Protocol scope and method
The scanner looks for three- and four-byte Annex-B start codes. It does not decode the bitstream payload.
NAL type = firstByteAfterStartCode & 0x1f.
Common questions
Does the H.264 NAL Unit Scanner leave my browser?
No application upload is used. Avoid putting sensitive production data in shareable URLs.
Is this a standards compliance test?
No. Confirm the edition and vendor profile with licensed documents and your target platform.
Offline diagnostic aid. Verify fields, version and vendor extensions before production use.