From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: Re: [PATCH v4 1/4] gpu: ipu-v3: ipu-ic: Rename yuv2rgb encoding matrices Date: Mon, 11 Feb 2019 10:58:37 +0100 Message-ID: <1549879117.7687.2.camel@pengutronix.de> References: <20190209014748.10427-1-slongerbeam@gmail.com> <20190209014748.10427-2-slongerbeam@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190209014748.10427-2-slongerbeam@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Steve Longerbeam , linux-media@vger.kernel.org Cc: Tim Harvey , "open list:DRM DRIVERS FOR FREESCALE IMX" , open list List-Id: dri-devel@lists.freedesktop.org On Fri, 2019-02-08 at 17:47 -0800, Steve Longerbeam wrote: > The ycbcr2rgb and inverse rgb2ycbcr matrices define the BT.601 encoding > coefficients, so rename them to indicate that. And add some comments > to make clear these are BT.601 coefficients encoding between YUV limited > range and RGB full range. The ic_csc_rgb2rgb matrix is just an identity > matrix, so rename to ic_csc_identity. No functional changes. > > Signed-off-by: Steve Longerbeam > --- > Changes in v2: > - rename ic_csc_rgb2rgb matrix to ic_csc_identity. > --- > drivers/gpu/ipu-v3/ipu-ic.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/ipu-v3/ipu-ic.c b/drivers/gpu/ipu-v3/ipu-ic.c > index 594c3cbc8291..3ef61f0b509b 100644 > --- a/drivers/gpu/ipu-v3/ipu-ic.c > +++ b/drivers/gpu/ipu-v3/ipu-ic.c > @@ -183,11 +183,13 @@ struct ic_csc_params { > }; > > /* > + * BT.601 encoding from RGB full range to YUV limited range: > + * > * Y = R * .299 + G * .587 + B * .114; > * U = R * -.169 + G * -.332 + B * .500 + 128.; > * V = R * .500 + G * -.419 + B * -.0813 + 128.; Hm, this is a conversion to full range BT.601. For limited range, the matrix coefficients 0.2990  0.5870  0.1140 -0.1687 -0.3313  0.5000 0.5000 -0.4187 -0.0813 should be multiplied with 219/255 (Y) and 224/255 (U,V), respectively: Y = R * .2568 + G * .5041 + B * .0979 + 16; U = R * -.1482 + G * -.2910 + B *  .4392 + 128; V = R * .4392 + G * -.3678 + B * -.0714 + 128; > */ > -static const struct ic_csc_params ic_csc_rgb2ycbcr = { > +static const struct ic_csc_params ic_csc_rgb2ycbcr_bt601 = { > .coeff = { > { 77, 150, 29 }, > { 469, 427, 128 }, > @@ -197,8 +199,11 @@ static const struct ic_csc_params ic_csc_rgb2ycbcr = { > .scale = 1, > }; > > -/* transparent RGB->RGB matrix for graphics combining */ > -static const struct ic_csc_params ic_csc_rgb2rgb = { > +/* > + * identity matrix, used for transparent RGB->RGB graphics > + * combining. > + */ > +static const struct ic_csc_params ic_csc_identity = { > .coeff = { > { 128, 0, 0 }, > { 0, 128, 0 }, > @@ -208,11 +213,13 @@ static const struct ic_csc_params ic_csc_rgb2rgb = { > }; > > /* > + * Inverse BT.601 encoding from YUV limited range to RGB full range: > + * > * R = (1.164 * (Y - 16)) + (1.596 * (Cr - 128)); > * G = (1.164 * (Y - 16)) - (0.392 * (Cb - 128)) - (0.813 * (Cr - 128)); > * B = (1.164 * (Y - 16)) + (2.017 * (Cb - 128); > */ This looks correct. > -static const struct ic_csc_params ic_csc_ycbcr2rgb = { > +static const struct ic_csc_params ic_csc_ycbcr2rgb_bt601 = { > .coeff = { > { 149, 0, 204 }, > { 149, 462, 408 }, > @@ -238,11 +245,11 @@ static int init_csc(struct ipu_ic *ic, > (priv->tpmem_base + ic->reg->tpmem_csc[csc_index]); > > if (inf == IPUV3_COLORSPACE_YUV && outf == IPUV3_COLORSPACE_RGB) > - params = &ic_csc_ycbcr2rgb; > + params = &ic_csc_ycbcr2rgb_bt601; > else if (inf == IPUV3_COLORSPACE_RGB && outf == IPUV3_COLORSPACE_YUV) > - params = &ic_csc_rgb2ycbcr; > + params = &ic_csc_rgb2ycbcr_bt601; > else if (inf == IPUV3_COLORSPACE_RGB && outf == IPUV3_COLORSPACE_RGB) > - params = &ic_csc_rgb2rgb; > + params = &ic_csc_identity; > else { > dev_err(priv->ipu->dev, "Unsupported color space conversion\n"); > return -EINVAL; regards Philipp