VERSIONS
--------

v0	Initial audio tool
	Old VAT and RTPv2(5) compatibility
	PCM DVI GSM LPC codecs

v1	Vicky's restructuring
	Dropped old VAT compat mode
	Used in ReLaTe trials
	New UI including small mode
	Video Sync code added

v2.0	Transmitter cleaned up
	Lots of bugs fixed
	Replaced DVI and LPC codecs with VAT4 versions
	Released in Boston WWW4

v2.1	Ported to Tcl7.3/Tk4.0
	Added UI response slider

v2.2	Added play and rec options

v2.3	Port to Tk4.1/Tcl7.5

v2.4a0	Port to Windows95
v2.4a1	Fixed active speaker indication
v2.4a2	Fixed GSM
v2.4a3	Release to MERCI partners for testing
v2.4a4	Fixed broken assertions...
v2.4a5	SGI fix
v2.4a6	Security holes fixed
	Assertion handling improved
	Start at encryption and multi-rate audio
v2.4a7  FreeBSD modifications
        Fixed playout calculation (probably)
v2.4a8  Added RTCP SDES TOOL field to stats panel
	Fixed version number
	Made packet repetition an option and set default to OFF
	Fixed encoding selection bugs
	Misc bug fixes....
v2.4a9	Fixed participant display when audio device is busy
	When device is busy audio controls get disabled
	Added code to set microphone gain under Win95
	Modified loop timing for win95 version so that it does not hog CPU
	Made session title appear as window title with -C flag
v2.4a10	Added OS type to RTCP tool string

v2.5a0	Fixed long DVI packet format. Now there is only one state (VAT comp).
	Reduced UI window border width. New look!
	Added scrollbar to participants window
	New participant stats code. Allows multiple windows...
	Attempt to fix some of the stats
	Popup window to request RTP name if resource not set
v2.5a1	Changed redundancy packet format to conform to UCL-INRIA spec
	Added error code to report use of old packet format
	New code to do encoding name stats
	Fixed RTCP RR packets to conform with latest spec
	Made RAT look in .RTPdefaults for user name
	Added IP address display in stats
v2.5a2	Highlight other RAT users in list of participants
	Ignore audio until RTCP packet received
v2.5a3	Added encryption (Darren said it's compatible with vat)

v2.6a0	Added command line option to set redundancy type
	Started to change payload type to match draft-perkins-rtp-redundancy-01.txt
	(Grouped headers, but haven't changed bit order yet...)
v2.6a1	Finished changing the payload type.
	Default redundancy pt=121
	Send initial RTCP message as soon as we start up...
v2.6a2	Allow window to resize horizontally (requested by vilhuber@cs.colorado.edu)
        Updated copyright notice.
        Updated about panel.
	Added -pt pt/codec/clock/channels command line option. 
	Example: "-pt 121/redundancy" to set redundancy payload type to 121
	Remove -rpt option (use -pt instead).
	Remove -f2 option.
	Change -f option to accept things like "-f pcm/dvi" to set redundancy type.
v2.6a3	Fixed packing order so it resizes horizontally correctly.
v2.6a4	New WIN32 version
	Changed priority of thread
	Fixed cushion code to work with I/O switching
	Linked tcl and tk with WIN32 binary so no DLLs are needed
v2.6a5	Partial rewrite of win32 audio driver to use static buffers
	Solved most win32 audio problems
v2.6a6	Made the prompt for .RTPdefaults information less user hostile
	Fixed LPC decoding on SGIs (-fsigned-char does it!?!)
v2.6a7	Removed old bitmap from control panel
	Rewrite of small user interface (command line option -smallui)
v2.6a8	Further rewrite of the small user interface
	Fixed SO_REUSEADDR
	HP-UX fixes
	Added "-crypt <key>" command line option to enable encryption
v2.6a9	Fix m/cast power meters when encryption is turned on.
v2.6a10	HP-UX fixes
v2.6a11	Remove debugging malloc when NDEBUG is defined. 
v2.6a12	Code cleanup in preparation for mixer
	Corrected URL on the about panel
v2.6a13	Code cleanup in preparation for mixer
	Added -li <local_interface> option for multihomed hosts
	Removed annoying transient tag from pop-up windows.
v2.6a14	Added an icon
	Win32 fixes
	Removed -li stuff, since it broke the win32 port.
	More HP-UX changes

