What is the source of files downloaded by GiP?

[CJB]

As the truncation issues pertain - the last Cabin Pressure was the
latest - I was wondering exactly where the programmes offered via
iPlayer and/or downloaded by GiP are actually sourced from.

It appears to me that the Beeb uses a capping system to record
programmes for iPlayer as they are being aired. That is they record
programmes off air - as they are being transmitted - much like the
pubic might do with a programmable VCR.

This would explain the truncations - especially pertinent to radio
programmes. If a programme was delayed due to say an extended news
bulletin, then it would no longer be correctly capped at the scheduled
time, and the end would indeed be truncated.

I guess that if complaints are received that a programme has been
truncated then the staff replace the file with a complete one kept for
that purpose.

CJB