Linux Video Capture: Add V4L2VideoCaptureDelegate{Single,Multi}Plane.

media/video/capture/linux/v4l2_video_capture_delegate.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 "media/video/capture/linux/v4l2_video_capture_delegate.h"
+
+#include <poll.h>
+#include <sys/fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include "base/bind.h"
+#include "base/files/file_enumerator.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/strings/stringprintf.h"
+#include "media/base/bind_to_current_loop.h"
+#include "media/video/capture/linux/v4l2_capture_delegate_multi_plane.h"
+#include "media/video/capture/linux/v4l2_capture_delegate_single_plane.h"
+#include "media/video/capture/linux/video_capture_device_linux.h"
+
+namespace media {
+
+// Desired number of video buffers to allocate. The actual number of allocated
+// buffers by v4l2 driver can be higher or lower than this number.
+// kNumVideoBuffers should not be too small, or Chrome may not return enough
+// buffers back to driver in time.
+const uint32 kNumVideoBuffers = 4;
+// Timeout in milliseconds v4l2_thread_ blocks waiting for a frame from the hw.
+const int kCaptureTimeoutMs = 200;
+// The number of continuous timeouts tolerated before treated as error.
+const int kContinuousTimeoutLimit = 10;
+// MJPEG is preferred if the requested width or height is larger than this.
+const int kMjpegWidth = 640;
+const int kMjpegHeight = 480;
+// Typical framerate, in fps
+const int kTypicalFramerate = 30;
+
+// V4L2 color formats supported by V4L2VideoCaptureDelegate derived classes.
+// This list is ordered by precedence of use -- but see caveats for MJPEG.
+static struct{
+  uint32_t fourcc;
+  VideoPixelFormat pixel_format;
+  size_t num_planes;
+} const kSupportedFormatsAndPlanarity[] = {
+  {V4L2_PIX_FMT_YUV420, PIXEL_FORMAT_I420, 1},
+  {V4L2_PIX_FMT_YUYV, PIXEL_FORMAT_YUY2, 1},
+  {V4L2_PIX_FMT_UYVY, PIXEL_FORMAT_UYVY, 1},
+#if !defined(OS_OPENBSD)
+  // TODO(mcasas): add V4L2_PIX_FMT_YVU420M when available in bots.
+  {V4L2_PIX_FMT_YUV420M, PIXEL_FORMAT_I420, 3},
+#endif
+  // MJPEG is usually sitting fairly low since we don't want to have to decode.
+  // However, is needed for large resolutions due to USB bandwidth limitations,
+  // so GetListOfUsableFourCcs() can duplicate it on top, see that method.
+  {V4L2_PIX_FMT_MJPEG, PIXEL_FORMAT_MJPEG, 1},
+  // JPEG works as MJPEG on some gspca webcams from field reports, see
+  // https://code.google.com/p/webrtc/issues/detail?id=529, put it as the least
+  // preferred format.
+  {V4L2_PIX_FMT_JPEG, PIXEL_FORMAT_MJPEG, 1},
+};
+
+// static
+scoped_refptr<V4L2VideoCaptureDelegate>
+V4L2VideoCaptureDelegate::CreateV4L2VideoCaptureDelegate(
+    const VideoCaptureDevice::Name& device_name,
+    const scoped_refptr<base::SingleThreadTaskRunner>& v4l2_task_runner,
+    int power_line_frequency) {
+  switch (device_name.capture_api_type()) {
+    case VideoCaptureDevice::Name::V4L2_SINGLE_PLANE:
+      return make_scoped_refptr(new V4L2CaptureDelegateSinglePlane(
+          device_name, v4l2_task_runner, power_line_frequency));
+    case VideoCaptureDevice::Name::V4L2_MULTI_PLANE:
+#if !defined(OS_OPENBSD)
+      return make_scoped_refptr(new V4L2CaptureDelegateMultiPlane(
+          device_name, v4l2_task_runner, power_line_frequency));
+    default:
+#endif
+      NOTIMPLEMENTED() << "Unknown V4L2 capture API type";
+      return scoped_refptr<V4L2VideoCaptureDelegate>();
+  }
+}
+
+//static
+size_t V4L2VideoCaptureDelegate::GetNumPlanesForFourCc(uint32_t fourcc) {
+  for (const auto& fourcc_and_pixel_format : kSupportedFormatsAndPlanarity) {
+    if (fourcc_and_pixel_format.fourcc == fourcc)
+      return fourcc_and_pixel_format.num_planes;
+  }
+  DVLOG(1) << "Unknown fourcc " << FourccToString(fourcc);
+  return 0;
+}
+
+// static
+VideoPixelFormat V4L2VideoCaptureDelegate::V4l2FourCcToChromiumPixelFormat(
+    uint32_t v4l2_fourcc) {
+  for (const auto& fourcc_and_pixel_format : kSupportedFormatsAndPlanarity) {
+    if (fourcc_and_pixel_format.fourcc == v4l2_fourcc)
+      return fourcc_and_pixel_format.pixel_format;
+  }
+  // Not finding a pixel format is OK during device capabilities enumeration.
