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 ?