Introduce a client minimum picture pool size

content/common/gpu/media/v4l2_video_decode_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 <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <sys/eventfd.h>
@@ skipping 174 matching lines @@
       output_dpb_size_(0),
       output_planes_count_(0),
       picture_clearing_count_(0),
       pictures_assigned_(false, false),
       device_poll_thread_("V4L2DevicePollThread"),
       make_context_current_(make_context_current),
       egl_display_(egl_display),
       egl_context_(egl_context),
       video_profile_(media::VIDEO_CODEC_PROFILE_UNKNOWN),
       output_format_fourcc_(0),
+      min_picture_count_(0),
       weak_this_factory_(this) {
   weak_this_ = weak_this_factory_.GetWeakPtr();
 }
 
 V4L2VideoDecodeAccelerator::~V4L2VideoDecodeAccelerator() {
   DCHECK(!decoder_thread_.IsRunning());
   DCHECK(!device_poll_thread_.IsRunning());
 
   DestroyInputBuffers();
   DestroyOutputBuffers();
 
   // These maps have members that should be manually destroyed, e.g. file
   // descriptors, mmap() segments, etc.
   DCHECK(input_buffer_map_.empty());
   DCHECK(output_buffer_map_.empty());
 }
 
 bool V4L2VideoDecodeAccelerator::Initialize(media::VideoCodecProfile profile,
+                                            uint32_t min_picture_count,
                                             Client* client) {
   DVLOG(3) << "Initialize()";
   DCHECK(child_task_runner_->BelongsToCurrentThread());
   DCHECK_EQ(decoder_state_, kUninitialized);
 
   client_ptr_factory_.reset(new base::WeakPtrFactory<Client>(client));
   client_ = client_ptr_factory_->GetWeakPtr();
 
   switch (profile) {
     case media::H264PROFILE_BASELINE:
       DVLOG(2) << "Initialize(): profile H264PROFILE_BASELINE";
       break;
     case media::H264PROFILE_MAIN:
       DVLOG(2) << "Initialize(): profile H264PROFILE_MAIN";
       break;
     case media::H264PROFILE_HIGH:
       DVLOG(2) << "Initialize(): profile H264PROFILE_HIGH";
       break;
     case media::VP8PROFILE_ANY:
       DVLOG(2) << "Initialize(): profile VP8PROFILE_ANY";
       break;
     case media::VP9PROFILE_ANY:
       DVLOG(2) << "Initialize(): profile VP9PROFILE_ANY";
       break;
     default:
       DLOG(ERROR) << "Initialize(): unsupported profile=" << profile;
       return false;
   };
   video_profile_ = profile;
+  min_picture_count_ = min_picture_count;
 
   if (egl_display_ == EGL_NO_DISPLAY) {
     LOG(ERROR) << "Initialize(): could not get EGLDisplay";
     return false;
   }
 
   // We need the context to be initialized to query extensions.
   if (!make_context_current_.Run()) {
     LOG(ERROR) << "Initialize(): could not make context current";
     return false;
@@ skipping 1577 matching lines @@
   memset(&ctrl, 0, sizeof(ctrl));
   ctrl.id = V4L2_CID_MIN_BUFFERS_FOR_CAPTURE;
   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_G_CTRL, &ctrl);
   output_dpb_size_ = ctrl.value;
 
   // Output format setup in Initialize().
 
   // Allocate the output buffers.
   struct v4l2_requestbuffers reqbufs;
   memset(&reqbufs, 0, sizeof(reqbufs));
-  reqbufs.count  = output_dpb_size_ + kDpbOutputBufferExtraCount;
+  reqbufs.count  = std::max(min_picture_count_,
+                            static_cast<uint32_t>(
+                                output_dpb_size_ + kDpbOutputBufferExtraCount));
   reqbufs.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
   reqbufs.memory = V4L2_MEMORY_MMAP;
   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_REQBUFS, &reqbufs);
 
   output_buffer_map_.resize(reqbufs.count);
 
   DVLOG(3) << "CreateOutputBuffers(): ProvidePictureBuffers(): "
            << "buffer_count=" << output_buffer_map_.size()
            << ", coded_size=" << coded_size_.ToString();
   child_task_runner_->PostTask(
@@ skipping 178 matching lines @@
   gfx::Size new_coded_size(base::checked_cast<int>(format.fmt.pix_mp.width),
                            base::checked_cast<int>(format.fmt.pix_mp.height));
   if (coded_size_ != new_coded_size) {
     DVLOG(3) << "IsResolutionChangeNecessary(): Resolution change detected";
     return true;
   }
   return false;
 }
 
 }  // namespace content