Linux video capture: handle devices that don't enumerate any frame rates

media/video/capture/linux/video_capture_device_factory_linux.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/video/capture/linux/video_capture_device_factory_linux.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #if defined(OS_OPENBSD)
 #include <sys/videoio.h>
@@ skipping 137 matching lines @@
         // TODO(mcasas): see http://crbug.com/249953, support these devices.
         NOTIMPLEMENTED();
       } else if (frame_size.type == V4L2_FRMSIZE_TYPE_CONTINUOUS) {
         // TODO(mcasas): see http://crbug.com/249953, support these devices.
         NOTIMPLEMENTED();
       }
       v4l2_frmivalenum frame_interval = {};
       frame_interval.pixel_format = pixel_format.pixelformat;
       frame_interval.width = frame_size.discrete.width;
       frame_interval.height = frame_size.discrete.height;
+      std::list<float> frame_rates;
       while (HANDLE_EINTR(ioctl(
                  fd.get(), VIDIOC_ENUM_FRAMEINTERVALS, &frame_interval)) == 0) {
         if (frame_interval.type == V4L2_FRMIVAL_TYPE_DISCRETE) {
           if (frame_interval.discrete.numerator != 0) {
-            supported_format.frame_rate =
+            frame_rates.push_back(
                 static_cast<float>(frame_interval.discrete.denominator) /
-                static_cast<float>(frame_interval.discrete.numerator);
-          } else {
-            supported_format.frame_rate = 0;
+                static_cast<float>(frame_interval.discrete.numerator));
           }
         } else if (frame_interval.type == V4L2_FRMIVAL_TYPE_CONTINUOUS) {
           // TODO(mcasas): see http://crbug.com/249953, support these devices.
           NOTIMPLEMENTED();
           break;
         } else if (frame_interval.type == V4L2_FRMIVAL_TYPE_STEPWISE) {
           // TODO(mcasas): see http://crbug.com/249953, support these devices.
           NOTIMPLEMENTED();
           break;
         }
+        ++frame_interval.index;
+      }
+
+      // Some devices, e.g. Kinect, do not enumerate any frame rates. For these
+      // devices, we do not want to lose all enumeration (pixel format and
+      // resolution), so we return a frame rate of zero instead.
+      if (frame_rates.empty())
+        frame_rates.push_back(0);
+
+      for (std::list<float>::iterator it = frame_rates.begin();
+           it != frame_rates.end(); ++it) {
+        supported_format.frame_rate = *it;
         supported_formats->push_back(supported_format);
         DVLOG(1) << device.name() << " " << supported_format.ToString();
-        ++frame_interval.index;
       }
       ++frame_size.index;
     }
     ++pixel_format.index;
   }
   return;
 }
 
 }  // namespace media