[FFmpeg-user] Video filtering for chroma dot crawl and rainbow effect

Andy Furniss adf.lists at gmail.com
Tue Jan 26 01:07:50 CET 2016

Andy Furniss wrote:
> Andy Furniss wrote:
>> Carl Eugen Hoyos wrote:
>>> Christian Johannesen <chrisjohannesen <at> gmail.com> writes:
>>>> ffmpeg.exe  -r 30000/1001 -i
>>>> D:\media\test_720x486i_dotcrawl.mov
>>> Please remove the input option -r unless you know exactly what
>>> you are doing.
>>>> -filter_complex [0:0]crop=704:480:8:6,pullup
>> Input on ticket is 4:2:0 and you can't crop vertically interlaced
>> 4:2:0 by 6 without messing up the chroma. AFAIK you need to crop 4
>> lines at a time.
>> Maybe you could crop 6 if you converted (interlace aware) to 4:2:2
>> crop and then interlace aware back to 4:2:0 (untested!).
> Hmm, after looking at the trac sample I think the chroma has already
> been scaled progressive = broken sample.
> I may be wrong! only looked quickly.

Looked again and I still think the "master" is broken. As noted in the
track it's size may be an issue by its self (as 420 interlaced would
normally be divisible by 4).

Ignoring that it seems that it has been converted/generated incorrectly
for 420 interlaced. The chroma has bled between the fields so even
something simple like yadif=1 alone produces corrupt output.

If you don't have access to better/"real" masters I don't think you can
get good results from this.

What produced this file with height 486?

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