Forum Linux.debian/ubuntu API pour camera/webcam

Posté par . Licence CC By‐SA.
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2
9
déc.
2019

Bonjour à tous,

Je viens de commencer un projet de traitement video.

Pour le moment je me sers d'une webcam usb classique.

J'ai regardé les quelques projets autours, que voici :
-libusb
-v4l2
-uvcvideo

J'ai regardé les sources du projet "guvcview". Ils utilisent v4l2 et uvcvideo.

Avez-vous déjà tenté de récupérer les flux video d'une camera ou webcam via usb ou ethernet ?

Je pense partir sur l'utilisation de la lib uvcvideo, et peut être de v4l2 si besoin.

Merci pour vos retour d'expérience.

  • # VLC/RTSP

    Posté par (site web personnel) . Évalué à 2.

    J'ai déjà utilisé VLC pour capturer un flux RTSP envoyé sur le réseau par une petite caméra. Pour capturer (presque) une heure de vidéo, mon entrée de crontab ressemblait à ceci :

    /usr/bin/vlc -vvv rtsp://spy.home:554/live/ch0 --sout=file/ts:/data/media/spy/record-$(/bin/date +"%Y-%m-%dT%H%M").ts -I dummy --stop-time=3590 vlc://quit

    Parfait pour garder un œil sur le chat.

    Debian Consultant @ DEBAMAX

    • [^] # Re: VLC/RTSP

      Posté par . Évalué à 1.

      Bonjour,

      Merci pour votre réponse.

      Je suis partie sur l'utilisation du driver UVC, qui est commun à tous les appareils.

      Je me heurte à un problème, voici le code que j’éxecute pour obtenir 30fps, un exemple de la libuvc.

      Avez-vous déjà fait un essai sur cette lib ?

       /* Initialize a UVC service context. Libuvc will set up its own libusb
 * context. Replace NULL with a libusb_context pointer to run libuvc
 * from an existing libusb context. */
 res = uvc_init(&ctx, NULL);
 if (res < 0) {
 uvc_perror(res, "uvc_init");
 return res;
 }
 puts("UVC initialized");
 /* Locates the first attached UVC device, stores in dev */
 res = uvc_find_device(
 ctx, &dev,
 3141, 25409, NULL); /* filter devices: vendor_id, product_id, "serial_num" */
 //33006, 48, NULL);
 //3141, 25409, NULL); /* filter devices: vendor_id, product_id, "serial_num" */
 //3141, 25409, "da1b7b94a31315e0");
 if (res < 0) {
 uvc_perror(res, "uvc_find_device"); /* no devices found */
 } else {
 puts("Device found");
 /* Try to open the device: requires exclusive access */
 //Special access : sudo sh -c "echo 'SUBSYSTEMS==\"usb\", ATTRS{idVendor}==\"0c45\", ATTRS{idProduct}==\"6341\", SYMLINK+=\"pt1\", GROUP=\"usb\", MODE=\"666\"' > /etc/udev/rules.d/99-pt1.rules"
 res = uvc_open(dev, &devh);
 if (res < 0) {
 uvc_perror(res, "uvc_open"); /* unable to open device */
 } else {
 puts("Device opened");
 /* Print out a message containing all the information that libuvc
 * knows about the device */
 uvc_print_diag(devh, stderr);
 /* Try to negotiate a 640x480 30 fps YUYV stream profile */
 res = uvc_get_stream_ctrl_format_size(
 devh, &ctrl, /* result stored in ctrl */
 UVC_FRAME_FORMAT_YUYV, /* YUV 422, aka YUV 4:2:2. try _COMPRESSED */
 640, 480, 30 /* width, height, fps */
 );
 /* Print out the result */
 uvc_print_stream_ctrl(&ctrl, stderr);
 if (res < 0) {
 uvc_perror(res, "get_mode"); /* device doesn't provide a matching stream */
 } else {
 /* Start the video stream. The library will call user function cb:
 * cb(frame, (void*) 12345)
 */
 res = uvc_start_streaming(devh, &ctrl, cb, user_ptr, 0);
 if (res < 0) {
 uvc_perror(res, "start_streaming"); /* unable to start stream */
 } else {
 puts("Streaming...");
 uvc_set_ae_mode(devh, 1); /* e.g., turn on auto exposure */
 QThread::msleep(10000); /* stream for 10 seconds */
 /* End the stream. Blocks until last callback is serviced */
 uvc_stop_streaming(devh);
 puts("Done streaming.");
 }
 }
 /* Release our handle on the device */
 uvc_close(devh);
 puts("Device closed");
 }
 /* Release the device descriptor */
 uvc_unref_device(dev);
 }
 /* Close the UVC context. This closes and cleans up any existing device handles,
 * and it closes the libusb context if one was not provided. */
 uvc_exit(ctx);
 puts("UVC exited");
 return 0;

