Re: [PATCH v2 1/4] [media] exynos-gsc: Use 576p instead 720p as a threshold for colorspaces
On 02/10/2017 08:38 PM, Russell King - ARM Linux wrote: > On Thu, Feb 09, 2017 at 05:04:17PM -0300, Thibault Saunier wrote: >> From: Javier Martinez Canillas >> >> The media documentation says that the V4L2_COLORSPACE_SMPTE170M colorspace >> should be used for SDTV and V4L2_COLORSPACE_REC709 for HDTV. But drivers >> don't agree on the display resolution that should be used as a threshold. >> >> Some drivers set V4L2_COLORSPACE_REC709 for 720p and higher while others >> set V4L2_COLORSPACE_REC709 for anything higher than 576p. Newers drivers >> use the latter and that also matches what user-space multimedia programs >> do (i.e: GStreamer), so change the driver logic to be aligned with this. >> >> Also, check for the resolution in G_FMT instead unconditionally setting >> the V4L2_COLORSPACE_REC709 colorspace. > > It would be nice to refer to some specification to justify the change, > rather than "let's follow what does". > > EIA CEA 861B talks about colorimetry for various resolutions: > > 5.1 480p, 480i, 576p, 576i, 240p, and 288p > The color space used by the 480-line, 576-line, 240-line, and 288-line > formats will likely be based on SMPTE 170M [1]. > > 5.2 1080i, 1080p, and 720p > The color space used by the high definition formats will likely be based > on ITU-R BT.709-4 [6]. > > Notice, however, that it says "will likely be" - it's not a requirement, > as it's expected that the colorspace will be part of the media metadata > (eg, contained in the transport stream.) In other words, it should be > configurable or ultimately provided by the ultimate source of the image. Colorspace information is transmitted as part of HDMI/DisplayPort meta-information (AVI InfoFrames, see CEA/CTA 861). Compressed video typically encodes the colorspace information as well. SDTV never had metainformation and you should fall back to SMPTE170M. Webcams/sensors should give sRGB unless otherwise indicated. If it is a sensor that expects further processing, then COLORSPACE_RAW can be used. Anything else is typically sRGB. Note that sRGB and SMPTE170M can be considered fall-back colorspaces in the absence of any other information. Regards, Hans
Re: [PATCH v2 1/4] [media] exynos-gsc: Use 576p instead 720p as a threshold for colorspaces
On Thu, Feb 09, 2017 at 05:04:17PM -0300, Thibault Saunier wrote: > From: Javier Martinez Canillas > > The media documentation says that the V4L2_COLORSPACE_SMPTE170M colorspace > should be used for SDTV and V4L2_COLORSPACE_REC709 for HDTV. But drivers > don't agree on the display resolution that should be used as a threshold. > > Some drivers set V4L2_COLORSPACE_REC709 for 720p and higher while others > set V4L2_COLORSPACE_REC709 for anything higher than 576p. Newers drivers > use the latter and that also matches what user-space multimedia programs > do (i.e: GStreamer), so change the driver logic to be aligned with this. > > Also, check for the resolution in G_FMT instead unconditionally setting > the V4L2_COLORSPACE_REC709 colorspace. It would be nice to refer to some specification to justify the change, rather than "let's follow what does". EIA CEA 861B talks about colorimetry for various resolutions: 5.1 480p, 480i, 576p, 576i, 240p, and 288p The color space used by the 480-line, 576-line, 240-line, and 288-line formats will likely be based on SMPTE 170M [1]. 5.2 1080i, 1080p, and 720p The color space used by the high definition formats will likely be based on ITU-R BT.709-4 [6]. Notice, however, that it says "will likely be" - it's not a requirement, as it's expected that the colorspace will be part of the media metadata (eg, contained in the transport stream.) In other words, it should be configurable or ultimately provided by the ultimate source of the image. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 1/4] [media] exynos-gsc: Use 576p instead 720p as a threshold for colorspaces
On 09.02.2017 21:04, Thibault Saunier wrote:
> From: Javier Martinez Canillas
>
> The media documentation says that the V4L2_COLORSPACE_SMPTE170M colorspace
> should be used for SDTV and V4L2_COLORSPACE_REC709 for HDTV. But drivers
> don't agree on the display resolution that should be used as a threshold.
