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ffmpeg/libavformat/v4l2.c

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/*
* Video4Linux2 grab interface
* Copyright (c) 2000,2001 Fabrice Bellard.
* Copyright (c) 2006 Luca Abeni.
*
* Part of this file is based on the V4L2 video capture example
* (http://v4l2spec.bytesex.org/v4l2spec/capture.c)
*
* Thanks to Michael Niedermayer for providing the mapping between
* V4L2_PIX_FMT_* and PIX_FMT_*
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <asm/types.h>
#include <linux/videodev2.h>
#include <time.h>
static const int desired_video_buffers = 256;
enum io_method {
io_read,
io_mmap,
io_userptr
};
struct video_data {
int fd;
int frame_format; /* V4L2_PIX_FMT_* */
enum io_method io_method;
int width, height;
int frame_rate;
int frame_rate_base;
int frame_size;
int top_field_first;
int buffers;
void **buf_start;
unsigned int *buf_len;
};
struct fmt_map {
enum PixelFormat ff_fmt;
int32_t v4l2_fmt;
};
static struct fmt_map fmt_conversion_table[] = {
{
.ff_fmt = PIX_FMT_YUV420P,
.v4l2_fmt = V4L2_PIX_FMT_YUV420,
},
{
.ff_fmt = PIX_FMT_YUV422P,
.v4l2_fmt = V4L2_PIX_FMT_YUV422P,
},
{
.ff_fmt = PIX_FMT_YUV422,
.v4l2_fmt = V4L2_PIX_FMT_YUYV,
},
{
.ff_fmt = PIX_FMT_UYVY422,
.v4l2_fmt = V4L2_PIX_FMT_UYVY,
},
{
.ff_fmt = PIX_FMT_YUV411P,
.v4l2_fmt = V4L2_PIX_FMT_YUV411P,
},
{
.ff_fmt = PIX_FMT_YUV410P,
.v4l2_fmt = V4L2_PIX_FMT_YUV410,
},
{
.ff_fmt = PIX_FMT_BGR24,
.v4l2_fmt = V4L2_PIX_FMT_BGR24,
},
{
.ff_fmt = PIX_FMT_RGB24,
.v4l2_fmt = V4L2_PIX_FMT_RGB24,
},
/*
{
.ff_fmt = PIX_FMT_RGBA32,
.v4l2_fmt = V4L2_PIX_FMT_BGR32,
},
*/
{
.ff_fmt = PIX_FMT_GRAY8,
.v4l2_fmt = V4L2_PIX_FMT_GREY,
},
};
static int device_open(const char *devname, uint32_t *capabilities)
{
struct v4l2_capability cap;
int fd;
int res;
fd = open(devname, O_RDWR /*| O_NONBLOCK*/, 0);
if (fd < 0) {
av_log(NULL, AV_LOG_ERROR, "Cannot open video device %s : %s\n",
devname, strerror(errno));
return -1;
}
res = ioctl(fd, VIDIOC_QUERYCAP, &cap);
// ENOIOCTLCMD definition only availble on __KERNEL__
if (res < 0 && errno == 515)
{
av_log(NULL, AV_LOG_ERROR, "QUERYCAP not implemented, probably V4L device but not supporting V4L2\n");
close(fd);
return -1;
}
if (res < 0) {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
strerror(errno));
close(fd);
return -1;
}
if ((cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) == 0) {
av_log(NULL, AV_LOG_ERROR, "Not a video capture device\n");
close(fd);
return -1;
}
*capabilities = cap.capabilities;
return fd;
}
static int device_init(int fd, int *width, int *height, int pix_fmt)
{
struct v4l2_format fmt;
int res;
memset(&fmt, 0, sizeof(struct v4l2_format));
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = *width;
fmt.fmt.pix.height = *height;
fmt.fmt.pix.pixelformat = pix_fmt;
fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
res = ioctl(fd, VIDIOC_S_FMT, &fmt);
if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {
av_log(NULL, AV_LOG_INFO, "The V4L2 driver changed the video from %dx%d to %dx%d\n", *width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);
*width = fmt.fmt.pix.width;
*height = fmt.fmt.pix.height;
}
return res;
}
static int first_field(int fd)
{
int res;
v4l2_std_id std;
res = ioctl(fd, VIDIOC_G_STD, &std);
if (res < 0) {
return 0;
}
if (std & V4L2_STD_NTSC) {
return 0;
}
return 1;
}
static uint32_t fmt_ff2v4l(enum PixelFormat pix_fmt)
{
int i;
for (i = 0; i < sizeof(fmt_conversion_table) / sizeof(struct fmt_map); i++) {
if (fmt_conversion_table[i].ff_fmt == pix_fmt) {
return fmt_conversion_table[i].v4l2_fmt;
}
}
return 0;
}
static enum PixelFormat fmt_v4l2ff(uint32_t pix_fmt)
{
int i;
