paranoia cleanups and a sync fix

Original commit message from CVS:
paranoia cleanups and a sync fix

25 files changed, 267 insertions, 135 deletions

diff --git a/ChangeLog b/ChangeLog
index 94f630311..f4a7886ce 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,53 @@
+2004-06-15  Thomas Vander Stichele  <thomas at apestaart dot org>
+
+	* sys/v4l/gstv4l.c: (plugin_init):
+	* sys/v4l/gstv4lcolorbalance.c:
+	* sys/v4l/gstv4lcolorbalance.h:
+	* sys/v4l/gstv4lelement.c:
+	* sys/v4l/gstv4lelement.h:
+	* sys/v4l/gstv4lmjpegsink.c: (gst_v4lmjpegsink_class_init):
+	* sys/v4l/gstv4lmjpegsink.h:
+	* sys/v4l/gstv4lmjpegsrc.c: (gst_v4lmjpegsrc_class_init):
+	* sys/v4l/gstv4lmjpegsrc.h:
+	* sys/v4l/gstv4lsrc.c: (gst_v4lsrc_get_fps_list),
+	(gst_v4lsrc_get_fps), (gst_v4lsrc_srcconnect),
+	(gst_v4lsrc_getcaps), (gst_v4lsrc_get):
+	* sys/v4l/gstv4lsrc.h:
+	* sys/v4l/gstv4ltuner.c:
+	* sys/v4l/gstv4ltuner.h:
+	* sys/v4l/gstv4lxoverlay.c:
+	* sys/v4l/gstv4lxoverlay.h:
+	* sys/v4l/v4l-overlay_calls.c: (gst_v4l_set_overlay),
+	(gst_v4l_set_window), (gst_v4l_enable_overlay):
+	* sys/v4l/v4l_calls.c: (gst_v4l_set_window_properties),
+	(gst_v4l_open), (gst_v4l_get_picture), (gst_v4l_get_audio),
+	(gst_v4l_set_audio):
+	* sys/v4l/v4l_calls.h:
+	* sys/v4l/v4lmjpegsink_calls.c: (gst_v4lmjpegsink_sync_thread),
+	(gst_v4lmjpegsink_queue_frame), (gst_v4lmjpegsink_sync_frame),
+	(gst_v4lmjpegsink_set_buffer), (gst_v4lmjpegsink_set_playback),
+	(gst_v4lmjpegsink_playback_init),
+	(gst_v4lmjpegsink_playback_start), (gst_v4lmjpegsink_get_buffer),
+	(gst_v4lmjpegsink_play_frame), (gst_v4lmjpegsink_wait_frame),
+	(gst_v4lmjpegsink_playback_stop),
+	(gst_v4lmjpegsink_playback_deinit):
+	* sys/v4l/v4lmjpegsink_calls.h:
+	* sys/v4l/v4lmjpegsrc_calls.c: (gst_v4lmjpegsrc_queue_frame),
+	(gst_v4lmjpegsrc_sync_next_frame), (gst_v4lmjpegsrc_set_buffer),
+	(gst_v4lmjpegsrc_set_capture), (gst_v4lmjpegsrc_set_capture_m),
+	(gst_v4lmjpegsrc_capture_init), (gst_v4lmjpegsrc_capture_start),
+	(gst_v4lmjpegsrc_grab_frame), (gst_v4lmjpegsrc_requeue_frame),
+	(gst_v4lmjpegsrc_capture_stop), (gst_v4lmjpegsrc_capture_deinit):
+	* sys/v4l/v4lmjpegsrc_calls.h:
+	* sys/v4l/v4lsrc_calls.c: (gst_v4lsrc_queue_frame),
+	(gst_v4lsrc_sync_frame), (gst_v4lsrc_set_capture),
+	(gst_v4lsrc_capture_init), (gst_v4lsrc_capture_start),
+	(gst_v4lsrc_grab_frame), (gst_v4lsrc_requeue_frame),
+	(gst_v4lsrc_capture_stop), (gst_v4lsrc_capture_deinit),
+	(gst_v4lsrc_try_palette):
+	* sys/v4l/v4lsrc_calls.h:
+	  bunch of paranoia cleanups
+
 2004-06-14  David Schleef  <ds@schleef.org>
 
 	* ext/cdparanoia/gstcdparanoia.c: (cdparanoia_init),
@@ -10,7 +60,7 @@
 
 	* ext/alsa/gstalsa.c: Use snd_pcm_hw_params_set_rate _near instead of
 	  snd_pcm_hw_params_set_rate  since the latter fails for no good 
-	  reason on some setups.<
+	  reason on some setups.
 
 2004-06-14  David Schleef  <ds@schleef.org>
 
@@ -21,7 +71,7 @@
 
 	* gst/ffmpegcolorspace/imgconvert.c: (img_convert):
 	Patch 1.3 broke the ordering of the colorspace info and
-	made the plugin basically work by coincidence, reodered
+	made the plugin basically work by coincidence, reordered
 	the info.
 
 2004-06-14  Thomas Vander Stichele  <thomas at apestaart dot org>
diff --git a/sys/v4l/gstv4l.c b/sys/v4l/gstv4l.c
index 1984a08a5..e87d867a0 100644
--- a/sys/v4l/gstv4l.c
+++ b/sys/v4l/gstv4l.c
@@ -1,4 +1,7 @@
-/* G-Streamer video4linux plugins
+/* GStreamer
+ *
+ * gstv4l.c: plugin for v4l elements
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -31,11 +34,14 @@
 #include "gstv4lmjpegsink.h"
 
 GST_DEBUG_CATEGORY (v4l_debug); /* used in v4l_calls.c and v4lsrc_calls.c */
+GST_DEBUG_CATEGORY_EXTERN (v4loverlay_debug);
 
 static gboolean
 plugin_init (GstPlugin * plugin)
 {
   GST_DEBUG_CATEGORY_INIT (v4l_debug, "v4l", 0, "V4L API calls");
+  GST_DEBUG_CATEGORY_INIT (v4loverlay_debug, "v4loverlay", 0,
+      "V4L overlay calls");
 
