You can optionally provide your own
	// root certificates and private key through tls.Config for mutually
	// authenticated TLS.
	tlsCfg := tls.Config{}
	creds := credentials.NewTLS(&tlsCfg)

	ctx, cancel := context.WithTimeout(context.Background(), connectTimeout)
	defer cancel()

	opts := []grpc.DialOption{
		grpc.WithTransportCredentials(creds),
		grpc.WithBlock(),
		grpc.WithReturnConnectionError(),
		grpc.FailOnNonTempDialError(true),
	}

	conn, err := grpc.DialContext(ctx, serverAddress, opts...)
	if err != nil {
		fmt.Printf("failed to dial gRPC connection: %v\n", err)
		os.Exit(1)
	}

	client := voicebiopb.NewVoiceBioServiceClient(conn)

	// Get server version.
	versionResp, err := client.Version(ctx, &voicebiopb.VersionRequest{})
	if err != nil {
		fmt.Printf("failed to get server version: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("%v\n", versionResp)
}

package main

import (
	// ...

	"crypto/tls"
	"crypto/x509"
	"fmt"
	"os"

	// ..
)

func main() {
	// ...

	// Root PEM certificate for validating self-signed server certificate
	var rootCert []byte

	// Client PEM certificate and private key.
	var certPem, keyPem []byte

	caCertPool := x509.NewCertPool()
	if ok := caCertPool.AppendCertsFromPEM(rootCert); !ok {
		fmt.Printf("unable to use given caCert\n")
		os.Exit(1)
	}

	clientCert, err := tls.X509KeyPair(certPem, keyPem)
	if err != nil {
		fmt.Printf("unable to use given client certificate and key: %v\n", err)
		os.Exit(1)
	}

	tlsCfg := tls.Config{
		RootCAs:      caCertPool,
		Certificates: []tls.Certificate{clientCert},
	}

	creds := credentials.NewTLS(&tlsCfg)

	// ...
}

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	voicebio "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {
	const (
		serverAddress = "localhost:2727"
	)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	opts := []grpc.DialOption{
		grpc.WithTransportCredentials(insecure.NewCredentials()), // Using a channel without TLS enabled.
		grpc.WithBlock(),
		grpc.WithReturnConnectionError(),
		grpc.FailOnNonTempDialError(true),
	}

	conn, err := grpc.DialContext(ctx, serverAddress, opts...)
	if err != nil {
		fmt.Printf("failed to dial gRPC connection: %v\n", err)
		os.Exit(1)
	}

	client := voicebio.NewVoiceBioServiceClient(conn)

	// Get server version.
	versionResp, err := client.Version(ctx, &voicebio.VersionRequest{})
	if err != nil {
		fmt.Printf("failed to get server version: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("%v\n", versionResp)

	// Get list model of models on the server.
	modelResp, err := client.ListModels(ctx, &voicebio.ListModelsRequest{})
	if err != nil {
		fmt.Printf("failed to get model list: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("Models:")
	for _, m := range modelResp.Models {
		fmt.Println(m)
	}
	fmt.Println()

	// Selecting the first model.
	cfg := &voicebio.EnrollmentConfig{
		ModelId:            modelResp.Models[0].Id,
		PreviousVoiceprint: nil,
	}

	// Opening audio file.
	audio, err := os.Open("test.wav")
	if err != nil {
		fmt.Printf("failed to open audio file: %v\n", err)
		os.Exit(1)
	}

	defer audio.Close()

	// Starting enrollment.
	result, err := StreamingEnroll(ctx, client, cfg, audio)
	if err != nil {
		fmt.Printf("failed to run streaming enrollment: %v\n", err)
		os.Exit(1)
	}

	// A certain minimum duration of speech is required for completing enrollment.
	// The enrollment status contains information on Whether that has been met or
	// whether additional audio is required.
	fmt.Printf("Enrollment Status: %v\n", result.EnrollmentStatus)

	// Saving the voiceprint data to a file. This can be provided again
	// in another StreamingEnroll request (for continuing enrollment) or
	// submitted for verification / identification requests.
	if err := os.WriteFile("voiceprint.bin", []byte(result.Voiceprint.Data), os.ModePerm); err != nil {
		fmt.Printf("failed to write voiceprint data: %v\n", err)
		os.Exit(1)
	}
}

