obs-studio/plugins/linux-v4l2/v4l2-helpers.c

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/*
Copyright (C) 2014 by Leonhard Oelke <leonhard@in-verted.de>
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 <sys/mman.h>
#include <util/bmem.h>
#include "v4l2-helpers.h"
#define blog(level, msg, ...) blog(level, "v4l2-helpers: " msg, ##__VA_ARGS__)
int_fast32_t v4l2_start_capture(int_fast32_t dev, struct v4l2_buffer_data *buf)
{
enum v4l2_buf_type type;
struct v4l2_buffer enq;
memset(&enq, 0, sizeof(enq));
enq.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
enq.memory = V4L2_MEMORY_MMAP;
for (enq.index = 0; enq.index < buf->count; ++enq.index) {
if (v4l2_ioctl(dev, VIDIOC_QBUF, &enq) < 0) {
blog(LOG_ERROR, "unable to queue buffer");
return -1;
}
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (v4l2_ioctl(dev, VIDIOC_STREAMON, &type) < 0) {
blog(LOG_ERROR, "unable to start stream");
return -1;
}
return 0;
}
int_fast32_t v4l2_stop_capture(int_fast32_t dev)
{
enum v4l2_buf_type type;
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (v4l2_ioctl(dev, VIDIOC_STREAMOFF, &type) < 0) {
blog(LOG_ERROR, "unable to stop stream");
return -1;
}
return 0;
}
int_fast32_t v4l2_create_mmap(int_fast32_t dev, struct v4l2_buffer_data *buf)
{
struct v4l2_requestbuffers req;
struct v4l2_buffer map;
memset(&req, 0, sizeof(req));
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
if (v4l2_ioctl(dev, VIDIOC_REQBUFS, &req) < 0) {
blog(LOG_ERROR, "Request for buffers failed !");
return -1;
}
if (req.count < 2) {
blog(LOG_ERROR, "Device returned less than 2 buffers");
return -1;
}
buf->count = req.count;
buf->info = bzalloc(req.count * sizeof(struct v4l2_mmap_info));
memset(&map, 0, sizeof(map));
map.type = req.type;
map.memory = req.memory;
for (map.index = 0; map.index < req.count; ++map.index) {
if (v4l2_ioctl(dev, VIDIOC_QUERYBUF, &map) < 0) {
blog(LOG_ERROR, "Failed to query buffer details");
return -1;
}
buf->info[map.index].length = map.length;
buf->info[map.index].start = v4l2_mmap(NULL, map.length,
PROT_READ | PROT_WRITE, MAP_SHARED,
dev, map.m.offset);
if (buf->info[map.index].start == MAP_FAILED) {
blog(LOG_ERROR, "mmap for buffer failed");
return -1;
}
}
return 0;
}
int_fast32_t v4l2_destroy_mmap(struct v4l2_buffer_data *buf)
{
for(uint_fast32_t i = 0; i < buf->count; ++i) {
if (buf->info[i].start != MAP_FAILED && buf->info[i].start != 0)
v4l2_munmap(buf->info[i].start, buf->info[i].length);
}
if (buf->count) {
bfree(buf->info);
buf->count = 0;
}
return 0;
}
int_fast32_t v4l2_set_input(int_fast32_t dev, int *input)
{
if (!dev || !input)
return -1;
return (*input == -1)
? v4l2_ioctl(dev, VIDIOC_G_INPUT, input)
: v4l2_ioctl(dev, VIDIOC_S_INPUT, input);
}
int_fast32_t v4l2_set_format(int_fast32_t dev, int *resolution,
int *pixelformat, int *bytesperline)
{
bool set = false;
int width, height;
struct v4l2_format fmt;
if (!dev || !resolution || !pixelformat || !bytesperline)
return -1;
/* We need to set the type in order to query the settings */
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (v4l2_ioctl(dev, VIDIOC_G_FMT, &fmt) < 0)
return -1;
if (*resolution != -1) {
v4l2_unpack_tuple(&width, &height, *resolution);
fmt.fmt.pix.width = width;
fmt.fmt.pix.height = height;
set = true;
}
if (*pixelformat != -1) {
fmt.fmt.pix.pixelformat = *pixelformat;
set = true;
}
if (set && (v4l2_ioctl(dev, VIDIOC_S_FMT, &fmt) < 0))
return -1;
*resolution = v4l2_pack_tuple(fmt.fmt.pix.width, fmt.fmt.pix.height);
*pixelformat = fmt.fmt.pix.pixelformat;
*bytesperline = fmt.fmt.pix.bytesperline;
return 0;
}
int_fast32_t v4l2_set_framerate(int_fast32_t dev, int *framerate)
{
bool set = false;
int num, denom;
struct v4l2_streamparm par;
if (!dev || !framerate)
return -1;
/* We need to set the type in order to query the stream settings */
par.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (v4l2_ioctl(dev, VIDIOC_G_PARM, &par) < 0)
return -1;
if (*framerate != -1) {
v4l2_unpack_tuple(&num, &denom, *framerate);
par.parm.capture.timeperframe.numerator = num;
par.parm.capture.timeperframe.denominator = denom;
set = true;
}
if (set && (v4l2_ioctl(dev, VIDIOC_S_PARM, &par) < 0))
return -1;
*framerate = v4l2_pack_tuple(par.parm.capture.timeperframe.numerator,
par.parm.capture.timeperframe.denominator);
return 0;
}