V210 issue fix + correct packing

internal/generator/v210_test.go

@@ -1,16 +1,43 @@
 package generator
 
-import "encoding/binary"
+import (
+	"encoding/binary"
+	"testing"
+)
+
+func TestV210Sizes(t *testing.T) {
+	tests := []struct {
+		width      int
+		activeLine int
+		line       int
+	}{
+		{width: 1920, activeLine: 5120, line: 5120},
+		{width: 1280, activeLine: 3424, line: 3456},
+		{width: 100, activeLine: 272, line: 384},
+		{width: 54, activeLine: 144, line: 256},
+		{width: 48, activeLine: 128, line: 128},
+	}
+	for _, tc := range tests {
+		if got := V210ActiveLineSize(tc.width); got != tc.activeLine {
+			t.Errorf("V210ActiveLineSize(%d) = %d, want %d", tc.width, got, tc.activeLine)
+		}
+		if got := V210LineSize(tc.width); got != tc.line {
+			t.Errorf("V210LineSize(%d) = %d, want %d", tc.width, got, tc.line)
+		}
+		if got := V210FrameSize(tc.width, 2); got != tc.line*2 {
+			t.Errorf("V210FrameSize(%d, 2) = %d, want %d", tc.width, got, tc.line*2)
+		}
+	}
+}
 
 func sampleV210(buf []byte, width, x, y int) (yc, cb, cr uint32) {
-	pixel := y*width + x
-	offset := (pixel / 6) * 16
+	offset := y*V210LineSize(width) + x/6*16
 	w0 := binary.LittleEndian.Uint32(buf[offset:])
 	w1 := binary.LittleEndian.Uint32(buf[offset+4:])
 	w2 := binary.LittleEndian.Uint32(buf[offset+8:])
 	w3 := binary.LittleEndian.Uint32(buf[offset+12:])
 
-	switch pixel % 6 {
+	switch x % 6 {
 	case 0:
 		return (w0 >> 10) & 0x3FF, w0 & 0x3FF, (w0 >> 20) & 0x3FF
 	case 1: