Parses a file stream.
Description
The file type is checked through the "ftyp" box.
Source
public function parse_ftyp() {
$box = new Box();
$status = $box->parse( $this->handle, $this->num_parsed_boxes );
if ( $status != FOUND ) {
return false;
}
if ( $box->type != 'ftyp' ) {
return false;
}
// Iterate over brands. See ISO/IEC 14496-12:2012(E) 4.3.1
if ( $box->content_size < 8 ) {
return false;
}
for ( $i = 0; $i + 4 <= $box->content_size; $i += 4 ) {
if ( !( $data = read( $this->handle, 4 ) ) ) {
return false;
}
if ( $i == 4 ) {
continue; // Skip minor_version.
}
if ( substr( $data, 0, 4 ) == 'avif' || substr( $data, 0, 4 ) == 'avis' ) {
return skip( $this->handle, $box->content_size - ( $i + 4 ) );
}
if ( $i > 32 * 4 ) {
return false; // Be reasonable.
}
}
return false; // No AVIF brand no good.
}
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