PeerStreamer

/*

 * Linux DV1394 interface

 * Copyright (c) 2003 Max Krasnyansky <maxk@qualcomm.com>

 *

 * 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 <unistd.h>

#include <fcntl.h>

#include <errno.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <sys/poll.h>

#include <sys/time.h>

#include <time.h>

#include "avformat.h"

#undef DV1394_DEBUG

#include "dv1394.h"

#include "dv.h"

struct dv1394_data {

    int fd;

    int channel;

    int format;

    void *ring; /* Ring buffer */

    int index;  /* Current frame index */

    int avail;  /* Number of frames available for reading */

    int done;   /* Number of completed frames */

    DVDemuxContext* dv_demux; /* Generic DV muxing/demuxing context */

};

/*

 * The trick here is to kludge around well known problem with kernel Ooopsing

 * when you try to capture PAL on a device node configure for NTSC. That's

 * why we have to configure the device node for PAL, and then read only NTSC

 * amount of data.

 */

static int dv1394_reset(struct dv1394_data *dv)

{

    struct dv1394_init init;

    init.channel     = dv->channel;

    init.api_version = DV1394_API_VERSION;

    init.n_frames    = DV1394_RING_FRAMES;

    init.format      = DV1394_PAL;

    if (ioctl(dv->fd, DV1394_INIT, &init) < 0)

        return -1;

    dv->avail  = dv->done = 0;

    return 0;

}

static int dv1394_start(struct dv1394_data *dv)

{

    /* Tell DV1394 driver to enable receiver */

    if (ioctl(dv->fd, DV1394_START_RECEIVE, 0) < 0) {

        perror("Failed to start receiver");

        return -1;

    }

    return 0;

}

static int dv1394_read_header(AVFormatContext * context, AVFormatParameters * ap)

{

    struct dv1394_data *dv = context->priv_data;

    const char *video_device;

    dv->dv_demux = dv_init_demux(context);

    if (!dv->dv_demux)

        goto failed;

    if (ap->standard && !strcasecmp(ap->standard, "pal"))

        dv->format = DV1394_PAL;

    else

        dv->format = DV1394_NTSC;

    if (ap->channel)

        dv->channel = ap->channel;

    else

        dv->channel = DV1394_DEFAULT_CHANNEL;

    /* Open and initialize DV1394 device */

    video_device = ap->device;

    if (!video_device)

        video_device = "/dev/dv1394/0";

    dv->fd = open(video_device, O_RDONLY);

    if (dv->fd < 0) {

        perror("Failed to open DV interface");

        goto failed;

    }

    if (dv1394_reset(dv) < 0) {

        perror("Failed to initialize DV interface");

        goto failed;

    }

    dv->ring = mmap(NULL, DV1394_PAL_FRAME_SIZE * DV1394_RING_FRAMES,

                    PROT_READ, MAP_PRIVATE, dv->fd, 0);

    if (dv->ring == MAP_FAILED) {

        perror("Failed to mmap DV ring buffer");

        goto failed;

    }

    if (dv1394_start(dv) < 0)

        goto failed;

    return 0;

failed:

    close(dv->fd);

    return AVERROR_IO;

}

static int dv1394_read_packet(AVFormatContext *context, AVPacket *pkt)

{

    struct dv1394_data *dv = context->priv_data;

    int size;

    size = dv_get_packet(dv->dv_demux, pkt);

    if (size > 0)

        return size;

    if (!dv->avail) {

        struct dv1394_status s;

        struct pollfd p;

        if (dv->done) {

            /* Request more frames */

            if (ioctl(dv->fd, DV1394_RECEIVE_FRAMES, dv->done) < 0) {

                /* This usually means that ring buffer overflowed.

                 * We have to reset :(.

                 */

                av_log(context, AV_LOG_ERROR, "DV1394: Ring buffer overflow. Reseting ..\n");

                dv1394_reset(dv);

                dv1394_start(dv);

            }

            dv->done = 0;

        }

        /* Wait until more frames are available */

restart_poll:

        p.fd = dv->fd;

        p.events = POLLIN | POLLERR | POLLHUP;

        if (poll(&p, 1, -1) < 0) {

            if (errno == EAGAIN || errno == EINTR)

                goto restart_poll;

            perror("Poll failed");

            return AVERROR_IO;

        }

        if (ioctl(dv->fd, DV1394_GET_STATUS, &s) < 0) {

            perror("Failed to get status");

            return AVERROR_IO;

        }

#ifdef DV1394_DEBUG

        fprintf(stderr, "DV1394: status\n"

                "\tactive_frame\t%d\n"

                "\tfirst_clear_frame\t%d\n"

                "\tn_clear_frames\t%d\n"

                "\tdropped_frames\t%d\n",

                s.active_frame, s.first_clear_frame,

                s.n_clear_frames, s.dropped_frames);

#endif

        dv->avail = s.n_clear_frames;

        dv->index = s.first_clear_frame;

        dv->done  = 0;

        if (s.dropped_frames) {

            av_log(context, AV_LOG_ERROR, "DV1394: Frame drop detected (%d). Reseting ..\n",

                    s.dropped_frames);

            dv1394_reset(dv);

            dv1394_start(dv);

        }

    }

#ifdef DV1394_DEBUG

    fprintf(stderr, "index %d, avail %d, done %d\n", dv->index, dv->avail,

            dv->done);

#endif

    size = dv_produce_packet(dv->dv_demux, pkt,

                             dv->ring + (dv->index * DV1394_PAL_FRAME_SIZE),

                             DV1394_PAL_FRAME_SIZE);

    dv->index = (dv->index + 1) % DV1394_RING_FRAMES;

    dv->done++; dv->avail--;

    return size;

}

static int dv1394_close(AVFormatContext * context)

{

    struct dv1394_data *dv = context->priv_data;

    /* Shutdown DV1394 receiver */

    if (ioctl(dv->fd, DV1394_SHUTDOWN, 0) < 0)

        perror("Failed to shutdown DV1394");

    /* Unmap ring buffer */

    if (munmap(dv->ring, DV1394_NTSC_FRAME_SIZE * DV1394_RING_FRAMES) < 0)

        perror("Failed to munmap DV1394 ring buffer");

    close(dv->fd);

    av_free(dv->dv_demux);

    return 0;

}

static AVInputFormat dv1394_format = {

    .name           = "dv1394",

    .long_name      = "dv1394 A/V grab",

    .priv_data_size = sizeof(struct dv1394_data),

    .read_header    = dv1394_read_header,

    .read_packet    = dv1394_read_packet,

    .read_close     = dv1394_close,

    .flags          = AVFMT_NOFILE

};

int dv1394_init(void)

{

    av_register_input_format(&dv1394_format);

    return 0;

}