3.1.5.2 NSCodec Compressed Bitmap Stream
The NSCodec Compressed Bitmap Stream (section 2.2.2) structure contains a stream of bitmap data compressed by using NSCodec bitmap compression techniques (section 3.1.8). NSCodec compressed bitmap data is sent encapsulated in a Set Surface Bits Surface Command ([MS-RDPBCGR] section 2.2.9.2.1) when sending a bitmap image that MUST NOT be cached, or in the Cache Bitmap - Revision 3 ([MS-RDPEGDI] section 2.2.2.2.1.2.8) Secondary Drawing Order when sending a bitmap image that MUST be cached (bitmap caching is discussed in [MS-RDPEGDI] section 3.1.1.1.1). In all of these cases, the data is encapsulated inside an Extended Bitmap Data ([MS-RDPBCGR] section 2.2.9.2.1.1) structure. If the data encapsulation is invalid or errors are encountered while decompressing NSCodec data (section 3.1.8.4), the connection SHOULD be dropped.