+  // Let the caller decide if PIXEL_FORMAT_UNKNOWN is an error or not.
+  DVLOG(1) << "Unsupported pixel format: " << FourccToString(v4l2_fourcc);
+  return PIXEL_FORMAT_UNKNOWN;
+}
+
+// static
+std::list<uint32_t> V4L2VideoCaptureDelegate::GetListOfUsableFourCcs(
+    bool prefer_mjpeg) {
+  std::list<uint32_t> supported_formats;
+  for (const auto& format : kSupportedFormatsAndPlanarity)
+    supported_formats.push_back(format.fourcc);
+
+  // Duplicate MJPEG on top of the list depending on |prefer_mjpeg|.
+  if (prefer_mjpeg)
+    supported_formats.push_front(V4L2_PIX_FMT_MJPEG);
+
+  return supported_formats;
+}
+
+//static
+std::string V4L2VideoCaptureDelegate::FourccToString(uint32_t fourcc) {
+  return base::StringPrintf("%c%c%c%c", fourcc & 0xFF, (fourcc >> 8) & 0xFF,
+                            (fourcc >> 16) & 0xFF, (fourcc >> 24) & 0xFF);
+}
+
+V4L2VideoCaptureDelegate::BufferTracker::BufferTracker() {
+}
+
+V4L2VideoCaptureDelegate::BufferTracker::~BufferTracker() {
+  for (const auto& plane : planes_) {
+    if (plane.start == nullptr)
+      continue;
+    const int result = munmap(plane.start, plane.length);
+    PLOG_IF(ERROR, result < 0) << "Error munmap()ing V4L2 buffer";
+  }
+}
+
+void V4L2VideoCaptureDelegate::BufferTracker::AddMmapedPlane(
+    uint8_t* const start,
+    size_t length) {
+  Plane plane;
+  plane.start = start;
+  plane.length = length;
+  planes_.push_back(plane);
+}
+
+V4L2VideoCaptureDelegate::V4L2VideoCaptureDelegate(
+    const VideoCaptureDevice::Name& device_name,
+    const scoped_refptr<base::SingleThreadTaskRunner>& v4l2_task_runner,
+    int power_line_frequency)
+    : capture_type_((device_name.capture_api_type() ==
+                     VideoCaptureDevice::Name::V4L2_SINGLE_PLANE)
+                        ? V4L2_BUF_TYPE_VIDEO_CAPTURE
+                        : V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE),
+      v4l2_task_runner_(v4l2_task_runner),
+      device_name_(device_name),
+      power_line_frequency_(power_line_frequency),
+      is_capturing_(false),
+      timeout_count_(0),
+      rotation_(0) {
+}
+
+V4L2VideoCaptureDelegate::~V4L2VideoCaptureDelegate() {
+}
+
+void V4L2VideoCaptureDelegate::AllocateAndStart(
+    int width,
+    int height,
+    float frame_rate,
+    scoped_ptr<VideoCaptureDevice::Client> client) {
+  DCHECK(v4l2_task_runner_->BelongsToCurrentThread());
+  DCHECK(client);
+  client_ = client.Pass();
+
+  // Need to open camera with O_RDWR after Linux kernel 3.3.
+  device_fd_.reset(HANDLE_EINTR(open(device_name_.id().c_str(), O_RDWR)));
+  if (!device_fd_.is_valid()) {
+    SetErrorState("Failed to open V4L2 device driver file.");
+    return;
+  }
+
+  v4l2_capability cap = {};
+  if (!((HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_QUERYCAP, &cap)) == 0) &&
+        ((cap.capabilities & V4L2_CAP_VIDEO_CAPTURE ||
+          cap.capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE) &&
+         !(cap.capabilities & V4L2_CAP_VIDEO_OUTPUT) &&
+         !(cap.capabilities & V4L2_CAP_VIDEO_OUTPUT_MPLANE)))) {
+    device_fd_.reset();
+    SetErrorState("This is not a V4L2 video capture device");
+    return;
+  }
+
+  // Get supported video formats in preferred order.
+  // For large resolutions, favour mjpeg over raw formats.
