Deinterlacing with QTGMC changes to 50p?
Hello,
I'm starting with deinterlacing with qtgmc. I deinterlace material from PAL DV and Video8 PAL. I use basic script: Code:
AVISource("U:\Media a traiter\tbd3.avi") In virtualdub2 i use streamcopy to keep the source file format, but doesn't seem to work. When finished, I have PAL 50p and the bitrate change from 56 mbs to 332 mbs ! Is it normal that the framerate is doubled ? Here are the information of the files: Original file Code:
Video Code:
Video Chrisbati |
interlaced frames video, 25 frames (50 fields) per second (25 frames i)
Code:
frame1 frame2 frame3 frame4 frame5 frame6 frame7 frame8 Code:
frame1 frame2 frame3 frame4 frame5 frame6 frame7 frame8 |
Yes QTGMC in the default setting doubles the frame rate but it uses complex math to achieve that it doesn't just repeat the fields. But when you encode to h.264 the size will go down, I personally get about 5-10 GB an hour files in 4:2:2 h.264 and 192 kbps stereo audio, Way better than DV and DVD in quality. And I keep the HuffYUV interlaced captures as master files not the de-interlaced ones.
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Don't use preset=slow. It blurs. The NR is too aggressive.
Do faster. If anything looks odd, do medium. If anything still odd, do manual switches, not a preset. The file size of the output file it is indeed 2x when you retain all fields. But when compressing, it goes down. The primary compressor here is not actually bitrate, but the GOP. If you get 1.5x, you're fine. If you get 1.25x, you're aggressive. If you have 1:1, then you overcompressed. Fields are 50% frames, but temporally offset. When you create frames from fields, data is duplicated. While you do get some movement frames, you also get a lot of outright duped frames. This is why deinterlacing back to 25fps/29.97fps is not "losing data". Not really. It's just not inventing new data. Both ways are fake, whether 50/59.94 or 25/29.97. Adding data has bad side effects at times. It's not a simple process. I've had to just dump even/odd fields before, due to either excessive work, or outright refusal to deinterlace well. Very often, it was a choice between 50/60 Yadif (some aliasing), or 25/30 QTGMC (no aliasing). Tough choices. |
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