ffmpeg/libavformat/dv1394.c

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/*
* Linux DV1394 interface
* Copyright (c) 2003 Max Krasnyansky <maxk@qualcomm.com>
*
* 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
*/
#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;
uint8_t *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;
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 */
dv->fd = open(context->filename, 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
av_log(context, AV_LOG_DEBUG, "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
av_log(context, AV_LOG_DEBUG, "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;
}
AVInputFormat dv1394_demuxer = {
.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
};