for (i = 0; i < sizeof(fmt_conversion_table) / sizeof(struct fmt_map); i++) {
if (fmt_conversion_table[i].v4l2_fmt == pix_fmt) {
return fmt_conversion_table[i].ff_fmt;
}
}
return -1;
}
static int mmap_init(struct video_data *s)
{
struct v4l2_requestbuffers req;
int i, res;
memset(&req, 0, sizeof(struct v4l2_requestbuffers));
req.count = desired_video_buffers;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
res = ioctl (s->fd, VIDIOC_REQBUFS, &req);
if (res < 0) {
if (errno == EINVAL) {
av_log(NULL, AV_LOG_ERROR, "Device does not support mmap\n");
} else {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS)\n");
}
return -1;
}
if (req.count < 2) {
av_log(NULL, AV_LOG_ERROR, "Insufficient buffer memory\n");
return -1;
}
s->buffers = req.count;
s->buf_start = av_malloc(sizeof(void *) * s->buffers);
if (s->buf_start == NULL) {
av_log(NULL, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");
return -1;
}
s->buf_len = av_malloc(sizeof(unsigned int) * s->buffers);
if (s->buf_len == NULL) {
av_log(NULL, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");
av_free(s->buf_start);
return -1;
}
for (i = 0; i < req.count; i++) {
struct v4l2_buffer buf;
memset(&buf, 0, sizeof(struct v4l2_buffer));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
res = ioctl (s->fd, VIDIOC_QUERYBUF, &buf);
if (res < 0) {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n");
return -1;
}
s->buf_len[i] = buf.length;
if (s->buf_len[i] < s->frame_size) {
av_log(NULL, AV_LOG_ERROR, "Buffer len [%d] = %d != %d\n", i, s->buf_len[i], s->frame_size);
return -1;
}
s->buf_start[i] = mmap (NULL, buf.length,
PROT_READ | PROT_WRITE, MAP_SHARED, s->fd, buf.m.offset);
if (s->buf_start[i] == MAP_FAILED) {
av_log(NULL, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
return -1;
}
}
return 0;
}
static int read_init(struct video_data *s)
{
return -1;
}
static int mmap_read_frame(struct video_data *s, void *frame, int64_t *ts)
{
struct v4l2_buffer buf;
int res;
memset(&buf, 0, sizeof(struct v4l2_buffer));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
/* FIXME: Some special treatment might be needed in case of loss of signal... */
while ((res = ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 &&
((errno == EAGAIN) || (errno == EINTR)));
if (res < 0) {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n", strerror(errno));
return -1;
}
assert (buf.index < s->buffers);
assert(buf.bytesused == s->frame_size);
/* Image is at s->buff_start[buf.index] */
memcpy(frame, s->buf_start[buf.index], buf.bytesused);
*ts = buf.timestamp.tv_sec * int64_t_C(1000000) + buf.timestamp.tv_usec;
res = ioctl (s->fd, VIDIOC_QBUF, &buf);
if (res < 0) {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF)\n");
return -1;
}
return s->buf_len[buf.index];
}
static int read_frame(struct video_data *s, void *frame, int64_t *ts)
{
return -1;
}
static int mmap_start(struct video_data *s)
{
enum v4l2_buf_type type;
int i, res;
for (i = 0; i < s->buffers; i++) {
struct v4l2_buffer buf;
memset(&buf, 0, sizeof(struct v4l2_buffer));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
res = ioctl (s->fd, VIDIOC_QBUF, &buf);
if (res < 0) {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno));
return -1;
}
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
res = ioctl (s->fd, VIDIOC_STREAMON, &type);
if (res < 0) {
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n", strerror(errno));
return -1;
}
return 0;
}
static void mmap_close(struct video_data *s)
{
enum v4l2_buf_type type;
int i;
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
/* We do not check for the result, because we could
* not do anything about it anyway...
