sys/v4l2/: implement read access. V4l2src will use read access if mmap doesn't work.

Original commit message from CVS:
* sys/v4l2/v4l2src_calls.c: (gst_v4l2src_capture_init),
(gst_v4l2src_capture_start), (gst_v4l2src_capture_stop),
(gst_v4l2src_capture_deinit):
* sys/v4l2/gstv4l2src.c: (gst_v4l2src_getcaps),
(gst_v4l2src_get_read), (gst_v4l2src_get_mmap), (gst_v4l2src_get):
implement read access. V4l2src will use read access if mmap doesn't
work.
* sys/v4l2/v4l2_calls.c: (gst_v4l2_get_capabilities),
(gst_v4l2_get_norm), (gst_v4l2_set_norm), (gst_v4l2_get_input),
(gst_v4l2_set_input), (gst_v4l2_get_output), (gst_v4l2_set_output),
(gst_v4l2_get_frequency), (gst_v4l2_set_frequency),
(gst_v4l2_signal_strength), (gst_v4l2_get_attribute),
(gst_v4l2_set_attribute):
don't GST_ELEMENT_ERROR on get/set functions. Fail silently instead,
but do output a debugging message

4 files changed, 254 insertions, 145 deletions

diff --git a/ChangeLog b/ChangeLog
index d8741e7ae..2cbcc9801 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2005-07-22  Benjamin Otte  <otte@gnome.org>
+
+	* sys/v4l2/v4l2src_calls.c: (gst_v4l2src_capture_init),
+	(gst_v4l2src_capture_start), (gst_v4l2src_capture_stop),
+	(gst_v4l2src_capture_deinit):
+	* sys/v4l2/gstv4l2src.c: (gst_v4l2src_getcaps),
+	(gst_v4l2src_get_read), (gst_v4l2src_get_mmap), (gst_v4l2src_get):
+	  implement read access. V4l2src will use read access if mmap doesn't
+	  work.
+	* sys/v4l2/v4l2_calls.c: (gst_v4l2_get_capabilities),
+	(gst_v4l2_get_norm), (gst_v4l2_set_norm), (gst_v4l2_get_input),
+	(gst_v4l2_set_input), (gst_v4l2_get_output), (gst_v4l2_set_output),
+	(gst_v4l2_get_frequency), (gst_v4l2_set_frequency),
+	(gst_v4l2_signal_strength), (gst_v4l2_get_attribute),
+	(gst_v4l2_set_attribute):
+	  don't GST_ELEMENT_ERROR on get/set functions. Fail silently instead,
+	  but do output a debugging message
+
 2005-07-22  Ronald S. Bultje  <rbultje@ronald.bitfreak.net>
 
 	* gst-libs/gst/riff/riff-media.c:
diff --git a/sys/v4l2/gstv4l2src.c b/sys/v4l2/gstv4l2src.c
index b563d9c61..44eb76418 100644
--- a/sys/v4l2/gstv4l2src.c
+++ b/sys/v4l2/gstv4l2src.c
@@ -23,6 +23,7 @@
 
 #include <string.h>
 #include <sys/time.h>
+#include <unistd.h>
 #include "v4l2src_calls.h"
 #include "gstv4l2tuner.h"
 
@@ -788,14 +789,10 @@ gst_v4l2src_getcaps (GstPad * pad)
       continue;
     }
     /* template */
-    if (min_w < 1)
-      min_w = 1;
-    if (min_h < 1)
-      min_h = 1;
-    if (max_w > 4096)
-      max_w = 4096;
-    if (max_h > 4096)
-      max_h = 4096;
+    min_w = CLAMP (min_w, 1, 4096);
+    min_h = CLAMP (min_h, 1, 4096);
+    max_w = CLAMP (max_w, min_w, 4096);
+    max_h = CLAMP (max_h, min_h, 4096);
 
     /* add to list */
     structure = gst_v4l2src_v4l2fourcc_to_caps (format->pixelformat);
@@ -814,20 +811,51 @@ gst_v4l2src_getcaps (GstPad * pad)
 }
 
 static GstData *
-gst_v4l2src_get (GstPad * pad)
+gst_v4l2src_get_read (GstV4l2Src * v4l2src)
 {
-  GstV4l2Src *v4l2src;
-  GstBuffer *buf;
-  gint i, num = -1;
-  gdouble fps = 0;
+  gint amount;
+  gint buffersize;
+
+  buffersize = v4l2src->format.fmt.pix.sizeimage;
+  do {
+    GstBuffer *buf =
+        gst_pad_alloc_buffer (v4l2src->srcpad, GST_BUFFER_OFFSET_NONE,
+        buffersize);
+    amount =
+        read (GST_V4L2ELEMENT (v4l2src)->video_fd, GST_BUFFER_DATA (buf),
+        buffersize);
+    if (amount == buffersize) {
+      gdouble fps = gst_v4l2src_get_fps (v4l2src);
 