   /* actually, we can survive without it, but I'll create
    * that handling later on. */
diff --git a/sys/v4l/gstv4lcolorbalance.c b/sys/v4l/gstv4lcolorbalance.c
index a224120ad..e1571579d 100644
--- a/sys/v4l/gstv4lcolorbalance.c
+++ b/sys/v4l/gstv4lcolorbalance.c
@@ -1,8 +1,9 @@
-/* GStreamer Color Balance interface implementation
- * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+/* GStreamer
  *
  * gstv4lcolorbalance.c: color balance interface implementation for V4L
  *
+ * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
diff --git a/sys/v4l/gstv4lcolorbalance.h b/sys/v4l/gstv4lcolorbalance.h
index c59d02441..f251a7c51 100644
--- a/sys/v4l/gstv4lcolorbalance.h
+++ b/sys/v4l/gstv4lcolorbalance.h
@@ -1,8 +1,9 @@
-/* G-Streamer generic V4L element - Color Balance interface implementation
- * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+/* GStreamer
  *
  * gstv4lcolorbalance.h: color balance interface implementation for V4L
  *
+ * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
diff --git a/sys/v4l/gstv4lelement.c b/sys/v4l/gstv4lelement.c
index ad52336b6..9fd9365d6 100644
--- a/sys/v4l/gstv4lelement.c
+++ b/sys/v4l/gstv4lelement.c
@@ -1,4 +1,7 @@
-/* G-Streamer generic V4L element - generic V4L calls handling
+/* GStreamer
+ *
+ * gstv4lelement.c: base class for V4L elements
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
diff --git a/sys/v4l/gstv4lelement.h b/sys/v4l/gstv4lelement.h
index ad9bb587d..aeaf197d0 100644
--- a/sys/v4l/gstv4lelement.h
+++ b/sys/v4l/gstv4lelement.h
@@ -1,4 +1,7 @@
-/* G-Streamer generic V4L element - generic V4L calls handling
+/* GStreamer
+ *
+ * gstv4lelement.h: base class for V4L elements
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
diff --git a/sys/v4l/gstv4lmjpegsink.c b/sys/v4l/gstv4lmjpegsink.c
index f6dc91892..42633d645 100644
--- a/sys/v4l/gstv4lmjpegsink.c
+++ b/sys/v4l/gstv4lmjpegsink.c
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video sink plugin
+/* GStreamer
+ *
+ * gstv4lmjpegsink.c: hardware MJPEG video sink plugin
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -24,6 +27,9 @@
 #include <string.h>
 #include "v4lmjpegsink_calls.h"
 
+GST_DEBUG_CATEGORY (v4lmjpegsink_debug);
+#define GST_CAT_DEFAULT v4lmjpegsink_debug
+
 /* elementfactory information */
 static GstElementDetails gst_v4lmjpegsink_details = {
   "Video (video4linux/MJPEG) sink",
@@ -129,26 +135,28 @@ gst_v4lmjpegsink_class_init (GstV4lMjpegSinkClass * klass)
   parent_class = g_type_class_ref (GST_TYPE_V4LELEMENT);
 
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_NUMBUFS,
-      g_param_spec_int ("num_buffers", "num_buffers", "num_buffers",
+      g_param_spec_int ("num-buffers", "num-buffers", "num-buffers",
           G_MININT, G_MAXINT, 0, G_PARAM_READWRITE));
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_BUFSIZE,
-      g_param_spec_int ("buffer_size", "buffer_size", "buffer_size",
+      g_param_spec_int ("buffer-size", "buffer-size", "buffer-size",
           G_MININT, G_MAXINT, 0, G_PARAM_READWRITE));
 
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_X_OFFSET,
-      g_param_spec_int ("x_offset", "x_offset", "x_offset",
+      g_param_spec_int ("x-offset", "x-offset", "x-offset",
           G_MININT, G_MAXINT, 0, G_PARAM_WRITABLE));
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_Y_OFFSET,
-      g_param_spec_int ("y_offset", "y_offset", "y_offset",
+      g_param_spec_int ("y-offset", "y-offset", "y-offset",
           G_MININT, G_MAXINT, 0, G_PARAM_WRITABLE));
 
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_FRAMES_DISPLAYED,
-      g_param_spec_int ("frames_displayed", "frames_displayed",
-          "frames_displayed", G_MININT, G_MAXINT, 0, G_PARAM_READABLE));
+      g_param_spec_int ("frames-displayed", "frames-displayed",
+          "frames-displayed", G_MININT, G_MAXINT, 0, G_PARAM_READABLE));
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_FRAME_TIME,
-      g_param_spec_int ("frame_time", "frame_time", "frame_time", G_MININT,
+      g_param_spec_int ("frame-time", "frame-time", "frame-time", G_MININT,
           G_MAXINT, 0, G_PARAM_READABLE));
 
+  GST_DEBUG_CATEGORY_INIT (v4lmjpegsink_debug, "v4lmjpegsink", 0,
+      "V4L MJPEG sink element");
   gobject_class->set_property = gst_v4lmjpegsink_set_property;
   gobject_class->get_property = gst_v4lmjpegsink_get_property;
 
diff --git a/sys/v4l/gstv4lmjpegsink.h b/sys/v4l/gstv4lmjpegsink.h
index d8578c6e1..be8a90349 100644
--- a/sys/v4l/gstv4lmjpegsink.h
+++ b/sys/v4l/gstv4lmjpegsink.h
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video sink plugin
+/* GStreamer
+ *
+ * gstv4lmjpegsink.h: hardware MJPEG video sink element
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
diff --git a/sys/v4l/gstv4lmjpegsrc.c b/sys/v4l/gstv4lmjpegsrc.c
index 53f11ca44..8377c7b75 100644
--- a/sys/v4l/gstv4lmjpegsrc.c
+++ b/sys/v4l/gstv4lmjpegsrc.c
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video source plugin
+/* GStreamer
+ *
+ * gstv4lmjpegsrc.c: hardware MJPEG video source plugin
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -24,6 +27,9 @@
 #include <string.h>
 #include "v4lmjpegsrc_calls.h"
 
+GST_DEBUG_CATEGORY (v4lmjpegsrc_debug);
+#define GST_CAT_DEFAULT v4lmjpegsrc_debug
+
 /* elementfactory information */
 static GstElementDetails gst_v4lmjpegsrc_details = {
   "Video (video4linux/MJPEG) Source",
@@ -208,6 +214,8 @@ gst_v4lmjpegsrc_class_init (GstV4lMjpegSrcClass * klass)
       G_STRUCT_OFFSET (GstV4lMjpegSrcClass, frame_lost), NULL, NULL,
       g_cclosure_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
 
+  GST_DEBUG_CATEGORY_INIT (v4lmjpegsrc_debug, "v4lmjpegsrc", 0,
+      "V4L MJPEG source element");
   gobject_class->set_property = gst_v4lmjpegsrc_set_property;
   gobject_class->get_property = gst_v4lmjpegsrc_get_property;
 
diff --git a/sys/v4l/gstv4lmjpegsrc.h b/sys/v4l/gstv4lmjpegsrc.h
index 923a007c8..3dcee4ce2 100644
--- a/sys/v4l/gstv4lmjpegsrc.h
+++ b/sys/v4l/gstv4lmjpegsrc.h
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video source plugin
+/* GStreamer
+ *
+ * gstv4lmjpegsrc.h: hardware MJPEG video source element
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
diff --git a/sys/v4l/gstv4lsrc.c b/sys/v4l/gstv4lsrc.c
index 66564a0a8..19026fca2 100644
--- a/sys/v4l/gstv4lsrc.c
+++ b/sys/v4l/gstv4lsrc.c
@@ -1,4 +1,7 @@
-/* G-Streamer BT8x8/V4L frame grabber plugin
+/* GStreamer
+ *
+ * gstv4lsrc.c: BT8x8/V4L source element
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -316,7 +319,7 @@ gst_v4lsrc_get_fps_list (GstV4lSrc * v4lsrc)
     /* index of 16 corresponds to 15 fps */
     current_fps = fps_index * 15.0 / 16;
     GST_DEBUG_OBJECT (v4lsrc, "device reports fps of %.4f", current_fps);
-    for (i = 1; i < 63; ++i) {
+    for (i = 0; i < 63; ++i) {
       /* set bits 16 to 21 to 0 */
       vwin->flags &= (0x3F00 - 1);
       /* set bits 16 to 21 to the index */
@@ -359,7 +362,7 @@ gst_v4lsrc_get_fps (GstV4lSrc * v4lsrc)
 
