diff --git a/app/src/main/java/nl/rogro82/pipup/PopupProps.kt b/app/src/main/java/nl/rogro82/pipup/PopupProps.kt
index 3f42f97..7234c84 100644
--- a/app/src/main/java/nl/rogro82/pipup/PopupProps.kt
+++ b/app/src/main/java/nl/rogro82/pipup/PopupProps.kt
@@ -104,8 +104,12 @@ data class PopupProps(
         // hardware decoder), false = always hardware, null/absent = automatic (software on
         // Android < 8 and on Amlogic SoCs, whose hardware decoder shares the video layer with
         // the HDMI input and freezes it when released - reported on a Xiaomi projector).
+        // height: optional explicit box height. When set, the stream area (and its poster)
+        // uses it until the first frame reports the stream's display aspect; without it the
+        // box takes the poster's aspect, which is wrong for anamorphic NVR snapshots.
         data class Video(val uri: String, val width: Int = DEFAULT_MEDIA_WIDTH, val muted: Boolean = false,
-                         val poster: String? = null, val softwareDecoder: Boolean? = null): Media()
+                         val poster: String? = null, val softwareDecoder: Boolean? = null,
+                         val height: Int? = null): Media()
         @JsonIgnoreProperties(ignoreUnknown = true)
         data class Image(val uri: String, val width: Int = DEFAULT_MEDIA_WIDTH): Media()
         @JsonIgnoreProperties(ignoreUnknown = true)
diff --git a/app/src/main/java/nl/rogro82/pipup/PopupView.kt b/app/src/main/java/nl/rogro82/pipup/PopupView.kt
index a9e2d5d..24f8475 100644
--- a/app/src/main/java/nl/rogro82/pipup/PopupView.kt
+++ b/app/src/main/java/nl/rogro82/pipup/PopupView.kt
@@ -418,10 +418,13 @@ sealed class PopupView(context: Context, val popup: PopupProps) : LinearLayout(c
                 this@Video.visibility = View.VISIBLE
             }
             frame.addView(textureView)
+            val provisionalHeight = provisionalVideoHeight(media.width, media.height)
             attachPoster(frame, media.poster,
-                FrameLayout.LayoutParams(media.width, media.width * 9 / 16).apply { gravity = Gravity.CENTER }
-            ) { pw, ph -> sizeTo(media.width, (media.width.toLong() * ph / pw).toInt()) }
-            sizeTo(media.width, media.width * 9 / 16)
+                FrameLayout.LayoutParams(media.width, provisionalHeight).apply { gravity = Gravity.CENTER }
+            ) { pw, ph ->
+                posterVideoHeight(media.width, media.height, pw, ph)?.let { sizeTo(media.width, it) }
+            }
+            sizeTo(media.width, provisionalHeight)
 
             val isRtsp = uri.startsWith("rtsp://", ignoreCase = true) || uri.startsWith("rtsps://", ignoreCase = true)
             val item = MediaItem.fromUri(uri)
@@ -967,3 +970,14 @@ internal fun heightForDisplayAspect(targetWidth: Int, width: Int, height: Int, p
     val displayWidth = width * ratio
     return Math.round(targetWidth * height / displayWidth)
 }
+
+/// Stream-area height before the first frame: an explicit [requestedHeight], else 16:9.
+internal fun provisionalVideoHeight(width: Int, requestedHeight: Int?): Int =
+    requestedHeight?.takeIf { it > 0 } ?: (width * 9 / 16)
+
+/// Height to resize the stream area to once the poster has decoded, or null to keep the box.
+/// With an explicit [requestedHeight] the box stays put: a camera snapshot can be anamorphic
+/// (an NVR's 704x480 still of a 4:3 picture), so its pixel size is not the stream's shape.
+internal fun posterVideoHeight(width: Int, requestedHeight: Int?, posterWidth: Int, posterHeight: Int): Int? =
+    if (requestedHeight != null && requestedHeight > 0) null
+    else (width.toLong() * posterHeight / posterWidth).toInt()
diff --git a/app/src/test/java/nl/rogro82/pipup/VideoPosterHeightTest.kt b/app/src/test/java/nl/rogro82/pipup/VideoPosterHeightTest.kt
new file mode 100644
index 0000000..fdf9099
--- /dev/null
+++ b/app/src/test/java/nl/rogro82/pipup/VideoPosterHeightTest.kt
@@ -0,0 +1,32 @@
+package nl.rogro82.pipup
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class VideoPosterHeightTest {
+    @Test
+    fun withoutRequestedHeightTheBoxStartsSixteenNine() {
+        assertEquals(360, provisionalVideoHeight(640, null))
+    }
+
+    @Test
+    fun requestedHeightSetsTheProvisionalBox() {
+        assertEquals(480, provisionalVideoHeight(640, 480))
+    }
+
+    @Test
+    fun nonPositiveRequestedHeightIsIgnored() {
+        assertEquals(360, provisionalVideoHeight(640, 0))
+    }
+
+    @Test
+    fun withoutRequestedHeightThePosterSetsTheShape() {
+        assertEquals(436, posterVideoHeight(640, null, 704, 480))
+    }
+
+    @Test
+    fun requestedHeightKeepsTheBoxForAnAnamorphicPoster() {
+        assertNull(posterVideoHeight(640, 480, 704, 480))
+    }
+}