doc: Updated CHANGELOG.

CHANGELOG.adoc

@@ -17,7 +17,7 @@ For a detailed view of what has changed, refer to the {uri-repo}/commits/master[
 * Default Docker Compose command now `pyrdp-mitm -h` to avoid confusing crash on `docker-compose up` ({uri-issue}173[#173])
 * Documentation updates and fixes ({uri-issue}165[#165], {uri-issue}166[#166], {uri-issue}172[#172])
 * Added `--disable-active-clipboard` switch to prevent clipboard request injection
-* Added `--gdi` switch to enable drawing orders. ({uri-issue}50[#50])
+* Added `--gdi` MITM switch to enable accelerated graphics pipeline (MS-RDPEGDI). ({uri-issue}50[#50])
 
 === Bug fixes
 

README.md

@@ -306,6 +306,15 @@ After 5 seconds, input / output is restored back to normal.
 #### Other MITM arguments
 Run `pyrdp-mitm.py --help` for a full list of arguments.
 
+##### `--gdi`: Accelerated Graphics Pipeline
+
+Tells the MITM to allow clients to use [Graphics Device Interface Acceleration][gdi] Extensions to stream
+drawing orders instead of raw bitmaps. The advantage of this mode is a significant reduction in required bandwidth
+for high resolution connections. PyRDP player support has been recently added and it is possible that some issues
+exist. As a result, this is currently an opt-in setting.
+
+[gdi]: https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpegdi/745f2eee-d110-464c-8aca-06fc1814f6ad
+
 ### Using the PyRDP Player
 Use `pyrdp-player.py` to run the player.
 

bin/pyrdp-mitm.py

@@ -49,7 +49,7 @@ def main():
     parser.add_argument("--crawler-match-file", help="File to be used by the crawler to chose what to download when scraping the client shared drives.", default=None)
     parser.add_argument("--crawler-ignore-file", help="File to be used by the crawler to chose what folders to avoid when scraping the client shared drives.", default=None)
     parser.add_argument("--no-replay", help="Disable replay recording", action="store_true")
-    parser.add_argument("--gdi", help="Enable drawing orders extensions (MS-RDPEGDI) support", action="store_true")
+    parser.add_argument("--gdi", help="Accept accelerated graphics pipeline (MS-RDPEGDI) extension", action="store_true")
 
     args = parser.parse_args()
     outDir = Path(args.output)