     /* index of 16 corresponds to 15 fps */
     current_fps = fps_index * 15.0 / 16;
-    GST_LOG_OBJECT (v4lsrc, "device reports fps of %.3f", current_fps);
+    GST_LOG_OBJECT (v4lsrc, "device reports fps of %.4f", current_fps);
     return current_fps;
   }
 
@@ -774,8 +777,9 @@ gst_v4lsrc_get (GstPad * pad)
   g_return_val_if_fail (pad != NULL, NULL);
 
   v4lsrc = GST_V4LSRC (gst_pad_get_parent (pad));
+  fps = gst_v4lsrc_get_fps (v4lsrc);
 
-  if (v4lsrc->use_fixed_fps && (fps = gst_v4lsrc_get_fps (v4lsrc)) == 0)
+  if (v4lsrc->use_fixed_fps && fps == 0.0)
     return NULL;
 
   if (v4lsrc->need_writes > 0) {
@@ -868,8 +872,10 @@ gst_v4lsrc_get (GstPad * pad)
   g_signal_emit (G_OBJECT (v4lsrc),
       gst_v4lsrc_signals[SIGNAL_FRAME_CAPTURE], 0);
 
+  /* this is the current timestamp */
   now = gst_element_get_time (GST_ELEMENT (v4lsrc));
-  until = GST_BUFFER_TIMESTAMP (buf) + v4lsrc->last_discont;
+
+  until = GST_BUFFER_TIMESTAMP (buf);
 
   GST_LOG_OBJECT (v4lsrc, "Current time %" GST_TIME_FORMAT
       ", buffer timestamp %" GST_TIME_FORMAT,
@@ -878,7 +884,10 @@ gst_v4lsrc_get (GstPad * pad)
     GST_LOG_OBJECT (v4lsrc, "waiting until %" GST_TIME_FORMAT,
         GST_TIME_ARGS (until));
     if (!gst_element_wait (GST_ELEMENT (v4lsrc), until))
-      g_warning ("gst_element_wait failed");
+      g_warning ("waiting from now %" GST_TIME_FORMAT
+          " until %" GST_TIME_FORMAT " failed",
+          GST_TIME_ARGS (now), GST_TIME_ARGS (until));
+    GST_LOG_OBJECT (v4lsrc, "wait done.");
   }
   /* check for discont; we do it after grabbing so that we drop the
    * first frame grabbed, but get an accurate discont event  */
diff --git a/sys/v4l/gstv4lsrc.h b/sys/v4l/gstv4lsrc.h
index 4cf3af2ae..a541784ca 100644
--- a/sys/v4l/gstv4lsrc.h
+++ b/sys/v4l/gstv4lsrc.h
@@ -1,4 +1,7 @@
-/* G-Streamer BT8x8/V4L frame grabber plugin
+/* GStreamer
+ *
+ * gstv4lsrc.h: BT8x8/V4L video source element
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -39,9 +42,9 @@ typedef struct _GstV4lSrcClass GstV4lSrcClass;
 enum
 {
   QUEUE_STATE_ERROR = -1,
-  QUEUE_STATE_READY_FOR_QUEUE,
-  QUEUE_STATE_QUEUED,
-  QUEUE_STATE_SYNCED
+  QUEUE_STATE_READY_FOR_QUEUE, /* the frame is ready to be queued for capture */
+  QUEUE_STATE_QUEUED,          /* the frame is queued for capture */
+  QUEUE_STATE_SYNCED           /* the frame is captured */
 };
 
 struct _GstV4lSrc
diff --git a/sys/v4l/gstv4ltuner.c b/sys/v4l/gstv4ltuner.c
index 616a56f6d..5d6815942 100644
--- a/sys/v4l/gstv4ltuner.c
+++ b/sys/v4l/gstv4ltuner.c
@@ -1,8 +1,9 @@
-/* GStreamer Tuner interface implementation
- * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+/* GStreamer
  *
  * gstv4ltuner.c: tuner interface implementation for V4L
  *
+ * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
diff --git a/sys/v4l/gstv4ltuner.h b/sys/v4l/gstv4ltuner.h
index 2777a2e46..c5337fe92 100644
--- a/sys/v4l/gstv4ltuner.h
+++ b/sys/v4l/gstv4ltuner.h
@@ -1,8 +1,9 @@
-/* G-Streamer generic V4L element - Tuner interface implementation
- * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+/* GStreamer
  *
  * gstv4ltuner.h: tuner interface implementation for V4L
  *
+ * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
diff --git a/sys/v4l/gstv4lxoverlay.c b/sys/v4l/gstv4lxoverlay.c
index 1bf5c2eef..c1167e010 100644
--- a/sys/v4l/gstv4lxoverlay.c
+++ b/sys/v4l/gstv4lxoverlay.c
@@ -1,8 +1,9 @@
-/* GStreamer X-based overlay interface implementation
- * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+/* GStreamer
  *
  * gstv4lxoverlay.c: X-based overlay interface implementation for V4L
  *
+ * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
diff --git a/sys/v4l/gstv4lxoverlay.h b/sys/v4l/gstv4lxoverlay.h
index 5c390ff72..4b27d5d1b 100644
--- a/sys/v4l/gstv4lxoverlay.h
+++ b/sys/v4l/gstv4lxoverlay.h
@@ -1,8 +1,9 @@
-/* G-Streamer generic V4L element - X overlay interface implementation
- * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+/* GStreamer
  *
  * gstv4lxoverlay.h: tv mixer interface implementation for V4L
  *
+ * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
diff --git a/sys/v4l/v4l-overlay_calls.c b/sys/v4l/v4l-overlay_calls.c
index 2736018e0..be6e1f13d 100644
--- a/sys/v4l/v4l-overlay_calls.c
+++ b/sys/v4l/v4l-overlay_calls.c
@@ -1,4 +1,7 @@
-/* G-Streamer generic V4L element - generic V4L overlay handling
+/* GStreamer
+ *
+ * v4l-overlay_calls.c: calls for generic V4L overlay handling
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -31,11 +34,8 @@
 #include <errno.h>
 #include "v4l_calls.h"
 
-#define DEBUG(format, args...) \
-	GST_DEBUG_OBJECT (\
-		GST_ELEMENT(v4lelement), \
-		"V4L-overlay: " format, ##args)
-
+GST_DEBUG_CATEGORY (v4loverlay_debug);
+#define GST_CAT_DEFAULT v4loverlay_debug
 