// StreamingEnroll wraps the streaming API for performing speaker enrollment
// (i.e. voiceprint generation) using  the given cfg.
//
// Data is read from the given audio reader into a buffer and streamed to VoiceBio
// server. The default buffer size may be overridden using Options when creating
// the Client.
//
// If any error occurs while reading the audio or sending it to the server, this
// method will immediately exit, returning that error.
func StreamingEnroll(
	ctx context.Context,
	client voicebio.VoiceBioServiceClient,
	cfg *voicebio.EnrollmentConfig,
	audio io.Reader,
) (*voicebio.StreamingEnrollResponse, error) {
	const (
		streamingBufSize = 1024
	)

	// Creating stream.
	stream, err := client.StreamingEnroll(ctx)
	if err != nil {
		return nil, err
	}

	// Sending audio.
	if err := sendAudio(stream, cfg, audio, streamingBufSize); err != nil && !errors.Is(err, io.EOF) {
		// if sendAudio encountered io.EOF, it's only a
		// notification that the stream has closed.  The actual
		// status will be obtained in the CloseAndRecv call. We
		// therefore return on non-EOF errors here.
		return nil, err
	}

	// Returning result.
	return stream.CloseAndRecv()
}

// sendAudio sends the config and audio to a stream.
func sendAudio(
	stream voicebio.VoiceBioService_StreamingEnrollClient,
	cfg *voicebio.EnrollmentConfig,
	audio io.Reader,
	bufSize uint32,
) error {
	// The first message needs to be a config message, and all subsequent
	// messages must be audio messages.

	// Send the config.
	if err := stream.Send(&voicebio.StreamingEnrollRequest{
		Request: &voicebio.StreamingEnrollRequest_Config{Config: cfg},
	}); err != nil {
		// if this failed, we don't need to CloseSend
		return err
	}

	// Stream the audio.
	buf := make([]byte, bufSize)
	for {
		n, err := audio.Read(buf)
		if n > 0 {
			if err2 := stream.Send(&voicebio.StreamingEnrollRequest{
				Request: &voicebio.StreamingEnrollRequest_Audio{
					Audio: &voicebio.Audio{Data: buf[:n]},
				},
			}); err2 != nil {
				// if we couldn't Send, the stream has
				// encountered an error and we don't need to
				// CloseSend.
				return err2
			}
		}

		if err != nil {
			// err could be io.EOF, or some other error reading from
			// audio.  In any case, we need to CloseSend, send the
			// appropriate error to errCh and return from the function
			if err2 := stream.CloseSend(); err2 != nil {
				return err2
			}

			if err != io.EOF {
				return err
			}

			return nil
		}
	}
}

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"strings"

	"golang.org/x/sync/errgroup"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	voicebio "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {
	const (
		serverAddress = "localhost:2727"
	)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	opts := []grpc.DialOption{
		grpc.WithTransportCredentials(insecure.NewCredentials()), // Using a channel without TLS enabled.
		grpc.WithBlock(),
		grpc.WithReturnConnectionError(),
		grpc.FailOnNonTempDialError(true),
	}

	conn, err := grpc.DialContext(ctx, serverAddress, opts...)
	if err != nil {
		fmt.Printf("failed to dial gRPC connection: %v\n", err)
		os.Exit(1)
	}

	client := voicebio.NewVoiceBioServiceClient(conn)

	// Get server version.
	versionResp, err := client.Version(ctx, &voicebio.VersionRequest{})
	if err != nil {
		fmt.Printf("failed to get server version: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("%v\n", versionResp)

	// Get list model of models on the server.
	modelResp, err := client.ListModels(ctx, &voicebio.ListModelsRequest{})
	if err != nil {
		fmt.Printf("failed to get model list: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("Models:")
	for _, m := range modelResp.Models {
		fmt.Println(m)
	}
	fmt.Println()

	// Selecting first model.
	m := modelResp.Models[0]

	// Setting audio format to be raw 16-bit signed little endian audio samples
	// recorded at the sample rate expected by the model.
	cfg := &voicebio.EnrollmentConfig{
		ModelId:            m.Id,
		PreviousVoiceprint: nil,
		AudioFormat: &voicebio.AudioFormat{AudioFormat: &voicebio.AudioFormat_AudioFormatRaw{
			AudioFormatRaw: &voicebio.AudioFormatRAW{
				Encoding:   voicebio.AudioEncoding_AUDIO_ENCODING_SIGNED,
				SampleRate: m.Attributes.SampleRate,
				BitDepth:   16,
				ByteOrder:  voicebio.ByteOrder_BYTE_ORDER_LITTLE_ENDIAN,
				Channels:   1,
			},
		},
		},
	}

	// Open microphone stream using sox's rec command and record
	// audio using the config specified above for *10 seconds*.
	maxDuration := 10
	args := fmt.Sprintf("-t raw -r %d -e signed -b 16 -L -c 1 - trim 0 %d", m.Attributes.SampleRate, maxDuration)
	cmd := exec.CommandContext(ctx, "rec", strings.Fields(args)...)
	cmd.Stderr = os.Stderr

	audio, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Printf("failed to open microphone stream: %v\n", err)
		os.Exit(1)
	}

	// Starting routines to record from microphone and stream to server
	// using an errgroup.Group that returns if either one encounters an error.
	eg, ctx := errgroup.WithContext(ctx)

	eg.Go(func() error {
		fmt.Printf("\n[INFO] recording %d seconds from microphone \n", maxDuration)

		if err := cmd.Run(); err != nil {
			return fmt.Errorf("record from microphone: %w", err)
		}

		return nil
	})

	// Starting enrollment.
	result, err := StreamingEnroll(ctx, client, cfg, audio)
	if err != nil {
		fmt.Printf("failed to run streaming enrollment: %v\n", err)
		os.Exit(1)
	}

	if err := eg.Wait(); err != nil {
		fmt.Printf("%v\n", err)
		os.Exit(1)
	}

	// A certain minimum duration of speech is required for completing enrollment.
	// The enrollment status contains information on Whether that has been met or
	// whether additional audio is required.
	fmt.Printf("Enrollment Status: %v\n", result.EnrollmentStatus)

	// Saving the voiceprint data to a file. This can be provided again
	// in another StreamingEnroll request (for continuing enrollment) or
	// submitted for verification / identification requests.
	if err := os.WriteFile("voiceprint.bin", []byte(result.Voiceprint.Data), os.ModePerm); err != nil {
		fmt.Printf("failed to wriet voiceprint data: %v\n", err)
		os.Exit(1)
	}
}

// StreamingEnroll wraps the streaming API for performing speaker enrollment
// (i.e. voiceprint generation) using  the given cfg.
//
// Data is read from the given audio reader into a buffer and streamed to VoiceBio
// server. The default buffer size may be overridden using Options when creating
// the Client.
//
// If any error occurs while reading the audio or sending it to the server, this
// method will immediately exit, returning that error.
func StreamingEnroll(
	ctx context.Context,
	client voicebio.VoiceBioServiceClient,
	cfg *voicebio.EnrollmentConfig,
	audio io.Reader,
) (*voicebio.StreamingEnrollResponse, error) {
	const (
		streamingBufSize = 1024
	)

	// Creating stream.
	stream, err := client.StreamingEnroll(ctx)
	if err != nil {
		return nil, err
	}

	// Sending audio.
	if err := sendAudio(stream, cfg, audio, streamingBufSize); err != nil && !errors.Is(err, io.EOF) {
		// if sendAudio encountered io.EOF, it's only a
		// notification that the stream has closed.  The actual
		// status will be obtained in the CloseAndRecv call. We
		// therefore return on non-EOF errors here.
		return nil, err
	}

	// Returning result.
	return stream.CloseAndRecv()
}

// sendAudio sends audio to a stream.
func sendAudio(
	stream voicebio.VoiceBioService_StreamingEnrollClient,
	cfg *voicebio.EnrollmentConfig,
	audio io.Reader,
	bufSize uint32,
) error {
	// The first message needs to be a config message, and all subsequent
	// messages must be audio messages.

