ADS Technologies USBAV-708 INSTANT VIDEOMPX, Руководство пользователя

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The encoding profiles available in DivX 5.1 create video that is guaranteed to
play back on DivX Certified devices. To facilitate this it is necessary to control
aspects of the video stream produced by the encoder in such a way that the
capabilities of the target device are not exceeded. The video buffer verifier is part
of this process.
The video buffer verifier forms part of a
virtual decoder that is attached to the
encoder, limiting its output in terms of certain device capabilities. These are the
sustainable rate at which the device and receive the video stream, the buffer
associated with the video stream within the device, and how full that buffer
should be before playback begins.
When playing DivX videos using some types of devices, such as a fast desktop
computer, these considerations can often be overlooked without any significant
consequences. However, when encoding for broadcast over an IP network (e.g.
the Internet), or for a hardware device with fixed sustainable throughput, it is
critical for uninterrupted playback that the abilities of the device are not
exceeded.
Consider a hardware DVD player featuring DivX support. The DVD-ROM drive in
the unit may have a limited sustainable transfer rate and a fixed-size cache
associated with it.
Suppose a sustainable transfer rate of 2000 kbps from the drive and a 4096
kilobit read cache. If the encoder were to encode at 2500 kbps for a long period
this would be 500 kbps in excess of the drives ability to read from the disc.
Assuming the 4096 kilobit cache was full to begin with a 500 kbps under-run
would exhaust the buffer and cause playback to pause after around 8 seconds.
As this example illustrates, it is important that the encoder considers the
sustainable bitrate, buffer size and initial buffer occupancy to avoid pausing.
What is the video buffer verifier?
Video buffer verifier
The video buffer verifier explained