V4L2 VDA/VEA: Use VIDIOC_G/S_SELECTION for accelerators

media/gpu/v4l2_video_encode_accelerator.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/gpu/v4l2_video_encode_accelerator.h"
 
 #include <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <string.h>
@@ skipping 1063 matching lines @@
   DCHECK(child_task_runner_->BelongsToCurrentThread());
   DCHECK(!input_streamon_);
   DCHECK(!output_streamon_);
 
   if (!SetOutputFormat(output_profile))
     return false;
 
   if (!NegotiateInputFormat(input_format))
     return false;
 
-  struct v4l2_crop crop;
-  memset(&crop, 0, sizeof(crop));
-  crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
-  crop.c.left = 0;
-  crop.c.top = 0;
-  crop.c.width = visible_size_.width();
-  crop.c.height = visible_size_.height();
-  IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_CROP, &crop);
+  struct v4l2_rect visible_rect;
+  visible_rect.left = 0;
+  visible_rect.top = 0;
+  visible_rect.width = visible_size_.width();
+  visible_rect.height = visible_size_.height();
 
-  // The width and height might be adjusted by driver.
-  // Need to read it back and set to visible_size_.
-  IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_G_CROP, &crop);
-  visible_size_.SetSize(crop.c.width, crop.c.height);
+  struct v4l2_selection selection_arg;
+  memset(&selection_arg, 0, sizeof(selection_arg));
+  selection_arg.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
+  selection_arg.target = V4L2_SEL_TGT_CROP;
+  selection_arg.r = visible_rect;
+
+  if (device_->Ioctl(VIDIOC_S_SELECTION, &selection_arg) == 0) {
+    DVLOG(2) << "VIDIOC_S_SELECTION is supported";
+    // The width and height might be adjusted by driver.
+    // Need to read it back and set to visible_size_.
+    IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_G_SELECTION, &selection_arg);

[wuchengli, 2017/07/18 05:46:22]

VIDIOC_S_SELECTION will adjust the rect. No need to call VIDIOC_G_SELECTION.
Remove this line.

+    visible_rect = selection_arg.r;
+  }
+  else {
+    DVLOG(2) << "Fallback to VIDIOC_S/G_CROP";
+    struct v4l2_crop crop;
+    memset(&crop, 0, sizeof(crop));
+    crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+    crop.c = visible_rect;
+    IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_CROP, &crop);
+    // The width and height might be adjusted by driver.
+    // Need to read it back and set to visible_size_.
+    IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_G_CROP, &crop);
+    visible_rect = crop.c;
+  }
+
+  visible_size_.SetSize(visible_rect.width, visible_rect.height);
   DVLOG(3) << "After adjusted by driver, visible_size_="
            << visible_size_.ToString();
 
   return true;
 }
 
 bool V4L2VideoEncodeAccelerator::IsCtrlExposed(uint32_t ctrl_id) {
   struct v4l2_queryctrl query_ctrl;
   memset(&query_ctrl, 0, sizeof(query_ctrl));
   query_ctrl.id = ctrl_id;
@@ skipping 226 matching lines @@
   memset(&reqbufs, 0, sizeof(reqbufs));
   reqbufs.count = 0;
   reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
   reqbufs.memory = V4L2_MEMORY_MMAP;
   IOCTL_OR_LOG_ERROR(VIDIOC_REQBUFS, &reqbufs);
 
   output_buffer_map_.clear();
 }
 
 }  // namespace media