diff options
Diffstat (limited to 'PROTOCOL')
| -rw-r--r-- | PROTOCOL | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/PROTOCOL b/PROTOCOL new file mode 100644 index 0000000..a0c999e --- /dev/null +++ b/PROTOCOL @@ -0,0 +1,139 @@ +Written by: Sascha Volkenandt <sascha@akv-soft.de> + +Project's homepage: http://www.magoa.net/linux/ + +Version: 0.0.3 + +Description: +------------ + +I call this protocol "VTP", the Video Transfer Protocol. I hope that's not +already claimed by someone ;). + +This Protocol was created for Video Transfers over a Network. It is a text- +based protocol like the FTP, and is used by a client to communicate with a +server providing different types of video data, such as live streams, +recordings or disc media. The basic communication consists of short text +commands sent by the client, answered by numerical codes accompanied by +human-readable messages. All messages should be finished by a full CR/LF +line-ending, which should preferably written as "\015\012", as this is fully +platform-independent. Nevertheless, a client or (especially) a server should +also act on "\n" line-endings. The MPEG data is being transmitted over a +separate data connection. + +TODO: +- PORT behaviour changed +- TUNE syntax changed +- connection IDs +- new command PLAY + + +Response Code Summary + +Code Meaning +220 Last command ok / connection ready +221 Service is closing the connection afterwards +500 The command was not recognized +501 The parameters couldn't be interpreted correctly +550 Action not taken, for various reason +551 Action not taken, a subsequent connection was unsuccessful +560 Live-Stream not available currently [changed in 0.0.3] +561 Capability not known [new in 0.0.2] +562 Pid currently not available [new in 0.0.3] +563 Stream not available currently [new in 0.0.3] + + +Command Reference + +Command: Connect to VTP Server +Responses: 220 - The server is ready +Description: Upon connection to the server (which usually listens at port + 2004), the first thing the client has to expect is a welcome message with + the "220" response code. The client may now send a CAPS command, to tell + the server it's capabilities. + +Command: CAPS <Capability> +Responses: 220 - This capability is known and will be used from now on. + 561 - This capability is unknown, try anotherone +Description: This command tells the server to serve media data in a specific + format, like "PES" (for MPEG2-PES) or "TS" (for MPEG2-TS). A client can + do several CAPS commands until the server accepts one. So a client should + try all formats it can handle, descending from the most preffered one. If + no such command is sent, streaming is defaulted to PES. + Capabilities currently used: + TS Transport Stream (all PIDs belonging to a channel) + TSPIDS Only in conjunction with TS: Stream PIDs separately upon request + (this enables the ADDP/DELP commands) + PES Program Elementary stream (Video and primary Audio stream) +[new in 0.0.2,updated in 0.0.3] + +Command: PROV <Priority> <Media> +Responses: 220 - Media available for receive + 501 - The parameters were incorrect + 550 - The media couldn't be identified + 560 - This server can currently not serve that media +Description: With this command, the server is asked if the given media can + be received. The Priority is a number between 0 and 100 (in case a media + can not be received by an unlimited number of clients, the server shall + grant higher priorities before lower ones, and it shall also quit streams + with lower permissions if a higher one is requested), or -1 to ask the + server if this media is available at all. + The Media is a string defining the wanted media type. This is currently for + free use, it could for example carry a VDR unique channel id, to specify + a TV channel. + +Command: PORT <Id> <Address and Port> +Responses: 220 - The data connection was opened + 501 - The parameter list was wrong + 551 - The data connection was refused by the client or timed out +Description: The PORT command tells the server the target of a following + media transmission. The parameter Id specifies an index which is used to + establish multiple data connections over one control connection. It is used + later in the ABRT command to close a specific data connection. The second + parameter argument has six comma-separated fields, of which the first four + represent the target IP address, in the byte-order as the dot-notation + would be printed. The last two fields represent the target port, with the + high-byte first. To calculate the actual values, you could use the + following: + Field(5) = (RealPort & 0xFF00) shr 8 + Field(6) = RealPort & 0xFF + Reversed: + RealPort = (Field(5) shl 8) + Field(6) + After receiving the port command, the data connection is opened but no data + is transferred, yet. + Id's currently used: + 0 Data connection for live streams + 1 Data connection for saved streams +[changed in 0.0.3] + +Command: TUNE <Priority> <Media> +Responses: 220 - Data connection was opened successfully + 550 - The media couldn't be identified + 560 - The live stream is unavailable +Description: This command tells the media server to start the transfer over a + connection to a remote target established by the PORT command before. + Please look at the PROV command for the meaning of the parameters. The + server begins to send MPEG data. After the transfer has been started, the + response code "220" is sent. + +Command: ADDP <Pid> +Responses: 220 - The requested Pid is transferring + 560 - The requested Pid is not available currently +Description: This tells the server to start the transfer of a specific Pid + over a data connection established by the PORT command before. + +Command: DELP <Pid> +Responses: 220 - The requested Pid is transferring + 560 - The requested Pid was not transferring +Description: This tells the server to stop the transfer of a specific Pid + enabled by DELP before. + +Command: ABRT <Id> +Responses: 220 - Data connection closed +Description: This one should be sent before requesting another media or when + a media isn't needed anymore. It terminates the data connection previously + opened by PORT. + +Command: QUIT +Responses: 221 - Connection is being closed afterwards +Description: This commands terminates the client connection. |