From 8a76079e1711cdf44b02901fb7772a426cfb7c2a Mon Sep 17 00:00:00 2001
From: He Junyan <junyan.he@intel.com>
Date: Sun, 21 Apr 2024 14:48:02 +0800
Subject: [PATCH] vah265enc: Do not touch the PTS of output frame

1. The PTS of all frames should not be changed.
2. Just update the DTS based on the PTS. For the frame which is not
   reordered, the DTS is equal to PTS. For frame which is reordered,
   the DTS is equal to previous DTS. For example:
   Input: F0[D0, P0] -- F1[D1, P1] -- F2[D2, P2] -- F3[D3, P3]
   Output: F0[I, D0, P0] -- F3[P, D0, P3] -- F1[B, D1, P1] -- F2[B, D2, P2]

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6764>
---
 .../gst-plugins-bad/sys/va/gstvah265enc.c     | 38 +++++++++++++------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/subprojects/gst-plugins-bad/sys/va/gstvah265enc.c b/subprojects/gst-plugins-bad/sys/va/gstvah265enc.c
index 4acbf1d26a..984aca27fa 100644
--- a/subprojects/gst-plugins-bad/sys/va/gstvah265enc.c
+++ b/subprojects/gst-plugins-bad/sys/va/gstvah265enc.c
@@ -333,6 +333,7 @@ struct _GstVaH265Enc
     guint cpb_length_bits;
   } rc;
 
+  GstClockTime last_dts;
   GstH265VPS vps_hdr;
   GstH265SPS sps_hdr;
 };
@@ -349,8 +350,7 @@ struct _GstVaH265EncFrame
 
   gint poc;
   gboolean last_frame;
-  /* The total frame count we handled. */
-  guint total_frame_count;
+  gboolean reorder;
 };
 
 /**
@@ -452,7 +452,7 @@ gst_va_h265_enc_frame_new (void)
   frame = g_new (GstVaH265EncFrame, 1);
   frame->last_frame = FALSE;
   frame->picture = NULL;
-  frame->total_frame_count = 0;
+  frame->reorder = FALSE;
 
   return frame;
 }
@@ -2193,6 +2193,9 @@ again:
     /* it will unref at pop_frame */
     f = g_queue_pop_nth (&base->reorder_list, index);
     g_assert (f == b_frame);
+
+    if (index > 0)
+      _enc_frame (f)->reorder = TRUE;
   } else {
     b_frame = NULL;
   }
@@ -2221,6 +2224,9 @@ _h265_pop_one_frame (GstVaBaseEnc * base, GstVideoCodecFrame ** out_frame)
   vaframe = _enc_frame (frame);
   if (vaframe->type != GST_H265_B_SLICE) {
     frame = g_queue_pop_tail (&base->reorder_list);
+    if (!g_queue_is_empty (&base->reorder_list))
+      vaframe->reorder = TRUE;
+
     goto get_one;
   }
 
@@ -2536,6 +2542,7 @@ gst_va_h265_enc_reset_state (GstVaBaseEnc * base)
   self->rc.target_bitrate_bits = 0;
   self->rc.cpb_length_bits = 0;
 
+  self->last_dts = GST_CLOCK_TIME_NONE;
   memset (&self->vps_hdr, 0, sizeof (GstH265VPS));
   memset (&self->sps_hdr, 0, sizeof (GstH265SPS));
 }
@@ -4613,7 +4620,6 @@ gst_va_h265_enc_new_frame (GstVaBaseEnc * base, GstVideoCodecFrame * frame)
   GstVaH265EncFrame *frame_in;
 
   frame_in = gst_va_h265_enc_frame_new ();
-  frame_in->total_frame_count = base->input_frame_count++;
   gst_video_codec_frame_set_user_data (frame, frame_in,
       gst_va_h265_enc_frame_free);
 
@@ -4630,14 +4636,22 @@ gst_va_h265_enc_prepare_output (GstVaBaseEnc * base,
 
   frame_enc = _enc_frame (frame);
 
-  frame->pts =
-      base->start_pts + base->frame_duration * frame_enc->total_frame_count;
-  /* The PTS should always be later than the DTS. */
-  frame->dts = base->start_pts + base->frame_duration *
-      ((gint64) base->output_frame_count -
-      (gint64) self->gop.num_reorder_frames);
-  base->output_frame_count++;
-  frame->duration = base->frame_duration;
+  if (frame_enc->reorder) {
+    if (!GST_CLOCK_TIME_IS_VALID (self->last_dts)) {
+      GST_WARNING_OBJECT (base, "Reorder frame poc: %d, system frame "
+          "number: %d without previous valid DTS.", frame_enc->poc,
+          frame->system_frame_number);
+      frame->dts = frame->pts;
+    } else {
+      GST_LOG_OBJECT (base, "Set reorder frame poc: %d, system frame "
+          "number: %d with DTS: %" GST_TIME_FORMAT, frame_enc->poc,
+          frame->system_frame_number, GST_TIME_ARGS (self->last_dts));
+      frame->dts = self->last_dts;
+    }
+  } else {
+    frame->dts = frame->pts;
+    self->last_dts = frame->dts;
+  }
 
   buf = gst_va_base_enc_create_output_buffer (base,
       frame_enc->picture, NULL, 0);