mirror of
https://github.com/pion/mediadevices.git
synced 2025-09-26 20:41:46 +08:00
318 lines
7.6 KiB
Go
318 lines
7.6 KiB
Go
package camera
|
|
|
|
// #include <linux/videodev2.h>
|
|
import "C"
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"image"
|
|
"io"
|
|
"os"
|
|
"path/filepath"
|
|
"strconv"
|
|
"sync"
|
|
|
|
"github.com/blackjack/webcam"
|
|
"github.com/pion/mediadevices/pkg/driver"
|
|
"github.com/pion/mediadevices/pkg/frame"
|
|
"github.com/pion/mediadevices/pkg/io/video"
|
|
"github.com/pion/mediadevices/pkg/prop"
|
|
)
|
|
|
|
const (
|
|
maxEmptyFrameCount = 5
|
|
prioritizedDevice = "video0"
|
|
)
|
|
|
|
var (
|
|
errReadTimeout = errors.New("read timeout")
|
|
errEmptyFrame = errors.New("empty frame")
|
|
// Reference: https://commons.wikimedia.org/wiki/File:Vector_Video_Standards2.svg
|
|
supportedResolutions = [][2]int{
|
|
{320, 240},
|
|
{640, 480},
|
|
{768, 576},
|
|
{800, 600},
|
|
{1024, 768},
|
|
{1280, 854},
|
|
{1280, 960},
|
|
{1280, 1024},
|
|
{1400, 1050},
|
|
{1600, 1200},
|
|
{2048, 1536},
|
|
{320, 200},
|
|
{800, 480},
|
|
{854, 480},
|
|
{1024, 600},
|
|
{1152, 768},
|
|
{1280, 720},
|
|
{1280, 768},
|
|
{1366, 768},
|
|
{1280, 800},
|
|
{1440, 900},
|
|
{1440, 960},
|
|
{1680, 1050},
|
|
{1920, 1080},
|
|
{2048, 1080},
|
|
{1920, 1200},
|
|
{2560, 1600},
|
|
}
|
|
)
|
|
|
|
// Camera implementation using v4l2
|
|
// Reference: https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/videodev.html#videodev
|
|
type camera struct {
|
|
path string
|
|
cam *webcam.Webcam
|
|
formats map[webcam.PixelFormat]frame.Format
|
|
reversedFormats map[frame.Format]webcam.PixelFormat
|
|
started bool
|
|
mutex sync.Mutex
|
|
cancel func()
|
|
}
|
|
|
|
func init() {
|
|
Initialize()
|
|
}
|
|
|
|
// Initialize finds and registers camera devices. This is part of an experimental API.
|
|
func Initialize() {
|
|
discovered := make(map[string]struct{})
|
|
discover(discovered, "/dev/v4l/by-path/*")
|
|
discover(discovered, "/dev/video*")
|
|
}
|
|
|
|
func discover(discovered map[string]struct{}, pattern string) {
|
|
devices, err := filepath.Glob(pattern)
|
|
if err != nil {
|
|
// No v4l device.
|
|
return
|
|
}
|
|
for _, device := range devices {
|
|
label := filepath.Base(device)
|
|
reallink, err := os.Readlink(device)
|
|
if err != nil {
|
|
reallink = label
|
|
} else {
|
|
reallink = filepath.Base(reallink)
|
|
}
|
|
if _, ok := discovered[reallink]; ok {
|
|
continue
|
|
}
|
|
|
|
discovered[reallink] = struct{}{}
|
|
cam := newCamera(device)
|
|
priority := driver.PriorityNormal
|
|
if reallink == prioritizedDevice {
|
|
priority = driver.PriorityHigh
|
|
}
|
|
driver.GetManager().Register(cam, driver.Info{
|
|
Label: label + LabelSeparator + reallink,
|
|
DeviceType: driver.Camera,
|
|
Priority: priority,
|
|
})
|
|
}
|
|
}
|
|
|
|
func newCamera(path string) *camera {
|
|
formats := map[webcam.PixelFormat]frame.Format{
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_YUV420): frame.FormatI420,
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_NV21): frame.FormatNV21,
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_NV12): frame.FormatNV12,
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_YUYV): frame.FormatYUYV,
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_UYVY): frame.FormatUYVY,
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_MJPEG): frame.FormatMJPEG,
|
|
webcam.PixelFormat(C.V4L2_PIX_FMT_Z16): frame.FormatZ16,
|
|
}
|
|
|
|
reversedFormats := make(map[frame.Format]webcam.PixelFormat)
|
|
for k, v := range formats {
|
|
reversedFormats[v] = k
|
|
}
|
|
|
|
c := &camera{
|
|
path: path,
|
|
formats: formats,
|
|
reversedFormats: reversedFormats,
|
|
}
|
|
return c
|
|
}
|
|
|
|
func getCameraReadTimeout() uint32 {
|
|
// default to 5 seconds
|
|
var readTimeoutSec uint32 = 5
|
|
if val, ok := os.LookupEnv("PION_MEDIADEVICES_CAMERA_READ_TIMEOUT"); ok {
|
|
if valInt, err := strconv.Atoi(val); err == nil {
|
|
if valInt > 0 {
|
|
readTimeoutSec = uint32(valInt)
|
|
}
|
|
}
|
|
}
|
|
return readTimeoutSec
|
|
}
|
|
|
|
func (c *camera) Open() error {
|
|
cam, err := webcam.Open(c.path)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Late frames should be discarded. Buffering should be handled in higher level.
