Introduce a client minimum picture pool size

content/common/gpu/media/v4l2_slice_video_decode_accelerator.cc

 // Copyright 2015 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 <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <sys/eventfd.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
@@ skipping 694 matching lines @@
   coded_size_.SetSize(base::checked_cast<int>(format.fmt.pix_mp.width),
                       base::checked_cast<int>(format.fmt.pix_mp.height));
   DCHECK_EQ(coded_size_.width() % 16, 0);
   DCHECK_EQ(coded_size_.height() % 16, 0);
 
   if (!gfx::Rect(coded_size_).Contains(gfx::Rect(visible_size_))) {
     LOG(ERROR) << "Got invalid adjusted coded size: " << coded_size_.ToString();
     return false;
   }
 
-  struct v4l2_requestbuffers reqbufs;
-  memset(&reqbufs, 0, sizeof(reqbufs));
-  reqbufs.count = num_pictures;
-  reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
-  reqbufs.memory = V4L2_MEMORY_MMAP;
-  IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_REQBUFS, &reqbufs);
-
-  if (reqbufs.count < num_pictures) {
-    PLOG(ERROR) << "Could not allocate enough output buffers";
-    return false;
-  }
-
-  output_buffer_map_.resize(reqbufs.count);
-
-  DVLOGF(3) << "buffer_count=" << output_buffer_map_.size()
+  DVLOGF(3) << "buffer_count=" << num_pictures
             << ", visible size=" << visible_size_.ToString()
             << ", coded size=" << coded_size_.ToString();
 
   child_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&VideoDecodeAccelerator::Client::ProvidePictureBuffers,
-                 client_, output_buffer_map_.size(), coded_size_,
+                 client_, num_pictures, coded_size_,
                  device_->GetTextureTarget()));
 
   // Wait for the client to call AssignPictureBuffers() on the Child thread.
   // We do this, because if we continue decoding without finishing buffer
   // allocation, we may end up Resetting before AssignPictureBuffers arrives,
   // resulting in unnecessary complications and subtle bugs.
   pictures_assigned_.Wait();
 
   return true;
 }
@@ skipping 661 matching lines @@
   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_REQBUFS, &reqbufs);
 
   return true;
 }
 
 void V4L2SliceVideoDecodeAccelerator::AssignPictureBuffers(
     const std::vector<media::PictureBuffer>& buffers) {
   DVLOGF(3);
   DCHECK(child_task_runner_->BelongsToCurrentThread());
 
-  if (buffers.size() != output_buffer_map_.size()) {
+  const uint32_t req_buffer_count = decoder_->GetRequiredNumOfPictures();
+
+  if (buffers.size() < req_buffer_count) {
     DLOG(ERROR) << "Failed to provide requested picture buffers. "
                 << "(Got " << buffers.size()
-                << ", requested " << output_buffer_map_.size() << ")";
+                << ", requested " << req_buffer_count << ")";
     NOTIFY_ERROR(INVALID_ARGUMENT);
     return;
   }
 
   if (!make_context_current_.Run()) {
     DLOG(ERROR) << "could not make context current";
     NOTIFY_ERROR(PLATFORM_FAILURE);
     return;
   }
 
   gfx::ScopedTextureBinder bind_restore(GL_TEXTURE_EXTERNAL_OES, 0);
 
   // It's safe to manipulate all the buffer state here, because the decoder
   // thread is waiting on pictures_assigned_.
+
+  // Allocate the output buffers.
+  struct v4l2_requestbuffers reqbufs;
+  memset(&reqbufs, 0, sizeof(reqbufs));
+  reqbufs.count = buffers.size();
+  reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+  reqbufs.memory = V4L2_MEMORY_MMAP;
+  IOCTL_OR_ERROR_RETURN(VIDIOC_REQBUFS, &reqbufs);
+
+  if (reqbufs.count != buffers.size()) {
+    DLOG(ERROR) << "Could not allocate enough output buffers";
+    NOTIFY_ERROR(PLATFORM_FAILURE);
+    return;
+  }
+
+  output_buffer_map_.resize(buffers.size());
+
   DCHECK(free_output_buffers_.empty());
   for (size_t i = 0; i < output_buffer_map_.size(); ++i) {
     DCHECK(buffers[i].size() == coded_size_);
 
     OutputRecord& output_record = output_buffer_map_[i];
     DCHECK(!output_record.at_device);
     DCHECK(!output_record.at_client);
     DCHECK_EQ(output_record.egl_image, EGL_NO_IMAGE_KHR);
     DCHECK_EQ(output_record.egl_sync, EGL_NO_SYNC_KHR);
     DCHECK_EQ(output_record.picture_id, -1);
@@ skipping 1065 matching lines @@
   if (!device)
     return SupportedProfiles();
 
   const uint32_t supported_formats[] = {
       V4L2_PIX_FMT_H264_SLICE, V4L2_PIX_FMT_VP8_FRAME};
   return device->GetSupportedDecodeProfiles(arraysize(supported_formats),
                                             supported_formats);
 }
 
 }  // namespace content