dv patch by Max Krasnyansky (maxk at qualcomm dot com)

Originally committed as revision 1493 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -53,6 +53,7 @@ gprof="no"
 v4l="yes"
 audio_oss="yes"
 audio_beos="no"
+dv1394="yes"
 network="yes"
 zlib="yes"
 mp3lame="no"
@@ -103,6 +104,7 @@ SHFLAGS=-nostart
 # disable linux things
 audio_oss="no"
 v4l="no"
+dv1394="no"
 # enable beos things
 audio_beos="yes"
 # no need for libm, but the inet stuff
@@ -117,6 +119,7 @@ fi ;;
 SunOS)
 v4l="no"
 audio_oss="no"
+dv1394="no"
 make="gmake"
 LDFLAGS=""
 FFSLDFLAGS=""
@@ -126,12 +129,14 @@ extralibs="$extralibs -lsocket -lnsl"
 FreeBSD)
 v4l="no"
 audio_oss="yes"
+dv1394="no"
 make="gmake"
 LDFLAGS="$LDFLAGS -export-dynamic"
 ;;
 BSD/OS)
 v4l="no"
 audio_oss="yes"
+dv1394="no"
 extralibs="-lpoll -lgnugetopt -lm"
 make="gmake"
 ;;
@@ -139,6 +144,7 @@ Darwin)
 cc="cc"
 v4l="no"
 audio_oss="no"
+dv1394="no"
 SHFLAGS="-dynamiclib"
 extralibs=""
 darwin="yes"
@@ -158,6 +164,7 @@ esac
 MINGW32*)
 v4l="no"
 audio_oss="no"
+dv1394="no"
 ffserver="no"
 network="no"
 mingw32="yes"
@@ -165,6 +172,7 @@ mingw32="yes"
 CYGWIN*)
 v4l="no"
 audio_oss="yes"
+dv1394="no"
 extralibs=""
 cygwin="yes"
 test -f /usr/include/inttypes.h || \
@@ -190,6 +198,7 @@ SLIBSUF=".dll"
 extralibs=""
 v4l="no"
 audio_oss="no"
+dv1394="no"
 network="no"
 ffserver="no"
 os2="yes"
@@ -287,6 +296,8 @@ for opt do
   ;;
   --disable-audio-beos) audio_beos="no"
   ;;
+  --disable-dv1394) dv1394="no"
+  ;;
   --disable-network) network="no"
   ;;
   --disable-zlib) zlib="no"
@@ -375,6 +386,7 @@ if test "$win32" = "yes" ; then
     cross_prefix="i386-mingw32msvc-"
     v4l="no"
     audio_oss="no"
+    dv1394="no"
     network="no"
 fi
 
@@ -382,6 +394,7 @@ if test "$mingw32" = "yes" ; then
     cross_prefix=""
     v4l="no"
     audio_oss="no"
+    dv1394="no"
     network="no"
 fi
 
@@ -543,6 +556,7 @@ echo "  --disable-altivec        disable AltiVec usage"
 echo "  --disable-audio-oss      disable OSS audio support [default=no]"
 echo "  --disable-audio-beos     disable BeOS audio support [default=no]"
 echo "  --disable-v4l            disable video4linux grabbing [default=no]"
+echo "  --disable-dv1394         disable DV1394 grabbing [default=no]"
 echo "  --disable-network        disable network support [default=no]"
 echo "  --disable-zlib           disable zlib [default=no]"
 echo "  --disable-simple_idct    disable simple IDCT routines [default=no]"
@@ -705,6 +719,11 @@ if test "$v4l" = "yes" ; then
   echo "CONFIG_VIDEO4LINUX=yes" >> config.mak
 fi
 
+if test "$dv1394" = "yes" ; then
+  echo "#define CONFIG_DV1394 1" >> $TMPH
+  echo "CONFIG_DV1394=yes" >> config.mak
+fi
+
 if test "$dlopen" = "yes" ; then
   echo "#define CONFIG_HAVE_DLOPEN 1" >> $TMPH
 fi

ffmpeg.c

@@ -158,14 +158,14 @@ static char *pass_logfilename = NULL;
 static int audio_stream_copy = 0;
 static int video_stream_copy = 0;
 
+static char *video_grab_format = "video4linux";
+static char *audio_grab_format = "audio_device";
+
 #define DEFAULT_PASS_LOGFILENAME "ffmpeg2pass"
 
