[FFmpeg-user] DV to bob deinterlaced HEVC

Matti Haveri matti.haveri at gmail.com
Thu Nov 12 21:10:51 EET 2020

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


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

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