The Future of HD

720pSD is 2.25x 480pSD, 720pHD is 1.33x 720pHD and finally 1080pHD is 2.25x 720pHD. Since every pixel needs to be processed those ratios pretty much determine how much slower it would be to encode 720pSD then 480pSD and so on. Since AVC do not encode every pixel, relationship between bitrate needed and picture size would not be linear as with encoding times. Here is the table to demonstrate that on single pass mencoder encodes on overclocked eMachine that roughly corresponds to 1.6GHz Core Duo.

Size	kbps	H264		kbps	XVID
480pSD	750	1.43xT-1.66xT (0.6xRT-0.7xRT)		850	1.85xT??? (0.54xRT???)
		17fps	43fps		16fps
720pSD	800-900	2.3xT-3.0xT (0.33xRT-0.43xRT)		1000	1.76xT(0.56xRT)
		10fps	25fps		18fps
720pHD	1250	3.5xT (0.285xRT)		1500	3.0xT(0.33xRT)
		8.55fps			10fps
1080pHD	2000+	7.1xT (0.14xRT)		2500	4.3xT(0.23xRT)
		4fps			7fps

So in reality it is not quite 2.25, 1.33, 2.25 but more like 1.5, 1.5, 2.0. Still it doesn’t change the picture that much… Today only 480pSD is about real time and 720pSD would need more then Core Duo2 to become practical that still would make 720pHD a bit better then half the real time and 1080p still way too slow to be practical. I guess there is no real reason for me to get Core Duo2 unless it is Quad and even then we could hope for 720pHD to be not too much slower then real time, but still slower. No need for more then XBOX or flat screen TV either – we are still in 480pSD world until I get that Quad.

P.S. I did run some test on 2.66GHz Core Duo2 MacBook and 720x304 DVD with Handbrake are about twice as fast then D805 at about 100fps/23.97~4xRT (0.25xT) vs. 29fps/23.97~1.23xRT(0.8xT). Upscaling to 720pHD on D805 it was 10fps/23.97~0.4xRT(2.4xT) vs. 12fps/23.97~0.5xRT(2xT) on MacBook under Windows or 14fps/23.97~0.6xRT(1.7xT) under OSX - OSX is more optimized, but still 2hr movie would take more then 2*3.5=7 hours to upscale to 720pHD and 2-pass encode. Definitely, HD is not here even with fastest Apple hardware.

Transcoding ATSC also was well just 15-40% faster 5.87fps/29.97~0.2xRT(5xT) vs. 4/29.97~0.14xRT(7xT) for 1080pHD and 9.63/29.97~0.3xRT(3xT) vs. 8.55/29.97~0.28xRT(3.5xT) for 720pHD, and as predicted, 480pSD was faster then RT at 69.25/59.94=1.15xRT or upto 75/59.94=`.25xRT on OSX. Two pass encodes of SD tapes with x264 under Vista run 53.70/30.25 or about the same as on Quad Xeon 3.4GHz Dell - 49.70/30.58. Finally comskip did run under wine faster then on Vista (250 fps vs. 192 fps).

P.P.S. There is a problem with ffmpeg and x264 muxer making .mp4 unplayable in QT. To fix it need to extract to raw with mp4box (06/2007 build) and remux (with -fps switch for 29.97). Also Sonic DS filter for MPEG-2 is way too slow - use Mainconcept.