Changes between Version 34 and Version 35 of PacketEncoding

Timestamp:

04/11/20 13:51:49 (2 years ago)

Author:

Antoine Martin

Comment:

--

PacketEncoding

@@ -11 +11 @@
 {{{#!div class="box"
 == Wire Format ==
-Each message may be split into multiple packets: large binary chunks (ie: compressed pixel data, large clipboard data, etc) will be sent in their own packet, skipping the generic compression layer.
+Each message may be split into multiple network packets as large binary chunks (ie: compressed pixel data, large clipboard data, etc) will be sent in their own packet, skipping the generic compression layer.
+
+The `compression` command line option only affects regular packets, not binary chunks. It is rarely a good idea to change it.
+
+In most cases, the packets are so small that compression is not even attempted.
+The data that does need to be compressed (ie: pixel data) uses other controls (ie: speed and quality options).
 
 [[BR]]
@@ -22 +27 @@
 
 [[BR]]
-The main chunk containing the message uses index 0 and it is encoded (see bencode / rencode below).
+The main chunk containing the message uses index 0 and it is encoded (see bencode / rencode below), and sent last.
+Each message consists of a list of values, the first item is the packet type (see [/wiki/NetworkProtocol]).
 
-The main message consists of a list of values, the first item is the packet type (see [/wiki/NetworkProtocol]).
-
-The other chunks replace the item found at the specified index in the main chunk. (which should be empty)
-The main chunk always comes last.
+The other chunks replace the items found at the specified index in the main chunk.
+ie:
+* chunk 1: some png pixel data
+* chunk 0 (the main packet): `[draw, ..., placeholder for the png data, ...]`
 [[BR]]
 
@@ -43 +49 @@
 
 The python client and server can specify which packet encoders should be enabled using the switch {{{--packet-encoders=}}} (or via the config file).
-For backwards compatibility, you should always enable {{{bencode}}} as this is the encoding used by default for connecting.
+For backwards compatibility, you should always enable {{{bencode}}} as some clients may use this encoding (ie: html5 client), at least initially.
 }}}
 
@@ -58 +64 @@
 {{{#!div class="box"
 == Compression ==
-There are up to 3 types of compressors supported:
+There are 3 compressors supported:
 * [http://www.zlib.net/ zlib] - which is always available but very inefficient
-* [https://code.google.com/p/lz4/ lz4] - available on most systems, used by default if present (more information here: #443, [http://ticki.github.io/blog/how-lz4-works/ how lz4 works])
-* [http://www.oberhumer.com/opensource/lzo/ lzo] not as efficient as lz4, but still much faster than zlib.
+* [https://code.google.com/p/lz4/ lz4] - used by default if present, fast! (more information here: #443, [http://ticki.github.io/blog/how-lz4-works/ how lz4 works])
+* [http://www.oberhumer.com/opensource/lzo/ lzo] not as efficient as lz4, but still much faster than zlib
+
+All [/wiki/Platforms supported platforms] have lz4 so zlib and lzo should not be used.
 
 You can select which compressors are enabled using the {{{--compressors=}}} switch (or the equivalent entry in the [/wiki/Configuration configuration] file).
@@ -67 +75 @@
 [[BR]]
 
-The compression level can be specified via the command line ("{{{-z LEVEL}}}" or "{{{--compress=LEVEL}}}").
+The compression level can be specified via the command line ("{{{-z LEVEL}}}" or "{{{--compress=LEVEL}}}"). It is generally best to not modify this option unless you really understand the implications.
 
 Here is what the {{{LEVEL}}} does:
@@ -85 +93 @@
 }}}
 
-{{{#!div class="box"
-== python-lz4 / python-lzo Installation ==
-We have an [/browser/xpra/trunk/rpmbuild/python-lz4.spec python-lz4 rpm specfile] and {{{RPM}}}s should be available for {{{Fedora}}} and {{{CentOS}}} 6.x in the RPM repository.
-[[BR]]
-Other distributions can install from source: [https://pypi.python.org/pypi/lz4 lz4].
-Some distributions provide packages for {{{python-lzo}}}
-[[BR]]
-The MS Windows and Mac OSX binary installers include lz4 (all builds) and lzo (Python 2.x only).
-}}}
 
 {{{#!div class="box"
@@ -100 +99 @@
 The default settings should end up using {{{lz4}}} and {{{rencode}}}, since those are by far the best options.
 
-The {{{zlib}}} and {{{bencode}}} options will remain for compatibility with clients which do not have support for them (ie: {{{Android}}}, html5..).
+The {{{zlib}}} and {{{bencode}}} options will remain for compatibility with clients which do not have support for them (ie: [/wiki/Clients/HTML5 HTML5])
 
 You can also change the current encoder/compressor at runtime: