src/content/common/gpu/media/v4l2_video_encode_accelerator.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <fcntl.h>
   6 #include <linux/videodev2.h>
   7 #include <poll.h>
   8 #include <sys/eventfd.h>
   9 #include <sys/ioctl.h>
  10 #include <sys/mman.h>
  11
  12 #include "base/callback.h"
  13 #include "base/command_line.h"
  14 #include "base/debug/trace_event.h"
  15 #include "base/message_loop/message_loop_proxy.h"
  16 #include "base/numerics/safe_conversions.h"
  17 #include "content/common/gpu/media/v4l2_video_encode_accelerator.h"
  18 #include "content/public/common/content_switches.h"
  19 #include "media/base/bitstream_buffer.h"
  20
  21 #define NOTIFY_ERROR(x)                            \
  22   do {                                             \
  23     SetEncoderState(kError);                       \
  24     DLOG(ERROR) << "calling NotifyError(): " << x; \
  25     NotifyError(x);                                \
  26   } while (0)
  27
  28 #define IOCTL_OR_ERROR_RETURN_VALUE(type, arg, value)              \
  29   do {                                                             \
  30     if (device_->Ioctl(type, arg) != 0) {                          \
  31       DPLOG(ERROR) << __func__ << "(): ioctl() failed: " << #type; \
  32       NOTIFY_ERROR(kPlatformFailureError);                         \
  33       return value;                                                \
  34     }                                                              \
  35   } while (0)
  36
  37 #define IOCTL_OR_ERROR_RETURN(type, arg) \
  38   IOCTL_OR_ERROR_RETURN_VALUE(type, arg, ((void)0))
  39
  40 #define IOCTL_OR_ERROR_RETURN_FALSE(type, arg) \
  41   IOCTL_OR_ERROR_RETURN_VALUE(type, arg, false)
  42
  43 #define IOCTL_OR_LOG_ERROR(type, arg)                              \
  44   do {                                                             \
  45     if (device_->Ioctl(type, arg) != 0)                            \
  46       DPLOG(ERROR) << __func__ << "(): ioctl() failed: " << #type; \
  47   } while (0)
  48
  49 namespace content {
  50
  51 struct V4L2VideoEncodeAccelerator::BitstreamBufferRef {
  52   BitstreamBufferRef(int32 id, scoped_ptr<base::SharedMemory> shm, size_t size)
  53       : id(id), shm(shm.Pass()), size(size) {}
  54   const int32 id;
  55   const scoped_ptr<base::SharedMemory> shm;
  56   const size_t size;
  57 };
  58
  59 V4L2VideoEncodeAccelerator::InputRecord::InputRecord() : at_device(false) {
  60 }
  61
  62 V4L2VideoEncodeAccelerator::OutputRecord::OutputRecord()
  63     : at_device(false), address(NULL), length(0) {
  64 }
  65
  66 V4L2VideoEncodeAccelerator::V4L2VideoEncodeAccelerator(
  67     scoped_ptr<V4L2Device> device)
  68     : child_message_loop_proxy_(base::MessageLoopProxy::current()),
  69       output_buffer_byte_size_(0),
  70       device_input_format_(media::VideoFrame::UNKNOWN),
  71       input_planes_count_(0),
  72       output_format_fourcc_(0),
  73       encoder_state_(kUninitialized),
  74       stream_header_size_(0),
  75       device_(device.Pass()),
  76       input_streamon_(false),
  77       input_buffer_queued_count_(0),
  78       input_memory_type_(V4L2_MEMORY_USERPTR),
  79       output_streamon_(false),
  80       output_buffer_queued_count_(0),
  81       encoder_thread_("V4L2EncoderThread"),
  82       device_poll_thread_("V4L2EncoderDevicePollThread"),
  83       weak_this_ptr_factory_(this) {
  84   weak_this_ = weak_this_ptr_factory_.GetWeakPtr();
  85 }
  86
  87 V4L2VideoEncodeAccelerator::~V4L2VideoEncodeAccelerator() {
  88   DCHECK(!encoder_thread_.IsRunning());
  89   DCHECK(!device_poll_thread_.IsRunning());
  90   DVLOG(4) << __func__;
  91
  92   DestroyInputBuffers();
  93   DestroyOutputBuffers();
  94 }
  95
  96 bool V4L2VideoEncodeAccelerator::Initialize(
  97     media::VideoFrame::Format input_format,
  98     const gfx::Size& input_visible_size,
  99     media::VideoCodecProfile output_profile,
 100     uint32 initial_bitrate,
 101     Client* client) {
 102   DVLOG(3) << __func__ << ": input_format="
 103            << media::VideoFrame::FormatToString(input_format)
 104            << ", input_visible_size=" << input_visible_size.ToString()
 105            << ", output_profile=" << output_profile
 106            << ", initial_bitrate=" << initial_bitrate;
 107
 108   visible_size_ = input_visible_size;
 109
 110   client_ptr_factory_.reset(new base::WeakPtrFactory<Client>(client));
 111   client_ = client_ptr_factory_->GetWeakPtr();
 112
 113   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 114   DCHECK_EQ(encoder_state_, kUninitialized);
 115
 116   struct v4l2_capability caps;
 117   memset(&caps, 0, sizeof(caps));
 118   const __u32 kCapsRequired = V4L2_CAP_VIDEO_CAPTURE_MPLANE |
 119                               V4L2_CAP_VIDEO_OUTPUT_MPLANE | V4L2_CAP_STREAMING;
 120   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_QUERYCAP, &caps);
 121   if ((caps.capabilities & kCapsRequired) != kCapsRequired) {
 122     DLOG(ERROR) << "Initialize(): ioctl() failed: VIDIOC_QUERYCAP: "
 123                    "caps check failed: 0x" << std::hex << caps.capabilities;
 124     return false;
 125   }
 126
 127   if (!SetFormats(input_format, output_profile)) {
 128     DLOG(ERROR) << "Failed setting up formats";
 129     return false;
 130   }
 131
 132   if (input_format != device_input_format_) {
 133     DVLOG(1) << "Input format not supported by the HW, will convert to "
 134              << media::VideoFrame::FormatToString(device_input_format_);
 135
 136     scoped_ptr<V4L2Device> device =
 137         V4L2Device::Create(V4L2Device::kImageProcessor);
 138     image_processor_.reset(new V4L2ImageProcessor(device.Pass()));
 139
 140     // Convert from input_format to device_input_format_, keeping the size
 141     // at visible_size_ and requiring the output buffers to be of at least
 142     // input_allocated_size_.
 143     if (!image_processor_->Initialize(
 144             input_format,
 145             device_input_format_,
 146             visible_size_,
 147             visible_size_,
 148             input_allocated_size_,
 149             base::Bind(&V4L2VideoEncodeAccelerator::ImageProcessorError,
 150                        weak_this_))) {
 151       DLOG(ERROR) << "Failed initializing image processor";
 152       return false;
 153     }
 154   }
 155
 156   if (!InitControls())
 157     return false;
 158
 159   if (!CreateOutputBuffers())
 160     return false;
 161
 162   if (!encoder_thread_.Start()) {
 163     DLOG(ERROR) << "Initialize(): encoder thread failed to start";
 164     return false;
 165   }
 166
 167   RequestEncodingParametersChange(initial_bitrate, kInitialFramerate);
 168
 169   SetEncoderState(kInitialized);
 170
 171   child_message_loop_proxy_->PostTask(
 172       FROM_HERE,
 173       base::Bind(&Client::RequireBitstreamBuffers,
 174                  client_,
 175                  kInputBufferCount,
 176                  image_processor_.get() ?
 177                      image_processor_->input_allocated_size() :
 178                      input_allocated_size_,
 179                  output_buffer_byte_size_));
 180   return true;
 181 }
 182
 183 void V4L2VideoEncodeAccelerator::ImageProcessorError() {
 184   DVLOG(1) << "Image processor error";
 185   NOTIFY_ERROR(kPlatformFailureError);
 186 }
 187
 188 void V4L2VideoEncodeAccelerator::Encode(
 189     const scoped_refptr<media::VideoFrame>& frame,
 190     bool force_keyframe) {
 191   DVLOG(3) << "Encode(): force_keyframe=" << force_keyframe;
 192   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 193
 194   if (image_processor_) {
 195     image_processor_->Process(
 196         frame,
 197         base::Bind(&V4L2VideoEncodeAccelerator::FrameProcessed,
 198                    weak_this_,
 199                    force_keyframe));
 200   } else {
 201     encoder_thread_.message_loop()->PostTask(
 202         FROM_HERE,
 203         base::Bind(&V4L2VideoEncodeAccelerator::EncodeTask,
 204                    base::Unretained(this),
 205                    frame,
 206                    force_keyframe));
 207   }
 208 }
 209
 210 void V4L2VideoEncodeAccelerator::UseOutputBitstreamBuffer(
 211     const media::BitstreamBuffer& buffer) {
 212   DVLOG(3) << "UseOutputBitstreamBuffer(): id=" << buffer.id();
 213   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 214
 215   if (buffer.size() < output_buffer_byte_size_) {
 216     NOTIFY_ERROR(kInvalidArgumentError);
 217     return;
 218   }
 219
 220   scoped_ptr<base::SharedMemory> shm(
 221       new base::SharedMemory(buffer.handle(), false));
 222   if (!shm->Map(buffer.size())) {
 223     NOTIFY_ERROR(kPlatformFailureError);
 224     return;
 225   }
 226
 227   scoped_ptr<BitstreamBufferRef> buffer_ref(
 228       new BitstreamBufferRef(buffer.id(), shm.Pass(), buffer.size()));
 229   encoder_thread_.message_loop()->PostTask(
 230       FROM_HERE,
 231       base::Bind(&V4L2VideoEncodeAccelerator::UseOutputBitstreamBufferTask,
 232                  base::Unretained(this),
 233                  base::Passed(&buffer_ref)));
 234 }
 235
 236 void V4L2VideoEncodeAccelerator::RequestEncodingParametersChange(
 237     uint32 bitrate,
 238     uint32 framerate) {
 239   DVLOG(3) << "RequestEncodingParametersChange(): bitrate=" << bitrate
 240            << ", framerate=" << framerate;
 241   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 242
 243   encoder_thread_.message_loop()->PostTask(
 244       FROM_HERE,
 245       base::Bind(
 246           &V4L2VideoEncodeAccelerator::RequestEncodingParametersChangeTask,
 247           base::Unretained(this),
 248           bitrate,
 249           framerate));
 250 }
 251
 252 void V4L2VideoEncodeAccelerator::Destroy() {
 253   DVLOG(3) << "Destroy()";
 254   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 255
 256   // We're destroying; cancel all callbacks.
 257   client_ptr_factory_.reset();
 258   weak_this_ptr_factory_.InvalidateWeakPtrs();
 259
 260   if (image_processor_.get())
 261     image_processor_.release()->Destroy();
 262
 263   // If the encoder thread is running, destroy using posted task.
 264   if (encoder_thread_.IsRunning()) {
 265     encoder_thread_.message_loop()->PostTask(
 266         FROM_HERE,
 267         base::Bind(&V4L2VideoEncodeAccelerator::DestroyTask,
 268                    base::Unretained(this)));
 269     // DestroyTask() will put the encoder into kError state and cause all tasks
 270     // to no-op.
 271     encoder_thread_.Stop();
 272   } else {
 273     // Otherwise, call the destroy task directly.
 274     DestroyTask();
 275   }
 276
 277   // Set to kError state just in case.
