fix: ensure there are no overflows in size calculation with trun

Eyevinn · Jan 15, 2025 · b8d62a8 · b8d62a8
1 parent 5295d3a
commit b8d62a8
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/mp4/trun.go b/mp4/trun.go
@@ -254,14 +254,14 @@ func (t *TrunBox) Size() uint64 {
 
 // expectedSize - calculate size for a given sample count
 func (t *TrunBox) expectedSize(sampleCount uint32) uint64 {
-	sz := boxHeaderSize + 8 // flags + entryCount
+	sz := uint64(boxHeaderSize + 8) // flags + entryCount
 	if t.HasDataOffset() {
 		sz += 4
 	}
 	if t.HasFirstSampleFlags() {
 		sz += 4
 	}
-	bytesPerSample := 0
+	var bytesPerSample uint64
 	if t.HasSampleDuration() {
 		bytesPerSample += 4
 	}
@@ -274,8 +274,8 @@ func (t *TrunBox) expectedSize(sampleCount uint32) uint64 {
 	if t.HasSampleCompositionTimeOffset() {
 		bytesPerSample += 4
 	}
-	sz += int(sampleCount) * bytesPerSample
-	return uint64(sz)
+	sz += uint64(sampleCount) * bytesPerSample
+	return sz
 }
 
 // Encode - write box to w