	// Send the config.
	if err := stream.Send(&voicebio.StreamingEnrollRequest{
		Request: &voicebio.StreamingEnrollRequest_Config{Config: cfg},
	}); err != nil {
		// if this failed, we don't need to CloseSend
		return err
	}

	// Stream the audio.
	buf := make([]byte, bufSize)
	for {
		n, err := audio.Read(buf)
		if n > 0 {
			if err2 := stream.Send(&voicebio.StreamingEnrollRequest{
				Request: &voicebio.StreamingEnrollRequest_Audio{
					Audio: &voicebio.Audio{Data: buf[:n]},
				},
			}); err2 != nil {
				// if we couldn't Send, the stream has
				// encountered an error and we don't need to
				// CloseSend.
				return err2
			}
		}

		if err != nil {
			// err could be io.EOF, or some other error reading from
			// audio.  In any case, we need to CloseSend, send the
			// appropriate error to errCh and return from the function
			if err2 := stream.CloseSend(); err2 != nil {
				return err2
			}

			if err != io.EOF {
				return err
			}

			return nil
		}
	}
}

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	voicebio "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {

	// Connect to server ...

	// Reading old voiceprint data.
	data, err := os.ReadFile("voiceprint.bin")
	if err != nil {
		fmt.Printf("\nfailed to read voiceprint data: %v\n", err)
		os.Exit(1)
	}

	cfg := &voicebio.EnrollmentConfig{
		ModelId:            modelResp.Models[0].Id,
		PreviousVoiceprint: &voicebio.Voiceprint{Data: string(data)},
	}

	// Send audio to server ...
}

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	voicebio "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {
	const (
		serverAddress = "localhost:2727"
	)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	opts := []grpc.DialOption{
		grpc.WithTransportCredentials(insecure.NewCredentials()), // Using a channel without TLS enabled.
		grpc.WithBlock(),
		grpc.WithReturnConnectionError(),
		grpc.FailOnNonTempDialError(true),
	}

	conn, err := grpc.DialContext(ctx, serverAddress, opts...)
	if err != nil {
		fmt.Printf("failed to dial gRPC connection: %v\n", err)
		os.Exit(1)
	}

	client := voicebio.NewVoiceBioServiceClient(conn)

	// Get server version.
	versionResp, err := client.Version(ctx, &voicebio.VersionRequest{})
	if err != nil {
		fmt.Printf("failed to get server version: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("%v\n", versionResp)

	// Get list model of models on the server.
	modelResp, err := client.ListModels(ctx, &voicebio.ListModelsRequest{})
	if err != nil {
		fmt.Printf("failed to get model list: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("Models:")
	for _, m := range modelResp.Models {
		fmt.Println(m)
	}
	fmt.Println()

	// Reading voiceprint data.
	data, err := os.ReadFile("voiceprint.bin")
	if err != nil {
		fmt.Printf("\nfailed to read voiceprint data: %v\n", err)
		os.Exit(1)
	}

	// Selecting the first model.
	cfg := &voicebio.VerificationConfig{
		ModelId:    modelResp.Models[0].Id,
		Voiceprint: &voicebio.Voiceprint{Data: string(data)},
	}

	// Opening audio file.
	audio, err := os.Open("test.wav")
	if err != nil {
		fmt.Printf("failed to open audio file: %v\n", err)
		os.Exit(1)
	}

	defer audio.Close()

	// Starting verification.
	resp, err := StreamingVerify(ctx, client, cfg, audio)
	if err != nil {
		fmt.Printf("failed to run streaming verification: %v\n", err)
		os.Exit(1)
	}

	// Server returns a similarity score along with whether the score
	// exceeded the server-configured threshold for being a match.
	fmt.Printf("Verification Score: %1.3f, Match: %v\n", resp.Result.SimilarityScore, resp.Result.IsMatch)
}

// StreamingVerify wraps the streaming API for performing speaker verification
// using  the given cfg.
//
// Data is read from the given audio reader into a buffer and streamed to VoiceBio
// server. The default buffer size may be overridden using Options when creating
// the Client.
//
// If any error occurs while reading the audio or sending it to the server, this
// method will immediately exit, returning that error.
func StreamingVerify(
	ctx context.Context,
	client voicebio.VoiceBioServiceClient,
	cfg *voicebio.VerificationConfig,
	audio io.Reader,
) (*voicebio.StreamingVerifyResponse, error) {
	const (
		streamingBufSize = 1024
	)

