[FFmpeg-devel] [RFC] Scalar color conversion utils (colorutils.[hc])?

[Michael Niedermayer]

On Sat, May 02, 2009 at 10:27:22AM +0200, Stefano Sabatini wrote:
> On date Saturday 2009-05-02 04:32:32 +0200, Michael Niedermayer encoded:
> > On Sat, May 02, 2009 at 12:48:11AM +0200, Stefano Sabatini wrote:
> [...]
> > > Attached stub, result of the test is:
> > > 
> > > Cannot find color 'foo'
> > > Cannot find color 'red'
> > > Cannot find color 'Red '
> > > Cannot find color 'RED'
> > > Red -> R(255) G(0) B(0)
> > > 0x000000 -> R(0) G(0) B(0)
> > > 0x3e34ff -> R(62) G(52) B(255)
> > > Invalid RGB color string: '0xfoobar'
> > > Invalid RGB color string: '0xffffeeeeeeee'
> > > 
> > > Conversion has to be implemented yet.
> > > 
> > > I wonder if the case-insensitive matching of the name is a feature
> > > worth to be implemented, but as far as I understood it would require a
> > > linear search as opposed to a binary search as currently implemented.
> > 
> > no
> 
> [...]
> > > +        rgb_color[3] = 255;
> > > +    } else {
> > > +        const ColorEntry *entry = NULL;
> > > +        entry = bsearch(color_string,
> > > +                        color_table,
> > > +                        FF_ARRAY_ELEMS(color_table),
> > > +                        sizeof(ColorEntry),
> > > +                        color_table_compare);
> > > +        if (!entry) {
> > > +            av_log(log_ctx, AV_LOG_DEBUG, "Cannot find color '%s'\n", color_string);
> > > +            return -1;
> > > +        }
> > > +        memcpy(rgb_color, entry->color, sizeof(*color) * 3);
> > > +    }
> > > +
> > > +    return av_convert_color(color,     dst_pix_fmt,   dst_colorspace,
> > > +                            rgb_color, PIX_FMT_RGB24, AV_COLORSPACE_RGB,
> > > +                            log_ctx);
> > 
> > i dont think it makes sense to mix color convert and color parse
> 
> That was to perform parsing and conversion in a single step. The
> alternative may be:
> 
> int av_parse_color(uint16_t *rgba_color, const char *color_string, void *log_ctx);
> 
> which would return an RGBA color, then the conversion may be done
> explicitely using:
> 
> av_convert_color(color,     dst_pix_fmt,   dst_colorspace,
>                  rgb_color, PIX_FMT_RGBA,  AV_COLORSPACE_RGB, log_ctx);
> 
> but I prefer the previous more flexible variant.

I think its better if we drop this patch then.

I will add the enum to AVCodecContext myself, the rest is currently not of
any relevance as it isnt and would not be used by anything. It requires lavfi
to be merged first ...

Once lavfi is merged this could be revissited but we surely wont combine
the string parsing with colorspace convertion because frankly that is
unflexible.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20090502/19ca1fe9/attachment.pgp>