Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct
QCamera/QtCamera GStreamer V4L problem
-
On Raspberry Pi 2B with Debian Jessie, Qt 5.5, the
qt5/qtmultimedia/examples/multimediawidgets/cameraapplication shows just one frame and gives these errors when changing mode (for example, by clicking on 'Capture Photo' button or 'Video' tab):CameraBin error: "Internal data flow error." CameraBin error: "Failed to allocate required memory."GStreamer warning/error output on launch:
0:00:01.898512576 1923 0x17bbb50 WARN v4l2 gstv4l2bufferpool.c:658:gst_v4l2_buffer_pool_start:<camera_source:pool:src> using 3 buffers instead of 2When clicking on 'Video' or 'Capture Photo':
0:00:32.243379958 1923 0x17bbb50 WARN v4l2allocator gstv4l2allocator.c:651:gst_v4l2_allocator_new:<camera_source:pool:src:allocator> Could not probe supported memory type, assuming MMAP is supported, this is expected for older drivers not yet ported to videobuf2 framework 0:00:33.208261007 1923 0x17bbb50 ERROR v4l2allocator gstv4l2allocator.c:727:gst_v4l2_allocator_start:<camera_source:pool:src:allocator> error requesting 2 buffers: Device or resource busy 0:00:33.209047925 1923 0x17bbb50 ERROR v4l2 gstv4l2bufferpool.c:768:gst_v4l2_buffer_pool_start:<camera_source:pool:src> we received 0 buffer from device '/dev/video0', we want at least 2 0:00:33.209696460 1923 0x17bbb50 ERROR bufferpool gstbufferpool.c:533:gst_buffer_pool_set_active:<camera_source:pool:src> start failed 0:00:33.210209266 1923 0x17bbb50 WARN v4l2src gstv4l2src.c:478:gst_v4l2src_decide_allocation:<camera_source> error: Failed to allocate required memory. 0:00:33.210667803 1923 0x17bbb50 WARN v4l2src gstv4l2src.c:478:gst_v4l2src_decide_allocation:<camera_source> error: Buffer pool activation failed 0:00:33.211621438 1923 0x17bbb50 WARN basesrc gstbasesrc.c:3161:gst_base_src_prepare_allocation:<camera_source> Subclass failed to decide allocation CameraBin error: "Failed to allocate required memory." 0:00:33.212857100 1923 0x17bbb50 WARN basesrc gstbasesrc.c:2933:gst_base_src_loop:<camera_source> error: Internal data flow error. 0:00:33.213240169 1923 0x17bbb50 WARN basesrc gstbasesrc.c:2933:gst_base_src_loop:<camera_source> error: streaming task paused, reason not-negotiated (-4) CameraBin error: "Internal data flow error."The libv4l log (it just stops):
libv4l2: open: 14 request == VIDIOC_QUERYCAP result == 0 request == VIDIOC_ENUMINPUT result == 0 request == VIDIOC_ENUMINPUT result == -1 (Invalid argument) request == VIDIOC_ENUMSTD result == -1 (Inappropriate ioctl for device) request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == -1 (Invalid argument) request == VIDIOC_G_STD result == -1 (Inappropriate ioctl for device) request == VIDIOC_G_INPUT result == 0 request == VIDIOC_ENUM_FMT index: 0, description: 4:2:0, packed YUV result == 0 request == VIDIOC_ENUM_FMT index: 1, description: 4:2:2, packed, YUYV result == 0 request == VIDIOC_ENUM_FMT index: 2, description: RGB24 (LE) result == 0 request == VIDIOC_ENUM_FMT index: 3, description: JPEG result == 0 request == VIDIOC_ENUM_FMT index: 4, description: H264 result == 0 request == VIDIOC_ENUM_FMT index: 5, description: MJPEG result == 0 request == VIDIOC_ENUM_FMT index: 6, description: 4:2:2, packed, YVYU result == 0 request == VIDIOC_ENUM_FMT index: 7, description: 4:2:2, packed, VYUY result == 0 request == VIDIOC_ENUM_FMT index: 8, description: 4:2:2, packed, UYVY result == 0 request == VIDIOC_ENUM_FMT index: 9, description: 4:2:0, packed, NV12 result == 0 request == VIDIOC_ENUM_FMT index: 10, description: RGB24 (BE) result == 0 request == VIDIOC_ENUM_FMT index: 11, description: 4:2:0, packed YVU result == 0 request == VIDIOC_ENUM_FMT index: 12, description: 4:2:0, packed, NV21 result == 0 request == VIDIOC_ENUM_FMT index: 13, description: RGB32 (BE) result == 0 request == VIDIOC_ENUM_FMT index: 14, description: result == -1 (Invalid argument) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YUYV 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YUYV 2592x1944 field: 1 bytesperline: 5184 imagesize: 10119168 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YUYV 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: UYVY 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: UYVY 2592x1944 field: 1 bytesperline: 5184 imagesize: 10119168 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: UYVY 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YU12 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YU12 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YU12 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YV12 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YV12 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YV12 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: JPEG 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: JPEG 2592x1944 field: 1 bytesperline: 2592 imagesize: 5059584 colorspace: 7, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: JPEG 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: MJPG 