All consumer video cameras (HD/HDMI) that I have come across (in PAL-land) can record in "50i", that is 25 interlaced frames/second.
My own hands-on experience tells me that when the cameras are configured in that way, the live video on the HDMI port will also be 50i.
However, I have recently had reports that some recent models (e.g. Canon Legria) will output 50p on the HDMI live output regardless of the recording being 50i.
This whole interlace thing is of course an historic artifact, but for my specific application it is really a useful feature.
(If I capture 50i and de-interlace it, I can achieve 20 ms timing resolution (50 fields/second) with half the data bandwith of 50p which gives 50 frames/second)
Anyone with insights on this?
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Bandwidth is the entire reason interlaced video exists. But once you start talking compressed video the bandwidth differential is much reduced, maybe even eliminated. Interlaced encoding is less efficient than progressive encoding. And at 50 fps progressive you can get away with less bitrate per frame to get the same visual quality vs. 25 fps.
Last edited by jagabo; 9th Nov 2017 at 09:04.
My Canon Legria G40 outputs both interlaced or progressive to HDMI depending on which is selected. All my video is done at 1080 50p 35Mbps and my PC has no problem running this. The big difference is that the internal video recorded on the SD cards is at 8 bit 4.2.0., whereas the HDMI output is 10 bit 4.2.2 which is great for recording high quality onto an external recorder in Prores or DNxHD.