diff --git a/filter/difference.go b/filter/diff.go
similarity index 56%
rename from filter/difference.go
rename to filter/diff.go
index 137a0b0d..d56524e2 100644
--- a/filter/difference.go
+++ b/filter/diff.go
@@ -11,7 +11,7 @@ AUTHORS
   Scott Barnard <scott@ausocean.org>
 
 LICENSE
-  difference.go is Copyright (C) 2020 the Australian Ocean Lab (AusOcean)
+  diff.go is Copyright (C) 2020 the Australian Ocean Lab (AusOcean)
 
   It is free software: you can redistribute it and/or modify them
   under the terms of the GNU General Public License as published by the
@@ -39,65 +39,54 @@ import (
 
 const defaultDiffThreshold = 3
 
-// Diff is a filter that provides basic motion detection. Difference calculates
-// the absolute difference for each pixel between two frames, then finds the mean. If
-// the mean is above a given threshold, then it is considered motion.
-type Diff struct {
-	debugging debugWindows
-	dst       io.WriteCloser
-	thresh    float64
-	prev      gocv.Mat
-}
+// NewDiff returns a pointer to a new difference motion filter.
+func NewDiff(dst io.WriteCloser, c config.Config) *Motion {
 
-// NewDiff returns a pointer to a new Diff struct.
-func NewDiff(dst io.WriteCloser, c config.Config) *Diff {
 	// Validate parameters.
 	if c.MotionThreshold <= 0 {
 		c.LogInvalidField("MotionThreshold", defaultDiffThreshold)
 		c.MotionThreshold = defaultDiffThreshold
 	}
 
-	return &Diff{
-		dst:       dst,
+	alg := &Diff{
 		thresh:    c.MotionThreshold,
 		prev:      gocv.NewMat(),
 		debugging: newWindows("DIFF"),
 	}
+
+	return NewMotion(dst, alg, c)
 }
 
-// Implements io.Closer.
-// Close frees resources used by gocv, because it has to be done manually, due to
-// it using c-go.
+// Diff is a motion detection algorithm. It calculates the absolute
+// difference for each pixel between two frames, then finds the mean.
+// If the mean is above a given threshold, it is considered motion.
+type Diff struct {
+	debugging debugWindows
+	thresh    float64
+	prev      gocv.Mat
+}
+
+// Close frees resources used by gocv. It has to be done manually,
+// due to gocv using c-go.
 func (d *Diff) Close() error {
-	d.prev.Close()
 	d.debugging.close()
+	d.prev.Close()
 	return nil
 }
 
-// Implements io.Writer.
-// Write applies the motion filter to the video stream. Only frames with motion
-// are written to the destination encoder, frames without are discarded.
-func (d *Diff) Write(f []byte) (int, error) {
+// Detect performs the motion detection on a frame. It returns true
+// if motion is detected.
+func (d *Diff) Detect(img *gocv.Mat) bool {
 	if d.prev.Empty() {
-		var err error
-		d.prev, err = gocv.IMDecode(f, gocv.IMReadColor)
-		if err != nil {
-			return 0, err
-		}
-		return len(f), nil
-	}
-
-	img, err := gocv.IMDecode(f, gocv.IMReadColor)
-	defer img.Close()
-	if err != nil {
-		return 0, err
+		d.prev = img.Clone()
+		return false
 	}
 
 	imgDelta := gocv.NewMat()
 	defer imgDelta.Close()
 
 	// Seperate foreground and background.
-	gocv.AbsDiff(img, d.prev, &imgDelta)
+	gocv.AbsDiff(*img, d.prev, &imgDelta)
 	gocv.CvtColor(imgDelta, &imgDelta, gocv.ColorBGRToGray)
 
 	mean := imgDelta.Mean().Val1
@@ -106,13 +95,8 @@ func (d *Diff) Write(f []byte) (int, error) {
 	d.prev = img.Clone()
 
