iPlayer streams at 50fps progressive?

[Jon Davies]

On 8 October 2015 at 12:02, John Warburton <john at johnwarburton.net> wrote:
> Hello,
>
> Is the BBC sending out live streams at 50fps progressive? FFprobe
> seems to think so. And the pictures look like they're at 50fps, either
> natively or de-interlaced.

I hadn't noticed that, but it does appear to be the case!

> When I pipe the output of get_iplayer watching BBC News 24 into
> ffprobe, taking great care not to re-code to anything on the way out,
> I get ffprobe showing me that the frame rate is 50fps.

I tried a somewhat simpler command line, getting the same result.  I
also remuxed the transport stream into an mp4, and ffprobe yields a
little more data:
      encoder         : XDCAM EX 720p50
which given that the XDCAM EX is a broadcast-quality camera, makes it
look like some metadata is making it all the way through from the
cameras themselves...

I also had a look at the bbc one live stream, which is also reporting
720p50.  And in general the hlsvhd mode (when it's available) is
720p50.  Unfortunately they seem to be sticking with 128k stereo aac,
and not feeding out anything with surround sound.

So, yes, they do appear to be broadcasting 720p50 live over the
internet - at about 6Mbps.

jon