dv1394.c 6.84 KB
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/*
 * Linux DV1394 interface
 * Copyright (c) 2003 Max Krasnyansky <maxk@qualcomm.com>
 *
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 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * 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
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */

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#include "config.h"
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#include <unistd.h>
#include <fcntl.h>
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#include <errno.h>
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#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <sys/time.h>
#include <time.h>
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#include <strings.h>
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#include "libavformat/avformat.h"
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#undef DV1394_DEBUG

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#include "libavformat/dv.h"
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#include "dv1394.h"

struct dv1394_data {
    int fd;
    int channel;
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    int format;
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    uint8_t *ring; /* Ring buffer */
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    int index;  /* Current frame index */
    int avail;  /* Number of frames available for reading */
    int done;   /* Number of completed frames */
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    DVDemuxContext* dv_demux; /* Generic DV muxing/demuxing context */
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};

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/*
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 * The trick here is to kludge around well known problem with kernel Ooopsing
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 * when you try to capture PAL on a device node configure for NTSC. That's
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 * why we have to configure the device node for PAL, and then read only NTSC
 * amount of data.
 */
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static int dv1394_reset(struct dv1394_data *dv)
{
    struct dv1394_init init;

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    init.channel     = dv->channel;
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    init.api_version = DV1394_API_VERSION;
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    init.n_frames    = DV1394_RING_FRAMES;
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    init.format      = DV1394_PAL;
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    if (ioctl(dv->fd, DV1394_INIT, &init) < 0)
        return -1;

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    dv->avail  = dv->done = 0;
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    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) {
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        av_log(NULL, AV_LOG_ERROR, "Failed to start receiver: %s\n", strerror(errno));
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        return -1;
    }
    return 0;
}

static int dv1394_read_header(AVFormatContext * context, AVFormatParameters * ap)
{
    struct dv1394_data *dv = context->priv_data;

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    dv->dv_demux = dv_init_demux(context);
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    if (!dv->dv_demux)
        goto failed;
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    if (ap->standard && !strcasecmp(ap->standard, "pal"))
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        dv->format = DV1394_PAL;
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    else
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        dv->format = DV1394_NTSC;
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    if (ap->channel)
        dv->channel = ap->channel;
    else
        dv->channel = DV1394_DEFAULT_CHANNEL;
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    /* Open and initialize DV1394 device */
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    dv->fd = open(context->filename, O_RDONLY);
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    if (dv->fd < 0) {
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        av_log(context, AV_LOG_ERROR, "Failed to open DV interface: %s\n", strerror(errno));
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        goto failed;
    }

    if (dv1394_reset(dv) < 0) {
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        av_log(context, AV_LOG_ERROR, "Failed to initialize DV interface: %s\n", strerror(errno));
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        goto failed;
    }

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    dv->ring = mmap(NULL, DV1394_PAL_FRAME_SIZE * DV1394_RING_FRAMES,
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                    PROT_READ, MAP_PRIVATE, dv->fd, 0);
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    if (dv->ring == MAP_FAILED) {
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        av_log(context, AV_LOG_ERROR, "Failed to mmap DV ring buffer: %s\n", strerror(errno));
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        goto failed;
    }

    if (dv1394_start(dv) < 0)
        goto failed;

    return 0;

failed:
    close(dv->fd);
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    return AVERROR(EIO);
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}

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static int dv1394_read_packet(AVFormatContext *context, AVPacket *pkt)
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{
    struct dv1394_data *dv = context->priv_data;
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    int size;

    size = dv_get_packet(dv->dv_demux, pkt);
    if (size > 0)
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        return size;
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    if (!dv->avail) {
        struct dv1394_status s;
        struct pollfd p;
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        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 :(.
                 */
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                av_log(context, AV_LOG_ERROR, "DV1394: Ring buffer overflow. Reseting ..\n");
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                dv1394_reset(dv);
                dv1394_start(dv);
            }
            dv->done = 0;
        }
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        /* Wait until more frames are available */
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restart_poll:
        p.fd = dv->fd;
        p.events = POLLIN | POLLERR | POLLHUP;
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        if (poll(&p, 1, -1) < 0) {
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            if (errno == EAGAIN || errno == EINTR)
                goto restart_poll;
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            av_log(context, AV_LOG_ERROR, "Poll failed: %s\n", strerror(errno));
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            return AVERROR(EIO);
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        }

        if (ioctl(dv->fd, DV1394_GET_STATUS, &s) < 0) {
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            av_log(context, AV_LOG_ERROR, "Failed to get status: %s\n", strerror(errno));
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            return AVERROR(EIO);
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        }
#ifdef DV1394_DEBUG
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        av_log(context, AV_LOG_DEBUG, "DV1394: status\n"
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                "\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;
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        dv->done  = 0;
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        if (s.dropped_frames) {
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            av_log(context, AV_LOG_ERROR, "DV1394: Frame drop detected (%d). Reseting ..\n",
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                    s.dropped_frames);

            dv1394_reset(dv);
            dv1394_start(dv);
        }
    }

#ifdef DV1394_DEBUG
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    av_log(context, AV_LOG_DEBUG, "index %d, avail %d, done %d\n", dv->index, dv->avail,
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            dv->done);
#endif

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    size = dv_produce_packet(dv->dv_demux, pkt,
                             dv->ring + (dv->index * DV1394_PAL_FRAME_SIZE),
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                             DV1394_PAL_FRAME_SIZE);
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    dv->index = (dv->index + 1) % DV1394_RING_FRAMES;
    dv->done++; dv->avail--;
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    return size;
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}

static int dv1394_close(AVFormatContext * context)
{
    struct dv1394_data *dv = context->priv_data;

    /* Shutdown DV1394 receiver */
    if (ioctl(dv->fd, DV1394_SHUTDOWN, 0) < 0)
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        av_log(context, AV_LOG_ERROR, "Failed to shutdown DV1394: %s\n", strerror(errno));
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    /* Unmap ring buffer */
    if (munmap(dv->ring, DV1394_NTSC_FRAME_SIZE * DV1394_RING_FRAMES) < 0)
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        av_log(context, AV_LOG_ERROR, "Failed to munmap DV1394 ring buffer: %s\n", strerror(errno));
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    close(dv->fd);
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    av_free(dv->dv_demux);
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    return 0;
}

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AVInputFormat dv1394_demuxer = {
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    .name           = "dv1394",
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    .long_name      = NULL_IF_CONFIG_SMALL("DV1394 A/V grab"),
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    .priv_data_size = sizeof(struct dv1394_data),
    .read_header    = dv1394_read_header,
    .read_packet    = dv1394_read_packet,
    .read_close     = dv1394_close,
    .flags          = AVFMT_NOFILE
};