+  const std::list<uint32_t>& desired_v4l2_formats =
+      GetListOfUsableFourCcs(width > kMjpegWidth || height > kMjpegHeight);
+  std::list<uint32_t>::const_iterator best = desired_v4l2_formats.end();
+
+  v4l2_fmtdesc fmtdesc = {};
+  fmtdesc.type = capture_type_;
+  for (; HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_ENUM_FMT, &fmtdesc)) == 0;
+       ++fmtdesc.index) {
+    best = std::find(desired_v4l2_formats.begin(), best, fmtdesc.pixelformat);
+  }
+  if (best == desired_v4l2_formats.end()) {
+    SetErrorState("Failed to find a supported camera format.");
+    return;
+  }
+
+  DVLOG(1) << "Chosen pixel format is " << FourccToString(*best);
+
+  v4l2_format video_fmt = {};
+  video_fmt.type = capture_type_;
+  if (!FillV4L2Format(&video_fmt, width, height, *best)) {
+    SetErrorState("Failed filling in V4L2 Format");
+    return;
+  }
+
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_S_FMT, &video_fmt)) < 0) {
+    SetErrorState("Failed to set video capture format");
+    return;
+  }
+  const VideoPixelFormat pixel_format =
+      V4l2FourCcToChromiumPixelFormat(video_fmt.fmt.pix.pixelformat);
+  if (pixel_format == PIXEL_FORMAT_UNKNOWN) {
+    SetErrorState("Unsupported pixel format");
+    return;
+  }
+
+  // Set capture framerate in the form of capture interval.
+  v4l2_streamparm streamparm = {};
+  streamparm.type = capture_type_;
+  // The following line checks that the driver knows about framerate get/set.
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_G_PARM, &streamparm)) >= 0) {
+    // Now check if the device is able to accept a capture framerate set.
+    if (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) {
+      // |frame_rate| is float, approximate by a fraction.
+      streamparm.parm.capture.timeperframe.numerator =
+          media::kFrameRatePrecision;
+      streamparm.parm.capture.timeperframe.denominator =
+          (frame_rate) ? (frame_rate * media::kFrameRatePrecision)
+                       : (kTypicalFramerate * media::kFrameRatePrecision);
+
+      if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_S_PARM, &streamparm)) <
+          0) {
+        SetErrorState("Failed to set camera framerate");
+        return;
+      }
+      DVLOG(2) << "Actual camera driverframerate: "
+               << streamparm.parm.capture.timeperframe.denominator << "/"
+               << streamparm.parm.capture.timeperframe.numerator;
+    }
+  }
+  // TODO(mcasas): what should be done if the camera driver does not allow
+  // framerate configuration, or the actual one is different from the desired?
+
+  // Set anti-banding/anti-flicker to 50/60Hz. May fail due to not supported
+  // operation (|errno| == EINVAL in this case) or plain failure.
+  if ((power_line_frequency_ == V4L2_CID_POWER_LINE_FREQUENCY_50HZ) ||
+      (power_line_frequency_ == V4L2_CID_POWER_LINE_FREQUENCY_60HZ) ||
+      (power_line_frequency_ == V4L2_CID_POWER_LINE_FREQUENCY_AUTO)) {
+    struct v4l2_control control = {};
+    control.id = V4L2_CID_POWER_LINE_FREQUENCY;
+    control.value = power_line_frequency_;
+    const int retval =
+        HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_S_CTRL, &control));
+    if (retval != 0)
+      DVLOG(1) << "Error setting power line frequency removal";
+  }
+
+  capture_format_.frame_size.SetSize(video_fmt.fmt.pix.width,
+                                     video_fmt.fmt.pix.height);
+  capture_format_.frame_rate = frame_rate;
+  capture_format_.pixel_format = pixel_format;
+
+  v4l2_requestbuffers r_buffer = {};
+  r_buffer.type = capture_type_;
+  r_buffer.memory = V4L2_MEMORY_MMAP;
+  r_buffer.count = kNumVideoBuffers;
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_REQBUFS, &r_buffer)) < 0) {
+    SetErrorState("Error requesting MMAP buffers from V4L2");
+    return;
+  }
+  DCHECK_LE(r_buffer.count, kNumVideoBuffers);

[Pawel Osciak, 2015/03/20 00:56:07]

count may be larger than what we requested and that should be fine.
kNumVideoBuffers is not Max

[mcasas, 2015/03/20 03:01:20]

Removed.

+  for (unsigned int i = 0; i < r_buffer.count; ++i) {
+    if (!MapAndQueueBuffer(i)) {
+      SetErrorState("Allocate buffer failed");
+      return;
+    }
+  }
+
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_STREAMON, &capture_type_))
+      < 0) {
+    SetErrorState("VIDIOC_STREAMON failed");
+    return;
+  }
+
+  is_capturing_ = true;
+  // Post task to start fetching frames from v4l2.
