vdr-plugin-streamdev/README

This is a "plugin" for the Video Disk Recorder (VDR).

Written by:                  Sascha Volkenandt <sascha@akv-soft.de>
Current maintainer:          Frank Schmirler <vdrdev@schmirler.de>

Project's homepage:          http://streamdev.vdr-developer.org/
Former project homepage:     http://linux.kompiliert.net/

Latest version available at: http://streamdev.vdr-developer.org/

See the file COPYING for license information.

Contents:
---------

1.   Description
2.   Installation
2.1  Compatibility
2.2  Compiling
2.3  Updating
3.   Usage
3.1  Usage HTTP server
3.2  Usage IGMP multicast server
3.3  Usage VDR-to-VDR server
3.4  Usage VDR-to-VDR client
4.   Other useful Plugins
4.1  Plugins for VDR-to-VDR clients
4.2  Plugins for Server
4.3  Alternatives
5.   externremux.sh
6.   Known Problems


1. Description:
---------------

This PlugIn is a VDR implementation of the VTP (Video Transfer Protocol) 
Version 0.0.3 (see file PROTOCOL) and a basic HTTP Streaming Protocol.

It consists of a server and a client part, but both parts are compiled together
with the PlugIn source, but appear as separate PlugIns to VDR. 

The client part acts as a full Input Device, so it can be used in conjunction 
with a DXR3-Card, XINE, SoftDevice or others to act as a working VDR 
installation without any DVB-Hardware including EPG-Handling.

The server part acts as a Receiver-Device and works transparently in the 
background within your running VDR. It can serve multiple clients and it can
distribute multiple input streams (i.e. from multiple DVB-cards) to multiple 
clients using the native VTP protocol (for VDR-clients), or using the HTTP 
protocol supporting clients such as XINE, MPlayer and so on. With XMMS or
WinAMP, you can also listen to radio channels over a HTTP connection.

It is possible to attach as many clients as the bus and network can handle, as
long as there is a device which can receive a specific channel. Multiple
channels homed on the same transponder (which is determined by it's frequency)
can be broadcasted with a single device.

Additional clients can be programmed using the Protocol Instructions inside
the PROTOCOL file.


2. Installation:
----------------

Let's say streamdev's version is 0.4.0 and vdr's version is 1.X.X. If you 
use anything else please exchange the version numbers appropriately (this
way I don't have to update this section all the times;) ).

After compiling the PlugIn as stated below, start either (or both) parts of it
by specifying "-P streamdev-client" and/or "-P streamdev-server" on the VDR
command line.

What's important is that the client requests a channel using its Unique Channel
ID. So, in order to find the channel at the server, it must have the same ID
that is used on the client. You can achieve this by putting the server's 
channels.conf on the client, preferably after scanning.

If you want to drive additional Input-Devices (with different sources) on the 
client, you can merge the channels.conf files. VDR will detect if the local 
device or the network device can receive the channels.

Last, but not least you have to copy the streamdev folder into the
"plugins/streamdev" subfolder of VDR's config-directory (which is equal to your
video-directory if not specified otherwise). For example, if you didn't specify
a separate config-directory, and specified your video directory as "/video0",
the directory has to be copied to /video0/plugins/streamdev.

The directory contains a file named streamdevhosts.conf which you must adjust
to your needs. The syntax is the same as for svdrphosts.conf, so please consult
VDR's documentation on how to fill that file, if you can't do it on-the-fly.

There's also a sample externremux.sh script in this directory. It is used by
streamdev's external remux feature. The sample script uses mencoder by default.
Please check the script for further information. You can specify a different
script location with the -r parameter. The VDR commandline would then include a
"-P 'streamdev-server -r /usr/local/bin/remux.sh'". Note the additional quotes,
as otherwise -r will be passed to VDR and not to streamdev.


2.1 Compatibility:
------------------

This version is compatible to VDR releases 1.4.x and 1.5 upto 1.5.8. If you are
running some older VDR release, streamdev-0.3.4 is your friend. Check higher
streamdev releases if you are running a more recent VDR.

