Podcast Pingback advertises one or more data receiving endpoints in the RSS feed for a podcast. RAD advertises an endpoint in the ID3 tag of the podcast audio.
The ability to include a specific ID3 tag in the audio content is potentially an added step and complication in the audio production process and may fall on staff who otherwise have little interest or technical involvement in this level of podcasting specifics. The approach of Pingback splits the dependencies between production and distribution, the implementation can be entirely downstream of the audio content production.
Decisions have to be made about which bits of the audio content are of interest ahead of time, to mark up. Conversely Pingback collects abstract data until such a point that a point of interest is identified and the data can be mined. If an area of interest is discovered later with RAD, a new audio file must be issued and the process would be reliant on as many podcast clients as possible picking up the new audio feed to get reliable analytics.
RAD only works with clients that support reading ID3 tags. This is particularly a concern with web browsers (e.g. player embeds in a website) which do not have this functionality natively. This may be resolved in a future update by defining a secondary way of identifying areas of interest in the audio in a way the browser can parse, but this then creates more than one source of truth for the standard.
Pingback requires an endpoint that accepts all events and then, potentially at a point in the future, those events need to be analysed to make sense of the data. Conversely, RAD events are already pre-defined, so the process simply totals the incoming events.
For similar reasons mentioned in the Feed vs ID3 section, this means the focus of the analytics have to be decided ahead of time and baked in to the audio file, but this does make parsing the received events simpler.
Pingback allows any part of the audio to be tracked, and decisions to be made at any point in time about what events are of interest, but it does require additional computation against the received events.
Pingback defines a basic list of events to be reported, there's no content to be parsed ahead of time by the client to know what events to report. Conversely, RAD requires the client to parse a list of events in the ID3 tag and then monitor for those events to occur.