fix: Add pasp box to declare square pixels (1:1) for web playback

The codec string fix caused videos to appear squished on web players
like Shaka. Adding an explicit pixel aspect ratio (pasp) box with
1:1 ratio tells the player not to apply any SAR scaling.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package/android/src/main/java/com/mrousavy/camera/core/HlsMuxer.kt

@@ -753,17 +753,32 @@ class HlsMuxer(
         dos.writeShort(-1)              // pre-defined
 
         output.write(buildAvcCBox(sps, pps))
+        output.write(buildPaspBox())
 
         return wrapBox("avc1", output.toByteArray())
     }
 
+    /**
+     * Builds pixel aspect ratio box to explicitly declare square pixels (1:1).
+     * This helps players correctly interpret video dimensions without SAR scaling.
+     */
+    private fun buildPaspBox(): ByteArray {
+        val output = ByteArrayOutputStream()
+        val dos = DataOutputStream(output)
+        dos.writeInt(1)  // hSpacing (horizontal)
+        dos.writeInt(1)  // vSpacing (vertical)
+        return wrapBox("pasp", output.toByteArray())
+    }
+
     private fun buildAvcCBox(sps: ByteArray, pps: ByteArray): ByteArray {
         val output = ByteArrayOutputStream()
         val dos = DataOutputStream(output)
 
-        val profileIdc = if (sps.isNotEmpty()) sps[0].toInt() and 0xFF else 0x42
-        val profileCompat = if (sps.size > 1) sps[1].toInt() and 0xFF else 0x00
-        val levelIdc = if (sps.size > 2) sps[2].toInt() and 0xFF else 0x1F
+        // SPS NAL unit format: [NAL header, profile_idc, constraint_flags, level_idc, ...]
+        // Skip byte 0 (NAL header, typically 0x67) to get the actual profile data
+        val profileIdc = if (sps.size > 1) sps[1].toInt() and 0xFF else 0x42
+        val profileCompat = if (sps.size > 2) sps[2].toInt() and 0xFF else 0x00
+        val levelIdc = if (sps.size > 3) sps[3].toInt() and 0xFF else 0x1F
 
         dos.writeByte(1)            // configuration version
         dos.writeByte(profileIdc)   // AVC profile