Add initial implementation of a v4l2 capture plugin

This patch adds a plugin to capture video data from v4l2 devices under linux.

obs/window-basic-main.cpp

@@ -498,6 +498,7 @@ void OBSBasic::OBSInit()
 	obs_load_module("linux-xshm");
 	obs_load_module("linux-xcomposite");
 	obs_load_module("linux-pulseaudio");
+	obs_load_module("linux-v4l2");
 #endif
 
 	if (!InitOutputs())

plugins/CMakeLists.txt

@@ -11,6 +11,7 @@ elseif("${CMAKE_SYSTEM_NAME}" MATCHES "Linux")
 	add_subdirectory(linux-xshm)
 	add_subdirectory(linux-xcomposite)
 	add_subdirectory(linux-pulseaudio)
+	add_subdirectory(linux-v4l2)
 endif()
 
 add_subdirectory(obs-x264)

plugins/linux-v4l2/CMakeLists.txt

@@ -0,0 +1,15 @@
+include_directories(SYSTEM "${CMAKE_SOURCE_DIR}/libobs")
+
+set(linux-v4l2_SOURCES
+	linux-v4l2.c
+	v4l2-input.c
+)
+
+add_library(linux-v4l2 MODULE
+	${linux-v4l2_SOURCES}
+)
+target_link_libraries(linux-v4l2
+	libobs
+)
+
+install_obs_plugin(linux-v4l2)

plugins/linux-v4l2/linux-v4l2.c

@@ -0,0 +1,28 @@
+/*
+Copyright (C) 2014 by Leonhard Oelke <[email protected]>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <obs-module.h>
+
+OBS_DECLARE_MODULE()
+
+extern struct obs_source_info v4l2_input;
+
+bool obs_module_load(uint32_t obs_version)
+{
+	UNUSED_PARAMETER(obs_version);
+	obs_register_source(&v4l2_input);
+	return true;
+}

