Alanh, your inability to accept the easily measured fact that at the bottom of a 50Hz 99.9% sine wave modulation the RF energy output by the AM transmitter remains low for many cycles of the medium wave carrier [and in modern transmitter design that the input power at that point in the modulation is quite low] is your own failure of understanding. I don't think it assists your case to raise that matter again here.
Yes years ago a lot of us noticed "jaggies". But your continual references to jaggies in 2012 in my opinion rejects the capacity of modern day deinterlacing processing to synthesize smooth lines.
In typical alanh fashion, you provide no raw image capture from an MPEG stream to support your contention each pair of fields was from one capture time (i.e. from one progressive frame) in 7's recent terrestrial broadcasting of Wimbledon. You provide opinion and assumption, but no evidence.
My recording made last night on a dedicated USB hard drive reveals fluid motion, consistent with normal 25i. If I could extract frames and upload them I would. But then it is not I who started this thread...
To illustrate what can be done if making an effort to investigate, I remind you of an old post of mine, following my analysis of the fields making up frames from the 2010 FIFA Word Cup:
MLXXX, on 17 July 2010 - 11:17 PM, said:
as they say, a picture speaks a thousand words!
I recorded the opening match of the world cup soccer in the evening of 11 June 2010 Eastern Australian time. The recording is currently taking up 14.5GB on a hard drive. I extracted four consecutive frames using VideoRedo TV suite H264. I then cropped out a 300x300 pixel section to highlight a moving object. It appears to be a microphone and/or camera suspended by a cable.
The software enables a capture of any frame in the source. If the source is 50p, there are 50 selectable frames per second. If the source is 50i, there are 25 selectable frames per second. The software options include deinterlacing set to on or off.
The frames are as follows:
To illustrate interlacing.
World Cup opening match 11/6/2010, Johannesburg, South Africa v Mexico
As the teams were entering playing field, 16 min 14 sec before start of play.
Captured Brisbane, 3D trial, MPEG-4 AVC, 1920x1080i50
Full Frame 00 - deinterlacing off: Saved as jpeg
Full Frame 00 - deinterlacing on: Saved as jpeg
Full Frame 03 - deinterlacing off: Saved as jpeg
Full Frame 03 - deinterlacing on: Saved as jpeg
Uncompressed montage of 300x300 crops from frames 00, 01, 02, 03 with deinterlacing off or on (beginning 150 pixels from top of frame, 500 pixels from left side of frame):
You will note that the frames with deinterlacing off are slightly sharper, but reveal a comb effect with the moving object. The teeth of the comb extend one pixel vertically and about 6 pixels across. There has been no rescaling of the original 1920x1080 side by side frame. The comb teeth would look twice as long if rescaled by a factor of 2 to give the correct aspect ratio.
Edited by MLXXX, 10 July 2012 - 04:57 AM.