25i vs 50p (QTGMC) with x264 at the same bitrate

Livesms · 5th June 2016, 14:07

Got 25fps interlaced source (DVB, TV show).
What is better way to encode it with x264 at the same bitrate
- leave interlaced and encode with --tff option
- deinterlace with QTGMC with double frame rate (50fps progressive) and encode as progressive at the same bitrate as planned for 25i source ?

Did some short test. Took a part (6000 frames, 720*576, DAR 16:9, 25 fps), encoded with x264 as interlaced (--tff) at 1150 kbps. Did the same encode at 1150 kbps but after deinterlacing (QTGMC - Slower).

Put both output files through Avisynth Compare (PSNR)

Code:

Compare( orig_video.QTGMC(), video25i.QTGMC(), "", "25i")
Compare( orig_video.QTGMC(), video50p, "", "50p")

and got
Overall PSNR: 40.9617 for 25i (then deintelaced and compared to deinterlaced original) and
Overall PSNR: 41.0287 for 25p (compared to deinterlaced original)...

Doubling framerate do not lead to quality loss at the same bitrate ?

5th June 2016, 14:07	#1 \| Link
Livesms Registered User Join Date: Mar 2006 Posts: 184	25i vs 50p (QTGMC) with x264 at the same bitrate Got 25fps interlaced source (DVB, TV show). What is better way to encode it with x264 at the same bitrate - leave interlaced and encode with --tff option - deinterlace with QTGMC with double frame rate (50fps progressive) and encode as progressive at the same bitrate as planned for 25i source ? Did some short test. Took a part (6000 frames, 720*576, DAR 16:9, 25 fps), encoded with x264 as interlaced (--tff) at 1150 kbps. Did the same encode at 1150 kbps but after deinterlacing (QTGMC - Slower). Put both output files through Avisynth Compare (PSNR) Code: Compare( orig_video.QTGMC(), video25i.QTGMC(), "", "25i") Compare( orig_video.QTGMC(), video50p, "", "50p") and got Overall PSNR: 40.9617 for 25i (then deintelaced and compared to deinterlaced original) and Overall PSNR: 41.0287 for 25p (compared to deinterlaced original)... Doubling framerate do not lead to quality loss at the same bitrate ?