Frequently Asked Question
How to determine latency?
The ADV202's latency is generally 1.5 fields in encode or decode mode.
If frames are input, the the latency is in frames.
ADI does not provide exact specification of latency, since it depends on a lot of factors which would make an exact specification difficult.
Complexity of input image, # of wavelet transform levels, choice of wavelet filters, choice of output format will all effect latency but nevertheless it will be kept in the 1.5 fields/frames range.
In order for the ADV202 to perform the rate control calculations, i.e. determine the compression ratio to keep a certain bit rate, or determine the compression ratio to keep a certain quality, it requires the wavelet information of one field/frame to be present on internal memory. Once the information of an entire field/frame is present the rate control calculation can be performed and the data can be output. Latency can be reduced in using single component input, 5/3 irreversible compression mode, .j2c output format, codeblock size of 128x32.