From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Longerbeam Subject: Re: [PATCH v4 1/4] gpu: ipu-v3: ipu-ic: Rename yuv2rgb encoding matrices Date: Mon, 11 Feb 2019 15:33:20 -0800 Message-ID: <8a3a9c63-d466-e328-d49a-1810952d2e9a@gmail.com> References: <20190209014748.10427-1-slongerbeam@gmail.com> <20190209014748.10427-2-slongerbeam@gmail.com> <1549879117.7687.2.camel@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1549879117.7687.2.camel@pengutronix.de> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Philipp Zabel , 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 2/11/19 1:58 AM, Philipp Zabel wrote: > 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. Agreed, the coefficients in the comments are correct, but the actual table values were a bit off. I will correct them for v5 (Green offset should be 272 in the table, not 266). Steve > >> -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