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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <errno.h>
#include <iomanip>
#include <memory.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <android-base/logging.h>
#include "assert.h"
#include "VideoCapture.h"
// NOTE: This developmental code does not properly clean up resources in case of failure
// during the resource setup phase. Of particular note is the potential to leak
// the file descriptor. This must be fixed before using this code for anything but
// experimentation.
bool VideoCapture::open(const char* deviceName, const int32_t width, const int32_t height) {
// If we want a polling interface for getting frames, we would use O_NONBLOCK
// int mDeviceFd = open(deviceName, O_RDWR | O_NONBLOCK, 0);
mDeviceFd = ::open(deviceName, O_RDWR, 0);
if (mDeviceFd < 0) {
PLOG(ERROR) << "failed to open device " << deviceName;
return false;
}
v4l2_capability caps;
{
int result = ioctl(mDeviceFd, VIDIOC_QUERYCAP, &caps);
if (result < 0) {
PLOG(ERROR) << "failed to get device caps for " << deviceName;
return false;
}
}
// Report device properties
LOG(INFO) << "Open Device: " << deviceName << " (fd = " << mDeviceFd << ")";
LOG(INFO) << " Driver: " << caps.driver;
LOG(INFO) << " Card: " << caps.card;
LOG(INFO) << " Version: " << ((caps.version >> 16) & 0xFF)
<< "." << ((caps.version >> 8) & 0xFF)
<< "." << (caps.version & 0xFF);
LOG(INFO) << " All Caps: " << std::hex << std::setw(8) << caps.capabilities;
LOG(INFO) << " Dev Caps: " << std::hex << caps.device_caps;
// Enumerate the available capture formats (if any)
LOG(INFO) << "Supported capture formats:";
v4l2_fmtdesc formatDescriptions;
formatDescriptions.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
for (int i=0; true; i++) {
formatDescriptions.index = i;
if (ioctl(mDeviceFd, VIDIOC_ENUM_FMT, &formatDescriptions) == 0) {
LOG(INFO) << " " << std::setw(2) << i
<< ": " << formatDescriptions.description
<< " " << std::hex << std::setw(8) << formatDescriptions.pixelformat
<< " " << std::hex << formatDescriptions.flags;
} else {
// No more formats available
break;
}
}
// Verify we can use this device for video capture
if (!(caps.capabilities & V4L2_CAP_VIDEO_CAPTURE) ||
!(caps.capabilities & V4L2_CAP_STREAMING)) {
// Can't do streaming capture.
LOG(ERROR) << "Streaming capture not supported by " << deviceName;
return false;
}
// Set our desired output format
v4l2_format format;
format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
format.fmt.pix.width = width;
format.fmt.pix.height = height;
LOG(INFO) << "Requesting format: "
<< ((char*)&format.fmt.pix.pixelformat)[0]
<< ((char*)&format.fmt.pix.pixelformat)[1]
<< ((char*)&format.fmt.pix.pixelformat)[2]
<< ((char*)&format.fmt.pix.pixelformat)[3]
<< "(" << std::hex << std::setw(8) << format.fmt.pix.pixelformat << ")";
if (ioctl(mDeviceFd, VIDIOC_S_FMT, &format) < 0) {
PLOG(ERROR) << "VIDIOC_S_FMT failed";
}
// Report the current output format
format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (ioctl(mDeviceFd, VIDIOC_G_FMT, &format) == 0) {
mFormat = format.fmt.pix.pixelformat;
mWidth = format.fmt.pix.width;
mHeight = format.fmt.pix.height;
mStride = format.fmt.pix.bytesperline;
LOG(INFO) << "Current output format: "
<< "fmt=0x" << std::hex << format.fmt.pix.pixelformat
<< ", " << std::dec << format.fmt.pix.width << " x " << format.fmt.pix.height
<< ", pitch=" << format.fmt.pix.bytesperline;
} else {
PLOG(ERROR) << "VIDIOC_G_FMT failed";
return false;
}
// Make sure we're initialized to the STOPPED state
mRunMode = STOPPED;
mFrames.clear();
// Ready to go!