 	// Draw debug information.
-	d.debugging.show(img, imgDelta, mean > d.thresh, nil, fmt.Sprintf("Mean: %f", mean), fmt.Sprintf("Threshold: %f", d.thresh))
+	d.debugging.show(*img, imgDelta, mean > d.thresh, nil, fmt.Sprintf("Mean: %f", mean), fmt.Sprintf("Threshold: %f", d.thresh))
 
-	// Don't write to destination if there is no motion.
-	if mean < d.thresh {
-		return len(f), nil
-	}
-
-	// Write to destination.
-	return d.dst.Write(f)
+	// Return if there is motion.
+	return mean > d.thresh
 }
diff --git a/filter/knn.go b/filter/knn.go
index 31c97c27..005dc204 100644
--- a/filter/knn.go
+++ b/filter/knn.go
@@ -29,7 +29,6 @@ LICENSE
 package filter
 
 import (
-	"fmt"
 	"image"
 	"io"
 
@@ -38,30 +37,15 @@ import (
 )
 
 const (
-	defaultKNNMinArea     = 25.0
-	defaultKNNThreshold   = 300
-	defaultKNNHistory     = 300
-	defaultKNNKernel      = 4
-	defaultKNNDownscaling = 2
-	defaultKNNInterval    = 1
+	defaultKNNMinArea   = 25.0
+	defaultKNNThreshold = 300
+	defaultKNNHistory   = 300
+	defaultKNNKernel    = 4
 )
 
-// KNN is a filter that provides basic motion detection. KNN is short for
-// K-Nearest Neighbours method.
-type KNN struct {
-	debugging debugWindows
-	dst       io.WriteCloser                // Destination to which motion containing frames go.
-	area      float64                       // The minimum area that a contour can be found in.
-	bs        *gocv.BackgroundSubtractorKNN // Uses the KNN algorithm to find the difference between the current and background frame.
-	knl       gocv.Mat                      // Matrix that is used for calculations.
-	hold      [][]byte                      // Will hold all frames up to hf (so only every hf frame is motion detected).
-	hf        int                           // The number of frames to be held.
-	hfCount   int                           // Counter for the hold array.
-	scale     float64                       // The factor that frames will be downscaled by for motion detection.
-}
+// NewKNN returns a pointer to a new KNN motion filter.
+func NewKNN(dst io.WriteCloser, c config.Config) *Motion {
 
-// NewKNN returns a pointer to a new KNN filter struct.
-func NewKNN(dst io.WriteCloser, c config.Config) *KNN {
 	// Validate parameters.
 	if c.MotionMinArea <= 0 {
 		c.LogInvalidField("MotionMinArea", defaultKNNMinArea)
@@ -75,37 +59,33 @@ func NewKNN(dst io.WriteCloser, c config.Config) *KNN {
 		c.LogInvalidField("MotionHistory", defaultKNNHistory)
 		c.MotionHistory = defaultKNNHistory
 	}
-	if c.MotionDownscaling <= 0 {
-		c.LogInvalidField("MotionDownscaling", defaultKNNDownscaling)
-		c.MotionDownscaling = defaultKNNDownscaling
-	}
-	if c.MotionInterval <= 0 {
-		c.LogInvalidField("MotionInterval", defaultKNNInterval)
-		c.MotionInterval = defaultKNNInterval
-	}
 	if c.MotionKernel <= 0 {
 		c.LogInvalidField("MotionKernel", defaultKNNKernel)
 		c.MotionKernel = defaultKNNKernel
 	}
 
 	bs := gocv.NewBackgroundSubtractorKNNWithParams(int(c.MotionHistory), c.MotionThreshold, false)
-	k := gocv.GetStructuringElement(gocv.MorphRect, image.Pt(int(c.MotionKernel), int(c.MotionKernel)))
-
-	return &KNN{
-		dst:       dst,
+	alg := &KNN{
 		area:      c.MotionMinArea,
 		bs:        &bs,
-		knl:       k,
-		hold:      make([][]byte, c.MotionInterval-1),
-		hf:        c.MotionInterval,
-		scale:     1 / float64(c.MotionDownscaling),
+		knl:       gocv.GetStructuringElement(gocv.MorphRect, image.Pt(int(c.MotionKernel), int(c.MotionKernel))),
 		debugging: newWindows("KNN"),
 	}
+
+	return NewMotion(dst, alg, c)
 }
 