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: MJPG 2592x1944 field: 1 bytesperline: 2592 imagesize: 5059584 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: MJPG 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: BGR4 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: BGR4 2592x1944 field: 1 bytesperline: 10368 imagesize: 20238336 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: BGR4 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: BGR3 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: BGR3 2592x1944 field: 1 bytesperline: 7776 imagesize: 15178752 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: BGR3 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: RGB3 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: RGB3 2592x1944 field: 1 bytesperline: 7776 imagesize: 15178752 colorspace: 8, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: RGB3 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: NV21 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: NV21 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: NV21 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: NV12 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: NV12 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: NV12 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YVYU 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YVYU 2592x1944 field: 1 bytesperline: 5184 imagesize: 10119168 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YVYU 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: H264 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: H264 2592x1944 field: 1 bytesperline: 2592 imagesize: 5059584 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: H264 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) libv4l2: close: 14 libv4l2: PLUGIN: dlopen(/usr/lib/arm-linux-gnueabihf/libv4l/plugins/libv4l-mplane.so); libv4l2: PLUGIN: plugin open() returned NULL libv4l2: open: 14 request == VIDIOC_QUERYCAP result == 0 request == VIDIOC_ENUMINPUT result == 0 request == VIDIOC_ENUMINPUT result == -1 (Invalid argument) request == VIDIOC_ENUMSTD result == -1 (Inappropriate ioctl for device) request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == 0 request == VIDIOC_QUERYCTRL result == -1 (Invalid argument) request == VIDIOC_G_STD result == -1 (Inappropriate ioctl for device) request == VIDIOC_S_INPUT result == 0 request == VIDIOC_ENUM_FMT index: 0, description: 4:2:0, packed YUV result == 0 request == VIDIOC_ENUM_FMT index: 1, description: 4:2:2, packed, YUYV result == 0 request == VIDIOC_ENUM_FMT index: 2, description: RGB24 (LE) result == 0 request == VIDIOC_ENUM_FMT index: 3, description: JPEG result == 0 request == VIDIOC_ENUM_FMT index: 4, description: H264 result == 0 request == VIDIOC_ENUM_FMT index: 5, description: MJPEG result == 0 request == VIDIOC_ENUM_FMT index: 6, description: 4:2:2, packed, YVYU result == 0 request == VIDIOC_ENUM_FMT index: 7, description: 4:2:2, packed, VYUY result == 0 request == VIDIOC_ENUM_FMT index: 8, description: 4:2:2, packed, UYVY result == 0 request == VIDIOC_ENUM_FMT index: 9, description: 4:2:0, packed, NV12 result == 0 request == VIDIOC_ENUM_FMT index: 10, description: RGB24 (BE) result == 0 request == VIDIOC_ENUM_FMT index: 11, description: 4:2:0, packed YVU result == 0 request == VIDIOC_ENUM_FMT index: 12, description: 4:2:0, packed, NV21 result == 0 request == VIDIOC_ENUM_FMT index: 13, description: RGB32 (BE) result == 0 request == VIDIOC_ENUM_FMT index: 14, description: result == -1 (Invalid argument) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YUYV 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YUYV 2592x1944 field: 1 bytesperline: 5184 imagesize: 10119168 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YUYV 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: UYVY 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: UYVY 2592x1944 field: 1 bytesperline: 5184 imagesize: 10119168 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: UYVY 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YU12 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YU12 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YU12 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YV12 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YV12 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YV12 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: JPEG 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: JPEG 2592x1944 field: 1 bytesperline: 2592 imagesize: 5059584 colorspace: 7, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: JPEG 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: MJPG 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: MJPG 2592x1944 field: 1 bytesperline: 2592 imagesize: 5059584 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: MJPG 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: BGR4 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: BGR4 2592x1944 field: 1 bytesperline: 10368 imagesize: 20238336 