      Le résultat est le suivant,

      14:47:00: Starting /home/jo/Qt_project/serveur_surveillance/build-serveur_surveillance-Desktop-Debug/serveur_surveillance...
TEST
4 Devices in list.
Number of possible configurations: 1 Device Class: 239 VendorID: 3141 ProductID: 25409
Interfaces: 4 ||| Number of alternate settings: 1 | Interface Number: 0 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 131 | Number of alternate settings: 7 | Interface Number: 1 | Number of endpoints: 0 | Interface Number: 1 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | Interface Number: 1 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | Interface Number: 1 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | Interface Number: 1 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | Interface Number: 1 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | Interface Number: 1 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | Number of alternate settings: 1 | Interface Number: 2 | Number of endpoints: 0 | Number of alternate settings: 2 | Interface Number: 3 | Number of endpoints: 0 | Interface Number: 3 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 132 | 
Number of possible configurations: 1 Device Class: 9 VendorID: 7531 ProductID: 2
Interfaces: 1 ||| Number of alternate settings: 1 | Interface Number: 0 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | 
Number of possible configurations: 1 Device Class: 0 VendorID: 33006 ProductID: 33
Interfaces: 1 ||| Number of alternate settings: 1 | Interface Number: 0 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | 
Number of possible configurations: 1 Device Class: 9 VendorID: 7531 ProductID: 1
Interfaces: 1 ||| Number of alternate settings: 1 | Interface Number: 0 | Number of endpoints: 1 | Descriptor Type: 5 | EP Address: 129 | 
unsupported descriptor subtype VS_STILL_IMAGE_FRAME
unsupported descriptor subtype VS_STILL_IMAGE_FRAME
unsupported descriptor subtype VS_COLORFORMAT
DEVICE CONFIGURATION (0c45:6341/[none]) ---
Status: idle
VideoControl:
 bcdUVC: 0x0100
VideoStreaming(1):
 bEndpointAddress: 129
 Formats:
 UncompressedFormat(1)
 bits per pixel: 16
 GUID: 5955593200001000800000aa00389b71 (YUY2)
 default frame: 1
 aspect ratio: 0x0
 interlace flags: 00
 copy protect: 00
 FrameDescriptor(1)
 capabilities: 00
 size: 640x480
 bit rate: 24576000-147456000
 max frame size: 614400
 default interval: 1/30
 interval[0]: 1/30
 interval[1]: 1/25
 interval[2]: 1/20
 interval[3]: 1/15
 interval[4]: 1/10
 interval[5]: 1/5
 ......................
 ......................
 FrameDescriptor(18)
 capabilities: 00
 size: 1280x720
 bit rate: 73728000-147456000
 max frame size: 1843200
 default interval: 1/10
 interval[0]: 1/10
 interval[1]: 1/5
 MJPEGFormat(2)
 bits per pixel: 0
 GUID: 4d4a5047000000000000000000000000 (MJPG)
 default frame: 1
 aspect ratio: 0x0
 interlace flags: 00
 copy protect: 00
 FrameDescriptor(1)
 capabilities: 00
 size: 640x480
 bit rate: 24599560-147597360
 max frame size: 614989
 default interval: 1/30
 interval[0]: 1/30
 interval[1]: 1/25
 interval[2]: 1/20
 interval[3]: 1/15
 interval[4]: 1/10
 interval[5]: 1/5
 .................................
 .................................
 FrameDescriptor(18)
 capabilities: 00
 size: 1280x720
 bit rate: 73751560-442509360
 max frame size: 1843789
 default interval: 1/30
 interval[0]: 1/30
 interval[1]: 1/25
 interval[2]: 1/20
 interval[3]: 1/15
 interval[4]: 1/10
 interval[5]: 1/5
END DEVICE CONFIGURATION
bmHint: 0001
bFormatIndex: 1
bFrameIndex: 1
dwFrameInterval: 333333
wKeyFrameRate: 0
wPFrameRate: 0
wCompQuality: 0
wCompWindowSize: 0
wDelay: 13646
dwMaxVideoFrameSize: 614400
dwMaxPayloadTransferSize: 3072
bInterfaceNumber: 1
attempt to claim already-claimed interface 1
14:47:01: Le programme s'est terminé subitement.
14:47:01: The process was ended forcefully.
14:47:01: /home/jo/Qt_project/serveur_surveillance/build-serveur_surveillance-Desktop-Debug/serveur_surveillance crashed.

      Je suis bloqué après cette ligne de code : attempt to claim already-claimed interface 1

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