-// Implements io.Closer.
-// Close frees resources used by gocv, because it has to be done manually, due to
-// it using c-go.
+// KNN is motion detection algorithm. KNN is short for
+// K-Nearest Neighbours method.
+type KNN struct {
+	debugging debugWindows
+	area      float64                       // The minimum area that a contour can be found in.
+	bs        *gocv.BackgroundSubtractorKNN // Uses the KNN algorithm to find the difference between the current and background frame.
+	knl       gocv.Mat                      // Matrix that is used for calculations.
+}
+
+// Close frees resources used by gocv. It has to be done manually,
+// due to gocv using c-go.
 func (m *KNN) Close() error {
 	m.bs.Close()
 	m.knl.Close()
@@ -113,31 +93,14 @@ func (m *KNN) Close() error {
 	return nil
 }
 
-// Implements io.Writer.
-// Write applies the motion filter to the video stream. Only frames with motion
-// are written to the destination encoder, frames without are discarded.
-func (m *KNN) Write(f []byte) (int, error) {
-	if m.hfCount < (m.hf - 1) {
-		m.hold[m.hfCount] = f
-		m.hfCount++
-		return len(f), nil
-	}
-	m.hfCount = 0
-
-	img, err := gocv.IMDecode(f, gocv.IMReadColor)
-	if err != nil {
-		return 0, fmt.Errorf("can't decode image: %w", err)
-	}
-	defer img.Close()
-
+// Detect performs the motion detection on a frame. It returns true
+// if motion is detected.
+func (m *KNN) Detect(img *gocv.Mat) bool {
 	imgDelta := gocv.NewMat()
 	defer imgDelta.Close()
 
-	// Downsize image to speed up calculations.
-	gocv.Resize(img, &img, image.Point{}, m.scale, m.scale, gocv.InterpolationNearestNeighbor)
-
 	// Seperate foreground and background.
-	m.bs.Apply(img, &imgDelta)
+	m.bs.Apply(*img, &imgDelta)
 
 	// Threshold imgDelta.
 	gocv.Threshold(imgDelta, &imgDelta, 25, 255, gocv.ThresholdBinary)
@@ -160,20 +123,8 @@ func (m *KNN) Write(f []byte) (int, error) {
 	}
 
 	// Draw debug information.
-	m.debugging.show(img, imgDelta, len(contours) > 0, &contours)
+	m.debugging.show(*img, imgDelta, len(contours) > 0, &contours)
 
-	// Don't write to destination if there is no motion.
-	if len(contours) == 0 {
-		return len(f), nil
-	}
-
-	// Write to destination, past 4 frames then current frame.
-	for i, h := range m.hold {
-		_, err := m.dst.Write(h)
-		m.hold[i] = nil
-		if err != nil {
-			return len(f), fmt.Errorf("could not write previous frames: %w", err)
-		}
-	}
-	return m.dst.Write(f)
+	// Return if there is motion.
+	return len(contours) > 0
 }
diff --git a/filter/mog.go b/filter/mog.go
index 93bd4f92..ab0ac2bc 100644
--- a/filter/mog.go
+++ b/filter/mog.go
@@ -3,7 +3,7 @@
 /*
 DESCRIPTION
   A filter that detects motion and discards frames without motion. The
-  filter uses a Mixture of Gaussians method (MoG) to determine what is
+  algorithm uses a Mixture of Gaussians method (MoG) to determine what is
   background and what is foreground.
 