 278   SetEncoderState(kError);
 279
 280   delete this;
 281 }
 282
 283 std::vector<media::VideoEncodeAccelerator::SupportedProfile>
 284 V4L2VideoEncodeAccelerator::GetSupportedProfiles() {
 285   std::vector<SupportedProfile> profiles;
 286   SupportedProfile profile;
 287
 288   const base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
 289   if (cmd_line->HasSwitch(switches::kEnableWebRtcHWVp8Encoding)) {
 290     profile.profile = media::VP8PROFILE_ANY;
 291     profile.max_resolution.SetSize(1920, 1088);
 292     profile.max_framerate_numerator = 30;
 293     profile.max_framerate_denominator = 1;
 294     profiles.push_back(profile);
 295   }
 296
 297   profile.profile = media::H264PROFILE_MAIN;
 298   profile.max_resolution.SetSize(1920, 1088);
 299   profile.max_framerate_numerator = 30;
 300   profile.max_framerate_denominator = 1;
 301   profiles.push_back(profile);
 302
 303   return profiles;
 304 }
 305
 306 void V4L2VideoEncodeAccelerator::FrameProcessed(
 307     bool force_keyframe,
 308     const scoped_refptr<media::VideoFrame>& frame) {
 309   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 310   DVLOG(3) << "FrameProcessed(): force_keyframe=" << force_keyframe;
 311
 312   encoder_thread_.message_loop()->PostTask(
 313       FROM_HERE,
 314       base::Bind(&V4L2VideoEncodeAccelerator::EncodeTask,
 315                  base::Unretained(this),
 316                  frame,
 317                  force_keyframe));
 318 }
 319
 320 void V4L2VideoEncodeAccelerator::EncodeTask(
 321     const scoped_refptr<media::VideoFrame>& frame,
 322     bool force_keyframe) {
 323   DVLOG(3) << "EncodeTask(): force_keyframe=" << force_keyframe;
 324   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 325   DCHECK_NE(encoder_state_, kUninitialized);
 326
 327   if (encoder_state_ == kError) {
 328     DVLOG(2) << "EncodeTask(): early out: kError state";
 329     return;
 330   }
 331
 332   encoder_input_queue_.push_back(frame);
 333   Enqueue();
 334
 335   if (force_keyframe) {
 336     // TODO(posciak): this presently makes for slightly imprecise encoding
 337     // parameters updates.  To precisely align the parameter updates with the
 338     // incoming input frame, we should queue the parameters together with the
 339     // frame onto encoder_input_queue_ and apply them when the input is about
 340     // to be queued to the codec.
 341     struct v4l2_ext_control ctrls[1];
 342     struct v4l2_ext_controls control;
 343     memset(&ctrls, 0, sizeof(ctrls));
 344     memset(&control, 0, sizeof(control));
 345     ctrls[0].id = V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE;
 346     ctrls[0].value = V4L2_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE_I_FRAME;
 347     control.ctrl_class = V4L2_CTRL_CLASS_MPEG;
 348     control.count = 1;
 349     control.controls = ctrls;
 350     IOCTL_OR_ERROR_RETURN(VIDIOC_S_EXT_CTRLS, &control);
 351   }
 352 }
 353
 354 void V4L2VideoEncodeAccelerator::UseOutputBitstreamBufferTask(
 355     scoped_ptr<BitstreamBufferRef> buffer_ref) {
 356   DVLOG(3) << "UseOutputBitstreamBufferTask(): id=" << buffer_ref->id;
 357   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 358
 359   encoder_output_queue_.push_back(
 360       linked_ptr<BitstreamBufferRef>(buffer_ref.release()));
 361   Enqueue();
 362
 363   if (encoder_state_ == kInitialized) {
 364     // Finish setting up our OUTPUT queue.  See: Initialize().
 365     // VIDIOC_REQBUFS on OUTPUT queue.
 366     if (!CreateInputBuffers())
 367       return;
 368     if (!StartDevicePoll())
 369       return;
 370     encoder_state_ = kEncoding;
 371   }
 372 }
 373
 374 void V4L2VideoEncodeAccelerator::DestroyTask() {
 375   DVLOG(3) << "DestroyTask()";
 376
 377   // DestroyTask() should run regardless of encoder_state_.
 378
 379   // Stop streaming and the device_poll_thread_.
 380   StopDevicePoll();
 381
 382   // Set our state to kError, and early-out all tasks.
 383   encoder_state_ = kError;
 384 }
 385
 386 void V4L2VideoEncodeAccelerator::ServiceDeviceTask() {
 387   DVLOG(3) << "ServiceDeviceTask()";
 388   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 389   DCHECK_NE(encoder_state_, kUninitialized);
 390   DCHECK_NE(encoder_state_, kInitialized);
 391
 392   if (encoder_state_ == kError) {
 393     DVLOG(2) << "ServiceDeviceTask(): early out: kError state";
 394     return;
 395   }
 396
 397   Dequeue();
 398   Enqueue();
 399
 400   // Clear the interrupt fd.
 401   if (!device_->ClearDevicePollInterrupt())
 402     return;
 403
 404   // Device can be polled as soon as either input or output buffers are queued.
 405   bool poll_device =
 406       (input_buffer_queued_count_ + output_buffer_queued_count_ > 0);
 407
 408   // ServiceDeviceTask() should only ever be scheduled from DevicePollTask(),
 409   // so either:
 410   // * device_poll_thread_ is running normally
 411   // * device_poll_thread_ scheduled us, but then a DestroyTask() shut it down,
 412   //   in which case we're in kError state, and we should have early-outed
 413   //   already.
 414   DCHECK(device_poll_thread_.message_loop());
 415   // Queue the DevicePollTask() now.
 416   device_poll_thread_.message_loop()->PostTask(
 417       FROM_HERE,
 418       base::Bind(&V4L2VideoEncodeAccelerator::DevicePollTask,
 419                  base::Unretained(this),
 420                  poll_device));
 421
 422   DVLOG(2) << __func__ << ": buffer counts: ENC["
 423            << encoder_input_queue_.size() << "] => DEVICE["
 424            << free_input_buffers_.size() << "+"
 425            << input_buffer_queued_count_ << "/"
 426            << input_buffer_map_.size() << "->"
 427            << free_output_buffers_.size() << "+"
 428            << output_buffer_queued_count_ << "/"
 429            << output_buffer_map_.size() << "] => OUT["
 430            << encoder_output_queue_.size() << "]";
 431 }
 432
 433 void V4L2VideoEncodeAccelerator::Enqueue() {
 434   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 435
 436   DVLOG(3) << "Enqueue() "
 437            << "free_input_buffers: " << free_input_buffers_.size()
 438            << "input_queue: " << encoder_input_queue_.size();
 439
 440   // Enqueue all the inputs we can.