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: BGR4 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: BGR3 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: BGR3 2592x1944 field: 1 bytesperline: 7776 imagesize: 15178752 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: BGR3 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: RGB3 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: RGB3 2592x1944 field: 1 bytesperline: 7776 imagesize: 15178752 colorspace: 8, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: RGB3 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: NV21 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: NV21 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: NV21 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: NV12 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: NV12 2592x1944 field: 1 bytesperline: 3888 imagesize: 7589376 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: NV12 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: YVYU 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: YVYU 2592x1944 field: 1 bytesperline: 5184 imagesize: 10119168 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: YVYU 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_ENUM_FRAMESIZES index: 0 pixelformat: H264 16x16 -> 2592x1944 result == 0 request == VIDIOC_TRY_FMT pixelformat: H264 2592x1944 field: 1 bytesperline: 2592 imagesize: 5059584 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_ENUM_FRAMEINTERVALS index: 0 pixelformat: H264 2592x1944: 1/90 -> 1/1 result == 0 request == VIDIOC_CROPCAP result == -1 (Inappropriate ioctl for device) request == VIDIOC_G_FMT pixelformat: BGR4 320x200 field: 1 bytesperline: 1280 imagesize: 266240 colorspace: 1, priv: feedcafe result == 0 request == VIDIOC_REQBUFS count: 0 type: 1 memory: 1 result == 0 request == VIDIOC_CREATE_BUFS result == 0 request == VIDIOC_REQBUFS count: 0 type: 1 memory: 2 result == -1 (Invalid argument) request == VIDIOC_REQBUFS count: 0 type: 1 memory: 4 result == -1 (Invalid argument) request == VIDIOC_G_CTRL result == -1 (Invalid argument) request == VIDIOC_REQBUFS count: 3 type: 1 memory: 1 result == 0 request == VIDIOC_QUERYBUF result == 0 request == VIDIOC_QUERYBUF result == 0 request == VIDIOC_QUERYBUF result == 0 libv4l2: Passing mmap((nil), 266240, ..., 0, through to the driver request == VIDIOC_QBUF result == 0 libv4l2: Passing mmap((nil), 266240, ..., 41000, through to the driver request == VIDIOC_QBUF result == 0 libv4l2: Passing mmap((nil), 266240, ..., 82000, through to the driver request == VIDIOC_QBUF result == 0 request == VIDIOC_STREAMON result == 0 request == VIDIOC_DQBUF timestamp -140454174.036203 result == 0 request == VIDIOC_G_CTRL result == -1 (Invalid argument) request == VIDIOC_DQBUF timestamp 8436.495678 result == 0 request == VIDIOC_DQBUF timestamp 8436.506770 result == 0 request == VIDIOC_QBUF result == 0 request == VIDIOC_DQBUF timestamp 8436.517860 result == 0 request == VIDIOC_QBUF result == 0 request == VIDIOC_DQBUF timestamp 8436.617679 result == 0The libv4l log after changing the mode to 'Video':
request == VIDIOC_QBUF result == 0 request == VIDIOC_QBUF result == 0 request == VIDIOC_QBUF result == 0 request == VIDIOC_G_FMT pixelformat: BGR4 320x200 field: 1 bytesperline: 1280 imagesize: 266240 colorspace: 1, priv: feedcafe result == 0 libv4l2: v4l2_buffers_mapped(): buffers still mapped libv4l2: v4l2_check_buffer_change_ok(): stream busy request == VIDIOC_REQBUFS count: 0 type: 1 memory: 1 result == -1 (Device or resource busy) request == VIDIOC_REQBUFS count: 0 type: 1 memory: 2 result == -1 (Invalid argument) request == VIDIOC_REQBUFS count: 0 type: 1 memory: 4 result == -1 (Invalid argument) request == VIDIOC_G_CTRL result == -1 (Invalid argument) libv4l2: v4l2_buffers_mapped(): buffers still mapped libv4l2: v4l2_check_buffer_change_ok(): stream busy request == VIDIOC_REQBUFS count: 2 type: 1 memory: 1 result == -1 (Device or resource busy)Qt is built from source. GStreamer Qt plugin is enabled. GStreamer 1.0, packages:
gstreamer1.0-plugins-bad gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-ugly gstreamer1.0-tools libgstreamer-plugins-bad1.0-0 libgstreamer-plugins-base1.0-0 libgstreamer1.0-0Video recording works fine with GStreamer:
gst-launch-1.0 v4l2src ! video/x-h264 ! avimux ! filesink location=1.mp4I've tried to hardcode the resolution, codec and capture mode (or even avoid setting the resolution), but result is the same. QML QtCamera obviously doesn't act differently.
What can be done?
update
I can run thatgst-launchcommand, then terminate it while launching the Qt application. And sometimes that makes the Qt application start and go past the first frame, so the ViewFinder displays the video correctly.update 2
I think there is a deadlock in QtMultimediaWidgets or in the Qt GStreamer plugin.After one or two frames the QPainter Surface doesn't manage to set
m_readytotruein time and rendering stalls. It sets it totrueafter the fact, but render/paint aren't called to make use of it.
