diff mbox

[v4,1/4,media] exynos-gsc: Use 576p instead 720p as a threshold for colorspaces

Message ID 20170213190836.26972-2-thibault.saunier@osg.samsung.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Thibault Saunier Feb. 13, 2017, 7:08 p.m. UTC
From: Javier Martinez Canillas <javier@osg.samsung.com>

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.

From EIA CEA 861B 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

This indicates that in the case that userspace does not specify what
colorspace should be used, we should use 576p  as a threshold to set
V4L2_COLORSPACE_REC709 instead of V4L2_COLORSPACE_REC709. Even if it is
only 'likely' and not a requirement it is the best guess we can make.

The stream should have been encoded with the information and userspace
has to pass it to the driver if it is not the case, otherwise we won't be
able to handle it properly anyhow.

Also, check for the resolution in G_FMT instead unconditionally setting
the V4L2_COLORSPACE_REC709 colorspace.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Thibault Saunier <thibault.saunier@osg.samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>

---

Changes in v4:
- Reword commit message to better back our assumptions on specifications

Changes in v3:
- Do not check values in the g_fmt functions as Andrzej explained in previous review
- Added 'Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>'

Changes in v2: None

 drivers/media/platform/exynos-gsc/gsc-core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

Fabien DESSENNE Feb. 14, 2017, 3:19 p.m. UTC | #1
Hi Thibault


On 13/02/17 20:08, Thibault Saunier wrote:
> From: Javier Martinez Canillas <javier@osg.samsung.com>
>
> 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.
>
>  From EIA CEA 861B 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
>
> This indicates that in the case that userspace does not specify what
> colorspace should be used, we should use 576p  as a threshold to set
> V4L2_COLORSPACE_REC709 instead of V4L2_COLORSPACE_REC709. Even if it is

typo -> "V4L2_COLORSPACE_REC709 instead of V4L2_COLORSPACE_SMPTE170M"


> only 'likely' and not a requirement it is the best guess we can make.
>
> The stream should have been encoded with the information and userspace
> has to pass it to the driver if it is not the case, otherwise we won't be
> able to handle it properly anyhow.
>
> Also, check for the resolution in G_FMT instead unconditionally setting
> the V4L2_COLORSPACE_REC709 colorspace.
>
> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
> Signed-off-by: Thibault Saunier <thibault.saunier@osg.samsung.com>
> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
>
> ---
>
> Changes in v4:
> - Reword commit message to better back our assumptions on specifications
>
> Changes in v3:
> - Do not check values in the g_fmt functions as Andrzej explained in previous review
> - Added 'Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>'
>
> Changes in v2: None
>
>   drivers/media/platform/exynos-gsc/gsc-core.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
> index 59a634201830..db7d9883861b 100644
> --- a/drivers/media/platform/exynos-gsc/gsc-core.c
> +++ b/drivers/media/platform/exynos-gsc/gsc-core.c
> @@ -472,7 +472,7 @@ 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;
> @@ -519,9 +519,13 @@ 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;
>   	pix_mp->num_planes	= frame->fmt->num_planes;
>   
> +	if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
> +		pix_mp->colorspace = V4L2_COLORSPACE_REC709;
> +	else /* SD */
> +		pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
> +
>   	for (i = 0; i < pix_mp->num_planes; ++i) {
>   		pix_mp->plane_fmt[i].bytesperline = (frame->f_width *
>   			frame->fmt->depth[i]) / 8;

BR
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Andrzej Hajda Feb. 21, 2017, 9:56 a.m. UTC | #2
On 13.02.2017 20:08, Thibault Saunier wrote:
> From: Javier Martinez Canillas <javier@osg.samsung.com>
>
> 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.
>
> >From EIA CEA 861B 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
>
> This indicates that in the case that userspace does not specify what
> colorspace should be used, we should use 576p  as a threshold to set
> V4L2_COLORSPACE_REC709 instead of V4L2_COLORSPACE_REC709. Even if it is
> only 'likely' and not a requirement it is the best guess we can make.
>
> The stream should have been encoded with the information and userspace
> has to pass it to the driver if it is not the case, otherwise we won't be
> able to handle it properly anyhow.
>
> Also, check for the resolution in G_FMT instead unconditionally setting
> the V4L2_COLORSPACE_REC709 colorspace.
>
> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
> Signed-off-by: Thibault Saunier <thibault.saunier@osg.samsung.com>
> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>

Hi Thibault,

Have you analyzed Hans response for the previous patchset [1] ?
I am not an expert in the subject but it seems he is right. GSCALER
datasheet uses term 'color space conversion' to describe conversions
between RGB and YCbCr, not for describe colorspaces as in V4L2.
GSC_(IN|OUT)_RGB_(HD|SD)_(WIDE|NARROW) macros used to set IN_CON and
OUT_CON registers of GSCALER are probably used incorrectly, they should
not be set according to pix_mp->colorspace but rather according to
pix_mp->ycbcr_enc and pix_mp->quantization. pix_mp->colorspace should be
just copied from output to capture side.

Please fix the patch accordingly, and if you are interested you can
prepare another patch to fix register setting.