plugins/linux-v4l2/v4l2-input.c

@@ -0,0 +1,352 @@
+/*
+Copyright (C) 2014 by Leonhard Oelke <[email protected]>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <inttypes.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/select.h>
+
+#include <linux/videodev2.h>
+
+#include <util/threading.h>
+#include <util/bmem.h>
+#include <obs.h>
+
+#define V4L2_DATA(voidptr) struct v4l2_data *data = voidptr;
+
+#define timeval2ns(tv) \
+	(((uint64_t) tv.tv_sec * 1000000000) + ((uint64_t) tv.tv_usec * 1000))
+
+static const char video[] = "/dev/video0";
+
+struct v4l2_buffer_data {
+	size_t length;
+	void *start;
+};
+
+struct v4l2_data {
+	pthread_t thread;
+	os_event_t event;
+	obs_source_t source;
+	uint_fast32_t linesize;
+
+	uint64_t frames;
+
+	int_fast32_t dev;
+	uint_fast32_t buf_count;
+	struct v4l2_buffer_data *buf;
+};
+
+/*
+ * start capture
+ */
+static int_fast32_t v4l2_start_capture(struct v4l2_data *data)
+{
+	enum v4l2_buf_type type;
+
+	for (uint_fast32_t i = 0; i < data->buf_count; ++i) {
+		struct v4l2_buffer buf;
+
+		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		buf.memory = V4L2_MEMORY_MMAP;
+		buf.index = i;
+
+		if (ioctl(data->dev, VIDIOC_QBUF, &buf) < 0) {
+			blog(LOG_ERROR, "v4l2-input: unable to queue buffer");
+			return -1;
+		}
+	}
+
+	type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	if (ioctl(data->dev, VIDIOC_STREAMON, &type) < 0) {
+		blog(LOG_ERROR, "v4l2-input: unable to start stream");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * stop capture
+ */
+static int_fast32_t v4l2_stop_capture(struct v4l2_data *data)
+{
+	enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+	if (ioctl(data->dev, VIDIOC_STREAMOFF, &type) < 0) {
+		blog(LOG_ERROR, "v4l2-input: unable to stop stream");
+	}
+
+	return 0;
+}
+
+/*
+ * create memory mapping for buffers
+ */
+static int_fast32_t v4l2_create_mmap(struct v4l2_data *data)
+{
+	struct v4l2_requestbuffers req;
+
+	req.count = 4;
+	req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	req.memory = V4L2_MEMORY_MMAP;
+
+	if (ioctl(data->dev, VIDIOC_REQBUFS, &req) < 0) {
+		blog(LOG_DEBUG, "v4l2-input: request for buffers failed !");
+		return -1;
+	}
+
+	if (req.count < 2) {
+		blog(LOG_DEBUG, "v4l2-input: not enough memory !");
+		return -1;
+	}
+
+	data->buf_count = req.count;
+	data->buf = bzalloc(req.count * sizeof(struct v4l2_buffer_data));
+
+	for (uint_fast32_t i = 0; i < req.count; ++i) {
+		struct v4l2_buffer buf;
+
+		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		buf.memory = V4L2_MEMORY_MMAP;
+		buf.index = i;
+
+		if (ioctl(data->dev, VIDIOC_QUERYBUF, &buf) < 0) {
+			blog(LOG_ERROR, "v4l2-input: failed to query buffer");
+			return -1;
+		}
+
+		data->buf[i].length = buf.length;
+		data->buf[i].start = mmap(NULL, buf.length,
+			PROT_READ | PROT_WRITE, MAP_SHARED,
+			data->dev, buf.m.offset);
+
+		if (data->buf[i].start == MAP_FAILED) {
+			blog(LOG_ERROR, "v4l2-input: mmap for buffer failed");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * destroy memory mapping for buffers
+ */
+static void v4l2_destroy_mmap(struct v4l2_data *data)
+{
+	for(uint_fast32_t i = 0; i < data->buf_count; ++i) {
+		if (data->buf[i].start != MAP_FAILED)
+			munmap(data->buf[i].start, data->buf[i].length);
+	}
+
+	data->buf_count = 0;
+	bfree(data->buf);
+}
+
+/*
+ * Worker thread to get video data
+ */
+static void *v4l2_thread(void *vptr)
+{
+	V4L2_DATA(vptr);
+
+	if (v4l2_start_capture(data) < 0)
+		goto exit;
+
+	while (os_event_try(data->event) == EAGAIN) {
+		int r;
+		fd_set fds;
+		struct timeval tv;
+		struct v4l2_buffer buf;
+		struct source_frame out;
+
+		FD_ZERO(&fds);
+		FD_SET(data->dev, &fds);
+
+		tv.tv_sec = 1;
+		tv.tv_usec = 0;
+
+		r = select(data->dev + 1, &fds, NULL, NULL, &tv);
+		if (r < 0) {
+			if (errno == EINTR)
