pub fn parse_mpeg2_sequence_header(sample: &[u8]) -> Option<Mpeg2SeqInfo>Expand description
MPEG-2 sequence header scan — ISO/IEC 13818-2 §6.2.2.1 (sequence
header, start code 00 00 01 B3) + §6.2.2.3 (sequence extension,
start code 00 00 01 B5 with extension_start_code_identifier==1).
The sequence header carries 12-bit horizontal_size_value and
vertical_size_value, tight for sizes ≤ 4095. The optional sequence
extension prepends 2-bit _extension fields that, when combined,
bring the total to 14 bits (sizes ≤ 16383). Pure MPEG-1 (start code
0xB3 only, no 0xB5) never has the extension and stays 12-bit.