-  v4l2src = GST_V4L2SRC (gst_pad_get_parent (pad));
+      GST_BUFFER_TIMESTAMP (buf) = v4l2src->handled * GST_SECOND / fps;
+      GST_BUFFER_DURATION (buf) = GST_SECOND / fps;
+      return GST_DATA (buf);
+    } else if (amount == -1) {
+      if (errno == EAGAIN || errno == EINTR) {
+        continue;
+      } else {
+        GST_ELEMENT_ERROR (v4l2src, RESOURCE, SYNC, (NULL),
+            ("error read()ing a buffer on device %s: %s",
+                GST_V4L2ELEMENT (v4l2src)->device, g_strerror (errno)));
+        gst_data_unref (GST_DATA (buf));
+        return NULL;
+      }
+    } else {
+      GST_ELEMENT_ERROR (v4l2src, RESOURCE, SYNC, (NULL),
+          ("error read()ing a buffer on device %s: got only %d bytes instead of expected %d",
+              GST_V4L2ELEMENT (v4l2src)->device, amount, buffersize));
+      gst_data_unref (GST_DATA (buf));
+      return NULL;
+    }
+  } while (TRUE);
+}
 
-  if (v4l2src->use_fixed_fps && (fps = gst_v4l2src_get_fps (v4l2src)) == 0) {
-    GST_ELEMENT_ERROR (v4l2src, RESOURCE, SETTINGS, (NULL),
-        ("could not get frame rate for element"));
-    return NULL;
-  }
+static GstData *
+gst_v4l2src_get_mmap (GstV4l2Src * v4l2src)
+{
+  GstBuffer *buf;
+  gint i, num = -1;
+  gdouble fps = gst_v4l2src_get_fps (v4l2src);
 
   if (v4l2src->need_writes > 0) {
     /* use last frame */
@@ -947,13 +975,35 @@ gst_v4l2src_get (GstPad * pad)
     }
   }
 
-  v4l2src->handled++;
-  g_signal_emit (G_OBJECT (v4l2src), gst_v4l2src_signals[SIGNAL_FRAME_CAPTURE],
-      0);
-
   return GST_DATA (buf);
 }
 
+static GstData *
+gst_v4l2src_get (GstPad * pad)
+{
+  GstV4l2Src *v4l2src = GST_V4L2SRC (gst_pad_get_parent (pad));
+  GstData *ret;
+
+  if (v4l2src->use_fixed_fps && gst_v4l2src_get_fps (v4l2src) == 0) {
+    GST_ELEMENT_ERROR (v4l2src, RESOURCE, SETTINGS, (NULL),
+        ("could not get frame rate for element"));
+    return NULL;
+  }
+
+  if (v4l2src->breq.memory == V4L2_MEMORY_MMAP) {
+    ret = gst_v4l2src_get_mmap (v4l2src);
+  } else {
+    ret = gst_v4l2src_get_read (v4l2src);
+  }
+
+  if (ret) {
+    v4l2src->handled++;
+    g_signal_emit (G_OBJECT (v4l2src),
+        gst_v4l2src_signals[SIGNAL_FRAME_CAPTURE], 0);
+  }
+  return ret;
+}
+
 static void
 gst_v4l2src_set_property (GObject * object,
     guint prop_id, const GValue * value, GParamSpec * pspec)
diff --git a/sys/v4l2/v4l2_calls.c b/sys/v4l2/v4l2_calls.c
index b630fc04b..b0a9e5f68 100644
--- a/sys/v4l2/v4l2_calls.c
+++ b/sys/v4l2/v4l2_calls.c
@@ -35,6 +35,8 @@
 #include "gstv4l2colorbalance.h"
 
 #include "gstv4l2src.h"
+/* until someone comes up with a general category... */
+#define GST_CAT_DEFAULT v4l2src_debug
 