 441   const int old_inputs_queued = input_buffer_queued_count_;
 442   // while (!ready_input_buffers_.empty()) {
 443   while (!encoder_input_queue_.empty() && !free_input_buffers_.empty()) {
 444     if (!EnqueueInputRecord())
 445       return;
 446   }
 447   if (old_inputs_queued == 0 && input_buffer_queued_count_ != 0) {
 448     // We just started up a previously empty queue.
 449     // Queue state changed; signal interrupt.
 450     if (!device_->SetDevicePollInterrupt())
 451       return;
 452     // Start VIDIOC_STREAMON if we haven't yet.
 453     if (!input_streamon_) {
 454       __u32 type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 455       IOCTL_OR_ERROR_RETURN(VIDIOC_STREAMON, &type);
 456       input_streamon_ = true;
 457     }
 458   }
 459
 460   // Enqueue all the outputs we can.
 461   const int old_outputs_queued = output_buffer_queued_count_;
 462   while (!free_output_buffers_.empty() && !encoder_output_queue_.empty()) {
 463     if (!EnqueueOutputRecord())
 464       return;
 465   }
 466   if (old_outputs_queued == 0 && output_buffer_queued_count_ != 0) {
 467     // We just started up a previously empty queue.
 468     // Queue state changed; signal interrupt.
 469     if (!device_->SetDevicePollInterrupt())
 470       return;
 471     // Start VIDIOC_STREAMON if we haven't yet.
 472     if (!output_streamon_) {
 473       __u32 type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
 474       IOCTL_OR_ERROR_RETURN(VIDIOC_STREAMON, &type);
 475       output_streamon_ = true;
 476     }
 477   }
 478 }
 479
 480 void V4L2VideoEncodeAccelerator::Dequeue() {
 481   DVLOG(3) << "Dequeue()";
 482   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 483
 484   // Dequeue completed input (VIDEO_OUTPUT) buffers, and recycle to the free
 485   // list.
 486   struct v4l2_buffer dqbuf;
 487   struct v4l2_plane planes[VIDEO_MAX_PLANES];
 488   while (input_buffer_queued_count_ > 0) {
 489     DVLOG(4) << "inputs queued: " << input_buffer_queued_count_;
 490     DCHECK(input_streamon_);
 491     memset(&dqbuf, 0, sizeof(dqbuf));
 492     memset(&planes, 0, sizeof(planes));
 493     dqbuf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 494     dqbuf.memory = V4L2_MEMORY_MMAP;
 495     dqbuf.m.planes = planes;
 496     dqbuf.length = input_planes_count_;
 497     if (device_->Ioctl(VIDIOC_DQBUF, &dqbuf) != 0) {
 498       if (errno == EAGAIN) {
 499         // EAGAIN if we're just out of buffers to dequeue.
 500         break;
 501       }
 502       DPLOG(ERROR) << "Dequeue(): ioctl() failed: VIDIOC_DQBUF";
 503       NOTIFY_ERROR(kPlatformFailureError);
 504       return;
 505     }
 506     InputRecord& input_record = input_buffer_map_[dqbuf.index];
 507     DCHECK(input_record.at_device);
 508     input_record.at_device = false;
 509
 510     input_record.frame = NULL;
 511     free_input_buffers_.push_back(dqbuf.index);
 512     input_buffer_queued_count_--;
 513   }
 514
 515   // Dequeue completed output (VIDEO_CAPTURE) buffers, and recycle to the
 516   // free list.  Notify the client that an output buffer is complete.
 517   while (output_buffer_queued_count_ > 0) {
 518     DCHECK(output_streamon_);
 519     memset(&dqbuf, 0, sizeof(dqbuf));
 520     memset(planes, 0, sizeof(planes));
 521     dqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
 522     dqbuf.memory = V4L2_MEMORY_MMAP;
 523     dqbuf.m.planes = planes;
 524     dqbuf.length = 1;
 525     if (device_->Ioctl(VIDIOC_DQBUF, &dqbuf) != 0) {
 526       if (errno == EAGAIN) {
 527         // EAGAIN if we're just out of buffers to dequeue.
 528         break;
 529       }
 530       DPLOG(ERROR) << "Dequeue(): ioctl() failed: VIDIOC_DQBUF";
 531       NOTIFY_ERROR(kPlatformFailureError);
 532       return;
 533     }
 534     const bool key_frame = ((dqbuf.flags & V4L2_BUF_FLAG_KEYFRAME) != 0);
 535     OutputRecord& output_record = output_buffer_map_[dqbuf.index];
 536     DCHECK(output_record.at_device);
 537     DCHECK(output_record.buffer_ref.get());
 538
 539     void* output_data = output_record.address;
 540     size_t output_size = dqbuf.m.planes[0].bytesused;
 541     // This shouldn't happen, but just in case. We should be able to recover
 542     // after next keyframe after showing some corruption.
 543     DCHECK_LE(output_size, output_buffer_byte_size_);
 544     if (output_size > output_buffer_byte_size_)
 545       output_size = output_buffer_byte_size_;
 546     uint8* target_data =
 547         reinterpret_cast<uint8*>(output_record.buffer_ref->shm->memory());
 548     if (output_format_fourcc_ == V4L2_PIX_FMT_H264) {
 549       if (stream_header_size_ == 0) {
 550         // Assume that the first buffer dequeued is the stream header.
 551         stream_header_size_ = output_size;
 552         stream_header_.reset(new uint8[stream_header_size_]);
 553         memcpy(stream_header_.get(), output_data, stream_header_size_);
 554       }
 555       if (key_frame &&
 556           output_buffer_byte_size_ - stream_header_size_ >= output_size) {
 557         // Insert stream header before every keyframe.
 558         memcpy(target_data, stream_header_.get(), stream_header_size_);
 559         memcpy(target_data + stream_header_size_, output_data, output_size);
 560         output_size += stream_header_size_;
 561       } else {
 562         memcpy(target_data, output_data, output_size);
 563       }
 564     } else {
 565       memcpy(target_data, output_data, output_size);
 566     }
 567
 568     DVLOG(3) << "Dequeue(): returning "
 569                 "bitstream_buffer_id=" << output_record.buffer_ref->id
 570              << ", size=" << output_size << ", key_frame=" << key_frame;
 571     child_message_loop_proxy_->PostTask(
 572         FROM_HERE,
 573         base::Bind(&Client::BitstreamBufferReady,
 574                    client_,
 575                    output_record.buffer_ref->id,
 576                    output_size,
 577                    key_frame));
 578     output_record.at_device = false;
 579     output_record.buffer_ref.reset();
 580     free_output_buffers_.push_back(dqbuf.index);
 581     output_buffer_queued_count_--;
 582   }
 583 }
 584
 585 bool V4L2VideoEncodeAccelerator::EnqueueInputRecord() {
 586   DVLOG(3) << "EnqueueInputRecord()";
 587   DCHECK(!free_input_buffers_.empty());
 588   DCHECK(!encoder_input_queue_.empty());
 589
 590   // Enqueue an input (VIDEO_OUTPUT) buffer.
 591   scoped_refptr<media::VideoFrame> frame = encoder_input_queue_.front();
 592   const int index = free_input_buffers_.back();
 593   InputRecord& input_record = input_buffer_map_[index];
 594   DCHECK(!input_record.at_device);
 595   struct v4l2_buffer qbuf;
 596   struct v4l2_plane qbuf_planes[VIDEO_MAX_PLANES];
 597   memset(&qbuf, 0, sizeof(qbuf));
 598   memset(qbuf_planes, 0, sizeof(qbuf_planes));
 599   qbuf.index = index;
 600   qbuf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 601   qbuf.m.planes = qbuf_planes;
 602
 603   DCHECK_EQ(device_input_format_, frame->format());
 604   for (size_t i = 0; i < input_planes_count_; ++i) {
 605     qbuf.m.planes[i].bytesused =
 606         base::checked_cast<__u32>(media::VideoFrame::PlaneAllocationSize(
 607             frame->format(), i, input_allocated_size_));
 608
 609     switch (input_memory_type_) {
 610       case V4L2_MEMORY_USERPTR:
 611         qbuf.m.planes[i].length = qbuf.m.planes[i].bytesused;
 612         qbuf.m.planes[i].m.userptr =
 613             reinterpret_cast<unsigned long>(frame->data(i));
 614         DCHECK(qbuf.m.planes[i].m.userptr);
 615         break;
 616
 617       case V4L2_MEMORY_DMABUF:
 618         qbuf.m.planes[i].m.fd = frame->dmabuf_fd(i);
 619         DCHECK_NE(qbuf.m.planes[i].m.fd, -1);
 620         break;
 621
 622       default:
 623         NOTREACHED();
 624         return false;
 625     }
 626   }
 627
 628   qbuf.memory = input_memory_type_;
 629   qbuf.length = input_planes_count_;
 630
 631   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_QBUF, &qbuf);
 632   input_record.at_device = true;
 633   input_record.frame = frame;
 634   encoder_input_queue_.pop_front();
 635   free_input_buffers_.pop_back();
 636   input_buffer_queued_count_++;
 637   return true;
 638 }
 639
 640 bool V4L2VideoEncodeAccelerator::EnqueueOutputRecord() {
 641   DVLOG(3) << "EnqueueOutputRecord()";
 642   DCHECK(!free_output_buffers_.empty());
 643   DCHECK(!encoder_output_queue_.empty());
 644
 645   // Enqueue an output (VIDEO_CAPTURE) buffer.
 646   linked_ptr<BitstreamBufferRef> output_buffer = encoder_output_queue_.back();
 647   const int index = free_output_buffers_.back();
 648   OutputRecord& output_record = output_buffer_map_[index];
 649   DCHECK(!output_record.at_device);
 650   DCHECK(!output_record.buffer_ref.get());
 651   struct v4l2_buffer qbuf;
 652   struct v4l2_plane qbuf_planes[1];
 653   memset(&qbuf, 0, sizeof(qbuf));
 654   memset(qbuf_planes, 0, sizeof(qbuf_planes));
 655   qbuf.index = index;
 656   qbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
 657   qbuf.memory = V4L2_MEMORY_MMAP;
 658   qbuf.m.planes = qbuf_planes;
 659   qbuf.length = 1;
 660   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_QBUF, &qbuf);
 661   output_record.at_device = true;
 662   output_record.buffer_ref = output_buffer;
 663   encoder_output_queue_.pop_back();
 664   free_output_buffers_.pop_back();
 665   output_buffer_queued_count_++;
 666   return true;
 667 }
 668
 669 bool V4L2VideoEncodeAccelerator::StartDevicePoll() {
 670   DVLOG(3) << "StartDevicePoll()";
 671   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 672   DCHECK(!device_poll_thread_.IsRunning());
 673
 674   // Start up the device poll thread and schedule its first DevicePollTask().
 675   if (!device_poll_thread_.Start()) {
 676     DLOG(ERROR) << "StartDevicePoll(): Device thread failed to start";
 677     NOTIFY_ERROR(kPlatformFailureError);
 678     return false;
 679   }
 680   // Enqueue a poll task with no devices to poll on -- it will wait only on the
 681   // interrupt fd.
 682   device_poll_thread_.message_loop()->PostTask(
 683       FROM_HERE,
 684       base::Bind(&V4L2VideoEncodeAccelerator::DevicePollTask,
 685                  base::Unretained(this),
 686                  false));
 687
 688   return true;
 689 }
 690
 691 bool V4L2VideoEncodeAccelerator::StopDevicePoll() {
 692   DVLOG(3) << "StopDevicePoll()";
 693
 694   // Signal the DevicePollTask() to stop, and stop the device poll thread.
