FFmpeg croma ghost problem

[marcorocchini]

Hi ....

please download my source HD 1920x1080 interlaced 4:2:2

https://www.dropbox.com/s/829iziwuetpdqm4/source422.MXF?dl=0

I would like encode in MP4 4:2:0 using ffmpeg

ffmpeg -y -i source422.mxf -s 1920x1080 -vf scale=interl=1 -c:v libx264 -profile:v main -pix_fmt yuv420p -an HaveCromaGhost.MP4

but this output [attached] have a croma ghost problem artifacts on video or I mistake?

Please consider this second commandline:

ffmpeg -y -i source422.mxf  -vf scale=interl=1 -c:v libx264 -profile:v main -pix_fmt yuv420p -an OK.MP4

This output [attached] is correct, don't have croma ghost.

So I wonder: why using the -S 1920x1080 the

-vf scale=interl=1

parameter don't act?

Is there a way to keep the -S 1920x1080 but let act as right the

-vf scale=interl=1

? thanks

[sneaker]

Did you try
-vf scale=width=1920:height=1080:interl=1
?

[marcorocchini]

Did you try
-vf scale=width=1920:height=1080:interl=1
?

 
ffmpeg -y -i source422.mxf -s 1920x1080 -vf scale=width=1920:height=1080:interl=1 -c:v libx264 -profile:v main -pix_fmt yuv420p -an Test2.MP4

yes cat , but the croma ghost persist

if possible I would keep (for various reasons) the -s 1920x1080 line, so I wonder if there is a way to encode well keeping this line

[sneaker]

I assume these "various reasons" are beyond human understanding.

[marcorocchini]

Oh yes in fact there are some feline reasons

[poisondeathray]

1920x1080 => 1920x1080 is a no-opt ; nothing happens . If you changed the dimensions, then it would be bad and you need to use the other way with -vf scale

The problem here is -pix_fmt is using progressive scaling for 422=>420 (The dimensions of the chroma planes are being scaled in progressive fashion instead of interlaced). The solution is to move -pix_fmt to -vf scale using interl=1 to indicate interlaced 422=>420

I assume you want interlaced encoding (MBAFF) , TFF, flagged 709

ffmpeg -i source422.MXF -s 1920x1080 -vf scale=w=1920:h=1080:interl=1,format=pix_fmts=yuv420p -flags +ildct+ilme -c:v libx264 -x264opts tff=1:colorprim=bt709:transfer=bt709:colormatrix=bt709 -profile:v main -an IM_A_BAD_CAT.mp4

[sneaker]

1920x1080 => 1920x1080 is a no-opt

Oh, the source is 1080 already? I didn't read properly...

[marcorocchini]

1920x1080 => 1920x1080 is a no-opt ; nothing happens . If you changed the dimensions, then it would be bad and you need to use the other way with -vf scale

The problem here is -pix_fmt is using progressive scaling for 422=>420 (The dimensions of the chroma planes are being scaled in progressive fashion instead of interlaced). The solution is to move -pix_fmt to -vf scale using interl=1 to indicate interlaced 422=>420

I assume you want interlaced encoding (MBAFF) , TFF, flagged 709

ffmpeg -i source422.MXF -s 1920x1080 -vf scale=w=1920:h=1080:interl=1,format=pix_fmts=yuv420p -flags +ildct+ilme -c:v libx264 -x264opts tff=1:colorprim=bt709:transfer=bt709:colormatrix=bt709 -profile:v main -an IM_A_BAD_CAT.mp4

[Attachment 42274 - Click to enlarge]

it works well
thanks