[PATCH v3] gstreamer: Read correct colorimetry from caps into the stream configuration

[Laurent Pinchart]

Hi Hou,

Thank you for the patch.

On Tue, Dec 17, 2024 at 11:24:22AM +0900, Hou Qi wrote:
> When libcamerasrc is negotiating with downstream element, it first
> extracts colorimetry field from downstream supported caps, then set
> this colorimetry to its stream configuration and propagates the
> colorimetry downstream.
> 
> Currently libamerasrc only considers the case there is one colorimetry
> in colorimetry field of downstream caps. But the issue is that
> downstream caps may report a list of supported colorimetry, which
> causes libcamerasrc to set unknown colorimetry to stream configuration
> and negotiate fail with downstream element.
> 
> In order to fix the issue, need to fixate colorimetry field before
> getting colorimetry string.
> 
> Signed-off-by: Hou Qi <qi.hou at nxp.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  src/gstreamer/gstlibcamera-utils.cpp | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp
> index a466b305..7b34c759 100644
> --- a/src/gstreamer/gstlibcamera-utils.cpp
> +++ b/src/gstreamer/gstlibcamera-utils.cpp
> @@ -493,9 +493,12 @@ void gst_libcamera_configure_stream_from_caps(StreamConfiguration &stream_cfg,
>  
>  	/* Configure colorimetry */
>  	if (gst_structure_has_field(s, "colorimetry")) {
> -		const gchar *colorimetry_str = gst_structure_get_string(s, "colorimetry");
> +		const gchar *colorimetry_str;
>  		GstVideoColorimetry colorimetry;
>  
> +		gst_structure_fixate_field(s, "colorimetry");
> +		colorimetry_str = gst_structure_get_string(s, "colorimetry");
> +
>  		if (!gst_video_colorimetry_from_string(&colorimetry, colorimetry_str))
>  			g_critical("Invalid colorimetry %s", colorimetry_str);
>  

-- 
Regards,

Laurent Pinchart