 /******************************************************
  * gst_v4l_set_overlay():
@@ -53,7 +53,7 @@ gst_v4l_set_overlay (GstV4lElement * v4lelement)
     g_free (v4lelement->display);
   v4lelement->display = g_strdup (g_getenv ("DISPLAY"));
 
-  DEBUG ("setting display to '%s'", v4lelement->display);
+  GST_DEBUG_OBJECT (v4lelement, "setting display to '%s'", v4lelement->display);
   GST_V4L_CHECK_NOT_OPEN (v4lelement);
 
   if (!v4lelement->display || v4lelement->display[0] != ':')
@@ -105,8 +105,8 @@ gst_v4l_set_window (GstElement * element,
   GstV4lElement *v4lelement = GST_V4LELEMENT (element);
   struct video_window vwin;
 
-  DEBUG ("setting video window to position (x,y/wxh) = %d,%d/%dx%d",
-      x, y, w, h);
+  GST_DEBUG_OBJECT (v4lelement,
+      "setting video window to position (x,y/wxh) = %d,%d/%dx%d", x, y, w, h);
   GST_V4L_CHECK_OPEN (v4lelement);
   GST_V4L_CHECK_OVERLAY (v4lelement);
 
@@ -117,7 +117,7 @@ gst_v4l_set_window (GstElement * element,
   vwin.flags = 0;
 
   if (clips && !(v4lelement->vcap.type & VID_TYPE_CLIPPING)) {
-    DEBUG ("Device \'%s\' doesn't do clipping",
+    GST_DEBUG_OBJECT (v4lelement, "Device \'%s\' doesn't do clipping",
         v4lelement->videodev ? v4lelement->videodev : "/dev/video");
     vwin.clips = 0;
   } else {
@@ -146,7 +146,8 @@ gst_v4l_enable_overlay (GstV4lElement * v4lelement, gboolean enable)
 {
   gint doit = enable ? 1 : 0;
 
-  DEBUG ("%s overlay", enable ? "enabling" : "disabling");
+  GST_DEBUG_OBJECT (v4lelement, "%s overlay",
+      enable ? "enabling" : "disabling");
   GST_V4L_CHECK_OPEN (v4lelement);
   GST_V4L_CHECK_OVERLAY (v4lelement);
 
diff --git a/sys/v4l/v4l_calls.c b/sys/v4l/v4l_calls.c
index d8ed3160a..6e6cb8e96 100644
--- a/sys/v4l/v4l_calls.c
+++ b/sys/v4l/v4l_calls.c
@@ -1,4 +1,7 @@
-/* G-Streamer generic V4L element - generic V4L calls handling
+/* GStreamer
+ *
+ * v4l_calls.c: generic V4L calls
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -43,7 +46,6 @@
 #include "gstv4lmjpegsink.h"
 
 GST_DEBUG_CATEGORY_EXTERN (v4l_debug);
-
 #define GST_CAT_DEFAULT v4l_debug
 
 static const char *picture_name[] = {
@@ -160,6 +162,11 @@ gst_v4l_open (GstV4lElement * v4lelement)
   /* open the device */
   v4lelement->video_fd = open (v4lelement->videodev, O_RDWR);
   if (!GST_V4L_IS_OPEN (v4lelement)) {
+    if (errno == ENODEV || errno == ENOENT) {
+      GST_ELEMENT_ERROR (v4lelement, RESOURCE, NOT_FOUND,
+          (_("Device \"%s\" does not exist."), v4lelement->videodev), (NULL));
+      return FALSE;
+    }
     GST_ELEMENT_ERROR (v4lelement, RESOURCE, OPEN_READ_WRITE,
         (_("Could not open device \"%s\" for reading and writing."),
             v4lelement->videodev), GST_ERROR_SYSTEM);
@@ -187,7 +194,7 @@ gst_v4l_open (GstV4lElement * v4lelement)
     return FALSE;
   }
 
-  GST_INFO ("Opened device \'%s\' (\'%s\') successfully\n",
+  GST_INFO_OBJECT (v4lelement, "Opened device \'%s\' (\'%s\') successfully\n",
       v4lelement->vcap.name, v4lelement->videodev);
 
   /* norms + inputs, for the tuner interface */
@@ -256,7 +263,7 @@ gst_v4l_close (GstV4lElement * v4lelement)
 
 /******************************************************
  * gst_v4l_get_num_chans()
- * return value: the numver of video input channels
+ * return value: the number of video input channels
  ******************************************************/
 
 gint
diff --git a/sys/v4l/v4l_calls.h b/sys/v4l/v4l_calls.h
index 0ab608c30..701868f8a 100644
--- a/sys/v4l/v4l_calls.h
+++ b/sys/v4l/v4l_calls.h
@@ -1,4 +1,7 @@
-/* G-Streamer generic V4L element - generic V4L calls handling
+/* GStreamer
+ *
+ * v4l_calls.h: header for generic V4L calls
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -127,7 +130,7 @@ gboolean gst_v4l_set_frequency  (GstV4lElement *v4lelement,
 gboolean gst_v4l_get_picture    (GstV4lElement *v4lelement,
 				 GstV4lPictureType type,
 				 gint          *value);
-gboolean gst_v4l_set_picture    (GstV4lElement *v4lelement,	
+gboolean gst_v4l_set_picture    (GstV4lElement *v4lelement,
 				 GstV4lPictureType type,
 				 gint           value);
 
diff --git a/sys/v4l/v4lmjpegsink_calls.c b/sys/v4l/v4lmjpegsink_calls.c
index 7c319470c..416f80ea0 100644
--- a/sys/v4l/v4lmjpegsink_calls.c
+++ b/sys/v4l/v4lmjpegsink_calls.c
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video sink plugin
+/* GStreamer
+ *
+ * v4lmjpegsink_calls.c: functions for hardware MJPEG video sink
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -36,11 +39,8 @@
 #define MAP_FAILED ( (caddr_t) -1 )
 #endif
 
-#define DEBUG(format, args...) \
-	GST_DEBUG_OBJECT (\
-		GST_ELEMENT(v4lmjpegsink), \
-		"V4LMJPEGSINK: " format, ##args)
-
+GST_DEBUG_CATEGORY_EXTERN (v4lmjpegsink_debug);
+#define GST_CAT_DEFAULT v4lmjpegsink_debug
 
 /******************************************************
  * gst_v4lmjpegsink_sync_thread()
@@ -53,7 +53,7 @@ gst_v4lmjpegsink_sync_thread (void *arg)
   GstV4lMjpegSink *v4lmjpegsink = GST_V4LMJPEGSINK (arg);
   gint frame = 0;               /* frame that we're currently syncing on */
 
-  DEBUG ("starting sync thread");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "starting sync thread");
 
 #if 0
   /* Allow easy shutting down by other processes... */
@@ -73,7 +73,7 @@ gst_v4lmjpegsink_sync_thread (void *arg)
     }
     g_mutex_unlock (v4lmjpegsink->mutex_queued_frames);
 
