diff --git a/testdata/ffmpeg.d/cmd/prune/main.go b/testdata/ffmpeg.d/cmd/prune/main.go
index c296cda..bf28185 100644
--- a/testdata/ffmpeg.d/cmd/prune/main.go
+++ b/testdata/ffmpeg.d/cmd/prune/main.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"log"
 	"math/big"
 	"os"
 	"os/exec"
@@ -15,7 +14,6 @@ import (
 	"strconv"
 	"strings"
 	"syscall"
-	"time"
 )
 
 func main() {
@@ -30,79 +28,65 @@ func main() {
 func Run(ctx context.Context, args []string) error {
 	cams, err := lsd(args[0])
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to lsd %s: %w", args[0], err)
 	}
 
 	for _, cam := range cams {
 		files, err := lsf(cam)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to lsf %s: %w", cam, err)
 		} else if len(files) < 1 {
 			continue
 		}
 
-		lastChunk := strings.Split(path.Base(files[len(files)-1]), ".")[0]
-		files = slices.DeleteFunc(files, func(f string) bool {
-			return strings.Contains(f, lastChunk)
-		})
-		if len(files) == 0 {
+		series := []string{}
+		for _, f := range files {
+			series = append(series, strings.Split(path.Base(f), ".")[0])
+		}
+		series = slices.Compact(series)
+		if len(series) < 1 {
 			continue
 		}
+		series = series[:len(series)-1]
 
-		lastMovementAt := time.Unix(0, 0)
-		prevF := files[0]
-		for _, f := range files[1:] {
-			prev, err := os.Stat(prevF)
-			if err != nil {
-				return err
-			}
-
-			if ok, err := hasMovement(ctx, prevF, f); err != nil {
-				return err
-			} else if ok {
-				lastMovementAt = prev.ModTime()
-			}
-
-			target := "trash"
-			if prev.ModTime().Before(lastMovementAt.Add(3 * time.Minute)) {
-				target = "movement"
-			}
-			if target == "trash" {
-				log.Println("deleting", prevF)
-				if err := os.Remove(prevF); err != nil {
+		for _, series := range series {
+			if err := func() error {
+				seriesFiles := []string{}
+				for _, file := range files {
+					if strings.HasPrefix(path.Base(file), series) {
+						seriesFiles = append(seriesFiles, file)
+					}
+				}
+				if seriesHasMovement, err := func() (bool, error) {
+					for i := 1; i < len(files); i++ {
+						f := files[i-1]
+						g := files[i]
+						if hasMovement, err := hasMovement(ctx, f, g); err != nil {
+							return false, fmt.Errorf("failed to check for movement between %s and %s: %w", f, g, err)
+						} else if hasMovement {
+							return true, nil
+						}
+					}
+					return false, nil
+				}(); err != nil {
 					return err
+				} else if seriesHasMovement {
+					for _, seriesFile := range seriesFiles {
+						if err := mv(strings.ReplaceAll(seriesFile, "record", "movement"), seriesFile); err != nil {
+							return fmt.Errorf("failed to mv series %s: %w", series, err)
+						}
+					}
+				} else {
+					for _, seriesFile := range seriesFiles {
+						if err := os.Remove(seriesFile); err != nil {
+							return fmt.Errorf("failed to rm series %s[%s]: %w", series, seriesFile, err)
+						}
+					}
 				}
-			} else if err := func() error {
-				gName := strings.ReplaceAll(prevF, "record", target)
-				if gName == prevF {
-					return fmt.Errorf("would overwrite original %s", prevF)
-				}
-				os.MkdirAll(path.Dir(gName), os.ModePerm)
-
-				log.Println("moving", prevF, "to", gName)
-
-				f, err := os.Open(prevF)
-				if err != nil {
-					return err
-				}
-				defer f.Close()
-
-				g, err := os.Create(gName)
-				if err != nil {
-					return err
-				}
-				defer g.Close()
-
-				if _, err := io.Copy(g, f); err != nil {
-					return err
-				}
-
-				return os.Remove(prevF)
+				return nil
 			}(); err != nil {
 				return err
 			}
-
-			prevF = f
 		}
 	}
 	return nil
@@ -117,11 +101,11 @@ func hasMovement(ctx context.Context, a, b string) (bool, error) {
 	hw := strings.Fields(string(sizeOfOutput))[2]
 	h, err := strconv.ParseInt(strings.Split(hw, "x")[0], 10, 16)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("failed parsing %s for HxW: %w", hw, err)
 	}
 	w, err := strconv.ParseInt(strings.Split(hw, "x")[1], 10, 16)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("failed parsing %s for HxW: %w", hw, err)
 	}
 	total := h * w
 
@@ -130,7 +114,7 @@ func hasMovement(ctx context.Context, a, b string) (bool, error) {
 
 	f, _, err := big.ParseFloat(string(compareOutput), 10, 0, big.ToNearestEven)
 	if err != nil {
-		return false, err
+		return false, fmt.Errorf("failed to parse %s for a number of changed pixels: %w", compareOutput, err)
 	}
 	i := new(big.Int)
 	f.Int(i)
@@ -140,6 +124,29 @@ func hasMovement(ctx context.Context, a, b string) (bool, error) {
 	return percentPixelsChanged > 10, nil
 }
 
+func mv(wPath, rPath string) error {
+	r, err := os.Open(rPath)
+	if err != nil {
+		return err
+	}
+	defer r.Close()
+
+	os.MkdirAll(path.Dir(wPath), os.ModePerm)
+	w, err := os.Create(wPath)
+	if err != nil {
+		return err
+	}
+	defer w.Close()
+
+	if _, err := io.Copy(w, r); err != nil {
+		w.Close()
+		os.Remove(wPath)
+		return err
+	}
+
+	return os.Remove(rPath)
+}
+
 func lsd(d string) ([]string, error) {
 	return ls(d, true)
 }
diff --git a/testdata/ffmpeg.d/cmd/prune/main_test.go b/testdata/ffmpeg.d/cmd/prune/main_test.go
index 431b0bb..920bad1 100644
--- a/testdata/ffmpeg.d/cmd/prune/main_test.go
+++ b/testdata/ffmpeg.d/cmd/prune/main_test.go
@@ -28,23 +28,20 @@ func TestRun(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	t.Log("lsd", path.Dir(d))
-	t.Log(lsd(path.Dir(d)))
-
-	t.Log("lsf", d)
-	t.Log(lsf(d))
-
 	if err := Run(context.Background(), []string{path.Dir(d)}); err != nil {
 		t.Fatal(err)
 	}
 
 	if results, err := lsf(path.Join(path.Dir(d), "movement")); err != nil {
-		t.Fatal(err)
-	} else if len(results) < 2 {
+		t.Fatal("failed to lsf for results:", err)
+	} else if len(results) < 3 {
 		t.Fatal(results)
-	} else if path.Base(results[0]) != "series.1.jpg" {
+	} else if path.Base(results[0]) != "series.0.jpg" {
 		t.Fatal(results)
-	} else if path.Base(results[1]) != "series.2.jpg" {
+	} else if path.Base(results[1]) != "series.1.jpg" {
+		t.Fatal(results)
+	} else if path.Base(results[2]) != "series.2.jpg" {
 		t.Fatal(results)
 	}
+	// TODO assert originals deleted
 }