Added usage of --stream-piece-selector=geom option.

doc/aria2c.1.asciidoc

@@ -254,22 +254,27 @@ aria2c -o myfile.zip "http://mirror1/file.zip" "http://mirror2/file.zip"
 
 [[aria2_optref_stream_piece_selector]]*--stream-piece-selector*=SELECTOR::
 
-Specify piece selection algorithm used in HTTP/FTP download. Piece
-means fixed length segment which is downloaded in parallel in
-segmented download. If 'default' is given, aria2 selects piece so that
-it reduces the number of establishing connection. This is reasonable
-default behaviour because establishing connection is an expensive
-operation.  If 'inorder' is given, aria2 selects piece which has
-minimum index. Index=0 means first of the file. This will be useful to
-view movie while downloading it.
-*<<aria2_optref_enable_http_pipelining, --enable-http-pipelining>>* option may
-be useful to reduce reconnection overhead.  Please note that aria2
-honors
-*<<aria2_optref_min_split_size, --min-split-size>>* option,
-so it will be necessary to specify a
-reasonable value to
-*<<aria2_optref_min_split_size, --min-split-size>>* option.
-Default: 'default'
+  Specify piece selection algorithm used in HTTP/FTP download. Piece
+  means fixed length segment which is downloaded in parallel in
+  segmented download. If 'default' is given, aria2 selects piece so
+  that it reduces the number of establishing connection. This is
+  reasonable default behaviour because establishing connection is an
+  expensive operation.  If 'inorder' is given, aria2 selects piece
+  which has minimum index. Index=0 means first of the file. This will
+  be useful to view movie while downloading it.
+  *<<aria2_optref_enable_http_pipelining, --enable-http-pipelining>>* option may
+  be useful to reduce reconnection overhead.  Please note that aria2
+  honors
+  *<<aria2_optref_min_split_size, --min-split-size>>* option,
+  so it will be necessary to specify a reasonable value to
+  *<<aria2_optref_min_split_size, --min-split-size>>* option.
+  If 'geom' is given, at the beginning aria2 selects piece which has
+  minimum index like 'inorder', but it exponentially increasingly
+  keeps space from previously selected piece. This will reduce the
+  number of establishing connection and at the same time it will
+  download the beginning part of the file first. This will be useful
+  to view movie while downloading it.
+  Default: 'default'
 
 [[aria2_optref_timeout]]*-t*, *--timeout*=SEC::
   Set timeout in seconds.

src/usage_text.h

@@ -804,7 +804,15 @@
     "                              Please note that aria2 honors\n"     \
     "                              --min-split-size option, so it will be necessary\n" \
     "                              to specify a reasonable value to\n"  \
-    "                              --min-split-size option.")
+    "                              --min-split-size option.\n"          \
+    "                              If 'geom' is given, at the beginning aria2\n" \
+    "                              selects piece which has minimum index like\n" \
+    "                              'inorder', but it exponentially increasingly\n" \
+    "                              keeps space from previously selected piece. This\n" \
+    "                              will reduce the number of establishing connection\n" \
+    "                              and at the same time it will download the\n" \
+    "                              beginning part of the file first. This will be\n" \
+    "                              useful to view movie while downloading it.")
 #define TEXT_TRUNCATE_CONSOLE_READOUT                                   \
   _(" --truncate-console-readout[=true|false] Truncate console readout to fit in\n"\
     "                              a single line.")