 695   if (!device_->SetDevicePollInterrupt())
 696     return false;
 697   device_poll_thread_.Stop();
 698   // Clear the interrupt now, to be sure.
 699   if (!device_->ClearDevicePollInterrupt())
 700     return false;
 701
 702   if (input_streamon_) {
 703     __u32 type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 704     IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_STREAMOFF, &type);
 705   }
 706   input_streamon_ = false;
 707
 708   if (output_streamon_) {
 709     __u32 type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
 710     IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_STREAMOFF, &type);
 711   }
 712   output_streamon_ = false;
 713
 714   // Reset all our accounting info.
 715   encoder_input_queue_.clear();
 716   free_input_buffers_.clear();
 717   for (size_t i = 0; i < input_buffer_map_.size(); ++i) {
 718     InputRecord& input_record = input_buffer_map_[i];
 719     input_record.at_device = false;
 720     input_record.frame = NULL;
 721     free_input_buffers_.push_back(i);
 722   }
 723   input_buffer_queued_count_ = 0;
 724
 725   free_output_buffers_.clear();
 726   for (size_t i = 0; i < output_buffer_map_.size(); ++i) {
 727     OutputRecord& output_record = output_buffer_map_[i];
 728     output_record.at_device = false;
 729     output_record.buffer_ref.reset();
 730     free_output_buffers_.push_back(i);
 731   }
 732   output_buffer_queued_count_ = 0;
 733
 734   encoder_output_queue_.clear();
 735
 736   DVLOG(3) << "StopDevicePoll(): device poll stopped";
 737   return true;
 738 }
 739
 740 void V4L2VideoEncodeAccelerator::DevicePollTask(bool poll_device) {
 741   DVLOG(3) << "DevicePollTask()";
 742   DCHECK_EQ(device_poll_thread_.message_loop(), base::MessageLoop::current());
 743
 744   bool event_pending;
 745   if (!device_->Poll(poll_device, &event_pending)) {
 746     NOTIFY_ERROR(kPlatformFailureError);
 747     return;
 748   }
 749
 750   // All processing should happen on ServiceDeviceTask(), since we shouldn't
 751   // touch encoder state from this thread.
 752   encoder_thread_.message_loop()->PostTask(
 753       FROM_HERE,
 754       base::Bind(&V4L2VideoEncodeAccelerator::ServiceDeviceTask,
 755                  base::Unretained(this)));
 756 }
 757
 758 void V4L2VideoEncodeAccelerator::NotifyError(Error error) {
 759   DVLOG(1) << "NotifyError(): error=" << error;
 760
 761   if (!child_message_loop_proxy_->BelongsToCurrentThread()) {
 762     child_message_loop_proxy_->PostTask(
 763         FROM_HERE,
 764         base::Bind(
 765             &V4L2VideoEncodeAccelerator::NotifyError, weak_this_, error));
 766     return;
 767   }
 768
 769   if (client_) {
 770     client_->NotifyError(error);
 771     client_ptr_factory_.reset();
 772   }
 773 }
 774
 775 void V4L2VideoEncodeAccelerator::SetEncoderState(State state) {
 776   DVLOG(3) << "SetEncoderState(): state=" << state;
 777
 778   // We can touch encoder_state_ only if this is the encoder thread or the
 779   // encoder thread isn't running.
 780   if (encoder_thread_.message_loop() != NULL &&
 781       encoder_thread_.message_loop() != base::MessageLoop::current()) {
 782     encoder_thread_.message_loop()->PostTask(
 783         FROM_HERE,
 784         base::Bind(&V4L2VideoEncodeAccelerator::SetEncoderState,
 785                    base::Unretained(this),
 786                    state));
 787   } else {
 788     encoder_state_ = state;
 789   }
 790 }
 791
 792 void V4L2VideoEncodeAccelerator::RequestEncodingParametersChangeTask(
 793     uint32 bitrate,
 794     uint32 framerate) {
 795   DVLOG(3) << "RequestEncodingParametersChangeTask(): bitrate=" << bitrate
 796            << ", framerate=" << framerate;
 797   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 798
 799   if (bitrate < 1)
 800     bitrate = 1;
 801   if (framerate < 1)
 802     framerate = 1;
 803
 804   struct v4l2_ext_control ctrls[1];
 805   struct v4l2_ext_controls control;
 806   memset(&ctrls, 0, sizeof(ctrls));
 807   memset(&control, 0, sizeof(control));
 808   ctrls[0].id = V4L2_CID_MPEG_VIDEO_BITRATE;
 809   ctrls[0].value = bitrate;
 810   control.ctrl_class = V4L2_CTRL_CLASS_MPEG;
 811   control.count = arraysize(ctrls);
 812   control.controls = ctrls;
 813   IOCTL_OR_ERROR_RETURN(VIDIOC_S_EXT_CTRLS, &control);
 814
 815   struct v4l2_streamparm parms;
 816   memset(&parms, 0, sizeof(parms));
 817   parms.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 818   // Note that we are provided "frames per second" but V4L2 expects "time per
 819   // frame"; hence we provide the reciprocal of the framerate here.
 820   parms.parm.output.timeperframe.numerator = 1;
 821   parms.parm.output.timeperframe.denominator = framerate;
 822   IOCTL_OR_ERROR_RETURN(VIDIOC_S_PARM, &parms);
 823 }
 824
 825 bool V4L2VideoEncodeAccelerator::SetOutputFormat(
 826     media::VideoCodecProfile output_profile) {
 827   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 828   DCHECK(!input_streamon_);
 829   DCHECK(!output_streamon_);
 830
 831   output_format_fourcc_ =
 832       V4L2Device::VideoCodecProfileToV4L2PixFmt(output_profile);
 833   if (!output_format_fourcc_) {
 834     DLOG(ERROR) << "Initialize(): invalid output_profile=" << output_profile;
 835     return false;
 836   }
 837
 838   output_buffer_byte_size_ = kOutputBufferSize;
 839
 840   struct v4l2_format format;
 841   memset(&format, 0, sizeof(format));
 842   format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
 843   format.fmt.pix_mp.width = visible_size_.width();
 844   format.fmt.pix_mp.height = visible_size_.height();
 845   format.fmt.pix_mp.pixelformat = output_format_fourcc_;
 846   format.fmt.pix_mp.plane_fmt[0].sizeimage =
 847       base::checked_cast<__u32>(output_buffer_byte_size_);
 848   format.fmt.pix_mp.num_planes = 1;
 849   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_FMT, &format);
 850
 851   // Device might have adjusted the required output size.
