linux-kernel - Re: [PATCH v1 06/24] media: v4l2: Trace calculated p/b0/b1 initial reflist

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Date:   Tue, 29 Mar 2022 17:08:00 +0200
From:   Sebastian Fricke <sebastian.fricke@...labora.com>
To:     Nicolas Dufresne <nicolas.dufresne@...labora.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>, kernel@...labora.com,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 06/24] media: v4l2: Trace calculated p/b0/b1 initial
 reflist

Hey Nicolas,

On 28.03.2022 15:59, Nicolas Dufresne wrote:
>This is crucial in verifying that the ordering is right, specially with
>more complex sorting needed for field decoding.

How about:

"""
Add debug print statements to print the content of P & B reference
lists, to verify that the ordering of the generated reference lists is
correct. This is escpecially important for the field decoding mode,
where sorting is more complex.
"""

>
>Signed-off-by: Nicolas Dufresne <nicolas.dufresne@...labora.com>
Tested-by: Sebastian Fricke <sebastian.fricke@...labora.com>
Reviewed-by: Sebastian Fricke <sebastian.fricke@...labora.com>

Greetings,
Sebastian

>---
> drivers/media/v4l2-core/v4l2-h264.c | 86 +++++++++++++++++++++++++++++
> 1 file changed, 86 insertions(+)
>
>diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c
>index d5698c981973..c9e18fd51d78 100644
>--- a/drivers/media/v4l2-core/v4l2-h264.c
>+++ b/drivers/media/v4l2-core/v4l2-h264.c
>@@ -241,6 +241,87 @@ static int v4l2_h264_b1_ref_list_cmp(const void *ptra, const void *ptrb,
> 	return poca < pocb ? -1 : 1;
> }
>
>+static char ref_type_to_char (u8 ref_type)
>+{
>+	switch (ref_type) {
>+	case V4L2_H264_FRAME_REF:
>+		return 'f';
>+	case V4L2_H264_TOP_FIELD_REF:
>+		return 't';
>+	case V4L2_H264_BOTTOM_FIELD_REF:
>+		return 'b';
>+	}
>+
>+	return '?';
>+}
>+
>+static const char *format_ref_list_p(const struct v4l2_h264_reflist_builder *builder,
>+				     struct v4l2_h264_reference *reflist,
>+				     char *out_str, const int len)
>+{
>+	int n = 0, i;
>+
>+	n += snprintf(out_str + n, len - n, "|");
>+
>+	for (i = 0; i < builder->num_valid; i++) {
>+		/* this is pic_num for frame and frame_num (wrapped) for field,
>+		 * but for frame pic_num is equal to frame_num (wrapped).
>+		 */
>+		int frame_num = builder->refs[reflist[i].index].frame_num;
>+		bool longterm = builder->refs[reflist[i].index].longterm;
>+
>+		n += scnprintf(out_str + n, len - n, "%i%c%c|",
>+			       frame_num, longterm ? 'l' : 's',
>+			       ref_type_to_char (reflist[i].fields));
>+	}
>+
>+	return out_str;
>+}
>+
>+static void print_ref_list_p(const struct v4l2_h264_reflist_builder *builder,
>+			     struct v4l2_h264_reference *reflist)
>+{
>+	char buf[1024];
>+
>+	pr_debug("ref_pic_list_p (cur_poc %u%c) %s\n",
>+		 builder->cur_pic_order_count,
>+		 ref_type_to_char(builder->cur_pic_fields),
>+		 format_ref_list_p(builder, reflist, buf, sizeof(buf)));
>+}
>+
>+static const char *format_ref_list_b(const struct v4l2_h264_reflist_builder *builder,
>+				     struct v4l2_h264_reference *reflist,
>+				     char *out_str, const int len)
>+{
>+	int n = 0, i;
>+
>+	n += snprintf(out_str + n, len - n, "|");
>+
>+	for (i = 0; i < builder->num_valid; i++) {
>+		int frame_num = builder->refs[reflist[i].index].frame_num;
>+		u32 poc = v4l2_h264_get_poc(builder, reflist + i);
>+		bool longterm = builder->refs[reflist[i].index].longterm;
>+
>+		n += scnprintf(out_str + n, len - n, "%i%c%c|",
>+			       longterm ? frame_num : poc,
>+			       longterm ? 'l' : 's',
>+			       ref_type_to_char(reflist[i].fields));
>+	}
>+
>+	return out_str;
>+}
>+
>+static void print_ref_list_b(const struct v4l2_h264_reflist_builder *builder,
>+			     struct v4l2_h264_reference *reflist, u8 list_num)
>+{
>+	char buf[1024];
>+
>+	pr_debug("ref_pic_list_b%u (cur_poc %u%c) %s",
>+		 list_num, builder->cur_pic_order_count,
>+		 ref_type_to_char (builder->cur_pic_fields),
>+		 format_ref_list_b(builder, reflist, buf, sizeof(buf)));
>+}
>+
> /**
>  * v4l2_h264_build_p_ref_list() - Build the P reference list
>  *
>@@ -261,6 +342,8 @@ v4l2_h264_build_p_ref_list(const struct v4l2_h264_reflist_builder *builder,
> 	       sizeof(builder->unordered_reflist[0]) * builder->num_valid);
> 	sort_r(reflist, builder->num_valid, sizeof(*reflist),
> 	       v4l2_h264_p_ref_list_cmp, NULL, builder);
>+
>+	print_ref_list_p(builder, reflist);
> }
> EXPORT_SYMBOL_GPL(v4l2_h264_build_p_ref_list);
>
>@@ -296,6 +379,9 @@ v4l2_h264_build_b_ref_lists(const struct v4l2_h264_reflist_builder *builder,
> 	if (builder->num_valid > 1 &&
> 	    !memcmp(b1_reflist, b0_reflist, builder->num_valid))
> 		swap(b1_reflist[0], b1_reflist[1]);
>+
>+	print_ref_list_b(builder, b0_reflist, 0);
>+	print_ref_list_b(builder, b1_reflist, 1);
> }
> EXPORT_SYMBOL_GPL(v4l2_h264_build_b_ref_lists);
>
>-- 
>2.34.1
>