[FFmpeg-user] DOWN CONVERSION ISSUE: From MXF (1080i AVC Intra) - MBAFF "interlacing" to DVCPRO

[Dave Bevan]

-----Original Message-----
From: ffmpeg-user-bounces at ffmpeg.org
[mailto:ffmpeg-user-bounces at ffmpeg.org] On Behalf Of Tim Nicholson
Sent: 26 March 2012 08:44
To: FFmpeg user questions and RTFMs
Subject: Re: [FFmpeg-user] DOWN CONVERSION ISSUE: From MXF (1080i AVC
Intra) - MBAFF "interlacing" to DVCPRO

On 25/03/12 15:43, Iban Garcia wrote:
> Hi,
> 
> I have taken from git the last version of ffmpeg. And I have made next

> test. The output.dv fields are not interlaced. The interlaced 
> information has been lost in the process.
> 
> # ffmpeg -y -threads 8 -i input.mxf -s 720x576 -pix_fmt yuv411p 
> -aspect
> 16:9 -an -r 25 -vf "setfield=1, fieldorder=bff" output.dv

> [..]

> sws_param:
> [fieldorder @ 0x646e80] output field order: bff [scale @ 0x6283a0] 
> w:1920 h:1080 fmt:yuv422p10le sar:1/1 -> w:720 h:576 fmt:yuv411p 
> sar:64/45 flags:0x4
> 

As your source is HD and you wish to output SD, you should really scale
the material properly using the "scale" filter with interlacing turned
on.

Something like:-

ffmpeg -y -threads 8 -i input.mxf \
-vf "setfield=1, scale=720:576:1, fieldorder=bff" \ -pix_fmt yuv411p
-aspect 16:9 -an -r 25 output.dv


------------------------------------------------------------------------
-------------------------
And you should also ensure you change colourspace too - HD is bt709
whereas SD is bt601. Add this to Tim's filter chain:

,colormatrix=bt709:bt601

--Dave.
------------------------------------------------------------------------
-------------------------



--
Tim
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