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ffmpeg/libavdevice/v4l.c

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/*
* Linux video grab interface
* Copyright (c) 2000,2001 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#undef __STRICT_ANSI__ //workaround due to broken kernel headers
#include "config.h"
#include "libavutil/rational.h"
#include "libavutil/imgutils.h"
#include "libavformat/avformat.h"
#include "libavcodec/dsputil.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/time.h>
#define _LINUX_TIME_H 1
#include <linux/videodev.h>
#include <time.h>
#include <strings.h>
typedef struct {
int fd;
int frame_format; /* see VIDEO_PALETTE_xxx */
int use_mmap;
AVRational time_base;
int64_t time_frame;
int frame_size;
struct video_capability video_cap;
struct video_audio audio_saved;
struct video_window video_win;
uint8_t *video_buf;
struct video_mbuf gb_buffers;
struct video_mmap gb_buf;
int gb_frame;
} VideoData;
static const struct {
int palette;
int depth;
enum PixelFormat pix_fmt;
} video_formats [] = {
{.palette = VIDEO_PALETTE_YUV420P, .depth = 12, .pix_fmt = PIX_FMT_YUV420P },
{.palette = VIDEO_PALETTE_YUV422, .depth = 16, .pix_fmt = PIX_FMT_YUYV422 },
{.palette = VIDEO_PALETTE_UYVY, .depth = 16, .pix_fmt = PIX_FMT_UYVY422 },
{.palette = VIDEO_PALETTE_YUYV, .depth = 16, .pix_fmt = PIX_FMT_YUYV422 },
/* NOTE: v4l uses BGR24, not RGB24 */
{.palette = VIDEO_PALETTE_RGB24, .depth = 24, .pix_fmt = PIX_FMT_BGR24 },
{.palette = VIDEO_PALETTE_RGB565, .depth = 16, .pix_fmt = PIX_FMT_BGR565 },
{.palette = VIDEO_PALETTE_GREY, .depth = 8, .pix_fmt = PIX_FMT_GRAY8 },
};
static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
{
VideoData *s = s1->priv_data;
AVStream *st;
int video_fd;
int desired_palette, desired_depth;
struct video_tuner tuner;
struct video_audio audio;
struct video_picture pict;
int j;
int vformat_num = FF_ARRAY_ELEMS(video_formats);
if (ap->time_base.den <= 0) {
av_log(s1, AV_LOG_ERROR, "Wrong time base (%d)\n", ap->time_base.den);
return -1;
}
s->time_base = ap->time_base;
s->video_win.width = ap->width;
s->video_win.height = ap->height;
st = av_new_stream(s1, 0);
if (!st)
return AVERROR(ENOMEM);
av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
video_fd = open(s1->filename, O_RDWR);
if (video_fd < 0) {
av_log(s1, AV_LOG_ERROR, "%s: %s\n", s1->filename, strerror(errno));
goto fail;
}
if (ioctl(video_fd, VIDIOCGCAP, &s->video_cap) < 0) {
av_log(s1, AV_LOG_ERROR, "VIDIOCGCAP: %s\n", strerror(errno));
goto fail;
}
if (!(s->video_cap.type & VID_TYPE_CAPTURE)) {
av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not handle capture\n");
goto fail;
}
/* no values set, autodetect them */
if (s->video_win.width <= 0 || s->video_win.height <= 0) {
if (ioctl(video_fd, VIDIOCGWIN, &s->video_win, sizeof(s->video_win)) < 0) {
av_log(s1, AV_LOG_ERROR, "VIDIOCGWIN: %s\n", strerror(errno));
goto fail;
}
}
if(av_image_check_size(s->video_win.width, s->video_win.height, 0, s1) < 0)
return -1;
desired_palette = -1;
desired_depth = -1;
for (j = 0; j < vformat_num; j++) {
if (ap->pix_fmt == video_formats[j].pix_fmt) {
desired_palette = video_formats[j].palette;
desired_depth = video_formats[j].depth;
break;
}
}
/* set tv standard */
if (ap->standard && !ioctl(video_fd, VIDIOCGTUNER, &tuner)) {
if (!strcasecmp(ap->standard, "pal"))
tuner.mode = VIDEO_MODE_PAL;
else if (!strcasecmp(ap->standard, "secam"))
tuner.mode = VIDEO_MODE_SECAM;
else
tuner.mode = VIDEO_MODE_NTSC;
ioctl(video_fd, VIDIOCSTUNER, &tuner);
}
/* unmute audio */
audio.audio = 0;
ioctl(video_fd, VIDIOCGAUDIO, &audio);
memcpy(&s->audio_saved, &audio, sizeof(audio));
audio.flags &= ~VIDEO_AUDIO_MUTE;
ioctl(video_fd, VIDIOCSAUDIO, &audio);
ioctl(video_fd, VIDIOCGPICT, &pict);
#if 0
printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
pict.colour,
pict.hue,
pict.brightness,
pict.contrast,
pict.whiteness);
#endif
/* try to choose a suitable video format */
pict.palette = desired_palette;
pict.depth= desired_depth;
if (desired_palette == -1 || ioctl(video_fd, VIDIOCSPICT, &pict) < 0) {
for (j = 0; j < vformat_num; j++) {
pict.palette = video_formats[j].palette;
pict.depth = video_formats[j].depth;
if (-1 != ioctl(video_fd, VIDIOCSPICT, &pict))
break;
}
if (j >= vformat_num)
goto fail1;
}
if (ioctl(video_fd, VIDIOCGMBUF, &s->gb_buffers) < 0) {
/* try to use read based access */
