[FFmpeg-devel] [PATCH] smptebars filter

[Stefano Sabatini]

On date Wednesday 2012-06-20 16:48:37 +0000, Paul B Mahol encoded:
> On 6/20/12, Tim Nicholson <nichot20 at yahoo.com> wrote:
> > On 20/06/12 09:19, Thierry Foucu wrote:
> >> On Wed, Jun 20, 2012 at 9:54 AM, Paul B Mahol <onemda at gmail.com> wrote:
> >>
> >>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> >>> ---
> >>>  doc/filters.texi             |   20 ++++
> >>>  libavfilter/Makefile         |    1 +
> >>>  libavfilter/allfilters.c     |    1 +
> >>>  libavfilter/vsrc_smptebars.c |  215
> >>> ++++++++++++++++++++++++++++++++++++++++++
> >>>  4 files changed, 237 insertions(+), 0 deletions(-)
> >>>  create mode 100644 libavfilter/vsrc_smptebars.c
> >>>
> >>> diff --git a/doc/filters.texi b/doc/filters.texi
> >>> index 566fbfc..0c0c490 100644
> >>> --- a/doc/filters.texi
> >>> +++ b/doc/filters.texi
> >>> @@ -3799,6 +3799,26 @@ the @code{mp=geq} filter:
> >>>  nullsrc=s=256x256, mp=geq=random(1)*255:128:128
> >>>  @end example
> >>>
> >>> + at section smptebars
> >>> +
> >>> +Generate SMPTE color bars.
> >>>
> >>
> >>
> >> Am i correct to assume that this SMPTE color bar is the SD version.
> >>
> >> For HD, I though to remember the SMPTE color bar is different.
> >> see http://en.wikipedia.org/wiki/File:SMPTE_Color_Bars_16x9.svg
> >>
> >> If so, should we not call this one SMPTE_SD? or add both into the same
> >> filter?
> >>
> >>
> >
> > I think bars should be in the correct format for the colorspace intended
> > with true black at RGB 16  units and true white at 235. (Those are the
> > European figures I guess they may differ for 525/60 standards)
> 
> Colors (rainbow and wobnair) are exactly as generated by y4mcolorbars.
> 
> Other colors like mentioned in comments are just made up and can not
> be really reproduced in RGB or YUV(J) colorspace.
> 
> Also drawutils only supports RGB color input.
> 
> >
> > ISTR that the blackest black on SMPTE bars is actually 2% below true
> > black in order to test for black clipping, but that true back on NTSC
> > was 5% up on true black in PAL back in the analogue days....
> >
> > As for HD bars being different, they certainly look different in HD on a
> > waveform monitor, but the different colorspace matrix will do that for
> > you. I'm not aware of the actual generated RGB levels being different,
> > but again this may be different outside of Europe...
> >
> > Time to dig out the specs again....

Updated (against a few patches which still need to be applied), but
you get the idea.
-- 
FFmpeg = Formidable & Fancy Moronic Peaceful Ecumenical Gem
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