>
> Some drivers set V4L2_COLORSPACE_REC709 for 720p and higher while others
> set V4L2_COLORSPACE_REC709 for anything higher than 576p. Newers drivers
> use the latter and that also matches what user-space multimedia programs
> do (i.e: GStreamer), so change the driver logic to be aligned with this.
>
> Also, check for the resolution in G_FMT instead unconditionally setting
> the V4L2_COLORSPACE_REC709 colorspace.
>
> Signed-off-by: Javier Martinez Canillas
Reviewed-by: Andrzej Hajda
--
Regards
Andrzej
> ---
> drivers/media/platform/exynos-gsc/gsc-core.c | 7 +--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c
> b/drivers/media/platform/exynos-gsc/gsc-core.c
> index cbb03768f5d7..2beb43401987 100644
> --- a/drivers/media/platform/exynos-gsc/gsc-core.c
> +++ b/drivers/media/platform/exynos-gsc/gsc-core.c
> @@ -445,7 +445,7 @@ int gsc_try_fmt_mplane(struct gsc_ctx *ctx, struct
> v4l2_format *f)
>
> pix_mp->num_planes = fmt->num_planes;
>
> - if (pix_mp->width >= 1280) /* HD */
> + if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
> pix_mp->colorspace = V4L2_COLORSPACE_REC709;
> else /* SD */
> pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
> @@ -492,7 +492,10 @@ int gsc_g_fmt_mplane(struct gsc_ctx *ctx, struct
> v4l2_format *f)
> pix_mp->height = frame->f_height;
> pix_mp->field = V4L2_FIELD_NONE;
> pix_mp->pixelformat = frame->fmt->pixelformat;
> - pix_mp->colorspace = V4L2_COLORSPACE_REC709;
> + if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
> + pix_mp->colorspace = V4L2_COLORSPACE_REC709;
> + else /* SD */
> + pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
> pix_mp->num_planes = frame->fmt->num_planes;
>
> for (i = 0; i < pix_mp->num_planes; ++i) {
--
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[PATCH v2 1/4] [media] exynos-gsc: Use 576p instead 720p as a threshold for colorspaces
From: Javier Martinez Canillas
The media documentation says that the V4L2_COLORSPACE_SMPTE170M colorspace
should be used for SDTV and V4L2_COLORSPACE_REC709 for HDTV. But drivers
don't agree on the display resolution that should be used as a threshold.
Some drivers set V4L2_COLORSPACE_REC709 for 720p and higher while others
set V4L2_COLORSPACE_REC709 for anything higher than 576p. Newers drivers
use the latter and that also matches what user-space multimedia programs
do (i.e: GStreamer), so change the driver logic to be aligned with this.
Also, check for the resolution in G_FMT instead unconditionally setting
the V4L2_COLORSPACE_REC709 colorspace.
Signed-off-by: Javier Martinez Canillas
---
drivers/media/platform/exynos-gsc/gsc-core.c | 7 +--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c
b/drivers/media/platform/exynos-gsc/gsc-core.c
index cbb03768f5d7..2beb43401987 100644
--- a/drivers/media/platform/exynos-gsc/gsc-core.c
+++ b/drivers/media/platform/exynos-gsc/gsc-core.c
@@ -445,7 +445,7 @@ int gsc_try_fmt_mplane(struct gsc_ctx *ctx, struct
v4l2_format *f)
pix_mp->num_planes = fmt->num_planes;
- if (pix_mp->width >= 1280) /* HD */
+ if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
pix_mp->colorspace = V4L2_COLORSPACE_REC709;
else /* SD */
pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
@@ -492,7 +492,10 @@ int gsc_g_fmt_mplane(struct gsc_ctx *ctx, struct
v4l2_format *f)
pix_mp->height = frame->f_height;
pix_mp->field = V4L2_FIELD_NONE;
pix_mp->pixelformat = frame->fmt->pixelformat;
- pix_mp->colorspace = V4L2_COLORSPACE_REC709;
+ if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
+ pix_mp->colorspace = V4L2_COLORSPACE_REC709;
+ else /* SD */
+ pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
pix_mp->num_planes = frame->fmt->num_planes;
for (i = 0; i < pix_mp->num_planes; ++i) {
--
2.11.1
--
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