Audio/Video Out of Sync

[tellyaddict]

My understanding of what Jim has said is that all the HLS recording modes are legacy streams served only by Akamai. For these legacy streams, the BBC send the programme files to Akamai and they (Akamai) then segment and upload the programme to their servers. It seems that the processing that Akamai are doing is what is at fault and causing the missing segment errors that we are seeing.

The new generation of HLS streams are the ones served by both Akamai and Limelight. In 2.95 they are the HVF modes. These programmes are segmented and packaged by the BBC and then sent to Akamai. Akamai are not processing these files and they are fault free.

The Olympics are mostly only being processed into HVF format, so the BBC is doing all the processing of these and Akamai are NOT being asked to process them for HLS (on the legacy system) which is why this option is not available on most Olympics content.

> So that would seem to be telling the worthy authors of GiP something useful
> for future development, but doesn't really explain the current problems.
> The best guess we can make using this new information would seem to be
> something like:
> 
> iPlayer is using the new servers whenever a browser doesn't have Flash
> installed, and the legacy ones for Flash browsers.  The new servers are
> geared up for the demand from the Olympics, but the old ones, being legacy,
> are being maintained on something akin to a best efforts basis, and the
> current level of demand on these legacy servers is causing glitches both in
> the recording/storing of programme data on them, and in downloading from
> them.  Hence the two types of error, with the first being fixed
> retroactively by Akamai, and the second fixable by the user redownloading.
> 
> It would be nice to have something less speculative, however.