+  v4l2_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&V4L2VideoCaptureDelegate::DoCapture, this));
+}
+
+void V4L2VideoCaptureDelegate::StopAndDeAllocate() {
+  DCHECK(v4l2_task_runner_->BelongsToCurrentThread());
+  // The order is important: stop streaming, clear |buffer_pool_|,
+  // thus munmap()ing the v4l2_buffers, and then return them to the OS.
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_STREAMOFF, &capture_type_))
+      < 0) {
+    SetErrorState("VIDIOC_STREAMOFF failed");
+    return;
+  }
+
+  buffer_tracker_pool_.clear();
+
+  v4l2_requestbuffers r_buffer = {};
+  r_buffer.type = capture_type_;
+  r_buffer.memory = V4L2_MEMORY_MMAP;
+  r_buffer.count = 0;
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_REQBUFS, &r_buffer)) < 0)
+    SetErrorState("Failed to VIDIOC_REQBUFS with count = 0");
+
+  // At this point we can close the device.
+  // This is also needed for correctly changing settings later via VIDIOC_S_FMT.
+  device_fd_.reset();
+  is_capturing_ = false;
+  client_.reset();
+}
+
+void V4L2VideoCaptureDelegate::SetRotation(int rotation) {
+  DCHECK(v4l2_task_runner_->BelongsToCurrentThread());
+  DCHECK(rotation >= 0 && rotation < 360 && rotation % 90 == 0);
+  rotation_ = rotation;
+}
+
+bool V4L2VideoCaptureDelegate::MapAndQueueBuffer(int index) {
+  v4l2_buffer buffer;
+  FillV4L2Buffer(&buffer, index);
+
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_QUERYBUF, &buffer)) < 0) {
+    DLOG(ERROR) << "Error querying status of a MMAP V4L2 buffer";
+    return false;
+  }
+
+  const scoped_refptr<BufferTracker>& buffer_tracker = CreateBufferTracker();
+  if (!buffer_tracker->Init(device_fd_.get(), buffer)) {
+    DLOG(ERROR) << "Error creating BufferTracker";
+    return false;
+  }
+  buffer_tracker_pool_.push_back(buffer_tracker);
+
+  // Enqueue the buffer in the drivers incoming queue.
+  if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_QBUF, &buffer)) < 0) {
+    DLOG(ERROR) << "Error enqueuing a V4L2 buffer back into the driver";
+    return false;
+  }
+  return true;
+}
+
+void V4L2VideoCaptureDelegate::FillV4L2Buffer(v4l2_buffer* buffer,
+                                              int i) const {
+  memset(buffer, 0, sizeof(*buffer));
+  buffer->memory = V4L2_MEMORY_MMAP;
+  buffer->index = i;
+  FinishFillingV4L2Buffer(buffer);
+}
+
+void V4L2VideoCaptureDelegate::DoCapture() {
+  DCHECK(v4l2_task_runner_->BelongsToCurrentThread());
+  if (!is_capturing_)
+    return;
+
+  pollfd device_pfd = {};
+  device_pfd.fd = device_fd_.get();
+  device_pfd.events = POLLIN;
+  const int result = HANDLE_EINTR(poll(&device_pfd, 1, kCaptureTimeoutMs));
+  if (result < 0) {
+    SetErrorState("Poll failed");
+    return;
+  }
+  // Check if poll() timed out; track the amount of times it did in a row and
+  // throw an error if it times out too many times.
+  if (result == 0) {
+    timeout_count_++;
+    if (timeout_count_ >= kContinuousTimeoutLimit) {
+      SetErrorState("Multiple continuous timeouts while read-polling.");
+      timeout_count_ = 0;
+      return;
+    }
+  } else {
+    timeout_count_ = 0;
+  }
+
+  // Deenqueue, send and reenqueue a buffer if the driver has filled one in.
+  if (device_pfd.revents & POLLIN) {
+    v4l2_buffer buffer;
+    FillV4L2Buffer(&buffer, 0);
+
+    if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_DQBUF, &buffer)) < 0) {
+      SetErrorState("Failed to dequeue capture buffer");
+      return;
+    }
+
+    SendBuffer(buffer_tracker_pool_[buffer.index]);
+
+    if (HANDLE_EINTR(ioctl(device_fd_.get(), VIDIOC_QBUF, &buffer)) < 0) {
+      SetErrorState("Failed to enqueue capture buffer");
+      return;
+    }
+  }
+
+  v4l2_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&V4L2VideoCaptureDelegate::DoCapture, this));
+}
+
+void V4L2VideoCaptureDelegate::SetErrorState(const std::string& reason) {
+  DCHECK(v4l2_task_runner_->BelongsToCurrentThread());
+  is_capturing_ = false;
+  client_->OnError(reason);
+}
+
+}  // namespace media