1 // Copyright (c) 2013 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include <Python.h> 6 #include <fcntl.h> 7 #include <linux/videodev2.h> 8 #include <sys/ioctl.h> 9 10 static int do_ioctl(int fd, int request, void* arg) { 11 int r; 12 do { 13 r = ioctl(fd, request, arg); 14 } while (-1 == r && EINTR == errno); 15 return r; 16 } 17 18 static void v4l2_enum_formats(const char *dev, int buf_type, 19 PyObject *formats) { 20 int fd = open(dev, O_RDWR | O_NONBLOCK, 0); 21 if (fd == -1) return; 22 23 for (int i = 0; ; ++i) { 24 char pixel_format[4]; 25 v4l2_fmtdesc format_desc; 26 27 memset(&format_desc, 0, sizeof(format_desc)); 28 format_desc.type = (v4l2_buf_type) buf_type; 29 format_desc.index = i; 30 if (-1 == do_ioctl(fd, VIDIOC_ENUM_FMT, &format_desc)) { 31 break; 32 } 33 pixel_format[0] = format_desc.pixelformat & 0xFF; 34 pixel_format[1] = (format_desc.pixelformat >> 8) & 0xFF; 35 pixel_format[2] = (format_desc.pixelformat >> 16) & 0xFF; 36 pixel_format[3] = (format_desc.pixelformat >> 24) & 0xFF; 37 PyObject* item = PyString_FromStringAndSize(pixel_format, 4); 38 PyList_Append(formats, item); 39 Py_DECREF(item); 40 } 41 close(fd); 42 } 43 44 static PyObject *v4l2_enum_capture_formats(PyObject *self, PyObject *args) { 45 const char *dev; 46 if (!PyArg_ParseTuple(args, "s", &dev)) 47 return NULL; 48 PyObject *formats = PyList_New(0); 49 v4l2_enum_formats(dev, V4L2_BUF_TYPE_VIDEO_CAPTURE, formats); 50 v4l2_enum_formats(dev, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, formats); 51 return formats; 52 } 53 54 static PyObject *v4l2_enum_output_formats(PyObject *self, PyObject *args) { 55 const char *dev; 56 if (!PyArg_ParseTuple(args, "s", &dev)) 57 return NULL; 58 PyObject *formats = PyList_New(0); 59 v4l2_enum_formats(dev, V4L2_BUF_TYPE_VIDEO_OUTPUT, formats); 60 v4l2_enum_formats(dev, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, formats); 61 return formats; 62 } 63 64 /* 65 * Bind Python function names to our C functions 66 */ 67 static PyMethodDef v4l2_methods[] = { 68 {"enum_capture_formats", v4l2_enum_capture_formats, METH_VARARGS}, 69 {"enum_output_formats", v4l2_enum_output_formats, METH_VARARGS}, 70 {NULL, NULL} 71 }; 72 73 /* 74 * Python calls this to let us initialize our module 75 */ 76 PyMODINIT_FUNC initv4l2() { 77 (void) Py_InitModule("v4l2", v4l2_methods); 78 } 79