2.2 Compiling:
--------------

  cd vdr-1.X.X/PLUGINS/src
  tar xvfz vdr-streamdev-0.4.0.tgz
  ln -s streamdev-0.4.0 streamdev
  cp -r streamdev/streamdev-server VDRCONFDIR/plugins/
  cd ../..
  make [options, if necessary] vdr
  make [options, if necessary] plugins

To build only the plugin, change into the streamdev source folder and issue
  make

2.3  Updating:
--------------

If you are updating streamdev from an earlier release, you might have to
perform some additional steps. Check which version you've been running before,
then read below for the necessary changes.

* Location of files:
--------------------
(Affected: 0.3.x)

Starting with streamdev 0.4.0, all additional files are kept in a directory
called "streamdev" inside VDR's plugin config directory. It is the new default
location of externremux.sh and the new place where streamdev-server expects
the file "streamdevhosts.conf". You will have to move this file to its new
location:

  mv VDRCONFDIR/plugins/streamdevhosts.conf VDRCONFDIR/plugins/streamdev/

Now check the contents of streamdevhosts.conf. Does it contain a "0.0.0.0/0"
entry? If your VDR machine is connected to the Internet, this line gives
*anyone* full access to streamdev, unless you took some other measures to
prevent this (e.g. firewall). You might want to remove this line and enable
HTTP authentication instead.

* Handling of externremux script:
---------------------------------
(Affected: 0.3.x, 0.4.0pre)

Streamdev server's externremux script became responsible for emitting all HTTP
headers. A quick and dirty extension to your current script would be:

  echo -ne 'Content-type: video/mpeg\r\n'
  echo -ne '\r\n'

However I encourage you to try the new externremux.sh script shipped with the
streamdev source distribution.

To emphasize the required change in externremux, the URL path for passing the
stream through externremux has changed from EXTERN to EXT.

3. Usage:
---------

Start the server core itself by specifying -Pstreamdev-server on your VDR 
commandline. To use the client core, specify -Pstreamdev-client. Both parts
can run in one VDR instance, if necessary.

The parameter "Suspend behaviour" allows you to specify how the server should 
react in case the client requests a channel that would require switching the
primary device (i.e. disrupt live-tv). If set to "Offer suspend mode", you will
have a new entry in the main menu. Activating that will put the server into
"Suspend Mode" (a picture is displayed on TV). Then, a client may switch the
primary card to wherever it likes to. While watching TV (Suspend deactivated),
the client may not switch the transponder on the primary device.  If you set
the behaviour to "Always suspended" (the default), there will be normal live-tv
on the server, but whenever a client decides to switch the transponder, the 
server will lose it's live-tv. Set to "Never suspended", the server always 
prevents the client from switching transponders. If you set "Client may 
suspend" to yes, the client can suspend the server remotely (this only applies
if "Offer suspend mode" is selected).

NOTE: This mainly applies to One-Card-Systems, since with multiple cards there
is no need to switch transponders on the primary interface, if the secondary
can stream a given channel (i.e. if it is not blocked by a recording). If both
cards are in use (i.e. when something is recorded, or by multiple clients), 
this applies to Multiple-Card-Systems as well.

3.1 Usage HTTP server:
----------------------

You can use the HTTP part by accessing the server with a HTTP-capable media
player (such as XINE, MPlayer, and so on, if you have appropriate MPEG2-codecs
installed). In the PlugIn's Setup, you can specify the port the server will
listen to with the parameter "HTTP Server Port". The parameter "HTTP Streamtype"
allows you to specify a default stream type, which is used if no specific type
has been requested in the URL (see below). The supported stream types are:

  TS     Transport Stream (i.e. a dump from the device)
  PES    Packetized Elemetary Stream (VDR's native recording format)
  PS     Program Stream (SVCD, DVD like stream)
  ES     Elementary Stream (only Video, if available, otherwise only Audio)
  EXT    Pass stream through external script (e.g. for converting with mencoder)

Assuming that you leave the default port (3000), point your web browser to

  http://hostname:3000/

You will be presented a menu with links to various channel lists, including M3U
playlist formats.

