nickluchen / dlb_lip_tool

dlb_liptool

• The dlb_liptool is an open-source tool to integrate the dlb_lip and libcec projects.
• The dlb_libtool can be used to demonstrate the functionality of the Latency Indication Protocol (LIP).
• The dlb_liptool uses the dlb_lip, an open-source implementation of the Latency Indication Protocol.
• libCEC(R) enables communication with other HDMI devcies using the Consumer Electronics Control (CEC) feature.

Getting started

To build the dlb_liptool, the dlb_lip and libcec projects are required.

Description

The Latency Indication Protocol (LIP) was developed by Dolby Laboratories Inc. in response to the lack of a capable HDMI signaling solution for A/V latency. The core idea is that LIP provides full transparency about the audio and video latency of all devices in an HDMI setup and thereby allows to apply necessary alignment at the source, where video is still compressed and thereby less costly to buffer.

The latency indication protocol is an extension of the Consumer Electronics Control (CEC) protocol designed for improved audio/video (A/V) synchronization when the audio and video content is decoded and rendered on different devices interconnected via HDMI.

A source device using LIP that has received information about downstream device latencies can optimally compensate the difference and ensure a proper A/V synchronization at the rendering points.

The functionality of the Latency Indication Protocol includes querying for the support of the protocol, sending information about the audio and video latency values of sink devices, and providing dynamic updates to the source device on changes in the cluster or processing mode of a sink device.

The Latency Indication Protocol is designed for specific device setups. The following scenarios are supported: [1] TV audio output connected to an audio system via ARC or eARC [2] Source device connected directly to a TV via HDMI [3] TV as the hub, connecting to a source device via HDMI, as well as to an audio system via ARC or eARC

Usage

The ./dlb_lip_tool/Readme.txt contains more advice about how to use the dlb_liptool.

Authors and acknowledgment

libCEC(R) is a trademark of Pulse-Eight Limited. The libCEC(R) consists of code written and distributed by Pulse-Eight Limited. http://libcec.pulse-eight.com/

License

The dlb_liptool project is distributed under the 3-Clause BSD License.

The libCEC(R) code used by this project is subject to other licensing terms. The libCEC(R) is dual-licensed; it can be redistributed and/or modified under the terms of the GNU General Public License. Alternatively, libCEC(R) can be licensed under a commercial license. For more information related to licensing libCEC(R) please see the libCEC(R) license. http://libcec.pulse-eight.com/