Use bounded contrast and bulk YUV writes in hardware rate probe

tools/chatgui-android/app/src/debug/java/com/utun/chat/data/CallVideoProbe.kt

@@ -92,10 +92,15 @@ class CallVideoProbe : Instrumentation() {
         for ((index, plane) in image.planes.withIndex()) {
             val width = image.width shr (if (index == 0) 0 else 1)
             val height = image.height shr (if (index == 0) 0 else 1)
-            val buffer = plane.buffer.duplicate(); val start = buffer.position()
-            for (y in 0 until height) for (x in 0 until width) {
-                random = random * 1664525 + 1013904223
-                buffer.put(start + y * plane.rowStride + x * plane.pixelStride, if (index == 0) (random ushr 24).toByte() else 128.toByte())
+            val buffer = plane.buffer.duplicate(); val start = buffer.position(); val row = ByteArray(width) { 128.toByte() }
+            for (y in 0 until height) {
+                // Ограниченный контраст: полностью случайный 8-bit шум превышает возможности аппаратного CBR даже при QP=51.
+                if (index == 0) for (x in 0 until width) {
+                    random = random * 1664525 + 1013904223; row[x] = (112 + (random ushr 27)).toByte()
+                }
+                val offset = start + y * plane.rowStride
+                if (plane.pixelStride == 1) { buffer.position(offset); buffer.put(row) }
+                else for (x in 0 until width) buffer.put(offset + x * plane.pixelStride, row[x])
             }
         }
         return random