[FFmpeg-user] DV to bob deinterlaced HEVC

Mark Filipak (ffmpeg) markfilipak at bog.us
Fri Nov 13 01:27:58 EET 2020

On 11/12/2020 02:10 PM, Matti Haveri wrote:
> My current plan to convert 4:3 PAL .dv to HEVC as a batch:
> for i in *.dv; do ffmpeg -i "$i"
> -vf bwdif=1,scale=788:576,crop=768:576:10:0,setsar=sar=1/1
> -c:v libx265 -crf 18 -preset slow -tag:v hvc1
> -c:a aac -b:a 128k "${i%.*}_converted.mp4"; done
> In my tests bwdif has less artifacts than yadif.
> I guess it is better to deinterlace first, then scale?
> 4:3 PAL .dv 720x576 (PAR 128/117) to square pixels:
> a) scale to 788x576 then crop to 768x576 or:
> b) crop to 702x576 then scale to 768x576
> http://web.archive.org/web/20140218044518/http://lipas.uwasa.fi/~f76998/video/conversion/
> I chose to scale, then crop because the different order
> 'crop=702:576:9:0,scale=768:576' produces the following alert
> (maybe this is just a cosmetic issue?):
> "[swscaler @ 0x1123e2000] Warning: data is not aligned!
> This can lead to a speed loss"
> I guess it doesn't matter in which order libx265 options -crf, -preset
> etc are?
> CRF 18-20(-22) seems like a sweet spot. CRF 24 or higher produce very
> ugly artifacts to noisy parts of the footage.
> There seems to be not much or any difference in quality between
> -preset slow vs medium.
> 25fps vs 50fps difference is there but not so great as I expected.
> - Matti
Do some research, Matti. If the PAL DVD is a movie, note its running time and compare to an NTSC DVD 
or Blu-ray running time. If the PAL DVD running time is 4% fast, then the video is actually p24. For 
movies, that's almost always the case. If so, try forcing 24FPS and let me know how it goes. If the 
video is okay (and it probably will be), then you will need to extract the audio, subs, and chapters 
separately, stretch them by 25/24, and merge them with the video -- you could try mkvmerge (or 
MKVToolNixGUI). Again, let me know how it goes.


11 Nov 2020 -- early in the pandemic.
Yesterday's new cases, China: 17, S.Korea: 146, U.S.: 142,906.
Yesterday's new deaths, China: 0, S.Korea: 2, U.S.: 1,479.
Today, U.S.: 4% of world population, 20% of cases, 19% of deaths.
Today, U.S. mortality: Of 7,143,501 resolved cases, 4% are dead.
Today, U.S. dead, pandemic: 247,398 (9 mo.), WWII: 419,000 (47 mo.).
Today, U.S. total cases: 3.2%. To reach herd immunity: at least 60%.
2021+ (no vaccine), U.S. reaches herd immunity, 8-million U.S. dead.
22 Jan: U.S. & S.Korea report 1st cases on the same day.
  6 Mar, testing to date, S.Korea: 140,000, U.S.: 2000.
  6 Mar, test results, S.Korea: 4 hours, U.S.: 1 to 2 weeks.
  1 Jun, total care-home deaths, S.Korea: 0, U.S.: 33,000 +/- 7,000.
  5 Aug, U.S. testing: only 1/4 of number needed; 4 day results.
  1 Sep, Nursing Assoc report: Over 60% of U.S. nurses lack PPE.
18 Sep, U.S. doctors & nurses still acutely lack PPE; 1200 dead.
15 Oct, projected GDP, China: up 1.9%, U.S.: down 3.6%.
19 Oct, CDC report: U.S. test results still take 3 days, average.

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