 852   size_t adjusted_output_buffer_size =
 853       base::checked_cast<size_t>(format.fmt.pix_mp.plane_fmt[0].sizeimage);
 854   DCHECK_GE(adjusted_output_buffer_size, output_buffer_byte_size_);
 855   output_buffer_byte_size_ = adjusted_output_buffer_size;
 856
 857   return true;
 858 }
 859
 860 bool V4L2VideoEncodeAccelerator::NegotiateInputFormat(
 861     media::VideoFrame::Format input_format) {
 862   DVLOG(3) << "NegotiateInputFormat()";
 863   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 864   DCHECK(!input_streamon_);
 865   DCHECK(!output_streamon_);
 866
 867   device_input_format_ = media::VideoFrame::UNKNOWN;
 868   input_planes_count_ = 0;
 869
 870   uint32 input_format_fourcc =
 871       V4L2Device::VideoFrameFormatToV4L2PixFmt(input_format);
 872   if (!input_format_fourcc) {
 873     DVLOG(1) << "Unsupported input format";
 874     return false;
 875   }
 876
 877   size_t input_planes_count = media::VideoFrame::NumPlanes(input_format);
 878   DCHECK_LE(input_planes_count, static_cast<size_t>(VIDEO_MAX_PLANES));
 879
 880   // First see if we the device can use the provided input_format directly.
 881   struct v4l2_format format;
 882   memset(&format, 0, sizeof(format));
 883   format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 884   format.fmt.pix_mp.width = visible_size_.width();
 885   format.fmt.pix_mp.height = visible_size_.height();
 886   format.fmt.pix_mp.pixelformat = input_format_fourcc;
 887   format.fmt.pix_mp.num_planes = input_planes_count;
 888   if (device_->Ioctl(VIDIOC_S_FMT, &format) != 0) {
 889     // Error or format unsupported by device, try to negotiate a fallback.
 890     input_format_fourcc = device_->PreferredInputFormat();
 891     input_format =
 892         V4L2Device::V4L2PixFmtToVideoFrameFormat(input_format_fourcc);
 893     if (input_format == media::VideoFrame::UNKNOWN)
 894       return false;
 895
 896     input_planes_count = media::VideoFrame::NumPlanes(input_format);
 897     DCHECK_LE(input_planes_count, static_cast<size_t>(VIDEO_MAX_PLANES));
 898
 899     // Device might have adjusted parameters, reset them along with the format.
 900     memset(&format, 0, sizeof(format));
 901     format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 902     format.fmt.pix_mp.width = visible_size_.width();
 903     format.fmt.pix_mp.height = visible_size_.height();
 904     format.fmt.pix_mp.pixelformat = input_format_fourcc;
 905     format.fmt.pix_mp.num_planes = input_planes_count;
 906     IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_FMT, &format);
 907     DCHECK_EQ(format.fmt.pix_mp.num_planes, input_planes_count);
 908   }
 909
 910   // Take device-adjusted sizes for allocated size.
 911   input_allocated_size_ = V4L2Device::CodedSizeFromV4L2Format(format);
 912   DCHECK(gfx::Rect(input_allocated_size_).Contains(gfx::Rect(visible_size_)));
 913
 914   device_input_format_ = input_format;
 915   input_planes_count_ = input_planes_count;
 916   return true;
 917 }
 918
 919 bool V4L2VideoEncodeAccelerator::SetFormats(
 920     media::VideoFrame::Format input_format,
 921     media::VideoCodecProfile output_profile) {
 922   DVLOG(3) << "SetFormats()";
 923   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
 924   DCHECK(!input_streamon_);
 925   DCHECK(!output_streamon_);
 926
 927   if (!SetOutputFormat(output_profile))
 928     return false;
 929
 930   if (!NegotiateInputFormat(input_format))
 931     return false;
 932
 933   struct v4l2_crop crop;
 934   memset(&crop, 0, sizeof(crop));
 935   crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
 936   crop.c.left = 0;
 937   crop.c.top = 0;
 938   crop.c.width = visible_size_.width();
 939   crop.c.height = visible_size_.height();
 940   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_CROP, &crop);
 941
 942   return true;
 943 }
 944
 945 bool V4L2VideoEncodeAccelerator::InitControls() {
 946   struct v4l2_ext_control ctrls[9];
 947   struct v4l2_ext_controls control;
 948   memset(&ctrls, 0, sizeof(ctrls));
 949   memset(&control, 0, sizeof(control));
 950   // No B-frames, for lowest decoding latency.
 951   ctrls[0].id = V4L2_CID_MPEG_VIDEO_B_FRAMES;
 952   ctrls[0].value = 0;
 953   // Enable frame-level bitrate control.
 954   ctrls[1].id = V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE;
 955   ctrls[1].value = 1;
 956   // Enable "tight" bitrate mode. For this to work properly, frame- and mb-level
 957   // bitrate controls have to be enabled as well.
 958   ctrls[2].id = V4L2_CID_MPEG_MFC51_VIDEO_RC_REACTION_COEFF;
 959   ctrls[2].value = 1;
 960   // Force bitrate control to average over a GOP (for tight bitrate
 961   // tolerance).
 962   ctrls[3].id = V4L2_CID_MPEG_MFC51_VIDEO_RC_FIXED_TARGET_BIT;
 963   ctrls[3].value = 1;
 964   // Quantization parameter maximum value (for variable bitrate control).
