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diff --git a/docx/09_lipsync.dox b/docx/09_lipsync.dox new file mode 100644 index 0000000..6229198 --- /dev/null +++ b/docx/09_lipsync.dox @@ -0,0 +1,37 @@ + /* + * Copyright (C) 2012, BMW AG + * + * This file is part of GENIVI Project AudioManager. + * + * Contributions are licensed to the GENIVI Alliance under one or more + * Contribution License Agreements. + * + * \copyright + * This Source Code Form is subject to the terms of the + * Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with + * this file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * \\author Christian Linke (christian.linke@bmw.de) + * + */ + /*! + \page lip Lipsync + + \section t The Task of the Audiomanager + It is the job of the AudioManager to retrieve all latency timing information from each connection, to aggregate this information and provide a latency # + information on a per MainConnection Basis. It is not the task of the AudioManager to actually delay or speed up video or audio signals to achieve a lipsync. + The actual correction shall be done in the with the information provided by the AudioManager. + The time information is always reported by the routingadapters for each connection. Delays that are introduced in a sink or a gateway are counting for the + connection that connects to this sink or gateway. + \section ex Example + \image html delay.jpg + + This graph shows how the delay is calculated: + - Connection 1 has a delay 2ms + 60ms that is added due to the gateway + - Connection 2 has a delay 0ms + 10ms due to sink + So the routing adapters report 62ms and 10ms, the audiomanager will add this to 72ms and report this value for the main connection from sink to source. + The videoplayer getting this information can now delay his video against the audio for 72ms and be in perfect lipsync.\n + After the buildup of a connection the first timing information needs to be sent within 5 seconds, the timing information from the routing adapters need to + be sent via 4 seconds. If the latency for a connection is variable and changes over lifetime of the connection, the routing adapters shall resend the value + and the audiomanager will correct the over all latency. +*/ |