	// Creating stream.
	stream, err := client.StreamingVerify(ctx)
	if err != nil {
		return nil, err
	}

	// Sending audio.
	if err := sendAudio(stream, cfg, audio, streamingBufSize); err != nil && !errors.Is(err, io.EOF) {
		// if sendAudio encountered io.EOF, it's only a
		// notification that the stream has closed.  The actual
		// status will be obtained in the CloseAndRecv call. We
		// therefore return on non-EOF errors here.
		return nil, err
	}

	// Returning result.
	return stream.CloseAndRecv()
}

// sendAudio sends the config and audio to a stream.
func sendAudio(
	stream voicebio.VoiceBioService_StreamingVerifyClient,
	cfg *voicebio.VerificationConfig,
	audio io.Reader,
	bufSize uint32,
) error {
	// The first message needs to be a config message, and all subsequent
	// messages must be audio messages.

	// Send the config.
	if err := stream.Send(&voicebio.StreamingVerifyRequest{
		Request: &voicebio.StreamingVerifyRequest_Config{Config: cfg},
	}); err != nil {
		// if this failed, we don't need to CloseSend
		return err
	}

	// Stream the audio.
	buf := make([]byte, bufSize)
	for {
		n, err := audio.Read(buf)
		if n > 0 {
			if err2 := stream.Send(&voicebio.StreamingVerifyRequest{
				Request: &voicebio.StreamingVerifyRequest_Audio{
					Audio: &voicebio.Audio{Data: buf[:n]},
				},
			}); err2 != nil {
				// if we couldn't Send, the stream has
				// encountered an error and we don't need to
				// CloseSend.
				return err2
			}
		}

		if err != nil {
			// err could be io.EOF, or some other error reading from
			// audio.  In any case, we need to CloseSend, send the
			// appropriate error to errCh and return from the function
			if err2 := stream.CloseSend(); err2 != nil {
				return err2
			}

			if err != io.EOF {
				return err
			}

			return nil
		}
	}
}

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"strings"

	"golang.org/x/sync/errgroup"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	voicebio "github.com/cobaltspeech/go-genproto/cobaltspeech/voicebio/v1"
)

func main() {
	const (
		serverAddress = "localhost:2727"
	)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	opts := []grpc.DialOption{
		grpc.WithTransportCredentials(insecure.NewCredentials()), // Using a channel without TLS enabled.
		grpc.WithBlock(),
		grpc.WithReturnConnectionError(),
		grpc.FailOnNonTempDialError(true),
	}

	conn, err := grpc.DialContext(ctx, serverAddress, opts...)
	if err != nil {
		fmt.Printf("failed to dial gRPC connection: %v\n", err)
		os.Exit(1)
	}

	client := voicebio.NewVoiceBioServiceClient(conn)

	// Get server version.
	versionResp, err := client.Version(ctx, &voicebio.VersionRequest{})
	if err != nil {
		fmt.Printf("failed to get server version: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("%v\n", versionResp)

	// Get list model of models on the server.
	modelResp, err := client.ListModels(ctx, &voicebio.ListModelsRequest{})
	if err != nil {
		fmt.Printf("failed to get model list: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("Models:")
	for _, m := range modelResp.Models {
		fmt.Println(m)
	}
	fmt.Println()

	// Selecting first model.
	m := modelResp.Models[0]

	// Reading voiceprint data.
	data, err := os.ReadFile("voiceprint.bin")
	if err != nil {
		fmt.Printf("\nfailed to read voiceprint data: %v\n", err)
		os.Exit(1)
	}

	// Setting audio format to be raw 16-bit signed little endian audio samples
	// recorded at the sample rate expected by the model.
	cfg := &voicebio.VerificationConfig{
		ModelId:    m.Id,
		Voiceprint: &voicebio.Voiceprint{Data: string(data)},
		AudioFormat: &voicebio.AudioFormat{AudioFormat: &voicebio.AudioFormat_AudioFormatRaw{
			AudioFormatRaw: &voicebio.AudioFormatRAW{
				Encoding:   voicebio.AudioEncoding_AUDIO_ENCODING_SIGNED,
				SampleRate: m.Attributes.SampleRate,
				BitDepth:   16,
				ByteOrder:  voicebio.ByteOrder_BYTE_ORDER_LITTLE_ENDIAN,
				Channels:   1,
			},
		},
		},
	}