 965   ctrls[4].id = V4L2_CID_MPEG_VIDEO_H264_MAX_QP;
 966   ctrls[4].value = 51;
 967   // Separate stream header so we can cache it and insert into the stream.
 968   ctrls[5].id = V4L2_CID_MPEG_VIDEO_HEADER_MODE;
 969   ctrls[5].value = V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE;
 970   // Enable macroblock-level bitrate control.
 971   ctrls[6].id = V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE;
 972   ctrls[6].value = 1;
 973   // Use H.264 level 4.0 to match the supported max resolution.
 974   ctrls[7].id = V4L2_CID_MPEG_VIDEO_H264_LEVEL;
 975   ctrls[7].value = V4L2_MPEG_VIDEO_H264_LEVEL_4_0;
 976   // Disable periodic key frames.
 977   ctrls[8].id = V4L2_CID_MPEG_VIDEO_GOP_SIZE;
 978   ctrls[8].value = 0;
 979   control.ctrl_class = V4L2_CTRL_CLASS_MPEG;
 980   control.count = arraysize(ctrls);
 981   control.controls = ctrls;
 982   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_EXT_CTRLS, &control);
 983
 984   return true;
 985 }
 986
 987 bool V4L2VideoEncodeAccelerator::CreateInputBuffers() {
 988   DVLOG(3) << "CreateInputBuffers()";
 989   // This function runs on encoder_thread_ after output buffers have been
 990   // provided by the client.
 991   DCHECK_EQ(encoder_thread_.message_loop(), base::MessageLoop::current());
 992   DCHECK(!input_streamon_);
 993
 994   struct v4l2_requestbuffers reqbufs;
 995   memset(&reqbufs, 0, sizeof(reqbufs));
 996   // Driver will modify to the appropriate number of buffers.
 997   reqbufs.count = 1;
 998   reqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
 999   // TODO(posciak): Once we start doing zero-copy, we should decide based on
1000   // the current pipeline setup which memory type to use. This should probably
1001   // be decided based on an argument to Initialize().
1002   if (image_processor_.get())
1003     input_memory_type_ = V4L2_MEMORY_DMABUF;
1004   else
1005     input_memory_type_ = V4L2_MEMORY_USERPTR;
1006
1007   reqbufs.memory = input_memory_type_;
1008   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_REQBUFS, &reqbufs);
1009
1010   DCHECK(input_buffer_map_.empty());
1011   input_buffer_map_.resize(reqbufs.count);
1012   for (size_t i = 0; i < input_buffer_map_.size(); ++i)
1013     free_input_buffers_.push_back(i);
1014
1015   return true;
1016 }
1017
1018 bool V4L2VideoEncodeAccelerator::CreateOutputBuffers() {
1019   DVLOG(3) << "CreateOutputBuffers()";
1020   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
1021   DCHECK(!output_streamon_);
1022
1023   struct v4l2_requestbuffers reqbufs;
1024   memset(&reqbufs, 0, sizeof(reqbufs));
1025   reqbufs.count = kOutputBufferCount;
1026   reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
1027   reqbufs.memory = V4L2_MEMORY_MMAP;
1028   IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_REQBUFS, &reqbufs);
1029
1030   DCHECK(output_buffer_map_.empty());
1031   output_buffer_map_.resize(reqbufs.count);
1032   for (size_t i = 0; i < output_buffer_map_.size(); ++i) {
1033     struct v4l2_plane planes[1];
1034     struct v4l2_buffer buffer;
1035     memset(&buffer, 0, sizeof(buffer));
1036     memset(planes, 0, sizeof(planes));
1037     buffer.index = i;
1038     buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
1039     buffer.memory = V4L2_MEMORY_MMAP;
1040     buffer.m.planes = planes;
1041     buffer.length = arraysize(planes);
1042     IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_QUERYBUF, &buffer);
1043     void* address = device_->Mmap(NULL,
1044                                   buffer.m.planes[0].length,
1045                                   PROT_READ | PROT_WRITE,
1046                                   MAP_SHARED,
1047                                   buffer.m.planes[0].m.mem_offset);
1048     if (address == MAP_FAILED) {
1049       DPLOG(ERROR) << "CreateOutputBuffers(): mmap() failed";
1050       return false;
1051     }
1052     output_buffer_map_[i].address = address;
1053     output_buffer_map_[i].length = buffer.m.planes[0].length;
1054     free_output_buffers_.push_back(i);
1055   }
1056
1057   return true;
1058 }
1059
1060 void V4L2VideoEncodeAccelerator::DestroyInputBuffers() {
1061   DVLOG(3) << "DestroyInputBuffers()";
1062   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
1063   DCHECK(!input_streamon_);
1064
1065   struct v4l2_requestbuffers reqbufs;
1066   memset(&reqbufs, 0, sizeof(reqbufs));
1067   reqbufs.count = 0;
1068   reqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
1069   reqbufs.memory = input_memory_type_;
1070   IOCTL_OR_LOG_ERROR(VIDIOC_REQBUFS, &reqbufs);
1071
1072   input_buffer_map_.clear();
1073   free_input_buffers_.clear();
1074 }
1075
1076 void V4L2VideoEncodeAccelerator::DestroyOutputBuffers() {
1077   DVLOG(3) << "DestroyOutputBuffers()";
1078   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
1079   DCHECK(!output_streamon_);
1080
1081   for (size_t i = 0; i < output_buffer_map_.size(); ++i) {
1082     if (output_buffer_map_[i].address != NULL)
1083       device_->Munmap(output_buffer_map_[i].address,
1084                       output_buffer_map_[i].length);
1085   }
1086
1087   struct v4l2_requestbuffers reqbufs;
1088   memset(&reqbufs, 0, sizeof(reqbufs));
1089   reqbufs.count = 0;
1090   reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
1091   reqbufs.memory = V4L2_MEMORY_MMAP;
1092   IOCTL_OR_LOG_ERROR(VIDIOC_REQBUFS, &reqbufs);
1093
1094   output_buffer_map_.clear();
1095   free_output_buffers_.clear();
1096 }
1097
1098 }  // namespace content