From f1f8731ff53df200f376ed16df5853116a394a41 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Sun, 30 Mar 2014 17:54:11 +0200
Subject: [PATCH] videodecoder: Handle reverse playback with multiple GOPs per
 discont group properly

baseparse will reverse each GOP for us already, so the segment events can
be after our keyframe. Make sure to get it and all other relevant sticky
events before starting to decode.
---
 gst-libs/gst/video/gstvideodecoder.c | 38 +++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/gst-libs/gst/video/gstvideodecoder.c b/gst-libs/gst/video/gstvideodecoder.c
index 7435014..cde265b 100644
--- a/gst-libs/gst/video/gstvideodecoder.c
+++ b/gst-libs/gst/video/gstvideodecoder.c
@@ -1928,19 +1928,10 @@ gst_video_decoder_flush_parse (GstVideoDecoder * dec, gboolean at_eos)
     walk = next;
   }
 
-  /* now we can process frames. Start by moving each frame from the parse_gather
-   * to the decode list, reverse the order as we go, and stopping when/if we
-   * copy a keyframe. */
-  GST_DEBUG_OBJECT (dec, "checking parsed frames for a keyframe to decode");
   walk = priv->parse_gather;
   while (walk) {
     GstVideoCodecFrame *frame = (GstVideoCodecFrame *) (walk->data);
-
-    /* remove from the gather list */
-    priv->parse_gather = g_list_remove_link (priv->parse_gather, walk);
-
-    /* move it to the front of the decode queue */
-    priv->decode = g_list_concat (walk, priv->decode);
+    GList *walk2;
 
     /* this is reverse playback, check if we need to apply some segment
      * to the output before decoding, as during decoding the segment.rate
@@ -1952,11 +1943,11 @@ gst_video_decoder_flush_parse (GstVideoDecoder * dec, gboolean at_eos)
      * pushing a segment before caps event. Negotiation only happens
      * when finish_frame is called.
      */
-    for (walk = frame->events; walk;) {
-      GList *cur = walk;
-      GstEvent *event = walk->data;
+    for (walk2 = frame->events; walk2;) {
+      GList *cur = walk2;
+      GstEvent *event = walk2->data;
 
-      walk = g_list_next (walk);
+      walk2 = g_list_next (walk2);
       if (GST_EVENT_TYPE (event) <= GST_EVENT_SEGMENT) {
 
         if (GST_EVENT_TYPE (event) == GST_EVENT_SEGMENT) {
@@ -1975,6 +1966,23 @@ gst_video_decoder_flush_parse (GstVideoDecoder * dec, gboolean at_eos)
       }
     }
 
+    walk = walk->next;
+  }
+
+  /* now we can process frames. Start by moving each frame from the parse_gather
+   * to the decode list, reverse the order as we go, and stopping when/if we
+   * copy a keyframe. */
+  GST_DEBUG_OBJECT (dec, "checking parsed frames for a keyframe to decode");
+  walk = priv->parse_gather;
+  while (walk) {
+    GstVideoCodecFrame *frame = (GstVideoCodecFrame *) (walk->data);
+
+    /* remove from the gather list */
+    priv->parse_gather = g_list_remove_link (priv->parse_gather, walk);
+
+    /* move it to the front of the decode queue */
+    priv->decode = g_list_concat (walk, priv->decode);
+
     /* if we copied a keyframe, flush and decode the decode queue */
     if (GST_VIDEO_CODEC_FRAME_IS_SYNC_POINT (frame)) {
       GST_DEBUG_OBJECT (dec, "found keyframe %p with PTS %" GST_TIME_FORMAT
@@ -1993,6 +2001,7 @@ gst_video_decoder_flush_parse (GstVideoDecoder * dec, gboolean at_eos)
   if (at_eos) {
     GstVideoDecoderClass *decoder_class;
 
+    GST_DEBUG_OBJECT (dec, "Finishing");
     decoder_class = GST_VIDEO_DECODER_GET_CLASS (dec);
     if (decoder_class->finish)
       res = decoder_class->finish (dec);
@@ -2257,6 +2266,7 @@ gst_video_decoder_new_frame (GstVideoDecoder * decoder)
   frame->duration = GST_CLOCK_TIME_NONE;
   frame->events = priv->current_frame_events;
   priv->current_frame_events = NULL;
+
   GST_VIDEO_DECODER_STREAM_UNLOCK (decoder);
 
   GST_LOG_OBJECT (decoder, "Created new frame %p (sfn:%d)",
-- 
2.7.4