-    DEBUG ("thread-syncing on next frame");
+    GST_DEBUG_OBJECT (v4lmjpegsink, "thread-syncing on next frame");
     if (ioctl (GST_V4LELEMENT (v4lmjpegsink)->video_fd, MJPIOC_SYNC,
             &(v4lmjpegsink->bsync)) < 0) {
       GST_ELEMENT_ERROR (v4lmjpegsink, RESOURCE, SYNC, (NULL),
@@ -100,7 +100,7 @@ gst_v4lmjpegsink_sync_thread (void *arg)
   }
 
 end:
-  DEBUG ("Sync thread got signalled to exit");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "Sync thread got signalled to exit");
   g_thread_exit (NULL);
   return NULL;
 }
@@ -115,7 +115,7 @@ end:
 static gboolean
 gst_v4lmjpegsink_queue_frame (GstV4lMjpegSink * v4lmjpegsink, gint num)
 {
-  DEBUG ("queueing frame %d", num);
+  GST_DEBUG_OBJECT (v4lmjpegsink, "queueing frame %d", num);
 
   /* queue on this frame */
   if (ioctl (GST_V4LELEMENT (v4lmjpegsink)->video_fd, MJPIOC_QBUF_PLAY,
@@ -143,7 +143,7 @@ gst_v4lmjpegsink_queue_frame (GstV4lMjpegSink * v4lmjpegsink, gint num)
 static gboolean
 gst_v4lmjpegsink_sync_frame (GstV4lMjpegSink * v4lmjpegsink, gint * num)
 {
-  DEBUG ("syncing on next frame");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "syncing on next frame");
 
   /* calculate next frame */
   v4lmjpegsink->current_frame =
@@ -175,8 +175,8 @@ gboolean
 gst_v4lmjpegsink_set_buffer (GstV4lMjpegSink * v4lmjpegsink,
     gint numbufs, gint bufsize)
 {
-  DEBUG ("setting buffer info to numbufs = %d, bufsize = %d KB",
-      numbufs, bufsize);
+  GST_DEBUG_OBJECT (v4lmjpegsink,
+      "setting buffer info to numbufs = %d, bufsize = %d KB", numbufs, bufsize);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
@@ -201,8 +201,8 @@ gst_v4lmjpegsink_set_playback (GstV4lMjpegSink * v4lmjpegsink,
   gint mw, mh;
   struct mjpeg_params bparm;
 
-  DEBUG
-      ("setting size = %dx%d, X/Y-offsets = %d/%d, norm = %d, interlacing = %d\n",
+  GST_DEBUG_OBJECT (v4lmjpegsink,
+      "setting size=%dx%d, X/Y offsets=%d/%d, norm=%d, interlacing=%d\n",
       width, height, x_offset, y_offset, norm, interlacing);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   /*GST_V4L_CHECK_NOT_ACTIVE(GST_V4LELEMENT(v4lmjpegsink)); */
@@ -317,7 +317,7 @@ gst_v4lmjpegsink_playback_init (GstV4lMjpegSink * v4lmjpegsink)
 {
   gint n;
 
-  DEBUG ("initting playback subsystem");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "initting playback subsystem");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
@@ -328,7 +328,7 @@ gst_v4lmjpegsink_playback_init (GstV4lMjpegSink * v4lmjpegsink)
     return FALSE;
   }
 
-  GST_INFO ("Got %ld buffers of size %ld KB",
+  GST_INFO_OBJECT (v4lmjpegsink, "Got %ld buffers of size %ld KB",
       v4lmjpegsink->breq.count, v4lmjpegsink->breq.size / 1024);
 
   /* Map the buffers */
@@ -378,7 +378,7 @@ gst_v4lmjpegsink_playback_start (GstV4lMjpegSink * v4lmjpegsink)
   GError *error;
   gint n;
 
-  DEBUG ("starting playback");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "starting playback");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
@@ -411,7 +411,7 @@ gst_v4lmjpegsink_playback_start (GstV4lMjpegSink * v4lmjpegsink)
 guint8 *
 gst_v4lmjpegsink_get_buffer (GstV4lMjpegSink * v4lmjpegsink, gint num)
 {
-  /*DEBUG("gst_v4lmjpegsink_get_buffer(), num = %d", num); */
+  /*GST_DEBUG_OBJECT (v4lmjpegsink, gst_v4lmjpegsink_get_buffer(), num = %d", num); */
 
   if (!GST_V4L_IS_ACTIVE (GST_V4LELEMENT (v4lmjpegsink)) ||
       !GST_V4L_IS_OPEN (GST_V4LELEMENT (v4lmjpegsink)))
@@ -434,7 +434,7 @@ gst_v4lmjpegsink_get_buffer (GstV4lMjpegSink * v4lmjpegsink, gint num)
 gboolean
 gst_v4lmjpegsink_play_frame (GstV4lMjpegSink * v4lmjpegsink, gint num)
 {
-  DEBUG ("playing frame %d", num);
+  GST_DEBUG_OBJECT (v4lmjpegsink, "playing frame %d", num);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
@@ -454,7 +454,8 @@ gst_v4lmjpegsink_play_frame (GstV4lMjpegSink * v4lmjpegsink, gint num)
 gboolean
 gst_v4lmjpegsink_wait_frame (GstV4lMjpegSink * v4lmjpegsink, gint * num)
 {
-  DEBUG ("waiting for next frame to be finished playing");
+  GST_DEBUG_OBJECT (v4lmjpegsink,
+      "waiting for next frame to be finished playing");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
@@ -476,7 +477,7 @@ gst_v4lmjpegsink_playback_stop (GstV4lMjpegSink * v4lmjpegsink)
 {
   gint num;
 
-  DEBUG ("stopping playback");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "stopping playback");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
@@ -504,7 +505,7 @@ gst_v4lmjpegsink_playback_deinit (GstV4lMjpegSink * v4lmjpegsink)
 {
   int n;
 
-  DEBUG ("quitting playback subsystem");
+  GST_DEBUG_OBJECT (v4lmjpegsink, "quitting playback subsystem");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsink));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsink));
 
diff --git a/sys/v4l/v4lmjpegsink_calls.h b/sys/v4l/v4lmjpegsink_calls.h
index 1a68a3c8f..beebaf450 100644
--- a/sys/v4l/v4lmjpegsink_calls.h
+++ b/sys/v4l/v4lmjpegsink_calls.h
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video sink plugin
+/* GStreamer
+ *
+ * v4lmjpegsink_calls.c: functions for hardware MJPEG video sink
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
diff --git a/sys/v4l/v4lmjpegsrc_calls.c b/sys/v4l/v4lmjpegsrc_calls.c
index 05bf87856..822fc6044 100644
--- a/sys/v4l/v4lmjpegsrc_calls.c
+++ b/sys/v4l/v4lmjpegsrc_calls.c
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video source plugin
+/* GStreamer
+ *
+ * v4lmjpegsrc_calls.c: functions for hardware MJPEG video source
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -37,10 +40,8 @@
 