 #if !defined(CONFIG_AUDIO_OSS) && !defined(CONFIG_AUDIO_BEOS)
 const char *audio_device = "none";
 #endif
-#ifndef CONFIG_VIDEO4LINUX
-const char *v4l_device = "none";
-#endif
 
 typedef struct AVOutputStream {
     int file_index;          /* file index */
@@ -1870,7 +1870,7 @@ void opt_audio_channels(const char *arg)
 
 void opt_video_device(const char *arg)
 {
-    v4l_device = strdup(arg);
+    video_device = strdup(arg);
 }
 
 void opt_audio_device(const char *arg)
@@ -1878,6 +1878,12 @@ void opt_audio_device(const char *arg)
     audio_device = strdup(arg);
 }
 
+void opt_dv1394(const char *arg)
+{
+    video_grab_format = "dv1394";
+    audio_grab_format = "none";
+}
+
 void opt_audio_codec(const char *arg)
 {
     AVCodec *p;
@@ -2455,7 +2461,7 @@ void prepare_grab(void)
     
     if (has_video) {
         AVInputFormat *fmt1;
-        fmt1 = av_find_input_format("video_grab_device");
+        fmt1 = av_find_input_format(video_grab_format);
         if (av_open_input_file(&ic, "", fmt1, 0, ap) < 0) {
             fprintf(stderr, "Could not find video grab device\n");
             exit(1);
@@ -2463,12 +2469,12 @@ void prepare_grab(void)
         /* by now video grab has one stream */
         ic->streams[0]->r_frame_rate = ap->frame_rate;
         input_files[nb_input_files] = ic;
-        dump_format(ic, nb_input_files, v4l_device, 0);
+        dump_format(ic, nb_input_files, video_device, 0);
         nb_input_files++;
     }
     if (has_audio) {
         AVInputFormat *fmt1;
-        fmt1 = av_find_input_format("audio_device");
+        fmt1 = av_find_input_format(audio_grab_format);
         if (av_open_input_file(&ic, "", fmt1, 0, ap) < 0) {
             fprintf(stderr, "Could not find audio grab device\n");
             exit(1);
@@ -2692,6 +2698,7 @@ const OptionDef options[] = {
     { "minrate", HAS_ARG, {(void*)opt_video_bitrate_min}, "set min video bitrate tolerance (in kbit/s)", "bitrate" },
     { "bufsize", HAS_ARG, {(void*)opt_video_buffer_size}, "set ratecontrol buffere size (in kbit)", "size" },
     { "vd", HAS_ARG | OPT_EXPERT, {(void*)opt_video_device}, "set video grab device", "device" },
+    { "dv1394", OPT_EXPERT, {(void*)opt_dv1394}, "set DV1394 options", "[channel]" },
     { "vcodec", HAS_ARG | OPT_EXPERT, {(void*)opt_video_codec}, "force video codec ('copy' to copy stream)", "codec" },
     { "me", HAS_ARG | OPT_EXPERT, {(void*)opt_motion_estimation}, "set motion estimation method", 
       "method" },

libavformat/Makefile

@@ -28,6 +28,10 @@ ifeq ($(CONFIG_VIDEO4LINUX),yes)
 OBJS+= grab.o
 endif
 
+ifeq ($(CONFIG_DV1394),yes)
+OBJS+= dv1394.o
+endif
+
 ifeq ($(CONFIG_AUDIO_OSS),yes)
 OBJS+= audio.o 
 endif

libavformat/allformats.c

@@ -21,6 +21,8 @@
 /* If you do not call this function, then you can select exactly which
    formats you want to support */
 
+char *video_device = "none";
+
 /**
  * Initialize libavcodec and register all the codecs and formats.
  */
@@ -62,6 +64,10 @@ void av_register_all(void)
     audio_init();
 #endif
 
+#ifdef CONFIG_DV1394
+    dv1394_init();
+#endif
+
     /* image formats */
     av_register_image_format(&pnm_image_format);
     av_register_image_format(&pbm_image_format);

