[FFmpeg-user] a -vf for broadcast safe

Carl Eugen Hoyos cehoyos at ag.or.at
Wed Dec 30 19:40:19 CET 2015


Dave Rice <dave <at> dericed.com> writes:

> Responding late, as I find myself in need of this 
> filter as well.

Instead, please explain your real-world reason why 
you need the filter:
Do you have input that does not conform to broadcast?
What does other "professional" software do with that 
input?
Or does FFmpeg take input that conforms and produces 
output that does not conform? In this case you have 
(likely) found a bug that we should try to fix...

> A sample that needs the filter can be generated via:
> 
> ffmpeg -f lavfi -i color=gray:s=256x256 
> -vf format=yuv444p,geq=lum=X,scale=out_range=tv

You created a formula that does not produce 
tv range as output (as indicated by the pix_fmt) 
but jpeg range. The scaler cannot know this, you 
have to tell it:
-vf format=yuv444p,geq=lum=X,scale=in_range=jpeg:out_range=tv

> ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers

For future questions, please understand that only 
current FFmpeg git head is supported on this 
mailing list.

>   built with Apple LLVM version 7.0.2 (clang-700.1.81)
>   configuration: --prefix=/usr/local/Cellar/ffmpeg/2.8.4 
> --enable-shared 

> --enable-pthreads --enable-ffplay --enable-vda

These have no effect, please remove them.

> --enable-gpl --enable-version3 --enable-hardcoded-tables 

> --enable-avresample --cc=clang

These should not be needed.

> --host-cflags= --host-ldflags= 

These just make reading the configure line more difficult.

> --enable-opencl --enable-libx264 --enable-libmp3lame

> --enable-libvo-aacenc

This was never useful together with libfaac and is now 
obsolete. (No runtime warning possible!)

> --enable-libxvid

This was never needed.

Carl Eugen



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