	// Open microphone stream using sox's rec command and record
	// audio using the config specified above for *10 seconds*.
	maxDuration := 10
	args := fmt.Sprintf("-t raw -r %d -e signed -b 16 -L -c 1 - trim 0 %d", m.Attributes.SampleRate, maxDuration)
	cmd := exec.CommandContext(ctx, "rec", strings.Fields(args)...)
	cmd.Stderr = os.Stderr

	audio, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Printf("failed to open microphone stream: %v\n", err)
		os.Exit(1)
	}

	// Starting routines to record from microphone and stream to server
	// using an errgroup.Group that returns if either one encounters an error.
	eg, ctx := errgroup.WithContext(ctx)

	eg.Go(func() error {
		fmt.Printf("\n[INFO] recording %d seconds from microphone \n", maxDuration)

		if err := cmd.Run(); err != nil {
			return fmt.Errorf("record from microphone: %w", err)
		}

		return nil
	})

	// Starting verification.
	resp, err := StreamingVerify(ctx, client, cfg, audio)
	if err != nil {
		fmt.Printf("failed to run streaming verification: %v\n", err)
		os.Exit(1)
	}

	// Server returns a similarity score along with whether the score
	// exceeded the server-configured threshold for being a match.
	fmt.Printf("Verification Score: %1.3f, Match: %v\n", resp.Result.SimilarityScore, resp.Result.IsMatch)
}

// StreamingVerify wraps the streaming API for performing speaker verification
// using  the given cfg.
//
// Data is read from the given audio reader into a buffer and streamed to VoiceBio
// server. The default buffer size may be overridden using Options when creating
// the Client.
//
// If any error occurs while reading the audio or sending it to the server, this
// method will immediately exit, returning that error.
func StreamingVerify(
	ctx context.Context,
	client voicebio.VoiceBioServiceClient,
	cfg *voicebio.VerificationConfig,
	audio io.Reader,
) (*voicebio.StreamingVerifyResponse, error) {
	const (
		streamingBufSize = 1024
	)

	// Creating stream.
	stream, err := client.StreamingVerify(ctx)
	if err != nil {
		return nil, err
	}

	// Sending audio.
	if err := sendAudio(stream, cfg, audio, streamingBufSize); err != nil && !errors.Is(err, io.EOF) {
		// if sendAudio encountered io.EOF, it's only a
		// notification that the stream has closed.  The actual
		// status will be obtained in the CloseAndRecv call. We
		// therefore return on non-EOF errors here.
		return nil, err
	}

	// Returning result.
	return stream.CloseAndRecv()
}

// sendAudio sends the config and audio to a stream.
func sendAudio(
	stream voicebio.VoiceBioService_StreamingVerifyClient,
	cfg *voicebio.VerificationConfig,
	audio io.Reader,
	bufSize uint32,
) error {
	// The first message needs to be a config message, and all subsequent
	// messages must be audio messages.

	// Send the config.
	if err := stream.Send(&voicebio.StreamingVerifyRequest{
		Request: &voicebio.StreamingVerifyRequest_Config{Config: cfg},
	}); err != nil {
		// if this failed, we don't need to CloseSend
		return err
	}

	// Stream the audio.
	buf := make([]byte, bufSize)
	for {
		n, err := audio.Read(buf)
		if n > 0 {
			if err2 := stream.Send(&voicebio.StreamingVerifyRequest{
				Request: &voicebio.StreamingVerifyRequest_Audio{
					Audio: &voicebio.Audio{Data: buf[:n]},
				},
			}); err2 != nil {
				// if we couldn't Send, the stream has
				// encountered an error and we don't need to
				// CloseSend.
				return err2
			}
		}

		if err != nil {
			// err could be io.EOF, or some other error reading from
			// audio.  In any case, we need to CloseSend, send the
			// appropriate error to errCh and return from the function
			if err2 := stream.CloseSend(); err2 != nil {
				return err2
			}

			if err != io.EOF {
				return err
			}

			return nil
		}
	}
}