add synchronized playback attempt

internal/playback/sync_attempt.go

@@ -0,0 +1,56 @@
+package playback
+
+import (
+	"context"
+	"errors"
+	"fmt"
+)
+
+func runSyncAttempt(
+	ctx context.Context,
+	factory SyncReaderFactory,
+	videoSink VideoSink,
+	audioSink AudioSink,
+	videoConfig FeedConfig,
+	audioConfig FeedConfig,
+) (resultErr error) {
+	reader, err := factory.OpenSync(
+		ctx,
+		videoConfig,
+		audioConfig,
+	)
+	if err != nil {
+		return fmt.Errorf("open sync group: %w", err)
+	}
+
+	defer func() {
+		if closeErr := reader.Close(); closeErr != nil {
+			closeErr = fmt.Errorf("close sync group: %w", closeErr)
+			resultErr = errors.Join(resultErr, closeErr)
+		}
+	}()
+
+	for {
+		frame, err := reader.ReadSync(ctx)
+		if err != nil {
+			if ctx.Err() != nil {
+				return ctx.Err()
+			}
+			return fmt.Errorf("read sync group: %w", err)
+		}
+
+		if err := videoSink.ConsumeVideo(ctx, frame.Video); err != nil {
+			if ctx.Err() != nil {
+				return ctx.Err()
+			}
+			return &videoSinkError{err: err}
+		}
+
+		if err := audioSink.ConsumeAudio(ctx, frame.Audio); err != nil {
+			if ctx.Err() != nil {
+				return ctx.Err()
+			}
+			return &audioSinkError{err: err}
+		}
+	}
+}