 #define MIN_BUFFERS_QUEUED 2
 
-#define DEBUG(format, args...) \
-	GST_DEBUG_OBJECT (\
-		GST_ELEMENT(v4lmjpegsrc), \
-		"V4LMJPEGSRC: " format, ##args)
+GST_DEBUG_CATEGORY_EXTERN (v4lmjpegsrc_debug);
+#define GST_CAT_DEFAULT v4lmjpegsrc_debug
 
 enum
 {
@@ -59,7 +60,7 @@ enum
 static gboolean
 gst_v4lmjpegsrc_queue_frame (GstV4lMjpegSrc * v4lmjpegsrc, gint num)
 {
-  DEBUG ("queueing frame %d", num);
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "queueing frame %d", num);
 
   if (v4lmjpegsrc->frame_queue_state[num] != QUEUE_STATE_READY_FOR_QUEUE) {
     return FALSE;
@@ -88,7 +89,7 @@ gst_v4lmjpegsrc_queue_frame (GstV4lMjpegSrc * v4lmjpegsrc, gint num)
 static gboolean
 gst_v4lmjpegsrc_sync_next_frame (GstV4lMjpegSrc * v4lmjpegsrc, gint * num)
 {
-  DEBUG ("syncing on next frame");
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "syncing on next frame");
 
   if (v4lmjpegsrc->num_queued <= 0) {
     return FALSE;
@@ -100,7 +101,7 @@ gst_v4lmjpegsrc_sync_next_frame (GstV4lMjpegSrc * v4lmjpegsrc, gint * num)
       GST_ELEMENT_ERROR (v4lmjpegsrc, RESOURCE, SYNC, (NULL), GST_ERROR_SYSTEM);
       return FALSE;
     }
-    DEBUG ("Sync got interrupted");
+    GST_DEBUG_OBJECT (v4lmjpegsrc, "Sync got interrupted");
   }
 
   *num = v4lmjpegsrc->bsync.frame;
@@ -122,8 +123,8 @@ gboolean
 gst_v4lmjpegsrc_set_buffer (GstV4lMjpegSrc * v4lmjpegsrc,
     gint numbufs, gint bufsize)
 {
-  DEBUG ("setting buffer info to numbufs = %d, bufsize = %d KB",
-      numbufs, bufsize);
+  GST_DEBUG_OBJECT (v4lmjpegsrc,
+      "setting buffer info to numbufs = %d, bufsize = %d KB", numbufs, bufsize);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -147,7 +148,8 @@ gst_v4lmjpegsrc_set_capture (GstV4lMjpegSrc * v4lmjpegsrc,
   int norm, input, mw;
   struct mjpeg_params bparm;
 
-  DEBUG ("setting decimation = %d, quality = %d", decimation, quality);
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "setting decimation = %d, quality = %d",
+      decimation, quality);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -207,7 +209,7 @@ gst_v4lmjpegsrc_set_capture_m (GstV4lMjpegSrc * v4lmjpegsrc,
   gint maxwidth;
   struct mjpeg_params bparm;
 
-  DEBUG ("setting x_offset = %d, y_offset = %d, "
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "setting x_offset = %d, y_offset = %d, "
       "width = %d, height = %d, h_decimation = %d, v_decimation = %d, quality = %d\n",
       x_offset, y_offset, width, height, h_decimation, v_decimation, quality);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
@@ -318,7 +320,7 @@ gst_v4lmjpegsrc_set_capture_m (GstV4lMjpegSrc * v4lmjpegsrc,
 gboolean
 gst_v4lmjpegsrc_capture_init (GstV4lMjpegSrc * v4lmjpegsrc)
 {
-  DEBUG ("initting capture subsystem");
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "initting capture subsystem");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -336,7 +338,7 @@ gst_v4lmjpegsrc_capture_init (GstV4lMjpegSrc * v4lmjpegsrc)
     return FALSE;
   }
 
-  GST_INFO ("Got %ld buffers of size %ld KB",
+  GST_INFO_OBJECT (v4lmjpegsrc, "Got %ld buffers of size %ld KB",
       v4lmjpegsrc->breq.count, v4lmjpegsrc->breq.size / 1024);
 
   /* keep track of queued buffers */
@@ -378,7 +380,7 @@ gst_v4lmjpegsrc_capture_start (GstV4lMjpegSrc * v4lmjpegsrc)
 {
   int n;
 
-  DEBUG ("starting capture");
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "starting capture");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -414,7 +416,7 @@ gboolean
 gst_v4lmjpegsrc_grab_frame (GstV4lMjpegSrc * v4lmjpegsrc,
     gint * num, gint * size)
 {
-  DEBUG ("grabbing frame");
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "grabbing frame");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -426,7 +428,8 @@ gst_v4lmjpegsrc_grab_frame (GstV4lMjpegSrc * v4lmjpegsrc,
       QUEUE_STATE_READY_FOR_QUEUE) {
     while (v4lmjpegsrc->frame_queue_state[v4lmjpegsrc->queue_frame] !=
         QUEUE_STATE_READY_FOR_QUEUE && !v4lmjpegsrc->quit) {
-      GST_DEBUG ("Waiting for frames to become available (%d < %d)",
+      GST_DEBUG_OBJECT (v4lmjpegsrc,
+          "Waiting for frames to become available (%d < %d)",
           v4lmjpegsrc->num_queued, MIN_BUFFERS_QUEUED);
       g_cond_wait (v4lmjpegsrc->cond_queue_state,
           v4lmjpegsrc->mutex_queue_state);
@@ -487,7 +490,7 @@ gst_v4lmjpegsrc_get_buffer (GstV4lMjpegSrc * v4lmjpegsrc, gint num)
 gboolean
 gst_v4lmjpegsrc_requeue_frame (GstV4lMjpegSrc * v4lmjpegsrc, gint num)
 {
-  DEBUG ("requeueing frame %d", num);
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "requeueing frame %d", num);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -523,7 +526,7 @@ gst_v4lmjpegsrc_capture_stop (GstV4lMjpegSrc * v4lmjpegsrc)
 {
   int n;
 
-  DEBUG ("stopping capture");
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "stopping capture");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
@@ -553,7 +556,7 @@ gst_v4lmjpegsrc_capture_stop (GstV4lMjpegSrc * v4lmjpegsrc)
 gboolean
 gst_v4lmjpegsrc_capture_deinit (GstV4lMjpegSrc * v4lmjpegsrc)
 {
-  DEBUG ("quitting capture subsystem");
+  GST_DEBUG_OBJECT (v4lmjpegsrc, "quitting capture subsystem");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lmjpegsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lmjpegsrc));
 
diff --git a/sys/v4l/v4lmjpegsrc_calls.h b/sys/v4l/v4lmjpegsrc_calls.h
index 6d4d2652a..e873ea014 100644
--- a/sys/v4l/v4lmjpegsrc_calls.h
+++ b/sys/v4l/v4lmjpegsrc_calls.h
@@ -1,4 +1,7 @@
-/* G-Streamer hardware MJPEG video source plugin
+/* GStreamer
+ *
+ * v4lmjpegsrc_calls.h: functions for hardware MJPEG video source
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
diff --git a/sys/v4l/v4lsrc_calls.c b/sys/v4l/v4lsrc_calls.c
index 718e8e4b2..6cf1df18a 100644
--- a/sys/v4l/v4lsrc_calls.c
+++ b/sys/v4l/v4lsrc_calls.c
@@ -1,4 +1,7 @@
-/* G-Streamer BT8x8/V4L frame grabber plugin
+/* GStreamer
+ *
+ * v4lsrc_calls.c: generic V4L source functions
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or
@@ -44,16 +47,6 @@ GST_DEBUG_CATEGORY_EXTERN (v4l_debug);
 
