From: Philipp Zabel <p.zabel@pengutronix.de>
To: Steve Longerbeam <slongerbeam@gmail.com>, linux-media@vger.kernel.org
Cc: Tim Harvey <tharvey@gateworks.com>,
"open list:DRM DRIVERS FOR FREESCALE IMX"
<dri-devel@lists.freedesktop.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 1/4] gpu: ipu-v3: ipu-ic: Rename yuv2rgb encoding matrices
Date: Mon, 11 Feb 2019 10:58:37 +0100 [thread overview]
Message-ID: <1549879117.7687.2.camel@pengutronix.de> (raw)
In-Reply-To: <20190209014748.10427-2-slongerbeam@gmail.com>
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 <slongerbeam@gmail.com>
> ---
> 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
next prev parent reply other threads:[~2019-02-11 9:58 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-09 1:47 [PATCH v4 0/4] media: imx: Add support for BT.709 encoding Steve Longerbeam
2019-02-09 1:47 ` [PATCH v4 1/4] gpu: ipu-v3: ipu-ic: Rename yuv2rgb encoding matrices Steve Longerbeam
2019-02-11 9:58 ` Philipp Zabel [this message]
2019-02-11 18:24 ` Steve Longerbeam
2019-02-12 10:17 ` Philipp Zabel
2019-02-12 17:42 ` Steve Longerbeam
2019-02-13 10:35 ` Philipp Zabel
2019-02-14 18:54 ` Steve Longerbeam
2019-02-11 23:33 ` Steve Longerbeam
2019-02-09 1:47 ` [PATCH v4 2/4] gpu: ipu-v3: ipu-ic: Simplify selection of encoding matrix Steve Longerbeam
2019-02-11 10:00 ` Philipp Zabel
2019-02-09 1:47 ` [PATCH v4 3/4] gpu: ipu-v3: ipu-ic: Add support for BT.709 encoding Steve Longerbeam
2019-02-11 10:12 ` Philipp Zabel
2019-02-12 1:20 ` Steve Longerbeam
2019-02-12 11:34 ` Philipp Zabel
2019-02-12 17:50 ` Steve Longerbeam
2019-02-09 1:47 ` [PATCH v4 4/4] media: imx: Allow BT.709 encoding for IC routes Steve Longerbeam
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