+				continue;
+			blog(LOG_DEBUG, "v4l2-input: select failed");
+			break;
+		} else if (r == 0) {
+			blog(LOG_DEBUG, "v4l2-input: select timeout");
+			continue;
+		}
+
+		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		buf.memory = V4L2_MEMORY_MMAP;
+
+		if (ioctl(data->dev, VIDIOC_DQBUF, &buf) < 0) {
+			if (errno == EAGAIN)
+				continue;
+			blog(LOG_DEBUG, "v4l2-input: failed to dequeue buffer");
+			break;
+		}
+
+		video_format_get_parameters(VIDEO_CS_709, VIDEO_RANGE_PARTIAL,
+				out.color_matrix, out.color_range_min,
+				out.color_range_max);
+		out.data[0] = (uint8_t *) data->buf[buf.index].start;
+		out.linesize[0] = data->linesize;
+		out.width = 640;
+		out.height = 480;
+		out.timestamp = timeval2ns(buf.timestamp);
+		out.format = VIDEO_FORMAT_YUY2;
+
+		obs_source_output_video(data->source, &out);
+
+		if (ioctl(data->dev, VIDIOC_QBUF, &buf) < 0) {
+			blog(LOG_DEBUG, "v4l2-input: failed to enqueue buffer");
+			break;
+		}
+
+		data->frames++;
+	}
+
+exit:
+	v4l2_stop_capture(data);
+	return NULL;
+}
+
+static const char* v4l2_getname(const char* locale)
+{
+	UNUSED_PARAMETER(locale);
+	return "V4L2 Capture Input";
+}
+
+static void v4l2_destroy(void *vptr)
+{
+	V4L2_DATA(vptr);
+
+	if (!data)
+		return;
+
+	if (data->thread) {
+		os_event_signal(data->event);
+		pthread_join(data->thread, NULL);
+	}
+
+	if (data->buf_count)
+		v4l2_destroy_mmap(data);
+
+	if (data->dev != -1)
+		close(data->dev);
+
+	bfree(data);
+}
+
+static void *v4l2_create(obs_data_t settings, obs_source_t source)
+{
+	UNUSED_PARAMETER(settings);
+
+	struct v4l2_capability cap;
+	struct v4l2_format fmt;
+	struct v4l2_streamparm par;
+
+	struct v4l2_data *data = bzalloc(sizeof(struct v4l2_data));
+	data->source = source;
+
+	blog(LOG_DEBUG, "v4l2-input: New input created");
+
+	data->dev = open(video, O_RDWR | O_NONBLOCK);
+	if (data->dev == -1) {
+		blog(LOG_ERROR, "v4l2-input: Unable to open device: %s", video);
+		goto fail;
+	}
+
+	if (ioctl(data->dev, VIDIOC_QUERYCAP, &cap) < 0) {
+		blog(LOG_ERROR, "v4l2-input: Unable to get capabilities !");
+		goto fail;
+	}
+
+	blog(LOG_DEBUG, "v4l2-input: Got capabilities for '%s'", cap.card);
+
+	/* TODO: check if device supports needed capabilities */
+
+	fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	fmt.fmt.pix.width = 640;
+	fmt.fmt.pix.height = 480;
+	fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
+	fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
+
+	if (ioctl(data->dev, VIDIOC_S_FMT, &fmt) < 0) {
+		blog(LOG_DEBUG, "v4l2-input: unable to set format");
+		goto fail;
+	}
+
+	par.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	par.parm.capture.timeperframe.numerator = 1;
+	par.parm.capture.timeperframe.denominator = 30;
+
+	if (ioctl(data->dev, VIDIOC_S_PARM, &par) < 0) {
+		blog(LOG_DEBUG, "v4l2-input: unable to set params");
+		goto fail;
+	}
+
+	data->linesize = fmt.fmt.pix.bytesperline;
+	blog(LOG_DEBUG, "v4l2-input: Linesize: %"PRIuFAST32, data->linesize);
+
+	if (v4l2_create_mmap(data) < 0) {
+		blog(LOG_ERROR, "v4l2-input: failed to map buffers");
+		goto fail;
+	}
+
+	if (os_event_init(&data->event, OS_EVENT_TYPE_MANUAL) != 0)
+		goto fail;
+	if (pthread_create(&data->thread, NULL, v4l2_thread, data) != 0)
+		goto fail;
+
+	return data;
+fail:
+	v4l2_destroy(data);
+	return NULL;
+}
+
+static uint32_t v4l2_getwidth(void *vptr)
+{
+	V4L2_DATA(vptr);
+
+	return 640;
+}
+
+static uint32_t v4l2_getheight(void *vptr)
+{
+	V4L2_DATA(vptr);
+
+	return 480;
+}
+
+struct obs_source_info v4l2_input = {
+	.id           = "v4l2_input",
+	.type         = OBS_SOURCE_TYPE_INPUT,
+	.output_flags = OBS_SOURCE_ASYNC_VIDEO,
+	.getname      = v4l2_getname,
+	.create       = v4l2_create,
+	.destroy      = v4l2_destroy,
+	.getwidth     = v4l2_getwidth,
+	.getheight    = v4l2_getheight
+};