 AUTHORS
@@ -29,7 +29,6 @@ LICENSE
 package filter
 
 import (
-	"fmt"
 	"image"
 	"io"
 
@@ -38,30 +37,15 @@ import (
 )
 
 const (
-	defaultMOGMinArea     = 25.0
-	defaultMOGThreshold   = 20.0
-	defaultMOGHistory     = 500
-	defaultMOGKernel      = 3
-	defaultMOGDownscaling = 2
-	defaultMOGInterval    = 1
+	defaultMOGMinArea   = 25.0
+	defaultMOGThreshold = 20.0
+	defaultMOGHistory   = 500
+	defaultMOGKernel    = 3
 )
 
-// MOG is a filter that provides basic motion detection. MoG is short for
-// Mixture of Gaussians method.
-type MOG struct {
-	debugging debugWindows
-	dst       io.WriteCloser                 // Destination to which motion containing frames go.
-	area      float64                        // The minimum area that a contour can be found in.
-	bs        *gocv.BackgroundSubtractorMOG2 // Uses the MOG algorithm to find the difference between the current and background frame.
-	knl       gocv.Mat                       // Matrix that is used for calculations.
-	hold      [][]byte                       // Will hold all frames up to hf (so only every hf frame is motion detected).
-	hf        int                            // The number of frames to be held.
-	hfCount   int                            // Counter for the hold array.
-	scale     float64                        // The factor that frames will be downscaled by for motion detection.
-}
+// NewMOG returns a pointer to a new MOG motion filter.
+func NewMOG(dst io.WriteCloser, c config.Config) *Motion {
 
-// NewMOG returns a pointer to a new MOG filter struct.
-func NewMOG(dst io.WriteCloser, c config.Config) *MOG {
 	// Validate parameters.
 	if c.MotionMinArea <= 0 {
 		c.LogInvalidField("MotionMinArea", defaultMOGMinArea)
@@ -75,36 +59,33 @@ func NewMOG(dst io.WriteCloser, c config.Config) *MOG {
 		c.LogInvalidField("MotionHistory", defaultMOGHistory)
 		c.MotionHistory = defaultMOGHistory
 	}
-	if c.MotionDownscaling <= 0 {
-		c.LogInvalidField("MotionDownscaling", defaultMOGDownscaling)
-		c.MotionDownscaling = defaultMOGDownscaling
-	}
-	if c.MotionInterval <= 0 {
-		c.LogInvalidField("MotionInterval", defaultMOGInterval)
-		c.MotionInterval = defaultMOGInterval
-	}
 	if c.MotionKernel <= 0 {
 		c.LogInvalidField("MotionKernel", defaultMOGKernel)
 		c.MotionKernel = defaultMOGKernel
 	}
 
 	bs := gocv.NewBackgroundSubtractorMOG2WithParams(int(c.MotionHistory), c.MotionThreshold, false)
-	k := gocv.GetStructuringElement(gocv.MorphRect, image.Pt(3, 3))
-	return &MOG{
-		dst:       dst,
+	alg := &MOG{
 		area:      c.MotionMinArea,
 		bs:        &bs,
-		knl:       k,
-		hold:      make([][]byte, c.MotionInterval-1),
-		hf:        c.MotionInterval,
-		scale:     1 / float64(c.MotionDownscaling),
+		knl:       gocv.GetStructuringElement(gocv.MorphRect, image.Pt(3, 3)),
 		debugging: newWindows("MOG"),
 	}
+
+	return NewMotion(dst, alg, c)
 }
 
-// Implements io.Closer.
-// Close frees resources used by gocv, because it has to be done manually, due to
-// it using c-go.
+// MOG is a motion detection algorithm. MoG is short for
+// Mixture of Gaussians method.
+type MOG struct {
+	debugging debugWindows
+	area      float64                        // The minimum area that a contour can be found in.
+	bs        *gocv.BackgroundSubtractorMOG2 // Uses the MOG algorithm to find the difference between the current and background frame.
+	knl       gocv.Mat                       // Matrix that is used for calculations.
+}
+
+// Close frees resources used by gocv. It has to be done manually,
+// due to gocv using c-go.
 func (m *MOG) Close() error {
 	m.bs.Close()
 	m.knl.Close()
@@ -112,31 +93,14 @@ func (m *MOG) Close() error {
 	return nil
 }
 