If you don't want to use the HTML menu or the M3U playlists, you can access the
streams directly like this:

  http://hostname:3000/3
  http://hostname:3000/S19.2E-0-12480-898

The first one will deliver a channel by number on the server, the second one
will request the channel by unique channel id. In addition, you can specify 
the desired stream type as a path to the channel.

  http://hostname:3000/TS/3
  http://hostname:3000/PES/S19.2E-0-12480-898

The first one would deliver the stream in TS, the second one in PES format. 
Possible values are 'PES', 'TS', 'PS', 'ES' and 'EXT'. You need to specify
the ES format explicitly if you want to listen to radio channels. Play them
back i.e. with mpg123.

  mpg123 http://hostname:3000/ES/200

With 'EXT' you can also add parameters which are passed as arguments to the
externremux script (e.g. http://hostname:3000/EXT;param1=value1;param2=value2/3)
Check your externremux.sh script for the parameters it understands. For details
on how to modify or write your own externremux.sh, please see the chapter upon
externremux.sh further down.

If you want to access streamdev's HTTP server from the Internet, do *not* grant
access for anyone by allowing any IP in "streamdevhosts.conf". Instead, pass the
"-a" commandline option to streamdev-server. It takes a username and a password
as argument. Clients with an IP not accepted by "streamdevhosts.conf" will then
have to login. The VDR commandline will have to look like this:

  vdr ... -P 'streamdev-server -a vdr:secret' ...

Note the single quotes, as otherwise "-a" will be passed to VDR and not to
streamdev-server. The login ("vdr" in the example above) doesn't have to exist
as a system account.

3.2 Usage IGMP multicast server:
--------------------------------

IGMP based multicast streaming is often used by settop boxes to receive IP TV.
Streamdev's multicast server allows you to feed live TV from VDR to such a
settop box. VLC is known to work well if you look for a software client.

The advantage of multicasting is that the actual stream is sent out only once,
regardless of how many clients want to receive it. The downside is, that you
cannot simply multicast across network boundaries. You need multicast routers.
For multicast streaming over the public Internet you would even need to register
for your own IP range. So don't even think of multicasting via Internet with
streamdev! Streamdev will send the stream only to one local ethernet segment and
all clients must be connected to this same segment. There must not be a router
inbetween. Also note that the client must not run on the streamdev-server
machine.

Each channel is offered on a different multicast IP. Channel 1 is available from
multicast IP 239.255.0.1, channel 2 from 239.255.0.2 and so on. The upper limit
is 239.255.254.255 which corresponds to channel 65279 (239.255.255.0/24 is
reserved according to RFC-2365).

Before you can use streamdev's multicast server, you might need to patch VDR.
Binding an IGMP socket is a privileged operation, so you must start VDR as root.
If you pass the -u option to VDR, it will drop almost all priviledges before
streamdev is even loaded. Apply vdr-cap_net_raw.diff to keep VDR from dropping
the CAP_NET_RAW capability required to bind the IGMP socket. The patch is part
of streamdev's source distribution. Check the patches subdirectory. There's no
need to patch VDR if it is kept running as root (not recommended).

The multicast server is disabled by default. Enter the streamdev-server setup
menu to enable it and - IMPORTANT - bind the multicast server to the IP of your
VDR server's LAN ethernet card. The multicast server will refuse to start with
the default bind adresse "0.0.0.0".

Now edit your streamdevhosts.conf. To allow streaming of all channels, it must
contain "239.255.0.0/16". Note that you cannot limit connections by client IP
here. You can however restrict which channels are allowed to be multicasted.
Enter individual multicast IPs instead of "239.255.0.0/16".

By default, the linux kernel will refuse to join more than 20 multicast groups.
You might want to increase this up to "number_of_channels + 1". Note that it's
"number_of_channels", not "maximum_channel_number".