return true;
}
void VideoCapture::close() {
LOG(DEBUG) << __FUNCTION__;
// Stream should be stopped first!
assert(mRunMode == STOPPED);
if (isOpen()) {
LOG(DEBUG) << "closing video device file handle " << mDeviceFd;
::close(mDeviceFd);
mDeviceFd = -1;
}
}
bool VideoCapture::startStream(std::function<void(VideoCapture*, imageBuffer*, void*)> callback) {
// Set the state of our background thread
int prevRunMode = mRunMode.fetch_or(RUN);
if (prevRunMode & RUN) {
// The background thread is already running, so we can't start a new stream
LOG(ERROR) << "Already in RUN state, so we can't start a new streaming thread";
return false;
}
// Tell the L4V2 driver to prepare our streaming buffers
v4l2_requestbuffers bufrequest;
bufrequest.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
bufrequest.memory = V4L2_MEMORY_MMAP;
bufrequest.count = 1;
if (ioctl(mDeviceFd, VIDIOC_REQBUFS, &bufrequest) < 0) {
PLOG(ERROR) << "VIDIOC_REQBUFS failed";
return false;
}
mNumBuffers = bufrequest.count;
mBufferInfos = std::make_unique<v4l2_buffer[]>(mNumBuffers);
mPixelBuffers = std::make_unique<void *[]>(mNumBuffers);
for (int i = 0; i < mNumBuffers; ++i) {
// Get the information on the buffer that was created for us
memset(&mBufferInfos[i], 0, sizeof(v4l2_buffer));
mBufferInfos[i].type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
mBufferInfos[i].memory = V4L2_MEMORY_MMAP;
mBufferInfos[i].index = i;
if (ioctl(mDeviceFd, VIDIOC_QUERYBUF, &mBufferInfos[i]) < 0) {
PLOG(ERROR) << "VIDIOC_QUERYBUF failed";
return false;
}
LOG(INFO) << "Buffer description:";
LOG(INFO) << " offset: " << mBufferInfos[i].m.offset;
LOG(INFO) << " length: " << mBufferInfos[i].length;
LOG(INFO) << " flags : " << std::hex << mBufferInfos[i].flags;
// Get a pointer to the buffer contents by mapping into our address space
mPixelBuffers[i] = mmap(
NULL,
mBufferInfos[i].length,
PROT_READ | PROT_WRITE,
MAP_SHARED,
mDeviceFd,
mBufferInfos[i].m.offset
);
if(mPixelBuffers[i] == MAP_FAILED) {
PLOG(ERROR) << "mmap() failed";
return false;
}
memset(mPixelBuffers[i], 0, mBufferInfos[i].length);
LOG(INFO) << "Buffer mapped at " << mPixelBuffers[i];
// Queue the first capture buffer
if (ioctl(mDeviceFd, VIDIOC_QBUF, &mBufferInfos[i]) < 0) {
PLOG(ERROR) << "VIDIOC_QBUF failed";
return false;
}
}
// Start the video stream
const int type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (ioctl(mDeviceFd, VIDIOC_STREAMON, &type) < 0) {
PLOG(ERROR) << "VIDIOC_STREAMON failed";
return false;
}
// Remember who to tell about new frames as they arrive
mCallback = callback;
// Fire up a thread to receive and dispatch the video frames
mCaptureThread = std::thread([this](){ collectFrames(); });
LOG(DEBUG) << "Stream started.";
return true;
}
void VideoCapture::stopStream() {
// Tell the background thread to stop
int prevRunMode = mRunMode.fetch_or(STOPPING);
if (prevRunMode == STOPPED) {
// The background thread wasn't running, so set the flag back to STOPPED
mRunMode = STOPPED;
} else if (prevRunMode & STOPPING) {
LOG(ERROR) << "stopStream called while stream is already stopping. "
<< "Reentrancy is not supported!";
return;