 #define GST_CAT_DEFAULT v4l_debug
 
-#define DEBUG(format, args...) \
-	GST_DEBUG_OBJECT (\
-		GST_ELEMENT(v4lsrc), \
-		"V4LSRC: " format, ##args)
-#define LOG(format, args...) \
-	GST_LOG_OBJECT (\
-		GST_ELEMENT(v4lsrc), \
-		"V4LSRC: " format, ##args)
-
-
 /* palette names */
 static const char *palette_name[] = {
   "",                           /* 0 */
@@ -78,6 +71,7 @@ static const char *palette_name[] = {
 /******************************************************
  * gst_v4lsrc_queue_frame():
  *   queue a frame for capturing
+ *   (ie. instruct the hardware to start capture)
  *   Requires queue_state lock to be held!
  * return value: TRUE on success, FALSE on error
  ******************************************************/
@@ -85,14 +79,14 @@ static const char *palette_name[] = {
 static gboolean
 gst_v4lsrc_queue_frame (GstV4lSrc * v4lsrc, gint num)
 {
-  LOG ("queueing frame %d", num);
+  GST_LOG_OBJECT (v4lsrc, "queueing frame %d", num);
 
   if (v4lsrc->frame_queue_state[num] != QUEUE_STATE_READY_FOR_QUEUE) {
     return FALSE;
   }
 
+  /* instruct the driver to prepare capture using buffer frame num */
   v4lsrc->mmap.frame = num;
-
   if (ioctl (GST_V4LELEMENT (v4lsrc)->video_fd,
           VIDIOCMCAPTURE, &(v4lsrc->mmap)) < 0) {
     GST_ELEMENT_ERROR (v4lsrc, RESOURCE, WRITE, (NULL),
@@ -115,7 +109,7 @@ gst_v4lsrc_queue_frame (GstV4lSrc * v4lsrc, gint num)
 static gboolean
 gst_v4lsrc_sync_frame (GstV4lSrc * v4lsrc, gint num)
 {
-  LOG ("Syncing on frame %d", num);
+  GST_LOG_OBJECT (v4lsrc, "VIOIOCSYNC on frame %d", num);
 
   if (v4lsrc->frame_queue_state[num] != QUEUE_STATE_QUEUED) {
     return FALSE;
@@ -128,8 +122,9 @@ gst_v4lsrc_sync_frame (GstV4lSrc * v4lsrc, gint num)
       GST_ELEMENT_ERROR (v4lsrc, RESOURCE, SYNC, (NULL), GST_ERROR_SYSTEM);
       return FALSE;
     }
-    DEBUG ("Sync got interrupted");
+    GST_DEBUG_OBJECT (v4lsrc, "Sync got interrupted");
   }
+  GST_LOG_OBJECT (v4lsrc, "VIOIOCSYNC on frame %d done", num);
 
   if (v4lsrc->clock) {
     v4lsrc->timestamp_sync = gst_clock_get_time (v4lsrc->clock);
@@ -156,7 +151,8 @@ gboolean
 gst_v4lsrc_set_capture (GstV4lSrc * v4lsrc,
     gint width, gint height, gint palette)
 {
-  DEBUG ("capture properties set to width = %d, height = %d, palette = %d",
+  GST_DEBUG_OBJECT (v4lsrc,
+      "capture properties set to width = %d, height = %d, palette = %d",
       width, height, palette);
 
   /*GST_V4L_CHECK_OPEN(GST_V4LELEMENT(v4lsrc)); */
@@ -179,11 +175,12 @@ gst_v4lsrc_set_capture (GstV4lSrc * v4lsrc,
 gboolean
 gst_v4lsrc_capture_init (GstV4lSrc * v4lsrc)
 {
-  DEBUG ("initting capture subsystem");
+  GST_DEBUG_OBJECT (v4lsrc, "initting capture subsystem");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lsrc));
 
-  /* request buffer info */
+  /* request the mmap buffer info:
+   * total size of mmap buffer, number of frames, offsets of frames */
   if (ioctl (GST_V4LELEMENT (v4lsrc)->video_fd, VIDIOCGMBUF,
           &(v4lsrc->mbuf)) < 0) {
     GST_ELEMENT_ERROR (v4lsrc, RESOURCE, READ, (NULL),
@@ -198,7 +195,7 @@ gst_v4lsrc_capture_init (GstV4lSrc * v4lsrc)
     return FALSE;
   }
 
-  GST_INFO ("Got %d buffers (\'%s\') of size %d KB",
+  GST_INFO_OBJECT (v4lsrc, "Got %d buffers (\'%s\') with total size %d KB",
       v4lsrc->mbuf.frames, palette_name[v4lsrc->mmap.format],
       v4lsrc->mbuf.size / (v4lsrc->mbuf.frames * 1024));
 
@@ -218,7 +215,7 @@ gst_v4lsrc_capture_init (GstV4lSrc * v4lsrc)
   GST_V4LELEMENT (v4lsrc)->buffer = mmap (0, v4lsrc->mbuf.size,
       PROT_READ | PROT_WRITE, MAP_SHARED, GST_V4LELEMENT (v4lsrc)->video_fd, 0);
   if (GST_V4LELEMENT (v4lsrc)->buffer == MAP_FAILED) {
-    GST_ELEMENT_ERROR (v4lsrc, RESOURCE, TOO_LAZY, (NULL),
+    GST_ELEMENT_ERROR (v4lsrc, RESOURCE, OPEN_READ_WRITE, (NULL),
         ("Error mapping video buffers: %s", g_strerror (errno)));
     GST_V4LELEMENT (v4lsrc)->buffer = NULL;
     return FALSE;
@@ -239,7 +236,7 @@ gst_v4lsrc_capture_start (GstV4lSrc * v4lsrc)
 {
   int n;
 
-  DEBUG ("starting capture");
+  GST_DEBUG_OBJECT (v4lsrc, "starting capture");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lsrc));
 
@@ -250,7 +247,8 @@ gst_v4lsrc_capture_start (GstV4lSrc * v4lsrc)
   v4lsrc->sync_frame = 0;
   v4lsrc->queue_frame = 0;
 
-  /* set all buffers ready to queue , this starts streaming capture */
+  /* set all buffers ready to queue, and queue captures to the device.
+   * This starts streaming capture */
   for (n = 0; n < v4lsrc->mbuf.frames; n++) {
     v4lsrc->frame_queue_state[n] = QUEUE_STATE_READY_FOR_QUEUE;
     if (!gst_v4lsrc_queue_frame (v4lsrc, n)) {
@@ -276,8 +274,7 @@ gst_v4lsrc_capture_start (GstV4lSrc * v4lsrc)
 gboolean
 gst_v4lsrc_grab_frame (GstV4lSrc * v4lsrc, gint * num)
 {
-  LOG ("(%" GST_TIME_FORMAT ") grabbing frame",
-      GST_TIME_ARGS (gst_clock_get_time (v4lsrc->clock)));
+  GST_LOG_OBJECT (v4lsrc, "grabbing frame");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lsrc));
 
