Repeat frames and dittos

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Repeat frames and dittos

DecodeIR v2.37 and later versions have a look-ahead facility that is not present in earlier ones. This distinguishes between two styles of data passed to them by the calling application. The remote control programming applications IR.exe and RMIR pass signals learned by a UEI remote that has itself performed a partial analysis of the signal. The data is passed in a structured form, divided into Once, Repeat and Extra sections. The data in each of these sections can be viewed in IR.exe if the "Force Learned Timings" option on the Advanced menu is selected. Because of this analysis, DecodeIR does not see the original signal in full and cannot determine such things as the number of repeats of the signal that were sent. Other applications such as the IRScope software for the IR Widget send the entire signal as unstructured data, which enables IR.exe to identify the number of repeats.

The look-ahead facility checks successive frames within a single signal to see if they are repeats – either identical repeats or, in certain protocols, frames of a repeat sequence that have a distinctive marker in either the start or end frame, or both, of the sequence. If a protocol has distinctive start or end frame markers and either or both of the start and end frames are missing, this is reported in the Misc field of the decode (but at present this may not be implemented for all protocols with such markers). If the data has been passed in an unstructured form then the number of repeats in the signal will also be reported in the Misc field in a form like "4 frames", or in version 2.39 and later, "+ 3 copies".

In the case of unstructured data, DecodeIR v2.38 extends the look-ahead to protocols in which repeat action is signalled not by a full repeat of the frame but by a much shorter frame that does not carry the signal data (or occasionally carries just part of this data). These frames serve as "ditto marks". If present then the number of such frames is reported in the Misc field in a form like "3 dittos", or in version 2.39 and later, "+ 3 dittos". If there are no repeat frames or ditto marks, then to avoid ambiguity this is reported as "no repeat".

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