 #define DEBUG(format, args...) \
 	GST_DEBUG_OBJECT (\
@@ -52,12 +54,12 @@ static gboolean
 gst_v4l2_get_capabilities (GstV4l2Element * v4l2element)
 {
   DEBUG ("getting capabilities");
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_QUERYCAP, &(v4l2element->vcap)) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Error getting %s capabilities: %s",
-            v4l2element->device, g_strerror (errno)));
+    GST_ERROR_OBJECT (v4l2element, "Error getting %s capabilities: %s",
+        v4l2element->device, g_strerror (errno));
     return FALSE;
   }
 
@@ -475,12 +477,13 @@ gboolean
 gst_v4l2_get_norm (GstV4l2Element * v4l2element, v4l2_std_id * norm)
 {
   DEBUG ("getting norm");
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_G_STD, norm) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to get the current norm for device %s: %s",
-            v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to get the current norm for device %s: %s", v4l2element->device,
+        g_strerror (errno));
     return FALSE;
   }
 
@@ -498,13 +501,15 @@ gboolean
 gst_v4l2_set_norm (GstV4l2Element * v4l2element, v4l2_std_id norm)
 {
   DEBUG ("trying to set norm to %llx", norm);
-  GST_V4L2_CHECK_OPEN (v4l2element);
-  GST_V4L2_CHECK_NOT_ACTIVE (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
+  if (!GST_V4L2_IS_ACTIVE (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_S_STD, &norm) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to set norm 0x%llx for device %s: %s",
-            norm, v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to set norm 0x%llx for device %s: %s", norm,
+        v4l2element->device, g_strerror (errno));
     return FALSE;
   }
 
@@ -524,12 +529,13 @@ gst_v4l2_get_input (GstV4l2Element * v4l2element, gint * input)
   gint n;
 
   DEBUG ("trying to get input");
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_G_INPUT, &n) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to get current input on device %s: %s",
-            v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to get current input on device %s: %s", v4l2element->device,
+        g_strerror (errno));
     return FALSE;
   }
 
@@ -549,13 +555,14 @@ gboolean
 gst_v4l2_set_input (GstV4l2Element * v4l2element, gint input)
 {
   DEBUG ("trying to set input to %d", input);
-  GST_V4L2_CHECK_OPEN (v4l2element);
-  GST_V4L2_CHECK_NOT_ACTIVE (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
+  if (!GST_V4L2_IS_ACTIVE (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_S_INPUT, &input) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to set input %d on device %s: %s",
-            input, v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element, "Failed to set input %d on device %s: %s",
+        input, v4l2element->device, g_strerror (errno));
     return FALSE;
   }
 
@@ -575,12 +582,13 @@ gst_v4l2_get_output (GstV4l2Element * v4l2element, gint * output)
   gint n;
 
   DEBUG ("trying to get output");
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_G_OUTPUT, &n) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to get current output on device %s: %s",
-            v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to get current output on device %s: %s", v4l2element->device,
+        g_strerror (errno));
     return FALSE;
   }
 
@@ -600,13 +608,15 @@ gboolean
 gst_v4l2_set_output (GstV4l2Element * v4l2element, gint output)
 {
   DEBUG ("trying to set output to %d", output);
-  GST_V4L2_CHECK_OPEN (v4l2element);
-  GST_V4L2_CHECK_NOT_ACTIVE (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
+  if (!GST_V4L2_IS_ACTIVE (v4l2element))
+    return FALSE;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_S_OUTPUT, &output) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to set output %d on device %s: %s",
-            output, v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to set current output on device %s to %d: %s",
+        v4l2element->device, output, g_strerror (errno));
     return FALSE;
   }
 
@@ -628,15 +638,16 @@ gst_v4l2_get_frequency (GstV4l2Element * v4l2element,
   GstTunerChannel *channel;
 
   DEBUG ("getting current tuner frequency");
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   channel = gst_tuner_get_channel (GST_TUNER (v4l2element));
 
   freq.tuner = tunernum;
   if (ioctl (v4l2element->video_fd, VIDIOC_G_FREQUENCY, &freq) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to get current tuner frequency for device %s: %s",
-            v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to get current tuner frequency for device %s: %s",
+        v4l2element->device, g_strerror (errno));
     return FALSE;
   }
 
@@ -660,8 +671,10 @@ gst_v4l2_set_frequency (GstV4l2Element * v4l2element,
   GstTunerChannel *channel;
 