|
|
cam.SetBufferCount(1)
|
|
c.cam = cam
|
|
return nil
|
|
}
|
|
|
|
func (c *camera) Close() error {
|
|
if c.cam == nil {
|
|
return nil
|
|
}
|
|
|
|
if c.cancel != nil {
|
|
// Let the reader knows that the caller has closed the camera
|
|
c.cancel()
|
|
// Wait until the reader unref the buffer
|
|
c.mutex.Lock()
|
|
defer c.mutex.Unlock()
|
|
|
|
// Note: StopStreaming frees frame buffers even if they are still used in Go code.
|
|
// There is currently no convenient way to do this safely.
|
|
// So, consumer of this stream must close camera after unusing all images.
|
|
c.cam.StopStreaming()
|
|
c.cancel = nil
|
|
}
|
|
c.cam.Close()
|
|
return nil
|
|
}
|
|
|
|
func (c *camera) VideoRecord(p prop.Media) (video.Reader, error) {
|
|
decoder, err := frame.NewDecoder(p.FrameFormat)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
pf := c.reversedFormats[p.FrameFormat]
|
|
_, _, _, err = c.cam.SetImageFormat(pf, uint32(p.Width), uint32(p.Height))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if p.FrameRate > 0 {
|
|
err = c.cam.SetFramerate(float32(p.FrameRate))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
if err := c.cam.StartStreaming(); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
cam := c.cam
|
|
|
|
readTimeoutSec := getCameraReadTimeout()
|
|
|
|
ctx, cancel := context.WithCancel(context.Background())
|
|
c.cancel = cancel
|
|
var buf []byte
|
|
r := video.ReaderFunc(func() (img image.Image, release func(), err error) {
|
|
// Lock to avoid accessing the buffer after StopStreaming()
|
|
c.mutex.Lock()
|
|
defer c.mutex.Unlock()
|
|
|
|
// Wait until a frame is ready
|
|
for i := 0; i < maxEmptyFrameCount; i++ {
|
|
if ctx.Err() != nil {
|
|
// Return EOF if the camera is already closed.
|
|
return nil, func() {}, io.EOF
|
|
}
|
|
|
|
err := cam.WaitForFrame(readTimeoutSec)
|
|
switch err.(type) {
|
|
case nil:
|
|
case *webcam.Timeout:
|
|
return nil, func() {}, errReadTimeout
|
|
default:
|
|
// Camera has been stopped.
|
|
return nil, func() {}, err
|
|
}
|
|
|
|
b, err := cam.ReadFrame()
|
|
if err != nil {
|
|
// Camera has been stopped.
|
|
return nil, func() {}, err
|
|
}
|
|
|
|
// Frame is empty.
|
|
// Retry reading and return errEmptyFrame if it exceeds maxEmptyFrameCount.
|
|
if len(b) == 0 {
|
|
continue
|
|
}
|
|
|
|
if len(b) > len(buf) {
|
|
// Grow the intermediate buffer
|
|
buf = make([]byte, len(b))
|
|
}
|
|
|
|
// move the memory from mmap to Go. This will guarantee that any data that's going out
|
|
// from this reader will be Go safe. Otherwise, it's possible that outside of this reader
|
|
// that this memory is still being used even after we close it.
|
|
n := copy(buf, b)
|
|
return decoder.Decode(buf[:n], p.Width, p.Height)
|
|
}
|
|
return nil, func() {}, errEmptyFrame
|
|
})
|
|
|
|
return r, nil
|
|
}
|
|
|
|
func (c *camera) Properties() []prop.Media {
|
|
properties := make([]prop.Media, 0)
|
|
for format := range c.cam.GetSupportedFormats() {
|
|
for _, frameSize := range c.cam.GetSupportedFrameSizes(format) {
|
|
supportedFormat, ok := c.formats[format]
|
|
if !ok {
|
|
continue
|
|
}
|
|
|
|
if frameSize.StepWidth == 0 || frameSize.StepHeight == 0 {
|
|
properties = append(properties, prop.Media{
|
|
Video: prop.Video{
|
|
Width: int(frameSize.MaxWidth),
|
|
Height: int(frameSize.MaxHeight),
|
|
FrameFormat: supportedFormat,
|
|
},
|
|
})
|
|
} else {
|
|
// FIXME: we should probably use a custom data structure to capture all of the supported resolutions
|
|
for _, supportedResolution := range supportedResolutions {
|
|
minWidth, minHeight := int(frameSize.MinWidth), int(frameSize.MinHeight)
|
|
maxWidth, maxHeight := int(frameSize.MaxWidth), int(frameSize.MaxHeight)
|
|
stepWidth, stepHeight := int(frameSize.StepWidth), int(frameSize.StepHeight)
|
|
width, height := supportedResolution[0], supportedResolution[1]
|
|
|
|
if width < minWidth || width > maxWidth ||
|
|
height < minHeight || height > maxHeight {
|
|
continue
|
|
}
|
|
|
|
if (width-minWidth)%stepWidth != 0 ||
|
|
(height-minHeight)%stepHeight != 0 {
|
|
continue
|
|
}
|
|
|
|
properties = append(properties, prop.Media{
|
|
Video: prop.Video{
|
|
Width: width,
|
|
Height: height,
|
|
FrameFormat: supportedFormat,
|
|
},
|
|
})
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return properties
|
|
}
|