I think it is recommended to send field by field to adv212 for decompression. Is it required to wait for 20ms between each field, or is it required to send the data continuously when ever it asks, with out any gap.
There is no requirement either way. However, it's better to send one codestream per field time. The reason for this is that the field size will vary with the complexity of the content as will the available buffering inside the ADV212. If you give the part data whenever it asks for it, then amount of buffering you need in your system will be much more random and many customers have trouble managing this.
If you always feed 1 field worth of data per field time, then your buffer size can be tied to your RCVAL and flow control will be more predictable.
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