Libav 0.7.1
libavdevice/dv1394.c
Go to the documentation of this file.
00001 /*
00002  * Linux DV1394 interface
00003  * Copyright (c) 2003 Max Krasnyansky <maxk@qualcomm.com>
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "config.h"
00023 #include <unistd.h>
00024 #include <fcntl.h>
00025 #include <errno.h>
00026 #include <poll.h>
00027 #include <sys/ioctl.h>
00028 #include <sys/mman.h>
00029 #include <sys/time.h>
00030 #include <time.h>
00031 #include <strings.h>
00032 
00033 #include "libavutil/log.h"
00034 #include "libavutil/opt.h"
00035 #include "libavformat/avformat.h"
00036 #include "libavformat/dv.h"
00037 #include "dv1394.h"
00038 
00039 struct dv1394_data {
00040     AVClass *class;
00041     int fd;
00042     int channel;
00043     int format;
00044 
00045     uint8_t *ring; /* Ring buffer */
00046     int index;  /* Current frame index */
00047     int avail;  /* Number of frames available for reading */
00048     int done;   /* Number of completed frames */
00049 
00050     DVDemuxContext* dv_demux; /* Generic DV muxing/demuxing context */
00051 };
00052 
00053 /*
00054  * The trick here is to kludge around well known problem with kernel Ooopsing
00055  * when you try to capture PAL on a device node configure for NTSC. That's
00056  * why we have to configure the device node for PAL, and then read only NTSC
00057  * amount of data.
00058  */
00059 static int dv1394_reset(struct dv1394_data *dv)
00060 {
00061     struct dv1394_init init;
00062 
00063     init.channel     = dv->channel;
00064     init.api_version = DV1394_API_VERSION;
00065     init.n_frames    = DV1394_RING_FRAMES;
00066     init.format      = DV1394_PAL;
00067 
00068     if (ioctl(dv->fd, DV1394_INIT, &init) < 0)
00069         return -1;
00070 
00071     dv->avail  = dv->done = 0;
00072     return 0;
00073 }
00074 
00075 static int dv1394_start(struct dv1394_data *dv)
00076 {
00077     /* Tell DV1394 driver to enable receiver */
00078     if (ioctl(dv->fd, DV1394_START_RECEIVE, 0) < 0) {
00079         av_log(NULL, AV_LOG_ERROR, "Failed to start receiver: %s\n", strerror(errno));
00080         return -1;
00081     }
00082     return 0;
00083 }
00084 
00085 static int dv1394_read_header(AVFormatContext * context, AVFormatParameters * ap)
00086 {
00087     struct dv1394_data *dv = context->priv_data;
00088 
00089     dv->dv_demux = dv_init_demux(context);
00090     if (!dv->dv_demux)
00091         goto failed;
00092 
00093 #if FF_API_FORMAT_PARAMETERS
00094     if (ap->standard) {
00095        if (!strcasecmp(ap->standard, "pal"))
00096            dv->format = DV1394_PAL;
00097        else
00098            dv->format = DV1394_NTSC;
00099     }
00100 
00101     if (ap->channel)
00102         dv->channel = ap->channel;
00103 #endif
00104 
00105     /* Open and initialize DV1394 device */
00106     dv->fd = open(context->filename, O_RDONLY);
00107     if (dv->fd < 0) {
00108         av_log(context, AV_LOG_ERROR, "Failed to open DV interface: %s\n", strerror(errno));
00109         goto failed;
00110     }
00111 
00112     if (dv1394_reset(dv) < 0) {
00113         av_log(context, AV_LOG_ERROR, "Failed to initialize DV interface: %s\n", strerror(errno));
00114         goto failed;
00115     }
00116 
00117     dv->ring = mmap(NULL, DV1394_PAL_FRAME_SIZE * DV1394_RING_FRAMES,
00118                     PROT_READ, MAP_PRIVATE, dv->fd, 0);
00119     if (dv->ring == MAP_FAILED) {
00120         av_log(context, AV_LOG_ERROR, "Failed to mmap DV ring buffer: %s\n", strerror(errno));
00121         goto failed;
00122     }
00123 
00124     if (dv1394_start(dv) < 0)
00125         goto failed;
00126 
00127     return 0;
00128 
00129 failed:
00130     close(dv->fd);
00131     return AVERROR(EIO);
00132 }
00133 
00134 static int dv1394_read_packet(AVFormatContext *context, AVPacket *pkt)
00135 {
00136     struct dv1394_data *dv = context->priv_data;
00137     int size;
00138 
00139     size = dv_get_packet(dv->dv_demux, pkt);
00140     if (size > 0)
00141         return size;
00142 
00143     if (!dv->avail) {
00144         struct dv1394_status s;
00145         struct pollfd p;
00146 
00147         if (dv->done) {
00148             /* Request more frames */
00149             if (ioctl(dv->fd, DV1394_RECEIVE_FRAMES, dv->done) < 0) {
00150                 /* This usually means that ring buffer overflowed.
