Many posts back it was mentioned they are not true 50fps, instead each frame from a 25fps is duplicated merely to allow BBC to boast about 50fps streaming.
On 2 May 2018 at 19:07, Owen Smith Owen Smith <[email protected]> wrote: > What do you mean this isn't a lossy transcoding? How can ffmpeg go from 50fps > to 25fps without losing anything? The > frames are not all complete frames, software can't just throw alternate > frames away. Well it could, but the only way > to do that is a full H.264 decode, then discard alternate frames, then a full > H.264 encode again which is going to > involve loss. > > Most frames are not fully present in the original stream, they are > interpolated from previous and subsequent frames. > You can't throw any of those away, because other frames are interpolated from > them. It would need to be a very special > original encode which had all even frames only interpolated from other even > frames and ditto for odd frames to allow > alternate frames to be discarded. And a special encode like that would bloat > the file size substantially, almost > doubling it I would expect. _______________________________________________ get_iplayer mailing list [email protected] http://lists.infradead.org/mailman/listinfo/get_iplayer
