Re: [FFmpeg-devel] [PATCH v2 4/4] swscale/output: add rgbaf32 output support

[Mark Reid <mindmark@gmail.com>]

On Wed, Nov 2, 2022 at 2:04 PM Michael Niedermayer <michael@niedermayer.cc>
wrote:

> On Sun, Oct 30, 2022 at 05:32:35PM -0700, mindmark@gmail.com wrote:
> > From: Mark Reid <mindmark@gmail.com>
> >
> > ---
> >  libswscale/output.c                      | 92 ++++++++++++++++++++++++
> >  libswscale/swscale_unscaled.c            |  4 +-
> >  libswscale/tests/floatimg_cmp.c          |  4 +-
> >  libswscale/utils.c                       | 16 +++--
> >  libswscale/yuv2rgb.c                     |  2 +
> >  tests/ref/fate/filter-pixdesc-rgbaf32be  |  1 +
> >  tests/ref/fate/filter-pixdesc-rgbaf32le  |  1 +
> >  tests/ref/fate/filter-pixdesc-rgbf32be   |  1 +
> >  tests/ref/fate/filter-pixdesc-rgbf32le   |  1 +
> >  tests/ref/fate/filter-pixfmts-copy       |  4 ++
> >  tests/ref/fate/filter-pixfmts-crop       |  4 ++
> >  tests/ref/fate/filter-pixfmts-field      |  4 ++
> >  tests/ref/fate/filter-pixfmts-fieldorder |  4 ++
> >  tests/ref/fate/filter-pixfmts-hflip      |  4 ++
> >  tests/ref/fate/filter-pixfmts-il         |  4 ++
> >  tests/ref/fate/filter-pixfmts-null       |  4 ++
> >  tests/ref/fate/filter-pixfmts-scale      |  4 ++
> >  tests/ref/fate/filter-pixfmts-transpose  |  4 ++
> >  tests/ref/fate/filter-pixfmts-vflip      |  4 ++
> >  tests/ref/fate/sws-floatimg-cmp          | 16 +++++
> >  20 files changed, 170 insertions(+), 8 deletions(-)
> >  create mode 100644 tests/ref/fate/filter-pixdesc-rgbaf32be
> >  create mode 100644 tests/ref/fate/filter-pixdesc-rgbaf32le
> >  create mode 100644 tests/ref/fate/filter-pixdesc-rgbf32be
> >  create mode 100644 tests/ref/fate/filter-pixdesc-rgbf32le
> >
> > diff --git a/libswscale/output.c b/libswscale/output.c
> > index 0e1c1225a0..e2ec9cbdf5 100644
> > --- a/libswscale/output.c
> > +++ b/libswscale/output.c
> > @@ -2474,6 +2474,92 @@ yuv2gbrpf32_full_X_c(SwsContext *c, const int16_t
> *lumFilter,
> >      }
> >  }
> >
> > +static void
> > +yuv2rgbaf32_full_X_c(SwsContext *c, const int16_t *lumFilter,
> > +                    const int16_t **lumSrcx, int lumFilterSize,
> > +                    const int16_t *chrFilter, const int16_t **chrUSrcx,
> > +                    const int16_t **chrVSrcx, int chrFilterSize,
> > +                    const int16_t **alpSrcx, uint8_t *dest,
> > +                    int dstW, int y)
> > +{
> > +    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->dstFormat);
> > +    int i;
> > +    int alpha = desc->flags & AV_PIX_FMT_FLAG_ALPHA;
> > +    int hasAlpha = alpha && alpSrcx;
> > +    int pixelStep = alpha ? 4 : 3;
> > +    uint32_t *dest32 = (uint32_t*)dest;
> > +    const int32_t **lumSrc  = (const int32_t**)lumSrcx;
> > +    const int32_t **chrUSrc = (const int32_t**)chrUSrcx;
> > +    const int32_t **chrVSrc = (const int32_t**)chrVSrcx;
> > +    const int32_t **alpSrc  = (const int32_t**)alpSrcx;
> > +    static const float float_mult = 1.0f / 65535.0f;
> > +    uint32_t a = av_float2int(1.0f);
> > +
> > +    for (i = 0; i < dstW; i++) {
> > +        int j;
> > +        int Y = -0x40000000;
> > +        int U = -(128 << 23);
> > +        int V = -(128 << 23);
> > +        int R, G, B, A;
> > +
> > +        for (j = 0; j < lumFilterSize; j++)
> > +            Y += lumSrc[j][i] * (unsigned)lumFilter[j];
> > +
> > +        for (j = 0; j < chrFilterSize; j++) {
> > +            U += chrUSrc[j][i] * (unsigned)chrFilter[j];
> > +            V += chrVSrc[j][i] * (unsigned)chrFilter[j];
> > +        }
> > +
> > +        Y >>= 14;
> > +        Y += 0x10000;
> > +        U >>= 14;
> > +        V >>= 14;
> > +
> > +        if (hasAlpha) {
> > +            A = -0x40000000;
> > +
> > +            for (j = 0; j < lumFilterSize; j++)
> > +                A += alpSrc[j][i] * (unsigned)lumFilter[j];
> > +
> > +            A >>= 1;
> > +            A += 0x20002000;
> > +            a = av_float2int(float_mult * (float)(av_clip_uintp2(A, 30)
> >> 14));
> > +        }
> > +
> > +        Y -= c->yuv2rgb_y_offset;
> > +        Y *= c->yuv2rgb_y_coeff;
> > +        Y += 1 << 13;
> > +        R = V * c->yuv2rgb_v2r_coeff;
> > +        G = V * c->yuv2rgb_v2g_coeff + U * c->yuv2rgb_u2g_coeff;
> > +        B =                            U * c->yuv2rgb_u2b_coeff;
> > +
>
> > +        R = av_clip_uintp2(Y + R, 30);
> > +        G = av_clip_uintp2(Y + G, 30);
> > +        B = av_clip_uintp2(Y + B, 30);
>
> these additions can overflow i think given sufficiently "bad" input
> especially with the bt2020 matrix
> ive posted a proposed solution for the rgba64 / gbrp16/32f cases
> something similar can be done here
>
> thx
>
>
Make sense. I'll take a look and submit a new version with the fix.
I also have some yuv to float16 patches coming that I will incorporate the
fix into too!


> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Opposition brings concord. Out of discord comes the fairest harmony.
> -- Heraclitus
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