} else {
// Block until the background thread is stopped
if (mCaptureThread.joinable()) {
mCaptureThread.join();
}
// Stop the underlying video stream (automatically empties the buffer queue)
const int type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (ioctl(mDeviceFd, VIDIOC_STREAMOFF, &type) < 0) {
PLOG(ERROR) << "VIDIOC_STREAMOFF failed";
}
LOG(DEBUG) << "Capture thread stopped.";
}
for (int i = 0; i < mNumBuffers; ++i) {
// Unmap the buffers we allocated
munmap(mPixelBuffers[i], mBufferInfos[i].length);
}
// Tell the L4V2 driver to release our streaming buffers
v4l2_requestbuffers bufrequest;
bufrequest.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
bufrequest.memory = V4L2_MEMORY_MMAP;
bufrequest.count = 0;
ioctl(mDeviceFd, VIDIOC_REQBUFS, &bufrequest);
// Drop our reference to the frame delivery callback interface
mCallback = nullptr;
// Release capture buffers
mNumBuffers = 0;
mBufferInfos = nullptr;
mPixelBuffers = nullptr;
}
bool VideoCapture::returnFrame(int id) {
if (mFrames.find(id) == mFrames.end()) {
LOG(WARNING) << "Invalid request to return a buffer " << id << " is ignored.";
return false;
}
// Requeue the buffer to capture the next available frame
if (ioctl(mDeviceFd, VIDIOC_QBUF, &mBufferInfos[id]) < 0) {
PLOG(ERROR) << "VIDIOC_QBUF failed";
return false;
}
// Remove ID of returned buffer from the set
mFrames.erase(id);
return true;
}
// This runs on a background thread to receive and dispatch video frames
void VideoCapture::collectFrames() {
// Run until our atomic signal is cleared
while (mRunMode == RUN) {
struct v4l2_buffer buf = {
.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
.memory = V4L2_MEMORY_MMAP
};
// Wait for a buffer to be ready
if (ioctl(mDeviceFd, VIDIOC_DQBUF, &buf) < 0) {
PLOG(ERROR) << "VIDIOC_DQBUF failed";
break;
}
mFrames.insert(buf.index);
// Update a frame metadata
mBufferInfos[buf.index] = buf;
// If a callback was requested per frame, do that now
if (mCallback) {
mCallback(this, &mBufferInfos[buf.index], mPixelBuffers[buf.index]);
}
}
// Mark ourselves stopped
LOG(DEBUG) << "VideoCapture thread ending";
mRunMode = STOPPED;
}
int VideoCapture::setParameter(v4l2_control& control) {
int status = ioctl(mDeviceFd, VIDIOC_S_CTRL, &control);
if (status < 0) {
PLOG(ERROR) << "Failed to program a parameter value "
<< "id = " << std::hex << control.id;
}
return status;
}
int VideoCapture::getParameter(v4l2_control& control) {
int status = ioctl(mDeviceFd, VIDIOC_G_CTRL, &control);
if (status < 0) {
PLOG(ERROR) << "Failed to read a parameter value"
<< " fd = " << std::hex << mDeviceFd
<< " id = " << control.id;
}
return status;
}
std::set<uint32_t> VideoCapture::enumerateCameraControls() {
// Retrieve available camera controls
struct v4l2_queryctrl ctrl = {
.id = V4L2_CTRL_FLAG_NEXT_CTRL
};
std::set<uint32_t> ctrlIDs;
while (0 == ioctl(mDeviceFd, VIDIOC_QUERYCTRL, &ctrl)) {
if (!(ctrl.flags & V4L2_CTRL_FLAG_DISABLED)) {
ctrlIDs.emplace(ctrl.id);
}
ctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
}
if (errno != EINVAL) {
PLOG(WARNING) << "Failed to run VIDIOC_QUERYCTRL";
}
return std::move(ctrlIDs);
}