00151                  * We have to reset :(.
00152                  */
00153 
00154                 av_log(context, AV_LOG_ERROR, "DV1394: Ring buffer overflow. Reseting ..\n");
00155 
00156                 dv1394_reset(dv);
00157                 dv1394_start(dv);
00158             }
00159             dv->done = 0;
00160         }
00161 
00162         /* Wait until more frames are available */
00163 restart_poll:
00164         p.fd = dv->fd;
00165         p.events = POLLIN | POLLERR | POLLHUP;
00166         if (poll(&p, 1, -1) < 0) {
00167             if (errno == EAGAIN || errno == EINTR)
00168                 goto restart_poll;
00169             av_log(context, AV_LOG_ERROR, "Poll failed: %s\n", strerror(errno));
00170             return AVERROR(EIO);
00171         }
00172 
00173         if (ioctl(dv->fd, DV1394_GET_STATUS, &s) < 0) {
00174             av_log(context, AV_LOG_ERROR, "Failed to get status: %s\n", strerror(errno));
00175             return AVERROR(EIO);
00176         }
00177         av_dlog(context, "DV1394: status\n"
00178                 "\tactive_frame\t%d\n"
00179                 "\tfirst_clear_frame\t%d\n"
00180                 "\tn_clear_frames\t%d\n"
00181                 "\tdropped_frames\t%d\n",
00182                 s.active_frame, s.first_clear_frame,
00183                 s.n_clear_frames, s.dropped_frames);
00184 
00185         dv->avail = s.n_clear_frames;
00186         dv->index = s.first_clear_frame;
00187         dv->done  = 0;
00188 
00189         if (s.dropped_frames) {
00190             av_log(context, AV_LOG_ERROR, "DV1394: Frame drop detected (%d). Reseting ..\n",
00191                     s.dropped_frames);
00192 
00193             dv1394_reset(dv);
00194             dv1394_start(dv);
00195         }
00196     }
00197 
00198     av_dlog(context, "index %d, avail %d, done %d\n", dv->index, dv->avail,
00199             dv->done);
00200 
00201     size = dv_produce_packet(dv->dv_demux, pkt,
00202                              dv->ring + (dv->index * DV1394_PAL_FRAME_SIZE),
00203                              DV1394_PAL_FRAME_SIZE);
00204     dv->index = (dv->index + 1) % DV1394_RING_FRAMES;
00205     dv->done++; dv->avail--;
00206 
00207     return size;
00208 }
00209 
00210 static int dv1394_close(AVFormatContext * context)
00211 {
00212     struct dv1394_data *dv = context->priv_data;
00213 
00214     /* Shutdown DV1394 receiver */
00215     if (ioctl(dv->fd, DV1394_SHUTDOWN, 0) < 0)
00216         av_log(context, AV_LOG_ERROR, "Failed to shutdown DV1394: %s\n", strerror(errno));
00217 
00218     /* Unmap ring buffer */
00219     if (munmap(dv->ring, DV1394_NTSC_FRAME_SIZE * DV1394_RING_FRAMES) < 0)
00220         av_log(context, AV_LOG_ERROR, "Failed to munmap DV1394 ring buffer: %s\n", strerror(errno));
00221 
00222     close(dv->fd);
00223     av_free(dv->dv_demux);
00224 
00225     return 0;
00226 }
00227 
00228 static const AVOption options[] = {
00229     { "standard", "", offsetof(struct dv1394_data, format), FF_OPT_TYPE_INT, {.dbl = DV1394_NTSC}, DV1394_PAL, DV1394_NTSC, AV_OPT_FLAG_DECODING_PARAM, "standard" },
00230     { "PAL",      "", 0, FF_OPT_TYPE_CONST, {.dbl = DV1394_PAL},   0, 0, AV_OPT_FLAG_DECODING_PARAM, "standard" },
00231     { "NTSC",     "", 0, FF_OPT_TYPE_CONST, {.dbl = DV1394_NTSC},  0, 0, AV_OPT_FLAG_DECODING_PARAM, "standard" },
00232     { "channel",  "", offsetof(struct dv1394_data, channel), FF_OPT_TYPE_INT, {.dbl = DV1394_DEFAULT_CHANNEL}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
00233     { NULL },
00234 };
00235 
00236 static const AVClass dv1394_class = {
00237     .class_name = "DV1394 indev",
00238     .item_name  = av_default_item_name,
00239     .option     = options,
00240     .version    = LIBAVUTIL_VERSION_INT,
00241 };
00242 
00243 AVInputFormat ff_dv1394_demuxer = {
00244     .name           = "dv1394",
00245     .long_name      = NULL_IF_CONFIG_SMALL("DV1394 A/V grab"),
00246     .priv_data_size = sizeof(struct dv1394_data),
00247     .read_header    = dv1394_read_header,
00248     .read_packet    = dv1394_read_packet,
00249     .read_close     = dv1394_close,
00250     .flags          = AVFMT_NOFILE,
00251     .priv_class     = &dv1394_class,
00252 };