   DEBUG ("setting current tuner frequency to %lu", frequency);
-  GST_V4L2_CHECK_OPEN (v4l2element);
-  GST_V4L2_CHECK_NOT_ACTIVE (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
+  if (!GST_V4L2_IS_ACTIVE (v4l2element))
+    return FALSE;
 
   channel = gst_tuner_get_channel (GST_TUNER (v4l2element));
 
@@ -671,9 +684,9 @@ gst_v4l2_set_frequency (GstV4l2Element * v4l2element,
   freq.frequency = frequency / channel->freq_multiplicator;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_S_FREQUENCY, &freq) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to set tuner frequency to %lu for device %s: %s",
-            frequency, v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to set current tuner frequency for device %s to %lu: %s",
+        v4l2element->device, frequency, g_strerror (errno));
     return FALSE;
   }
 
@@ -694,13 +707,14 @@ gst_v4l2_signal_strength (GstV4l2Element * v4l2element,
   struct v4l2_tuner tuner;
 
   DEBUG ("trying to get signal strength");
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   tuner.index = tunernum;
   if (ioctl (v4l2element->video_fd, VIDIOC_G_TUNER, &tuner) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to get signal strength for device %s: %s",
-            v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to get signal strength for device %s: %s", v4l2element->device,
+        g_strerror (errno));
     return FALSE;
   }
 
@@ -722,16 +736,17 @@ gst_v4l2_get_attribute (GstV4l2Element * v4l2element,
 {
   struct v4l2_control control;
 
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   DEBUG ("getting value of attribute %d", attribute_num);
 
   control.id = attribute_num;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_G_CTRL, &control) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to get value for control %d on device %s: %s",
-            attribute_num, v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to get value for control %d on device %s: %s", attribute_num,
+        v4l2element->device, g_strerror (errno));
     return FALSE;
   }
 
@@ -753,7 +768,8 @@ gst_v4l2_set_attribute (GstV4l2Element * v4l2element,
 {
   struct v4l2_control control;
 
-  GST_V4L2_CHECK_OPEN (v4l2element);
+  if (!GST_V4L2_IS_OPEN (v4l2element))
+    return FALSE;
 
   DEBUG ("setting value of attribute %d to %d", attribute_num, value);
 
@@ -761,9 +777,9 @@ gst_v4l2_set_attribute (GstV4l2Element * v4l2element,
   control.value = value;
 
   if (ioctl (v4l2element->video_fd, VIDIOC_S_CTRL, &control) < 0) {
-    GST_ELEMENT_ERROR (v4l2element, RESOURCE, SETTINGS, (NULL),
-        ("Failed to set value %d for control %d on device %s: %s",
-            value, attribute_num, v4l2element->device, g_strerror (errno)));
+    GST_WARNING_OBJECT (v4l2element,
+        "Failed to set value %d for control %d on device %s: %s", value,
+        attribute_num, v4l2element->device, g_strerror (errno));
     return FALSE;
   }
 
diff --git a/sys/v4l2/v4l2src_calls.c b/sys/v4l2/v4l2src_calls.c
index 79d4aa7fa..a6c119554 100644
--- a/sys/v4l2/v4l2src_calls.c
+++ b/sys/v4l2/v4l2src_calls.c
@@ -249,72 +249,92 @@ gst_v4l2src_capture_init (GstV4l2Src * v4l2src)
     v4l2src->breq.count = GST_V4L2_MIN_BUFFERS;
   }
   v4l2src->breq.type = v4l2src->format.type;
-  v4l2src->breq.memory = V4L2_MEMORY_MMAP;
-  if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_REQBUFS,
-          &v4l2src->breq) < 0) {
+  if (GST_V4L2ELEMENT (v4l2src)->vcap.capabilities & V4L2_CAP_STREAMING) {
+    v4l2src->breq.memory = V4L2_MEMORY_MMAP;
+    if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_REQBUFS,
+            &v4l2src->breq) < 0) {
+      GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ,
+          (_("Could not get buffers from device \"%s\"."),
+              GST_V4L2ELEMENT (v4l2src)->device),
+          ("error requesting %d buffers: %s", v4l2src->breq.count,
+              g_strerror (errno)));
+      return FALSE;
+    }
+    GST_LOG_OBJECT (v4l2src, "using default mmap method");
+  } else if (GST_V4L2ELEMENT (v4l2src)->vcap.capabilities & V4L2_CAP_READWRITE) {
+    v4l2src->breq.memory = 0;
+    GST_INFO_OBJECT (v4l2src, "using fallback read method");
+  } else {
     GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ,
-        (_("Could not get buffers from device \"%s\"."),
+        (_("the driver of device \"%s\" is broken."),
             GST_V4L2ELEMENT (v4l2src)->device),
-        ("error requesting %d buffers: %s", v4l2src->breq.count,
-            g_strerror (errno)));
+        ("no supported read capability from %s",
+            GST_V4L2ELEMENT (v4l2src)->device));
     return FALSE;
   }
 