  #First 100 channels:
  bash# sysctl -w net.ipv4.igmp_max_memberships=101

  #All channels:
  bash# COUNT=$(grep -c '^[^:]' PATH_TO_YOUR/channels.conf)
  bash# sysctl -w net.ipv4.igmp_max_memberships=$COUNT

A multicast server never knows how many clients are actually receiving a stream.
If a client signals that it leaves a multicast group, the server has to query
for other listeners before it can stop the stream. This may delay zapping from
one transponder to an other. The client will probably requests the new channel
before the previous stream has been stopped. If there's no free DVB card, VDR
won't be able to fulfill the request until a DVB card becomes available and the
client resends the request.

3.3 Usage VDR-to-VDR server:
----------------------------

You can activate the VDR-to-VDR server part in the PlugIn's Setup Menu. It is
deactivated by default. The Parameter "VDR-to-VDR Server Port" specifies the 
port where you want the server to listen for incoming connections. The server
will be activated when you push the OK button inside the setup menu, so there's
no need to restart VDR.

3.4 Usage VDR-to-VDR client:
----------------------------

Streamdev-client adds a "Suspend Server" item to VDR's mainmenu. With the
setup parameter "Hide Mainmenu Entry" you can hide this menu item if you don't
need it. "Suspend Server" is only useful if the server runs in "Offer suspend
mode" with "Client may suspend" enabled.

The parameter "Remote IP" uses an IP-Adress-Editor, where you can just enter
the IP number with the number keys on your remote. After three digits (or if 
the next digit would result in an invalid IP adress, or if the first digit is
0), the current position jumps to the next one. You can change positions with 
the left and right buttons, and you can cycle the current position using up 
and down. To confirm the entered address, press OK. So, if you want to enter 
the IP address "127.0.0.1", just mark the corresponding entry as active and 
type "127001<OK>" on your remote. If you want to enter "192.168.1.12", type 
"1921681<Right>12<OK>". 

The parameters "Remote IP" and "Remote Port" in the client's setup specify the 
address of the remote VDR-to-VDR server to connect to. Activate the client by
setting "Start Client" to yes. It is disabled by default, because it wouldn't
make much sense to start the client without specifying a server anyway. The 
client is activated after you push the OK button, so there's no need to restart
VDR. Deactivation on-the-fly is not possible, so in order to deactivate the 
client, you will have to restart VDR. However requests to switch channels will
be refused by streamdev-client once it has been deactivated. All other settings
can be changed without restarting VDR.

The client will try to connect to the server (in case it isn't yet) whenever 
a remote channel is requested. Just activate the client and switch to a 
channel that's not available by local devices. If anything goes wrong with the 
connection between the two, you will see it in the logfile instantly. If you 
now switch the client to a channel which isn't covered by it's own local
devices, it will ask the server for it. If the server can (currently) receive
that channel, the client will show it until you switch again, or until the 
server needs that card (if no other is free) for a recording on a different 
transponder.

Only the needed PIDs are transferred, and additional PIDs can be turned on
during an active transfer. This makes it possible to switch languages, receive
additional channels (for recording on the client) and use plugins that use
receivers themselves (like osdteletext).

With "Filter Streaming" enabled, the client will receive meta information like
EPG data and service information, just as if the client had its own DVB card.
Link channels and even a client-side EPG scan have been reported to work.

Finally with the maximum and minimum priority, you can keep VDR from considering
streamdev in certain cases. If for instance you have a streamdev client with its
own DVB card, VDR would normally use streamdev for recording. If this is not
what you want, you could set the maximum priority to 0. As recordings usually
have a much higher priority (default 50), streamdev is now no longer used for
recordings. The two parameters define the inclusive range of priorities for
which streamdev will accept to tune. Setting the minimum priority to a higher
value than the maximum, you will get two ranges: "up to maximum" and "minimum
and above".

Note that streamdev-client acts similar to a DVB card. It is possible to receive
multiple channels simultaneously, but only from the same transponder. Just add
additional instances of streamdev-client and you will be able to receive as many
transponders at a time. The same trick allows a client to receive channels from
different servers. To create an additional instance, copy the streamdev-client
binary to a different name (e.g. streamdev-client2):

  cd VDRPLUGINLIBDIR
  cp libvdr-streamdev-client.so.1.X.X libvdr-streamdev-client2.so.1.X.X

Now add -Pstreamdev-client2 to the VDR commandline. In the VDR plugin setup
a second streamdev-client entry should show up. Both instances have to be
configured individually.


4. Other useful Plugins:
------------------------

4.1 Plugins for VDR-to-VDR clients:
-----------------------------------

The following plugins are useful for VDR-to-VDR clients (i.e. VDRs running the
streamdev-client):

* remotetimers (http://vdr.schmirler.de/)
Add, edit, delete timers on client and server

* timersync (http://phivdr.dyndns.org/vdr/vdr-timersync/)
Automatically syncronizes timer lists of client and server. All recordings will
be made on the server

* remoteosd (http://vdr.schmirler.de/)
Provides access to the server's OSD menu
  
* epgsync (http://vdr.schmirler.de/)
Import EPG from server VDR

* femon (http://www.saunalahti.fi/~rahrenbe/vdr/femon/)
Display signal information from server's DVB card. SVDRP support must be enabled
in femon's setup

4.2 Plugins for Server:
-----------------------

* dummydevice (http://phivdr.dyndns.org/vdr/vdr-dummydevice/)
Recommended on a headless server (i.e. a server with no real output device).
Without this plugin, a budget DVB card could become VDR's primary device. This
causes unwanted sideeffects in certain situations.

4.3 Alternatives:
-----------------

* xineliboutput (http://phivdr.dyndns.org/vdr/vdr-xineliboutput/)
With its networking option, xineliboutput provides an alternative to streamdev.
You will get the picture of the server VDR, including its OSD. However you
won't get independent clients, as they all share the same output.

5. externremux.sh:
------------------

When selecting streamtype "EXT", the TS stream from VDR is passed through an
external program for further processing. By default a script installed at
VDRCONFDIR/plugins/streamdev/externremux.sh is expected, however you may
specify a different location as parameter -r to the streamdev-server plugin
(see chapter upon Installation above).

The TS stream is passed to the script on stdin, the resulting stream is expected
on stdout. The following parameters are passed to the script in the environment:

* Information on the channel:
  REMUX_CHANNEL_ID    VDR channel ID
  REMUX_CHANNEL_NAME  Channel name
  REMUX_VTYPE         Video type (2 for MPEG-2)
  REMUX_VPID          Video PID (undefined if audio only)
  REMUX_PPID          PCR PID (undefined if equal to VPID)
  REMUX_TPID          Teletext PID (undefined if not available)
  REMUX_APID          Space separated list of audio pids
  REMUX_ALANG         Space separated list of audio languages
  REMUX_DPID          Space separated list of dolby pids
  REMUX_DLANG         Space separated list of dolby languages
  REMUX_SPID          Space separated list of subtitle pids
  REMUX_SLANG         Space separated list of subtitle languages
  REMUX_PARAM_*       All (user supplied) parameters (e.g. REMUX_PARAM_x)

* Information on the connection (CGI like)
  REMOTE_ADDR         Client IP
  SERVER_NAME         Local IP
  SERVER_PORT         Local port
  SERVER_PROTOCOL     Streamdev protocol (HTTP, VTP, IGMP)
  SERVER_SOFTWARE     Streamdev version
  All HTTP headers converted to uppercase, '-' replaced by '_' (e.g. USER_AGENT)

The script should perform the following steps (pseudocode):

  if (SERVER_PROTOCOL == HTTP)
    write headers (including Content-Type) to STDOUT
    write empty line to STDOUT
    if (REQUEST_METHOD == HEAD)
      exit
    endif
  endif
  while (read STDIN)
    remux to STDOUT
  wend

  onSIGINT/SIGKILL: cleanup and exit

6. Known Problems:
------------------

* In VDR-to-VDR setup, the availability of a channel is checked with a different
priority than the actual channel switch. The later always uses priority 0.
Usually a channel switch for live TV has priority 0 anyway, so it is not a
problem here. However timers usually have a higher priority. Either avoid
client side recordings or set the priority of client side timers to 0.