v4l.c File Reference

#include "config.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>
#include <linux/videodev.h>
#include <time.h>

Go to the source code of this file.

Data Structures
struct	VideoData
Defines
#define	_LINUX_TIME_H   1
Functions
static int	grab_read_header (AVFormatContext *s1, AVFormatParameters *ap)
static int	v4l_mm_read_picture (VideoData *s, uint8_t *buf)
static int	grab_read_packet (AVFormatContext *s1, AVPacket *pkt)
static int	grab_read_close (AVFormatContext *s1)
Variables
struct {
int   palette
int   depth
enum PixelFormat   pix_fmt
}	video_formats []
AVInputFormat	v4l_demuxer

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Define Documentation

#define _LINUX_TIME_H   1

Definition at line 30 of file v4l.c.

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Function Documentation

static int grab_read_close

(

AVFormatContext *

s1

)

[static]

Definition at line 330 of file v4l.c.

References VideoData::audio_saved, VideoData::fd, VideoData::gb_buffers, s1, VideoData::use_mmap, and VideoData::video_buf.

{
    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;
}

static int grab_read_header	(	AVFormatContext *	s1,
		AVFormatParameters *	ap
	)			[static]

Definition at line 67 of file v4l.c.

References av_log(), AV_LOG_ERROR, av_new_stream(), av_set_pts_info(), AVERROR, AVRational::den, VideoData::frame_rate, frame_rate, VideoData::frame_rate_base, VideoData::height, AVFormatParameters::height, height, AVRational::num, AVFormatParameters::pix_fmt, s1, AVFormatParameters::time_base, VideoData::video_cap, video_formats, VideoData::width, AVFormatParameters::width, and width.

{
    VideoData *s = s1->priv_data;
    AVStream *st;
    int width, height;
    int video_fd, frame_size;
    int ret, frame_rate, frame_rate_base;
    int desired_palette, desired_depth;
    struct video_tuner tuner;
    struct video_audio audio;
    struct video_picture pict;
    int j;
    int vformat_num = sizeof(video_formats) / sizeof(video_formats[0]);

    if (ap->width <= 0 || ap->height <= 0 || ap->time_base.den <= 0) {
        av_log(s1, AV_LOG_ERROR, "Bad capture size (%dx%d) or wrong time base (%d)\n",
            ap->width, ap->height, ap->time_base.den);

        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, "Capture size is out of range: %dx%d\n",
            width, height);

        return -1;
    }

    st = av_new_stream(s1, 0);
    if (!st)
        return AVERROR(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_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;
    }

    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 || (ret = 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;
    }

    ret = ioctl(video_fd,VIDIOCGMBUF,&s->gb_buffers);
    if (ret < 0) {
        /* try to use read based access */
        struct video_window win;
        int val;

        win.x = 0;
        win.y = 0;
        win.width = width;
        win.height = height;
        win.chromakey = -1;
        win.flags = 0;

        ioctl(video_fd, VIDIOCSWIN, &win);

        s->frame_format = pict.palette;

        val = 1;
        ioctl(video_fd, VIDIOCCAPTURE, &val);

        s->time_frame = av_gettime() * s->frame_rate / s->frame_rate_base;
        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->frame_rate / s->frame_rate_base;

        /* start to grab the first frame */
        s->gb_buf.frame = s->gb_frame % s->gb_buffers.frames;
        s->gb_buf.height = height;
        s->gb_buf.width = width;
        s->gb_buf.format = pict.palette;

        ret = ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
        if (ret < 0) {
            if (errno != EAGAIN) {
            fail1:
                av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not support suitable format\n");
            } 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) {
            frame_size = width * 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;
    s->frame_size = frame_size;

    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 = 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 grab_read_packet	(	AVFormatContext *	s1,
		AVPacket *	pkt
	)			[static]

Definition at line 290 of file v4l.c.

References av_gettime(), VideoData::frame_rate, VideoData::frame_rate_base, NULL, s1, and VideoData::time_frame.

{
    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->frame_rate_base / s->frame_rate - curtime;
        if (delay <= 0) {
            if (delay < INT64_C(-1000000) * s->frame_rate_base / s->frame_rate) {
                /* 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 v4l_mm_read_picture	(	VideoData *	s,
		uint8_t *	buf
	)			[static]

Definition at line 264 of file v4l.c.

References av_log(), AV_LOG_ERROR, AVERROR, VideoData::fd, VideoData::frame_size, VideoData::gb_buf, VideoData::gb_buffers, VideoData::gb_frame, NULL, and VideoData::video_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;
}

---

Variable Documentation

int depth

Definition at line 53 of file v4l.c.

Referenced by bmp_decode_frame(), decode_frame(), decode_macroblock(), dvbsub_parse_clut_segment(), encode_frame(), ff_pnm_decode_header(), flic_decode_init(), guess_mv(), pam_encode_frame(), sunrast_decode_frame(), targa_decode_rle(), tta_decode_frame(), and txd_decode_frame().

int palette

Definition at line 52 of file v4l.c.

Referenced by avs_read_packet(), decode_frame(), encode_frame(), get_alpha_info_pal8(), gif_read_image(), pcx_decode_frame(), seqvideo_decode(), set_palette(), and txd_decode_frame().

enum PixelFormat pix_fmt

Definition at line 54 of file v4l.c.

Referenced by dc1394_read_common(), and yuv4_read_header().

AVInputFormat v4l_demuxer

Initial value:

 {
    "video4linux",
    NULL_IF_CONFIG_SMALL("video grab"),
    sizeof(VideoData),
    NULL,
    grab_read_header,
    grab_read_packet,
    grab_read_close,
    .flags = AVFMT_NOFILE,
}

Definition at line 346 of file v4l.c.

struct { ... } video_formats[] [static]

Referenced by grab_read_header().

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