v3.0.0	Restructure code for audio translator/mixer
	Extended ascii hostnames (>15 chars) - useful for unicast
	Additional RTP header validation
v3.0.1	Major restucturing of main_rat.c, and split into several separate files.
	Fixes for Linux.
	Include full/half duplex stuff in all versions.
v3.0.2	Bug fixes to auddev_linux.c
	Fixes to RTCP header checks on little-endian machines.
	Now obeys xresources settings.
v3.0.3	Experimental release for Linux
	Some fixes to encryption code: it still doesn't work though...
v3.0.4	Major mods to init_session.c
	Added mixer code to linux port.
v3.0.5	Fake TS start if we TOG packets
	Fix RTCP timestamp epoch to 1900 not 1970 to conform to RFC1889
	Fix display of group address in options panel.
	Fix CNAME.
	Extensive changes for the audio transcoder/mixer.
	New HP-UX audio device driver from UiO added.
v3.0.6	More changes for the audio transcoder/mixer.
	Fixes to Linux audio driver when in half-duplex mode.
	Added the -version option.
v3.0.7	Major changes for the audio transcoder/mixer: First version to work at all!
	Now sources $HOME/.rat as tcl on startup
	Linux fixes
v3.0.8	CNAME now uses dotted-quad representation of the IP address, not FQDN.
	16bit linear audio throughout main code: not all device drivers fixed yet.
	Make DVI the default primary encoding.
	Added L16 (16bit linear, uncompressed) codec.
	Both sides of transcoder/mixer use same SSRC/CNAME.
	Calculate RTCP reporting interval, rather than using constant 6 seconds.
	Major rewrite of transmitter and receiver code (supports multiple red)
	Added CSRC processing to receiver
	Fix indication of active speakers
	Update device buffer cushion code
	Removed small (ReLaTe) UI
	Minor redisign of option UI
	Added lecture mode
	Linux port now works again
v3.0.9	Added minimal LBL conference bus support 
	Enabled voice-switching of video using LBL conference bus/vic
	Fixed SGI 16 bit
	Fixed WIN32 16 bit
	Slight highlighting of participants after they stop speaking
	Now uses tk4.2/tcl7.6
v3.0.10 Prehang and posthang added to new code
	IP_MULTICAST_LOOP is now on for the session port
	We can now parse our BYE message although it is wrong
	Packet repetition added to new code
	Audio DC bias removal added for all platforms
v3.0.11	We can no longer parse our BYE message, since it is wrong!
	More UI changes... (packet format uses pull down menus)
	Disable powermeters option added
	Selective muting of participants possible with middle mouse button.
	Automatic bias removal (turns off if not needed)
	Fix handling of RTP packets with CSRC data
	Rewrite of RTCP handling code...
	Fix RTCP BYE packet
	Transcoder/mixer now passes RTCP packets
	Exponential fade on packets   (no good)
	LPC redundancy alignment code (also no good)
v3.0.12 Linear fade on repeated packets
	Fade on repeated LPC decoded packets
	Prevention of mixing dummies with no decompressed data
	Packet length shown in UI
	Can select N-level redundancy from command line (-f pcm/dvi/lpc for example)
	Fix parsing of command line options
	Lecture mode is on by default
	Turn off lecture mode as soon as we send data
	Added -loopback_rtp option for loopback of the RTP packets (RTCP loopback is always on)
	Added audio device trading via the LBL conference bus
	Added flakeway operation
v3.0.13	Integrated transcoder/mixer into the main Rat code.
v3.0.14	Move to tcl-7.6p2/tk-4.2p2
	Fix linux/HP-UX ports
	Fix for flakeaway
v3.0.15	Assorted bug fixes
