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libavdevice/dv1394.c

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00001 /*
00002  * Linux DV1394 interface
00003  * Copyright (c) 2003 Max Krasnyansky <maxk@qualcomm.com>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "libavformat/avformat.h"
00034 
00035 #undef DV1394_DEBUG
00036 
00037 #include "libavformat/dv.h"
00038 #include "dv1394.h"
00039 
00040 struct dv1394_data {
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 (ap->standard && !strcasecmp(ap->standard, "pal"))
00094         dv->format = DV1394_PAL;
00095     else
00096         dv->format = DV1394_NTSC;
00097 
00098     if (ap->channel)
00099         dv->channel = ap->channel;
00100     else
00101         dv->channel = DV1394_DEFAULT_CHANNEL;
00102 
00103     /* Open and initialize DV1394 device */
00104     dv->fd = open(context->filename, O_RDONLY);
00105     if (dv->fd < 0) {
00106         av_log(context, AV_LOG_ERROR, "Failed to open DV interface: %s\n", strerror(errno));
00107         goto failed;
00108     }
00109 
00110     if (dv1394_reset(dv) < 0) {
00111         av_log(context, AV_LOG_ERROR, "Failed to initialize DV interface: %s\n", strerror(errno));
00112         goto failed;
00113     }
00114 
00115     dv->ring = mmap(NULL, DV1394_PAL_FRAME_SIZE * DV1394_RING_FRAMES,
00116                     PROT_READ, MAP_PRIVATE, dv->fd, 0);
00117     if (dv->ring == MAP_FAILED) {
00118         av_log(context, AV_LOG_ERROR, "Failed to mmap DV ring buffer: %s\n", strerror(errno));
00119         goto failed;
00120     }
00121 
00122     if (dv1394_start(dv) < 0)
00123         goto failed;
00124 
00125     return 0;
00126 
00127 failed:
00128     close(dv->fd);
00129     return AVERROR(EIO);
00130 }
00131 
00132 static int dv1394_read_packet(AVFormatContext *context, AVPacket *pkt)
00133 {
00134     struct dv1394_data *dv = context->priv_data;
00135     int size;
00136 
00137     size = dv_get_packet(dv->dv_demux, pkt);
00138     if (size > 0)
00139         return size;
00140 
00141     if (!dv->avail) {
00142         struct dv1394_status s;
00143         struct pollfd p;
00144 
00145         if (dv->done) {
00146             /* Request more frames */
00147             if (ioctl(dv->fd, DV1394_RECEIVE_FRAMES, dv->done) < 0) {
00148                 /* This usually means that ring buffer overflowed.
00149                  * We have to reset :(.
00150                  */
00151 
00152                 av_log(context, AV_LOG_ERROR, "DV1394: Ring buffer overflow. Reseting ..\n");
00153 
00154                 dv1394_reset(dv);
00155                 dv1394_start(dv);
00156             }
00157             dv->done = 0;
00158         }
00159 
00160         /* Wait until more frames are available */
00161 restart_poll:
00162         p.fd = dv->fd;
00163         p.events = POLLIN | POLLERR | POLLHUP;
00164         if (poll(&p, 1, -1) < 0) {
00165             if (errno == EAGAIN || errno == EINTR)
00166                 goto restart_poll;
00167             av_log(context, AV_LOG_ERROR, "Poll failed: %s\n", strerror(errno));
00168             return AVERROR(EIO);
00169         }
00170 
00171         if (ioctl(dv->fd, DV1394_GET_STATUS, &s) < 0) {
00172             av_log(context, AV_LOG_ERROR, "Failed to get status: %s\n", strerror(errno));
00173             return AVERROR(EIO);
00174         }
00175 #ifdef DV1394_DEBUG
00176         av_log(context, AV_LOG_DEBUG, "DV1394: status\n"
00177                 "\tactive_frame\t%d\n"
00178                 "\tfirst_clear_frame\t%d\n"
00179                 "\tn_clear_frames\t%d\n"
00180                 "\tdropped_frames\t%d\n",
00181                 s.active_frame, s.first_clear_frame,
00182                 s.n_clear_frames, s.dropped_frames);
00183 #endif
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 #ifdef DV1394_DEBUG
00199     av_log(context, AV_LOG_DEBUG, "index %d, avail %d, done %d\n", dv->index, dv->avail,
00200             dv->done);
00201 #endif
00202 
00203     size = dv_produce_packet(dv->dv_demux, pkt,
00204                              dv->ring + (dv->index * DV1394_PAL_FRAME_SIZE),
00205                              DV1394_PAL_FRAME_SIZE);
00206     dv->index = (dv->index + 1) % DV1394_RING_FRAMES;
00207     dv->done++; dv->avail--;
00208 
00209     return size;
00210 }
00211 
00212 static int dv1394_close(AVFormatContext * context)
00213 {
00214     struct dv1394_data *dv = context->priv_data;
00215 
00216     /* Shutdown DV1394 receiver */
00217     if (ioctl(dv->fd, DV1394_SHUTDOWN, 0) < 0)
00218         av_log(context, AV_LOG_ERROR, "Failed to shutdown DV1394: %s\n", strerror(errno));
00219 
00220     /* Unmap ring buffer */
00221     if (munmap(dv->ring, DV1394_NTSC_FRAME_SIZE * DV1394_RING_FRAMES) < 0)
00222         av_log(context, AV_LOG_ERROR, "Failed to munmap DV1394 ring buffer: %s\n", strerror(errno));
00223 
00224     close(dv->fd);
00225     av_free(dv->dv_demux);
00226 
00227     return 0;
00228 }
00229 
00230 AVInputFormat dv1394_demuxer = {
00231     .name           = "dv1394",
00232     .long_name      = NULL_IF_CONFIG_SMALL("DV1394 A/V grab"),
00233     .priv_data_size = sizeof(struct dv1394_data),
00234     .read_header    = dv1394_read_header,
00235     .read_packet    = dv1394_read_packet,
00236     .read_close     = dv1394_close,
00237     .flags          = AVFMT_NOFILE
00238 };

Generated on Fri Sep 16 2011 17:17:47 for FFmpeg by  doxygen 1.7.1