Sync pdf expert between devices

In home television viewing experiences involving high definition programs displayed sync pdf expert between devices a flat panel TV the sound heard by the viewer most commonly leads the video seen by the viewer by a significant and often noticeable amount of time. The error typically slowly varies by a significant amount throughout a television program and frequently varies from noticeable to unnoticeable amounts several times per hour. In industry terminology the lip sync error is expressed as an amount of time the audio departs from perfect synchronization with the video where a positive time number indicates the audio leads the video and a negative number indicates the audio lags the video. 1359-1, and other references below.

AV-sync timing, either in the form of interleaved video and audio data or by explicit relative time-stamping of data. The processing of data must respect the relative data timing by e. If the processing does not respect the AV-sync error, it will increase whenever data gets lost because of transmission errors or because of missing or mis-timed processing. The AV-sync delay is normally fixed.

If the sound source is 340 meters from the microphone, then the sound arrives approximately 1 second later than the light. The AV-sync delay increases with distance. During mixing of video clips normally either the audio or video needs to be delayed so they are synchronized. The AV-sync delay is static, but can vary with the individual clip. A video camera with built-in microphones or line-in may not delay sound and video paths by the same number of milliseconds. A video camera should have some sort of explicit AV-sync timing put into the video and audio streams.

The AV-sync delay normally increases with time. There is extensive use of audio and video signal processing circuitry with significant delays in television systems. Particular video signal processing circuitry which is widely used and contributes significant video delays include frame synchronizers, digital video effects processors, video noise reduction, format converters and MPEG pre-preprocessing. The video monitor processing circuit may delay the video stream. Pixelated displays require video format conversion and deinterlace processing which can add one or more frames of video delay.

A video monitor with built-in speakers or line-out may not delay sound and video paths by the same number of milliseconds. Some video monitors contain internal user-adjustable audio delays to aid in correction of errors. In RTP’s case, each media stream has its own timestamp using an independent clock rate and per-stream randomized starting value. Many software clients do not send RTCP at all or send non-compliant data.