-// Implements io.Writer.
-// Write applies the motion filter to the video stream. Only frames with motion
-// are written to the destination encoder, frames without are discarded.
-func (m *MOG) Write(f []byte) (int, error) {
-	if m.hfCount < (m.hf - 1) {
-		m.hold[m.hfCount] = f
-		m.hfCount++
-		return len(f), nil
-	}
-
-	m.hfCount = 0
-	img, err := gocv.IMDecode(f, gocv.IMReadColor)
-	if err != nil {
-		return 0, fmt.Errorf("image can't be decoded: %w", err)
-	}
-	defer img.Close()
-
+// Detect performs the motion detection on a frame. It returns true
+// if motion is detected.
+func (m *MOG) Detect(img *gocv.Mat) bool {
 	imgDelta := gocv.NewMat()
 	defer imgDelta.Close()
 
-	// Downsize image to speed up calculations.
-	gocv.Resize(img, &img, image.Point{}, m.scale, m.scale, gocv.InterpolationNearestNeighbor)
-
 	// Seperate foreground and background.
-	m.bs.Apply(img, &imgDelta)
+	m.bs.Apply(*img, &imgDelta)
 
 	// Threshold imgDelta.
 	gocv.Threshold(imgDelta, &imgDelta, 25, 255, gocv.ThresholdBinary)
@@ -159,20 +123,8 @@ func (m *MOG) Write(f []byte) (int, error) {
 	}
 
 	// Draw debug information.
-	m.debugging.show(img, imgDelta, len(contours) > 0, &contours)
+	m.debugging.show(*img, imgDelta, len(contours) > 0, &contours)
 
