Using ffmpeg to halve frame rate

RS richard22j at
Wed Apr 18 02:40:56 PDT 2018

On 17/04/18 22:27, Nick Payne wrote:

> I just ran another test on some 1280x720 50fps and 1280x720 25fps
> downloads from the last UK snooker championship. As before, the 25fps
> downloads were reduced to about 1/3 previous size by Handbrake (eg a
> 4h58m match that was 5.03Gb came down to 1.55Gb). However, the 50fps
> downloads were reduced by far more with exactly the same settings in
> Handbrake - for example, a 4h44m match that was a 10.2Gb download from
> GiP came down to 1.48Gb, and a 4h14m 8.93Gb file came down to 1.30Gb.
> This leads me to wonder if the 50fps downloads are from a 25fps original
> and just have each frame duplicated, as after running through Handbrake,
> the file sizes just seem proportional to the length of the program, and
> whether 50fps or 25fps has no effect on the file size.
That's interesting.  I did wonder how the BBC was generating its 50fps 
material.  It seemed surprising that it would shoot all its material at 
a higher frame rate than broadcast just for the benefit of the iPlayer.

If I want to achieve a 50fps frame rate by duplicating frames I can do 
that myself.  For the BBC to duplicate frames is a waste of everyone's 
time and bandwidth.

Best wishes

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