-  if (v4l2src->breq.count < GST_V4L2_MIN_BUFFERS) {
-    GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ,
-        (_("Could not get enough buffers from device \"%s\"."),
-            GST_V4L2ELEMENT (v4l2src)->device),
-        ("we received %d, we want at least %d", v4l2src->breq.count,
-            GST_V4L2_MIN_BUFFERS));
-    v4l2src->breq.count = buffers;
-    return FALSE;
-  }
-  if (v4l2src->breq.count != buffers)
-    g_object_notify (G_OBJECT (v4l2src), "num_buffers");
-
-  GST_INFO_OBJECT (v4l2src,
-      "Got %d buffers (" GST_FOURCC_FORMAT ") of size %d KB\n",
-      v4l2src->breq.count,
-      GST_FOURCC_ARGS (v4l2src->format.fmt.pix.pixelformat),
-      v4l2src->format.fmt.pix.sizeimage / 1024);
-
-  /* Map the buffers */
-  v4l2src->pool = g_new (GstV4l2BufferPool, 1);
-  gst_atomic_int_init (&v4l2src->pool->refcount, 1);
-  v4l2src->pool->video_fd = GST_V4L2ELEMENT (v4l2src)->video_fd;
-  v4l2src->pool->buffer_count = v4l2src->breq.count;
-  v4l2src->pool->buffers = g_new0 (GstV4l2Buffer, v4l2src->breq.count);
-
-  for (n = 0; n < v4l2src->breq.count; n++) {
-    GstV4l2Buffer *buffer = &v4l2src->pool->buffers[n];
-
-    gst_atomic_int_init (&buffer->refcount, 1);
-    buffer->pool = v4l2src->pool;
-    buffer->buffer.index = n;
-    buffer->buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-    if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_QUERYBUF,
-            &buffer->buffer) < 0) {
-      GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ, (NULL),
-          ("Could not get buffer properties of buffer %d: %s", n,
-              g_strerror (errno)));
-      gst_v4l2src_capture_deinit (v4l2src);
-      return FALSE;
-    }
-    buffer->start =
-        mmap (0, buffer->buffer.length, PROT_READ | PROT_WRITE, MAP_SHARED,
-        GST_V4L2ELEMENT (v4l2src)->video_fd, buffer->buffer.m.offset);
-    if (buffer->start == MAP_FAILED) {
-      GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ, (NULL),
-          ("Could not mmap video buffer %d: %s", n, g_strerror (errno)));
-      buffer->start = 0;
-      gst_v4l2src_capture_deinit (v4l2src);
+  if (v4l2src->breq.memory > 0) {
+    if (v4l2src->breq.count < GST_V4L2_MIN_BUFFERS) {
+      GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ,
+          (_("Could not get enough buffers from device \"%s\"."),
+              GST_V4L2ELEMENT (v4l2src)->device),
+          ("we received %d, we want at least %d", v4l2src->breq.count,
+              GST_V4L2_MIN_BUFFERS));
+      v4l2src->breq.count = buffers;
       return FALSE;
     }
-    buffer->length = buffer->buffer.length;
-    if (!gst_v4l2src_queue_frame (v4l2src, n)) {
-      gst_v4l2src_capture_deinit (v4l2src);
-      return FALSE;
+    if (v4l2src->breq.count != buffers)
+      g_object_notify (G_OBJECT (v4l2src), "num_buffers");
+
+    GST_INFO_OBJECT (v4l2src,
+        "Got %d buffers (" GST_FOURCC_FORMAT ") of size %d KB\n",
+        v4l2src->breq.count,
+        GST_FOURCC_ARGS (v4l2src->format.fmt.pix.pixelformat),
+        v4l2src->format.fmt.pix.sizeimage / 1024);
+
+    /* Map the buffers */
+    GST_LOG_OBJECT (v4l2src, "initiating buffer pool");
+
+    v4l2src->pool = g_new (GstV4l2BufferPool, 1);
+    gst_atomic_int_init (&v4l2src->pool->refcount, 1);
+    v4l2src->pool->video_fd = GST_V4L2ELEMENT (v4l2src)->video_fd;
+    v4l2src->pool->buffer_count = v4l2src->breq.count;
+    v4l2src->pool->buffers = g_new0 (GstV4l2Buffer, v4l2src->breq.count);
+
+    for (n = 0; n < v4l2src->breq.count; n++) {
+      GstV4l2Buffer *buffer = &v4l2src->pool->buffers[n];
+
+      gst_atomic_int_init (&buffer->refcount, 1);
+      buffer->pool = v4l2src->pool;
+      buffer->buffer.index = n;
+      buffer->buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+      if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_QUERYBUF,
+              &buffer->buffer) < 0) {
+        GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ, (NULL),
+            ("Could not get buffer properties of buffer %d: %s", n,
+                g_strerror (errno)));
+        gst_v4l2src_capture_deinit (v4l2src);
+        return FALSE;
+      }
+      buffer->start =
+          mmap (0, buffer->buffer.length, PROT_READ | PROT_WRITE, MAP_SHARED,
+          GST_V4L2ELEMENT (v4l2src)->video_fd, buffer->buffer.m.offset);
+      if (buffer->start == MAP_FAILED) {
+        GST_ELEMENT_ERROR (v4l2src, RESOURCE, READ, (NULL),
+            ("Could not mmap video buffer %d: %s", n, g_strerror (errno)));
+        buffer->start = 0;
+        gst_v4l2src_capture_deinit (v4l2src);
+        return FALSE;
+      }
+      buffer->length = buffer->buffer.length;
+      if (!gst_v4l2src_queue_frame (v4l2src, n)) {
+        gst_v4l2src_capture_deinit (v4l2src);
+        return FALSE;
+      }
     }
+  } else {
+    GST_LOG_OBJECT (v4l2src, "no buffer pool used");
+    v4l2src->pool = NULL;
   }
 
