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5th June 2016, 14:07 | #1 | Link |
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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") 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, 16:14 | #2 | Link |
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1- interlaced encoding usually is more efficient than encoding interlaced content as progressive, but it's still less efficient than encoding progressive content as progressive;
2- qtgmc include a denoiser, you can try with its losselss mode; 3- doubling framerate usually give almost identical couples of frames so don't take so much bitrate.
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5th June 2016, 16:18 | #3 | Link | |
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Quote:
2. denoiser included with QTGMC enabled by default ? 3. Yes, deinterlacing with doubling framerate produce 2 almost indetial frames (with minimum difference) instead of 1 frame (interlaced with 2 fields). |
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5th June 2016, 18:06 | #4 | Link | |
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Quote:
http://avisynth.nl/index.php/QTGMC
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6th June 2016, 10:59 | #5 | Link |
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Thanks. Tried to use denoise with QTGMC and got an error with dfttest.dll (will ask in QTGMC thread)
One more question - is there any avisynth plugin to provide comparing of two video as from visual quality (how similiar it looks to original in fact, not in ephemeral PSNR) ? |
8th June 2016, 23:06 | #6 | Link | |
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Still, there will certainly be content/bitrate combinations where 25i with a bad post-decoder deinterlacer will outperform 50p with a good pre-encode deinterlacer. IIRC, in VC-1 we found a 20% advantage for 25i v. 50p in this case. It likely would be somewhat more for H.264 due to the availability of MBAFF. |
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9th June 2016, 18:35 | #7 | Link |
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sure I can't get access to the high pro test clip and encoders of yours but, I made a quick test with parkrun_ter, with
Code:
assumetff() qtgmc(SourceMatch=3, Lossless=2,NoiseProcess=1, NoiseRestore=1.0, Sigma=2.0 ) codec settings Code:
"%~dp0avs4x26x.exe" -L "%~dp0x264.exe" --pass 1 -B 6000 --preset slow -o NUL %1 "%~dp0avs4x26x.exe" -L "%~dp0x264.exe" --pass 2 -B 6000 --preset slow --ssim --psnr -o %1_qtgmc.mp4 %1 "%~dp0avs4x26x.exe" -L "%~dp0x264.exe" --pass 1 -B 6000 --tff --preset slow -o NUL %1 "%~dp0avs4x26x.exe" -L "%~dp0x264.exe" --pass 2 -B 6000 --tff --preset slow --ssim --psnr -o %1_interlaced.mp4 %1 results are interlaced ssim 77.32887 psnr 36.083 qtgmc ssim 81.72833 psnr 37.444
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powered by Google Translator Last edited by Motenai Yoda; 9th June 2016 at 18:50. |
13th June 2016, 20:45 | #8 | Link |
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All in all... got tons of DVB video - MPEG-2 (PAL), 720*576 (16:9), 25 FPS, Interlaced (TFF), ~3100 kbps
Need to reencode all video to free some space. Decided to reencode with x264 for 0.10 bit per pixel (~ 1100 kbps). What way is better - reencode with x264 as interlaced or deinterlace it to progressive (50 fps) and reencode as progressive (50 fps) as the same 1100 kbps... |
14th June 2016, 06:36 | #9 | Link | |
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There's probably no short cut to doing a visual comparison for this. |
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15th June 2016, 12:24 | #10 | Link |
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I've done another comparison with all four ldv's 576i25 sequencies
while x264 preserve deinterlaced one's "structure" better, combed parts seems to force it to mantain fine details/high frequencies (or generate some sort of grain). https://www.sendspace.com/file/616xsx likely with further high bitrate 25i will outcome 50p even on the structure
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powered by Google Translator Last edited by Motenai Yoda; 15th June 2016 at 12:26. |
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25i, 50p, interlaced, x264 |
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