*/
ioctl(s->fd, VIDIOC_STREAMOFF, &type);
for (i = 0; i < s->buffers; i++) {
munmap(s->buf_start[i], s->buf_len[i]);
}
av_free(s->buf_start);
av_free(s->buf_len);
}
static int v4l2_read_header(AVFormatContext *s1, AVFormatParameters *ap)
{
struct video_data *s = s1->priv_data;
AVStream *st;
int width, height;
int res, frame_rate, frame_rate_base;
uint32_t desired_format, capabilities;
const char *video_device;
if (ap->width <= 0 || ap->height <= 0 || ap->time_base.den <= 0) {
av_log(s1, AV_LOG_ERROR, "Missing/Wrong parameters\n");
return -1;
}
width = ap->width;
height = ap->height;
frame_rate = ap->time_base.den;
frame_rate_base = ap->time_base.num;
if((unsigned)width > 32767 || (unsigned)height > 32767) {
av_log(s1, AV_LOG_ERROR, "Wrong size %dx%d\n", width, height);
return -1;
}
st = av_new_stream(s1, 0);
if (!st) {
return -ENOMEM;
}
av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
s->width = width;
s->height = height;
s->frame_rate = frame_rate;
s->frame_rate_base = frame_rate_base;
video_device = ap->device;
if (!video_device) {
video_device = "/dev/video";
}
capabilities = 0;
s->fd = device_open(video_device, &capabilities);
if (s->fd < 0) {
av_free(st);
return AVERROR_IO;
}
av_log(s1, AV_LOG_INFO, "[%d]Capabilities: %x\n", s->fd, capabilities);
desired_format = fmt_ff2v4l(ap->pix_fmt);
if (desired_format == 0 || (device_init(s->fd, &width, &height, desired_format) < 0)) {
int i, done;
done = 0; i = 0;
while (!done) {
desired_format = fmt_conversion_table[i].v4l2_fmt;
if (device_init(s->fd, &width, &height, desired_format) < 0) {
desired_format = 0;
i++;
} else {
done = 1;
}
if (i == sizeof(fmt_conversion_table) / sizeof(struct fmt_map)) {
done = 1;
}
}
}
if (desired_format == 0) {
av_log(s1, AV_LOG_ERROR, "Cannot find a proper format.\n");
close(s->fd);
av_free(st);
return AVERROR_IO;
}
s->frame_format = desired_format;
st->codec->pix_fmt = fmt_v4l2ff(desired_format);
s->frame_size = avpicture_get_size(st->codec->pix_fmt, width, height);
if (capabilities & V4L2_CAP_STREAMING) {
s->io_method = io_mmap;
res = mmap_init(s);
if (res == 0) {
res = mmap_start(s);
}
} else {
s->io_method = io_read;
res = read_init(s);
}
if (res < 0) {
close(s->fd);
av_free(st);
return AVERROR_IO;
}
s->top_field_first = first_field(s->fd);
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_RAWVIDEO;
st->codec->width = width;
st->codec->height = height;
st->codec->time_base.den = frame_rate;
st->codec->time_base.num = frame_rate_base;
st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;
return 0;
}
static int v4l2_read_packet(AVFormatContext *s1, AVPacket *pkt)
{
struct video_data *s = s1->priv_data;
int res;
if (av_new_packet(pkt, s->frame_size) < 0)
return AVERROR_IO;
if (s->io_method == io_mmap) {
res = mmap_read_frame(s, pkt->data, &pkt->pts);
} else if (s->io_method == io_read) {
res = read_frame(s, pkt->data, &pkt->pts);
} else {
return AVERROR_IO;
}
if (res < 0) {
return AVERROR_IO;
}
if (s1->streams[0]->codec->coded_frame) {
s1->streams[0]->codec->coded_frame->interlaced_frame = 1;
s1->streams[0]->codec->coded_frame->top_field_first = s->top_field_first;
}
return s->frame_size;
}
static int v4l2_read_close(AVFormatContext *s1)
{
struct video_data *s = s1->priv_data;
if (s->io_method == io_mmap) {
mmap_close(s);
}
close(s->fd);
return 0;
}
AVInputFormat v4l2_demuxer = {
"video4linux2",
"video grab",
sizeof(struct video_data),
NULL,
v4l2_read_header,
v4l2_read_packet,
v4l2_read_close,
.flags = AVFMT_NOFILE,
};
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