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Difference between revisions of "Introduction to CEC"

(What is CEC ?)
(Message features)
 
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=== Message features ===
 
=== Message features ===
 +
According to the HDMI-CEC specification, features are classified into two groups, end-user and supporting features. Some other "administrative" messages related to the general protocol are not officially classified.
 +
 +
=== End-user features ===
 
; One Touch Play
 
; One Touch Play
: The One Touch Play feature allows a device to be played and become the active source with a single button press.
+
: Allows a device to be played and become the active source with a single button press.
; Routing Control
+
: This feature is used to control the routing of the HDMI network, by controlling CEC Switches.
+
 
; System Standby
 
; System Standby
: This broadcast message can be used to switch all CEC devices to standby.
+
: Enables the user to switch all devices to standby with one button press.
 
; One Touch Record
 
; One Touch Record
: This feature allows the user to easily start a recording of the source that is being displayed on the TV, just by selecting a Recording Device and giving the record command.
+
: Offers a What You See Is What You Record (WYSIWYR) facility, meaning that whatever is shown on the TV screen is recorded on a selected Recording Device.
 
; Timer programming
 
; Timer programming
: This feature allows a device (e.g. the TV) to set a timer recording on a Recording Device.
+
: Allows the user to program the timers in a Recording Device from an EPG running on a TV or STB.
; System Information
+
: This feature allows devices to automatically use the same OSD and Menu language settings as the TV and also for a TV to discover the current language when it is being installed.
+
 
; Deck Control
 
; Deck Control
: This feature allows a Playback Device (a deck or disc player or recorder) to be controlled by another device (e.g. the TV).
+
: Enables a device to control (e.g. play, fast forward etc.) and interrogate a Playback Device (a deck).
 
; Tuner Control
 
; Tuner Control
: This feature allows a device (e.g. the TV) to control another CEC device’s tuner.
+
: Allows a device to control the tuner of another device.
; OSD Display
+
: This feature allows a device to transfer a text string to the TV for On Screen Display.
+
; Device OSD Name Transfer
+
: This feature is used to request the preferred name of a device to be used in any on screen display (e.g. menus), which reference that device.
+
 
; Device Menu Control
 
; Device Menu Control
: This feature allows device menus to be controlled via the TV remote control as if it was using its own remote control and allow the TV to be aware when another device has a menu on its display.
+
: Enables a device to control the menu of another device by passing through user interface commands.
 
; Remote Control Pass Through
 
; Remote Control Pass Through
: This feature is used to pass remote control commands received by one device (typically the TV) through to another device in the network.
+
: Enables remote control commands to be passed through to other devices within the system.
; Give Device Power Status
+
: This message is used to determine the current power status of a target device.
+
 
; System Audio Control
 
; System Audio Control
: This feature allows an audio amplifier to provide the audio for a source that is being displayed on a TV.
+
: Allows an Audio Amplifier / Receiver to be used with the TV. The volume can be controlled using any the remote controls of any suitably-equipped devices in the system.
; Audio Rate Control
+
 
: This feature allows the audio playback rate of a Source Device to be controlled by another device, e.g. an Audio System.
+
=== Supporting features ===
 +
; Device OSD Name Transfer
 +
: Enables devices to upload their preferred OSD name to the TV. The TV can then use this name in any menus associated with that device.
 +
; Device Power Status
 +
: Allows the current power status of a device to be discovered.
 +
; OSD Display
 +
: Enables a device to use the on-screen display of the TV to display text strings.
 +
; Routing Control
 +
: Allows the control of CEC Switches for streaming of a new source device.
 +
; System Information
 +
: Queries the system to determine device addresses and language.
 
; Vendor Specific Commands
 
; Vendor Specific Commands
: This feature allows a set of vendor specific commands to be used to communicate between devices.
+
: Allows a set of vendor-defined commands to be used between devices of that vendor.
 +
; Audio Rate Control
 +
: Allows an Amplifier to fractionally increase or decrease the playback rate of an audio source.
 +
 
 +
=== General protocol messages ===
 +
; Abort mechanisms
 +
: Enables messages to handle abort mechanism

Latest revision as of 03:02, 14 January 2011

Introduction

What is CEC ?

CEC stands for Consumer Electronics Control.

CEC is a set of commands that utilizes HDMI’s two-way communication to allow for single remote control of any CEC-enabled devices connected with HDMI. For example, CEC includes one-touch play, so that one touch of play on the DVD will trigger the necessary commands over HDMI for the entire system to power on and auto-configure itself to respond to the command. CEC has a variety of common commands as part of its command set, and manufacturers who implement CEC must do so in a way that ensures that these common command sets interoperate amongst all devices, regardless of manufacturer.

CEC is an optional feature within the HDMI specification, which is supported by some manufacturers under their own proprietary names for their implementation of part of the CEC command set.

CEC implementation

CEC uses a one-wire bus running at approx. 400 Hz and is able to send around 30 bytes per second.

CEC availability

CEC is already available today but with a very limited multi-vendor interoperability.

Manufacturer Brand
Panasonic EZSynch / HDAVI / Viera Link
Sony Bravia Theater Synch / Bravia Link
Sharp AQUOS FamiLink
Toshiba CE-Link / Regza Link
Samsung AnyNet+
LG SimpLink

Messaging

Message types

  • Request : ask another device to take an action or give information
  • Informative : status messages

Message targets

  • Targeted : sent to a unique device
  • Broadcast : sent to all the devices within the CEC networks

Message features

According to the HDMI-CEC specification, features are classified into two groups, end-user and supporting features. Some other "administrative" messages related to the general protocol are not officially classified.

End-user features

One Touch Play
Allows a device to be played and become the active source with a single button press.
System Standby
Enables the user to switch all devices to standby with one button press.
One Touch Record
Offers a What You See Is What You Record (WYSIWYR) facility, meaning that whatever is shown on the TV screen is recorded on a selected Recording Device.
Timer programming
Allows the user to program the timers in a Recording Device from an EPG running on a TV or STB.
Deck Control
Enables a device to control (e.g. play, fast forward etc.) and interrogate a Playback Device (a deck).
Tuner Control
Allows a device to control the tuner of another device.
Device Menu Control
Enables a device to control the menu of another device by passing through user interface commands.
Remote Control Pass Through
Enables remote control commands to be passed through to other devices within the system.
System Audio Control
Allows an Audio Amplifier / Receiver to be used with the TV. The volume can be controlled using any the remote controls of any suitably-equipped devices in the system.

Supporting features

Device OSD Name Transfer
Enables devices to upload their preferred OSD name to the TV. The TV can then use this name in any menus associated with that device.
Device Power Status
Allows the current power status of a device to be discovered.
OSD Display
Enables a device to use the on-screen display of the TV to display text strings.
Routing Control
Allows the control of CEC Switches for streaming of a new source device.
System Information
Queries the system to determine device addresses and language.
Vendor Specific Commands
Allows a set of vendor-defined commands to be used between devices of that vendor.
Audio Rate Control
Allows an Amplifier to fractionally increase or decrease the playback rate of an audio source.

General protocol messages

Abort mechanisms
Enables messages to handle abort mechanism