int val;
s->video_win.x = 0;
s->video_win.y = 0;
s->video_win.chromakey = -1;
s->video_win.flags = 0;
if (ioctl(video_fd, VIDIOCSWIN, s->video_win) < 0) {
av_log(s1, AV_LOG_ERROR, "VIDIOCSWIN: %s\n", strerror(errno));
goto fail;
}
s->frame_format = pict.palette;
val = 1;
if (ioctl(video_fd, VIDIOCCAPTURE, &val) < 0) {
av_log(s1, AV_LOG_ERROR, "VIDIOCCAPTURE: %s\n", strerror(errno));
goto fail;
}
s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;
s->use_mmap = 0;
} else {
s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_SHARED, video_fd, 0);
if ((unsigned char*)-1 == s->video_buf) {
s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_PRIVATE, video_fd, 0);
if ((unsigned char*)-1 == s->video_buf) {
av_log(s1, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
goto fail;
}
}
s->gb_frame = 0;
s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;
/* start to grab the first frame */
s->gb_buf.frame = s->gb_frame % s->gb_buffers.frames;
s->gb_buf.height = s->video_win.height;
s->gb_buf.width = s->video_win.width;
s->gb_buf.format = pict.palette;
if (ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
if (errno != EAGAIN) {
fail1:
av_log(s1, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));
} else {
av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not receive any video signal\n");
}
goto fail;
}
for (j = 1; j < s->gb_buffers.frames; j++) {
s->gb_buf.frame = j;
ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
}
s->frame_format = s->gb_buf.format;
s->use_mmap = 1;
}
for (j = 0; j < vformat_num; j++) {
if (s->frame_format == video_formats[j].palette) {
s->frame_size = s->video_win.width * s->video_win.height * video_formats[j].depth / 8;
st->codec->pix_fmt = video_formats[j].pix_fmt;
break;
}
}
if (j >= vformat_num)
goto fail;
s->fd = video_fd;
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_RAWVIDEO;
st->codec->width = s->video_win.width;
st->codec->height = s->video_win.height;
st->codec->time_base = s->time_base;
st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;
return 0;
fail:
if (video_fd >= 0)
close(video_fd);
return AVERROR(EIO);
}
static int v4l_mm_read_picture(VideoData *s, uint8_t *buf)
{
uint8_t *ptr;
while (ioctl(s->fd, VIDIOCSYNC, &s->gb_frame) < 0 &&
(errno == EAGAIN || errno == EINTR));
ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];
memcpy(buf, ptr, s->frame_size);
/* Setup to capture the next frame */
s->gb_buf.frame = s->gb_frame;
if (ioctl(s->fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
if (errno == EAGAIN)
av_log(NULL, AV_LOG_ERROR, "Cannot Sync\n");
else
av_log(NULL, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));
return AVERROR(EIO);
}
/* This is now the grabbing frame */
s->gb_frame = (s->gb_frame + 1) % s->gb_buffers.frames;
return s->frame_size;
}
static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
{
VideoData *s = s1->priv_data;
int64_t curtime, delay;
struct timespec ts;
/* Calculate the time of the next frame */
s->time_frame += INT64_C(1000000);
/* wait based on the frame rate */
for(;;) {
curtime = av_gettime();
delay = s->time_frame * s->time_base.num / s->time_base.den - curtime;
if (delay <= 0) {
if (delay < INT64_C(-1000000) * s->time_base.num / s->time_base.den) {
/* printf("grabbing is %d frames late (dropping)\n", (int) -(delay / 16666)); */
s->time_frame += INT64_C(1000000);
}
break;
}
ts.tv_sec = delay / 1000000;
ts.tv_nsec = (delay % 1000000) * 1000;
nanosleep(&ts, NULL);
}
if (av_new_packet(pkt, s->frame_size) < 0)
return AVERROR(EIO);
pkt->pts = curtime;
/* read one frame */
if (s->use_mmap) {
return v4l_mm_read_picture(s, pkt->data);
} else {
if (read(s->fd, pkt->data, pkt->size) != pkt->size)
return AVERROR(EIO);
return s->frame_size;
}
}
static int grab_read_close(AVFormatContext *s1)
{
VideoData *s = s1->priv_data;
if (s->use_mmap)
munmap(s->video_buf, s->gb_buffers.size);
/* mute audio. we must force it because the BTTV driver does not
return its state correctly */
s->audio_saved.flags |= VIDEO_AUDIO_MUTE;
ioctl(s->fd, VIDIOCSAUDIO, &s->audio_saved);
close(s->fd);
return 0;
}
AVInputFormat ff_v4l_demuxer = {
"video4linux",
NULL_IF_CONFIG_SMALL("Video4Linux device grab"),
sizeof(VideoData),
NULL,
grab_read_header,
grab_read_packet,
grab_read_close,
.flags = AVFMT_NOFILE,
};
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