@@ -289,7 +286,8 @@ gst_v4lsrc_grab_frame (GstV4lSrc * v4lsrc, gint * num)
       QUEUE_STATE_READY_FOR_QUEUE) {
     while (v4lsrc->frame_queue_state[v4lsrc->queue_frame] !=
         QUEUE_STATE_READY_FOR_QUEUE && !v4lsrc->quit) {
-      GST_DEBUG ("Waiting for frames to become available (%d < %d)",
+      GST_DEBUG_OBJECT (v4lsrc,
+          "Waiting for frames to become available (%d < %d)",
           v4lsrc->num_queued, MIN_BUFFERS_QUEUED);
       g_cond_wait (v4lsrc->cond_queue_state, v4lsrc->mutex_queue_state);
     }
@@ -312,7 +310,7 @@ gst_v4lsrc_grab_frame (GstV4lSrc * v4lsrc, gint * num)
   }
   v4lsrc->sync_frame = (v4lsrc->sync_frame + 1) % v4lsrc->mbuf.frames;
 
-  LOG ("(%" GST_TIME_FORMAT ") grabbed frame %d",
+  GST_LOG_OBJECT (v4lsrc, "(%" GST_TIME_FORMAT ") grabbed frame %d",
       GST_TIME_ARGS (gst_clock_get_time (v4lsrc->clock)), *num);
 
   g_mutex_unlock (v4lsrc->mutex_queue_state);
@@ -323,7 +321,7 @@ gst_v4lsrc_grab_frame (GstV4lSrc * v4lsrc, gint * num)
 
 /******************************************************
  * gst_v4lsrc_get_buffer():
- *   get the address of the just-capture buffer
+ *   get the address of the given frame number in the mmap'd buffer
  * return value: the buffer's address or NULL
  ******************************************************/
 
@@ -350,7 +348,7 @@ gst_v4lsrc_get_buffer (GstV4lSrc * v4lsrc, gint num)
 gboolean
 gst_v4lsrc_requeue_frame (GstV4lSrc * v4lsrc, gint num)
 {
-  LOG ("requeueing frame %d", num);
+  GST_LOG_OBJECT (v4lsrc, "requeueing frame %d", num);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lsrc));
 
@@ -384,7 +382,7 @@ gst_v4lsrc_requeue_frame (GstV4lSrc * v4lsrc, gint num)
 gboolean
 gst_v4lsrc_capture_stop (GstV4lSrc * v4lsrc)
 {
-  DEBUG ("stopping capture");
+  GST_DEBUG_OBJECT (v4lsrc, "stopping capture");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lsrc));
 
@@ -420,18 +418,26 @@ gst_v4lsrc_capture_stop (GstV4lSrc * v4lsrc)
 gboolean
 gst_v4lsrc_capture_deinit (GstV4lSrc * v4lsrc)
 {
-  DEBUG ("quitting capture subsystem");
+  GST_DEBUG_OBJECT (v4lsrc, "quitting capture subsystem");
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_ACTIVE (GST_V4LELEMENT (v4lsrc));
 
   /* free buffer tracker */
   g_mutex_free (v4lsrc->mutex_queue_state);
+  v4lsrc->mutex_queue_state = NULL;
   g_cond_free (v4lsrc->cond_queue_state);
+  v4lsrc->cond_queue_state = NULL;
   g_free (v4lsrc->frame_queue_state);
+  v4lsrc->frame_queue_state = NULL;
   g_free (v4lsrc->use_num_times);
+  v4lsrc->use_num_times = NULL;
 
   /* unmap the buffer */
-  munmap (GST_V4LELEMENT (v4lsrc)->buffer, v4lsrc->mbuf.size);
+  if (munmap (GST_V4LELEMENT (v4lsrc)->buffer, v4lsrc->mbuf.size) == -1) {
+    GST_ELEMENT_ERROR (v4lsrc, RESOURCE, CLOSE, (NULL),
+        ("error munmap'ing capture buffer: %s", g_strerror (errno)));
+    return FALSE;
+  }
   GST_V4LELEMENT (v4lsrc)->buffer = NULL;
 
   return TRUE;
@@ -463,7 +469,7 @@ gst_v4lsrc_try_palette (GstV4lSrc * v4lsrc, gint palette)
   struct video_mbuf vmbuf;
   struct video_mmap vmmap;
 
-  DEBUG ("gonna try out palette format %d (%s)",
+  GST_DEBUG_OBJECT (v4lsrc, "gonna try out palette format %d (%s)",
       palette, palette_name[palette]);
   GST_V4L_CHECK_OPEN (GST_V4LELEMENT (v4lsrc));
   GST_V4L_CHECK_NOT_ACTIVE (GST_V4LELEMENT (v4lsrc));
@@ -478,7 +484,7 @@ gst_v4lsrc_try_palette (GstV4lSrc * v4lsrc, gint palette)
   buffer = mmap (0, vmbuf.size, PROT_READ | PROT_WRITE,
       MAP_SHARED, GST_V4LELEMENT (v4lsrc)->video_fd, 0);
   if (buffer == MAP_FAILED) {
-    GST_ELEMENT_ERROR (v4lsrc, RESOURCE, TOO_LAZY, (NULL),
+    GST_ELEMENT_ERROR (v4lsrc, RESOURCE, OPEN_READ_WRITE, (NULL),
         ("Error mapping our try-out buffer: %s", g_strerror (errno)));
     return FALSE;
   }
@@ -490,7 +496,7 @@ gst_v4lsrc_try_palette (GstV4lSrc * v4lsrc, gint palette)
   vmmap.frame = frame;
   if (ioctl (GST_V4LELEMENT (v4lsrc)->video_fd, VIDIOCMCAPTURE, &vmmap) < 0) {
     if (errno != EINVAL)        /* our format failed! */
-      GST_ELEMENT_ERROR (v4lsrc, RESOURCE, TOO_LAZY, (NULL),
+      GST_ELEMENT_ERROR (v4lsrc, RESOURCE, OPEN_READ_WRITE, (NULL),
           ("Error queueing our try-out buffer: %s", g_strerror (errno)));
     munmap (buffer, vmbuf.size);
     return FALSE;
diff --git a/sys/v4l/v4lsrc_calls.h b/sys/v4l/v4lsrc_calls.h
index 2a58691ce..9b013fc7b 100644
--- a/sys/v4l/v4lsrc_calls.h
+++ b/sys/v4l/v4lsrc_calls.h
@@ -1,4 +1,7 @@
-/* G-Streamer BT8x8/V4L frame grabber plugin
+/* GStreamer
+ *
+ * v4lsrc_calls.h: functions for V4L video source
+ *
  * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
  *
  * This library is free software; you can redistribute it and/or