[1]: https://lkml.org/lkml/2017/2/10/473

Regards
Andrzej

>
> ---
>
> Changes in v4:
> - Reword commit message to better back our assumptions on specifications
>
> Changes in v3:
> - Do not check values in the g_fmt functions as Andrzej explained in previous review
> - Added 'Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>'
>
> Changes in v2: None
>
>  drivers/media/platform/exynos-gsc/gsc-core.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
> index 59a634201830..db7d9883861b 100644
> --- a/drivers/media/platform/exynos-gsc/gsc-core.c
> +++ b/drivers/media/platform/exynos-gsc/gsc-core.c
> @@ -472,7 +472,7 @@ 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;
> @@ -519,9 +519,13 @@ 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;
>  	pix_mp->num_planes	= frame->fmt->num_planes;
>  
> +	if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
> +		pix_mp->colorspace = V4L2_COLORSPACE_REC709;
> +	else /* SD */
> +		pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
> +
>  	for (i = 0; i < pix_mp->num_planes; ++i) {
>  		pix_mp->plane_fmt[i].bytesperline = (frame->f_width *
>  			frame->fmt->depth[i]) / 8;


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Thibault Saunier Feb. 21, 2017, 6:04 p.m. UTC | #3
Hello Andrzej,

On 02/21/2017 06:56 AM, Andrzej Hajda wrote:
> On 13.02.2017 20:08, Thibault Saunier wrote:
>> From: Javier Martinez Canillas <javier@osg.samsung.com>
>>
>> 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.
>>
>> >From EIA CEA 861B 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
>>
>> This indicates that in the case that userspace does not specify what
>> colorspace should be used, we should use 576p  as a threshold to set
>> V4L2_COLORSPACE_REC709 instead of V4L2_COLORSPACE_REC709. Even if it is
>> only 'likely' and not a requirement it is the best guess we can make.
>>
>> The stream should have been encoded with the information and userspace
>> has to pass it to the driver if it is not the case, otherwise we won't be
>> able to handle it properly anyhow.
>>
>> Also, check for the resolution in G_FMT instead unconditionally setting
>> the V4L2_COLORSPACE_REC709 colorspace.
>>
>> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
>> Signed-off-by: Thibault Saunier <thibault.saunier@osg.samsung.com>
>> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
> Hi Thibault,
>
> Have you analyzed Hans response for the previous patchset [1] ?
> I am not an expert in the subject but it seems he is right. GSCALER
> datasheet uses term 'color space conversion' to describe conversions
> between RGB and YCbCr, not for describe colorspaces as in V4L2.
> GSC_(IN|OUT)_RGB_(HD|SD)_(WIDE|NARROW) macros used to set IN_CON and
> OUT_CON registers of GSCALER are probably used incorrectly, they should
> not be set according to pix_mp->colorspace but rather according to
> pix_mp->ycbcr_enc and pix_mp->quantization. pix_mp->colorspace should be
> just copied from output to capture side.
>
> Please fix the patch accordingly, and if you are interested you can
> prepare another patch to fix register setting.

OK, so what you describe here for the colorspace  is exactly what I am 
doing in my next patch right?
I am going to fixup them up as suggested in your other review.

I will also have a look at fixing register setting and figure out what 
you explained.

Thanks for the review.

Regards,

Thibault Saunier

> [1]: https://lkml.org/lkml/2017/2/10/473
>
> Regards
> Andrzej
>
>> ---
>>
>> Changes in v4:
>> - Reword commit message to better back our assumptions on specifications
>>
>> Changes in v3:
>> - Do not check values in the g_fmt functions as Andrzej explained in previous review
>> - Added 'Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>'
>>
>> Changes in v2: None
>>
>>   drivers/media/platform/exynos-gsc/gsc-core.c | 8 ++++++--
>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
>> index 59a634201830..db7d9883861b 100644
>> --- a/drivers/media/platform/exynos-gsc/gsc-core.c
>> +++ b/drivers/media/platform/exynos-gsc/gsc-core.c
>> @@ -472,7 +472,7 @@ 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;
>> @@ -519,9 +519,13 @@ 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;
>>   	pix_mp->num_planes	= frame->fmt->num_planes;
>>   
>> +	if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
>> +		pix_mp->colorspace = V4L2_COLORSPACE_REC709;
>> +	else /* SD */
>> +		pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
>> +
>>   	for (i = 0; i < pix_mp->num_planes; ++i) {
>>   		pix_mp->plane_fmt[i].bytesperline = (frame->f_width *
>>   			frame->fmt->depth[i]) / 8;
>

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diff mbox

Patch

diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
index 59a634201830..db7d9883861b 100644
--- a/drivers/media/platform/exynos-gsc/gsc-core.c
+++ b/drivers/media/platform/exynos-gsc/gsc-core.c
@@ -472,7 +472,7 @@  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;
@@ -519,9 +519,13 @@  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;
 	pix_mp->num_planes	= frame->fmt->num_planes;
 
+	if (pix_mp->width > 720 && pix_mp->height > 576) /* HD */
+		pix_mp->colorspace = V4L2_COLORSPACE_REC709;
+	else /* SD */
+		pix_mp->colorspace = V4L2_COLORSPACE_SMPTE170M;
+
 	for (i = 0; i < pix_mp->num_planes; ++i) {
 		pix_mp->plane_fmt[i].bytesperline = (frame->f_width *
 			frame->fmt->depth[i]) / 8;