From da89903f81849fa61e0224d50c214ff3140cd9fc Mon Sep 17 00:00:00 2001
From: Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
Date: Wed, 1 Feb 2012 12:47:56 +0100
Subject: [PATCH] h264parse: disable optimized packetized processing for
 reverse playback

... as baseparse then provides whole chunks of data (as it should) at once
to be parsed, and so the assumptions used to optimize are no longer valid.

Fixes #667560.
---
 gst/videoparsers/gsth264parse.c | 16 ++++++++++++----
 gst/videoparsers/gsth264parse.h |  1 +
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/gst/videoparsers/gsth264parse.c b/gst/videoparsers/gsth264parse.c
index 182b00e929..230fd85c64 100644
--- a/gst/videoparsers/gsth264parse.c
+++ b/gst/videoparsers/gsth264parse.c
@@ -675,7 +675,7 @@ gst_h264_parse_check_valid_frame (GstBaseParse * parse,
   while (TRUE) {
     GstH264ParserResult pres;
 
-    if (h264parse->packetized)
+    if (h264parse->packetized_chunked)
       pres =
           gst_h264_parser_identify_nalu_unchecked (nalparser, data, current_off,
           size, &nalu);
@@ -697,7 +697,8 @@ gst_h264_parse_check_valid_frame (GstBaseParse * parse,
           h264parse->nalu = nalu;
 
         /* need 2 bytes of next nal */
-        if (!h264parse->packetized && (nalu.offset + nalu.size + 4 + 2 > size)) {
+        if (!h264parse->packetized_chunked &&
+            (nalu.offset + nalu.size + 4 + 2 > size)) {
           if (GST_BASE_PARSE_DRAINING (parse)) {
             drain = TRUE;
           } else {
@@ -705,7 +706,7 @@ gst_h264_parse_check_valid_frame (GstBaseParse * parse,
             current_off = nalu.sc_offset;
             goto more;
           }
-        } else if (h264parse->packetized) {
+        } else if (h264parse->packetized_chunked) {
           /* normal next nal based collection not possible,
            * _chain will have to tell us whether this was last one for AU */
           drain = h264parse->packetized_last;
@@ -776,7 +777,7 @@ gst_h264_parse_check_valid_frame (GstBaseParse * parse,
 
     /* In packetized mode we know there's only on NALU in each input packet,
      * but we may not have seen the whole AU already, possibly need more */
-    if (h264parse->packetized) {
+    if (h264parse->packetized_chunked) {
       if (drain)
         break;
       /* next NALU expected at end of current data */
@@ -1862,6 +1863,13 @@ gst_h264_parse_chain (GstPad * pad, GstBuffer * buffer)
             nalu.data + nalu.offset, nalu.size);
         /* at least this should make sense */
         GST_BUFFER_TIMESTAMP (sub) = GST_BUFFER_TIMESTAMP (buffer);
+        /* transfer flags (e.g. DISCONT) for first fragment */
+        if (nalu.offset <= nl)
+          gst_buffer_copy_metadata (sub, buffer, GST_BUFFER_COPY_FLAGS);
+        /* in reverse playback, baseparse gathers buffers, so we cannot
+         * guarantee a buffer to contain a single whole NALU */
+        h264parse->packetized_chunked =
+            (GST_BASE_PARSE (h264parse)->segment.rate > 0.0);
         h264parse->packetized_last =
             (nalu.offset + nalu.size + nl >= GST_BUFFER_SIZE (buffer));
         GST_LOG_OBJECT (h264parse, "pushing NAL of size %d, last = %d",
diff --git a/gst/videoparsers/gsth264parse.h b/gst/videoparsers/gsth264parse.h
index 812ac4fb88..ff6eb59f01 100644
--- a/gst/videoparsers/gsth264parse.h
+++ b/gst/videoparsers/gsth264parse.h
@@ -72,6 +72,7 @@ struct _GstH264Parse
   guint format;
   guint current_off;
   gboolean packetized_last;
+  gboolean packetized_chunked;
 
   GstClockTime last_report;
   gboolean push_codec;