From dba3bdd0cf68d7e441ee670281c1a6bf16715f88 Mon Sep 17 00:00:00 2001
From: Seungha Yang <seungha@centricular.com>
Date: Fri, 7 Mar 2025 01:09:23 +0900
Subject: [PATCH] h264ccextractor,h265ccextractor: Do not resend caps per
 output buffer

Send caps event only when it's required

Fixes: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/4281
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8596>
---
 .../ext/closedcaption/gsth264ccextractor.c       | 16 ++++++++++++++--
 .../ext/closedcaption/gsth265ccextractor.c       | 16 ++++++++++++++--
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/subprojects/gst-plugins-bad/ext/closedcaption/gsth264ccextractor.c b/subprojects/gst-plugins-bad/ext/closedcaption/gsth264ccextractor.c
index 17b44f7900..d7a57bc7a2 100644
--- a/subprojects/gst-plugins-bad/ext/closedcaption/gsth264ccextractor.c
+++ b/subprojects/gst-plugins-bad/ext/closedcaption/gsth264ccextractor.c
@@ -96,6 +96,7 @@ struct _GstH264CCExtractor
   gboolean on_eos;
   gint fps_n;
   gint fps_d;
+  gboolean need_negotiate;
 };
 
 #define gst_h264_cc_extractor_parent_class parent_class
@@ -199,6 +200,8 @@ gst_h264_cc_extractor_set_format (GstVideoDecoder * decoder,
   GstCaps *caps;
   gboolean ret;
 
+  self->need_negotiate = TRUE;
+
   /* Assume caption type is cea708 raw which is common cc type
    * embedded in SEI */
   if (self->caption_type == GST_VIDEO_CAPTION_TYPE_UNKNOWN)
@@ -225,7 +228,12 @@ static gboolean
 gst_h264_cc_extractor_negotiate (GstVideoDecoder * decoder)
 {
   GstH264CCExtractor *self = GST_H264_CC_EXTRACTOR (decoder);
-  GstCaps *caps = gst_video_caption_type_to_caps (self->caption_type);
+  GstCaps *caps;
+
+  if (!self->need_negotiate)
+    return TRUE;
+
+  caps = gst_video_caption_type_to_caps (self->caption_type);
 
   gst_caps_set_simple (caps,
       "framerate", GST_TYPE_FRACTION, self->fps_n, self->fps_d, NULL);
@@ -233,6 +241,8 @@ gst_h264_cc_extractor_negotiate (GstVideoDecoder * decoder)
   gst_pad_set_caps (decoder->srcpad, caps);
   gst_caps_unref (caps);
 
+  self->need_negotiate = FALSE;
+
   return TRUE;
 }
 
@@ -425,8 +435,10 @@ gst_h264_cc_extractor_output_picture (GstH264Decoder * decoder,
     }
   }
 
-  if (updated)
+  if (updated) {
+    self->need_negotiate = TRUE;
     gst_video_decoder_negotiate (videodec);
+  }
 
   gst_h264_picture_unref (picture);
 
diff --git a/subprojects/gst-plugins-bad/ext/closedcaption/gsth265ccextractor.c b/subprojects/gst-plugins-bad/ext/closedcaption/gsth265ccextractor.c
index 9a0dc90020..054101e009 100644
--- a/subprojects/gst-plugins-bad/ext/closedcaption/gsth265ccextractor.c
+++ b/subprojects/gst-plugins-bad/ext/closedcaption/gsth265ccextractor.c
@@ -93,6 +93,7 @@ struct _GstH265CCExtractor
   gboolean on_eos;
   gint fps_n;
   gint fps_d;
+  gboolean need_negotiate;
 };
 
 #define gst_h265_cc_extractor_parent_class parent_class
@@ -194,6 +195,8 @@ gst_h265_cc_extractor_set_format (GstVideoDecoder * decoder,
   GstCaps *caps;
   gboolean ret;
 
+  self->need_negotiate = TRUE;
+
   /* Assume caption type is cea708 raw which is common cc type
    * embedded in SEI */
   if (self->caption_type == GST_VIDEO_CAPTION_TYPE_UNKNOWN)
@@ -220,7 +223,12 @@ static gboolean
 gst_h265_cc_extractor_negotiate (GstVideoDecoder * decoder)
 {
   GstH265CCExtractor *self = GST_H265_CC_EXTRACTOR (decoder);
-  GstCaps *caps = gst_video_caption_type_to_caps (self->caption_type);
+  GstCaps *caps;
+
+  if (!self->need_negotiate)
+    return TRUE;
+
+  caps = gst_video_caption_type_to_caps (self->caption_type);
 
   gst_caps_set_simple (caps,
       "framerate", GST_TYPE_FRACTION, self->fps_n, self->fps_d, NULL);
@@ -228,6 +236,8 @@ gst_h265_cc_extractor_negotiate (GstVideoDecoder * decoder)
   gst_pad_set_caps (decoder->srcpad, caps);
   gst_caps_unref (caps);
 
+  self->need_negotiate = FALSE;
+
   return TRUE;
 }
 
@@ -399,8 +409,10 @@ gst_h265_cc_extractor_output_picture (GstH265Decoder * decoder,
     }
   }
 
-  if (updated)
+  if (updated) {
+    self->need_negotiate = TRUE;
     gst_video_decoder_negotiate (videodec);
+  }
 
   gst_h265_picture_unref (picture);