-	// Don't write to destination if there is no motion.
-	if len(contours) == 0 {
-		return len(f), nil
-	}
-
-	// Write to destination, past 4 frames then current frame.
-	for i, h := range m.hold {
-		_, err := m.dst.Write(h)
-		m.hold[i] = nil
-		if err != nil {
-			return len(f), fmt.Errorf("could not write previous frames: %w", err)
-		}
-	}
-	return m.dst.Write(f)
+	// Return if there is motion.
+	return len(contours) > 0
 }
diff --git a/filter/motion.go b/filter/motion.go
new file mode 100644
index 00000000..d2af00d9
--- /dev/null
+++ b/filter/motion.go
@@ -0,0 +1,132 @@
+// +build !circleci
+
+/*
+DESCRIPTION
+  A filter that detects motion and discards frames without motion. This
+  filter can use different algorithms for motion detection.
+
+AUTHORS
+  Scott Barnard <scott@ausocean.org>
+
+LICENSE
+  motion.go is Copyright (C) 2019 the Australian Ocean Lab (AusOcean)
+
+  It is free software: you can redistribute it and/or modify them
+  under the terms of the GNU General Public License as published by the
+  Free Software Foundation, either version 3 of the License, or (at your
+  option) any later version.
+
+  It is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+  for more details.
+
+  You should have received a copy of the GNU General Public License
+  in gpl.txt.  If not, see http://www.gnu.org/licenses.
+*/
+
+package filter
+
+import (
+	"fmt"
+	"image"
+	"io"
+
+	"bitbucket.org/ausocean/av/revid/config"
+	"gocv.io/x/gocv"
+)
+
+const (
+	defaultMotionDownscaling = 1
+	defaultMotionInterval    = 5
+	defaultMotionPadding     = 10
+)
+
+// MotionAlgorithm is the interface the motion filter expects for
+// motion detection algorithms.
+type MotionAlgorithm interface {
+	Detect(img *gocv.Mat) bool
+	Close() error
+}
+
+// Motion is a filter that performs motion detection using a supplied
+// motion detection algorithm.
+type Motion struct {
+	dst       io.WriteCloser  // Destination to which motion containing frames go.
+	algorithm MotionAlgorithm // Algorithm to use for motion detection.
+	scale     float64         // The factor that frames will be downscaled by for motion detection.
+	sample    uint            // Interval that motion detection is performed at.
+	padding   uint            // The amount of frames before and after motion that will be kept.
+
+	t    uint // Frame counter.
+	send uint // Amount of frames to send.
+
+	frames chan []byte // Used for storing frames.
+}
+
+// NewMotion returns a pointer to a new Motion filter struct.
+func NewMotion(dst io.WriteCloser, alg MotionAlgorithm, c config.Config) *Motion {
+
+	// Validate parameters.
+	if c.MotionPadding == 0 {
+		c.LogInvalidField("MotionPadding", defaultMotionPadding)
+		c.MotionPadding = defaultMotionPadding
+	}
+	if c.MotionDownscaling <= 0 {
+		c.LogInvalidField("MotionDownscaling", defaultMotionDownscaling)
+		c.MotionDownscaling = defaultMotionDownscaling
+	}
+	if c.MotionInterval <= 0 {
+		c.LogInvalidField("MotionInterval", defaultMotionInterval)
+		c.MotionInterval = defaultMotionInterval
+	}
+
+	return &Motion{
+		dst:       dst,
+		algorithm: alg,
+		scale:     1 / float64(c.MotionDownscaling),
+		sample:    uint(c.MotionInterval),
+		padding:   c.MotionPadding,
+		frames:    make(chan []byte, c.MotionInterval+int(c.MotionPadding)),
+	}
+}
+
+// Implements io.Closer.
+// Close frees resources used by gocv, because it has to be done manually, due to
+// it using c-go.
+func (m *Motion) Close() error {
+	return m.algorithm.Close()
+}
+
+// Write applies the motion filter to the video stream. Only frames with motion
+// are written to the destination encoder, frames without are discarded.
+func (m *Motion) Write(f []byte) (int, error) {
+	// Decode image into Mat.
+	img, err := gocv.IMDecode(f, gocv.IMReadColor)
+	if err != nil {
+		return 0, fmt.Errorf("image can't be decoded: %w", err)
+	}
+	defer img.Close()
+
+	// Downsize image to speed up calculations.
+	gocv.Resize(img, &img, image.Point{}, m.scale, m.scale, gocv.InterpolationNearestNeighbor)
+
+	// Filter on an interval.
+	if m.t == m.sample/2 {
+		if m.algorithm.Detect(&img) {
+			m.send = m.sample + 2*m.padding - 1
+		}
+	}
+	m.t = (m.t + 1) % m.sample // Increment counter.
+
+	// Send frames.
+	m.frames <- f        // Put current frame into buffer.
+	toSend := <-m.frames // Get oldest frame out of circular buffer.
+
+	if m.send > 0 {
+		m.send--
+		return m.dst.Write(toSend)
+	}
+
+	return len(f), nil
+}
diff --git a/revid/config/config.go b/revid/config/config.go
index 9414b5ae..48a9f288 100644
--- a/revid/config/config.go
+++ b/revid/config/config.go
@@ -276,6 +276,7 @@ type Config struct {
 	MotionHistory   uint    // Length of filter's history (KNN & MOG only).
 	MotionKernel    uint    // Size of kernel used for filling holes and removing noise (KNN only).
 	MotionPixels    int     // Number of pixels with motion that is needed for a whole frame to be considered as moving (Basic only).
+	MotionPadding   uint    // Number of frames to keep before and after motion detected.
 
 	// If true will restart reading of input after an io.EOF.
 	Loop bool
@@ -315,6 +316,7 @@ var TypeData = map[string]string{
 	"MotionInterval":    "int",
 	"MotionKernel":      "uint",
 	"MotionMinArea":     "float",
+	"MotionPadding":     "uint",
 	"MotionPixels":      "int",
 	"MotionThreshold":   "float",
 	"Output":            "enum:File,Http,Rtmp,Rtp",
diff --git a/revid/revid.go b/revid/revid.go
index 1ef886d8..69646547 100644
--- a/revid/revid.go
+++ b/revid/revid.go
@@ -821,6 +821,13 @@ func (r *Revid) Update(vars map[string]string) error {
 				break
 			}
 			r.cfg.MotionHistory = uint(v)
+		case "MotionPadding":
+			v, err := strconv.Atoi(value)
+			if err != nil || v <= 0 {
+				r.cfg.Logger.Log(logger.Warning, pkg+"invalid MotionPadding var", "value", value)
+				break
+			}
+			r.cfg.MotionPadding = uint(v)
 		case "MotionPixels":
 			v, err := strconv.Atoi(value)
 			if err != nil {