   GST_V4L2_SET_ACTIVE (GST_V4L2ELEMENT (v4l2src));
@@ -344,11 +364,13 @@ gst_v4l2src_capture_start (GstV4l2Src * v4l2src)
 
   v4l2src->quit = FALSE;
 
-  if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_STREAMON, &type) < 0) {
-    GST_ELEMENT_ERROR (v4l2src, RESOURCE, OPEN_READ, (NULL),
-        ("Error starting streaming capture from device %s: %s",
-            GST_V4L2ELEMENT (v4l2src)->device, g_strerror (errno)));
-    return FALSE;
+  if (v4l2src->breq.memory != 0) {
+    if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_STREAMON, &type) < 0) {
+      GST_ELEMENT_ERROR (v4l2src, RESOURCE, OPEN_READ, (NULL),
+          ("Error starting streaming capture from device %s: %s",
+              GST_V4L2ELEMENT (v4l2src)->device, g_strerror (errno)));
+      return FALSE;
+    }
   }
 
   v4l2src->is_capturing = TRUE;
@@ -372,13 +394,16 @@ gst_v4l2src_capture_stop (GstV4l2Src * v4l2src)
   GST_V4L2_CHECK_OPEN (GST_V4L2ELEMENT (v4l2src));
   GST_V4L2_CHECK_ACTIVE (GST_V4L2ELEMENT (v4l2src));
 
-  /* we actually need to sync on all queued buffers but not
-   * on the non-queued ones */
-  if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_STREAMOFF, &type) < 0) {
-    GST_ELEMENT_ERROR (v4l2src, RESOURCE, CLOSE, (NULL),
-        ("Error stopping streaming capture from device %s: %s",
-            GST_V4L2ELEMENT (v4l2src)->device, g_strerror (errno)));
-    return FALSE;
+  if (v4l2src->breq.memory != 0) {
+    /* we actually need to sync on all queued buffers but not
+     * on the non-queued ones */
+    if (ioctl (GST_V4L2ELEMENT (v4l2src)->video_fd, VIDIOC_STREAMOFF,
+            &type) < 0) {
+      GST_ELEMENT_ERROR (v4l2src, RESOURCE, CLOSE, (NULL),
+          ("Error stopping streaming capture from device %s: %s",
+              GST_V4L2ELEMENT (v4l2src)->device, g_strerror (errno)));
+      return FALSE;
+    }
   }
 
   /* make an optional pending wait stop */