> Having said all that, my entirely subjective conclusions at > the moment are that the 720p video I get out of ffmpeg+x264 > when encoded as Baseline at around 3Mbps[0] compares > extremely favourably to the iPlayer HD content (which is > High profile, if memory serves) at the same bitrate. I > don’t know whether this is down to me not being able to > spot the difference from 10 inches away from the screen, > whether it’s that x264 is a better encoder than whatever > Red Bee uses, or whether it’s simply the case that High > Profile is used because Flash can decode it more > efficiently[1] than if it were Baseline. Also, noting that > at 720p25, 3Mbps ought to be enough!
x264 is almost certainly better than whatever Red Bee use though I think the keyframe interval in iPlayer is lower than the x264 defaults. (and the ffmpeg presets aren't very good) In theory High and Baseline should have approximately the same decode complexity since the High Profile features should reduce bitrate. The overhead of High Profile should then be cancelled out by this lower bitrate. iPlayer does disable CABAC which is an easy way of reducing Flash performance. For 720p25 you might need more than 3.5Mbps for more demanding scenes. (Except increasing the bitrate or using a better encoder will make iPlayer look better than the broadcast...) - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
