From 10bc8fdfd2ccb2e9ff49bac0d9f09987439366b3 Mon Sep 17 00:00:00 2001
From: Edward Hervey <edward@centricular.com>
Date: Fri, 24 Nov 2017 15:37:44 +0100
Subject: [PATCH] rtspsrc: Do more checks for seekability

When receiving a seek event, check whether we can actually seek based
on the information the server provided.

Also add more documentation on what the seekable field means
---
 gst/rtsp/gstrtspsrc.c | 17 ++++++++++++++++-
 gst/rtsp/gstrtspsrc.h |  9 ++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/gst/rtsp/gstrtspsrc.c b/gst/rtsp/gstrtspsrc.c
index 518d0e3a4d..086e2ea27d 100644
--- a/gst/rtsp/gstrtspsrc.c
+++ b/gst/rtsp/gstrtspsrc.c
@@ -2282,7 +2282,7 @@ gst_rtspsrc_perform_seek (GstRTSPSrc * src, GstEvent * event)
   const gchar *seek_style = NULL;
 
   if (event) {
-    GST_DEBUG_OBJECT (src, "doing seek with event");
+    GST_DEBUG_OBJECT (src, "doing seek with event %" GST_PTR_FORMAT, event);
 
     gst_event_parse_seek (event, &rate, &format, &flags,
         &cur_type, &cur, &stop_type, &stop);
@@ -2294,6 +2294,14 @@ gst_rtspsrc_perform_seek (GstRTSPSrc * src, GstEvent * event)
     /* we need TIME format */
     if (format != src->segment.format)
       goto no_format;
+
+    /* Check if we are not at all seekable */
+    if (src->seekable == -1.0)
+      goto not_seekable;
+
+    /* Additional seeking-to-beginning-only check */
+    if (src->seekable == 0.0 && cur != 0)
+      goto not_seekable;
   } else {
     GST_DEBUG_OBJECT (src, "doing seek without event");
     flags = 0;
@@ -2425,6 +2433,11 @@ no_format:
     GST_DEBUG_OBJECT (src, "unsupported format given, seek aborted.");
     return FALSE;
   }
+not_seekable:
+  {
+    GST_DEBUG_OBJECT (src, "stream is not seekable");
+    return FALSE;
+  }
 }
 
 static gboolean
@@ -2622,6 +2635,8 @@ gst_rtspsrc_handle_src_query (GstPad * pad, GstObject * parent,
           }
         }
 
+        GST_LOG_OBJECT (src, "seekable : %d", seekable);
+
         gst_query_set_seeking (query, GST_FORMAT_TIME, seekable, start,
             duration);
         res = TRUE;
diff --git a/gst/rtsp/gstrtspsrc.h b/gst/rtsp/gstrtspsrc.h
index 97a0d194d5..57921d2e19 100644
--- a/gst/rtsp/gstrtspsrc.h
+++ b/gst/rtsp/gstrtspsrc.h
@@ -270,7 +270,14 @@ struct _GstRTSPSrc {
   /* supported methods */
   gint               methods;
 
-  /* Same semantic as described in gst_rtsp_media_seekable */
+  /* seekability
+   * -1.0 : Stream is not seekable
+   *  0.0 : seekable only to the beginning
+   * G_MAXFLOAT : Any value is possible
+   *
+   * Any other positive value indicates the longest duration
+   * between any two random access points
+   *  */
   gfloat             seekable;
   GstClockTime       last_pos;