        Hang onto multiple encoded data in receiver
        Logic into UI for redundant coding types  
	Fix LPC redundancy (Ho Ho)
	Fix sending L16 with redundancy
	Fix auto-select of "Mike mutes net" when running on a half-duplex machine
	TCL_ALL_EVENTS in event processing loop (sockets from tcl scripts->fileevents)
v3.0.16	Bug fixes to the transmitter
	Fix CSRC processing
v3.0.17	Fixes for Win32
v3.0.18	Fix RTCP BYE packet on little-endian machines
	Muting of output now frees data
	Fix reception of 160ms packets 
	Fix uninitialised variable in rtcp_db 
v3.0.19	Remove spurious debugging messages when we can't open the audio device
	Cleanup HP-UX audio driver
v3.0.20	Can now select line-in/microphone input on SGI machines
	Added -K option to enable encryption (synonym for -crypt)
	Cleanup Linux audio driver
	Cleanup Sparc audio driver
	Cleanup for draft-ietf-avt-profile-new-00
	Added -double_speed (16kHz) option
	Transcoder no longer hits stdin/stdout with audio ioctls
	Rewrite and optimize decryption of RTCP packets
	RTCP timer reconsideration done for every RTCP packet received (following presentation at Memphis IETF...)
	RTCP SR and SDES fixes
	Can now send/display PHONE, LOC and EMAIL SDES items.
	Fixed mike mutes net operation for half duplex cards.
	FreeBSD port now works.
	Win32 version uses registry to store defaults.
v3.0.21	Added signal handler, to catch SIGINT and exit cleanly (with RTCP BYE)
	Linux device driver now accepts 16kHz operation.
	Assorted bug fixes to Linux device driver.
	Initialise device_time variable: prevents crash if we can't access the audio device.
	The use of strdup() interacts badly with xmalloc(). Fixed.
	Fixed transcoder RTCP BYE handling
v3.0.22	Remove debugging messages in statistics.c
	Remove WBS codec
	Remove -double_speed option
v3.0.23	Linux port uses both audio channels, rather than just the left channel
        Linux port no longer repeatedly resets the volume to 50% 
	Bug fix for HP-UX audio driver (Terje Vernly <terjeve@newlearning.no>)
	Fix CPU usage on Win32
v3.0.24	Fix encryption
	Fix loopback of packets
	Fix crash in LBL conference bus code, sending focus when the CNAME was NULL
	Fix RTCP header validation
	Fix RTP header validation when padding bit is set
	Fix voice switching of video using LBL conference bus with vic
	Modifications to WIN32 silence detection as PC hardware often breaks previous algorithm.
	Assorted Win32 bug fixes
	Win32 HOMEDIR bug fix. 
3.0.25	Assorted Win32 fixes.
3.0.26  Fixed bug in net.c that caused packets to cease processing on some Win32
	boxes.
3.0.27	Fix transcoder problems on half-duplex machines. Thanks to Sachin Sheth 
	for providing the fix.
	Fix fonts for solaris 2.6.
	* Released 15 August 1998
3.0.28	Update copyright notice (the dates were wrong!)
	Endian fix to the RTCP packet forwarding code (Thanks to Sachin Sheth).
	Fixed HOMEDIR problem introduced in 3.0.27 for Win32.
	Fixed catch when sourcing ~/rat.
	* Released 22 September 1998

TODO -- They're features not bugs dammit!
----

- UI lets you select packets larger than the MTU, which can't be sent
- Set microphone/line-in and speaker/headset/line-out from command line
- N-level redundancy handling (UI doesn't support it yet...)
- Transcoder doesn't fully support encryption (both sides must use the same key at present)
- CNAME is wrong on Win32 if RAT can't find the USER environment variable
- Highlighting of active speakers still doesn't work properly :-(