libavformat/dv1394.c

+/*
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <unistd.h>
+#include <fcntl.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"
+
+int dv1394_channel = DV1394_DEFAULT_CHANNEL;
+
+struct dv1394_data {
+    int fd;
+    int channel;
+    int width, height;
+    int frame_rate;
+    int frame_size;
+
+    void *ring; /* Ring buffer */
+    int index;  /* Current frame index */
+    int avail;  /* Number of frames available for reading */
+    int done;   /* Number of completed frames */
+};
+
+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_NTSC;
+
+    if (ioctl(dv->fd, DV1394_INIT, &init) < 0)
+        return -1;
+
+    dv->avail = 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;
+    AVStream *st;
+
+    st = av_new_stream(context, 0);
+    if (!st)
+        return -ENOMEM;
+
+    dv->width   = DV1394_WIDTH;
+    dv->height  = DV1394_HEIGHT;
+    dv->channel = dv1394_channel;
+
+    dv->frame_rate = 30;
+
+    dv->frame_size = DV1394_NTSC_FRAME_SIZE;
+
+    /* Open and initialize DV1394 device */
+
+    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_NTSC_FRAME_SIZE * DV1394_RING_FRAMES,
+                    PROT_READ, MAP_PRIVATE, dv->fd, 0);
+    if (!dv->ring) {
+        perror("Failed to mmap DV ring buffer");
+        goto failed;
+    }
+
+    st->codec.codec_type = CODEC_TYPE_VIDEO;
+    st->codec.codec_id   = CODEC_ID_DVVIDEO;
+    st->codec.width      = dv->width;
+    st->codec.height     = dv->height;
+    st->codec.frame_rate = dv->frame_rate * FRAME_RATE_BASE;
+
+    st->codec.bit_rate   = 25000000;  /* Consumer DV is 25Mbps */
+
+    av_set_pts_info(context, 48, 1, 1000000);
+
+    if (dv1394_start(dv) < 0)
+        goto failed;
+
+    return 0;
+
+failed:
+    close(dv->fd);
+    av_free(st);
+    return -EIO;
+}
+
+static inline int __copy_frame(struct dv1394_data *dv, void *buf)
+{
+    char *ptr = dv->ring + (dv->index * dv->frame_size);
+
+    memcpy(buf, ptr, dv->frame_size);
+
+    dv->index = (dv->index + 1) % DV1394_RING_FRAMES;
+    dv->avail--;
+    dv->done++;
+
+    return dv->frame_size;
+}
+
+static int dv1394_read_packet(AVFormatContext * context, AVPacket * pkt)
+{
+    struct dv1394_data *dv = context->priv_data;
+    int len;
+
+    if (!dv->avail) {
+        struct dv1394_status s;
+        struct pollfd p;
+        p.fd = dv->fd;
+        p.events = POLLIN | POLLERR | POLLHUP;
+
+        /* Wait until more frames are available */
+        if (poll(&p, 1, -1) < 0) {
+            perror("Poll failed");
+            return -EIO;
+        }
+
+        if (ioctl(dv->fd, DV1394_GET_STATUS, &s) < 0) {
+            perror("Failed to get status");
+            return -EIO;
+        }
+#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) {
+            fprintf(stderr, "DV1394: Frame drop detected (%d). Reseting ..\n",
+                    s.dropped_frames);
+
+            dv1394_reset(dv);
+            dv1394_start(dv);
+        }
+    }
+
+    if (av_new_packet(pkt, dv->frame_size) < 0)
+        return -EIO;
+
+#ifdef DV1394_DEBUG
+    fprintf(stderr, "index %d, avail %d, done %d\n", dv->index, dv->avail,
+            dv->done);
+#endif
+
+    len = __copy_frame(dv, pkt->data);
+    pkt->pts = av_gettime() & ((1LL << 48) - 1);
+
+    if (!dv->avail && 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 :(.
+             */
+
+            fprintf(stderr, "DV1394: Ring buffer overflow. Reseting ..\n");
+
+            dv1394_reset(dv);
+            dv1394_start(dv);
+        }
+    }
+
+    return len;
+}
+
+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);
+
+    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;
+}

libavformat/dv1394.h

+/*
+ * dv1394.h - DV input/output over IEEE 1394 on OHCI chips
+ *   Copyright (C)2001 Daniel Maas <dmaas@dcine.com>
+ *     receive, proc_fs by Dan Dennedy <dan@dennedy.org>
+ *
+ * based on:
+ *   video1394.h - driver for OHCI 1394 boards
+ *   Copyright (C)1999,2000 Sebastien Rougeaux <sebastien.rougeaux@anu.edu.au>
+ *                          Peter Schlaile <udbz@rz.uni-karlsruhe.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _DV_1394_H
+#define _DV_1394_H
+
+#define DV1394_DEFAULT_CHANNEL 0x63
+#define DV1394_DEFAULT_CARD    0
+#define DV1394_RING_FRAMES     20
+
+#define DV1394_WIDTH  720
+#define DV1394_HEIGHT 480
+
+/* This is the public user-space interface. Try not to break it. */
+
+#define DV1394_API_VERSION 0x20011127
+
+/* ********************
+   **                **
+   **   DV1394 API   **
+   **                **
+   ********************
+
+   There are two methods of operating the DV1394 DV output device.
+
+   1)
+
+   The simplest is an interface based on write(): simply write
+   full DV frames of data to the device, and they will be transmitted
+   as quickly as possible. The FD may be set for non-blocking I/O,
+   in which case you can use select() or poll() to wait for output
+   buffer space.
+
+   To set the DV output parameters (e.g. whether you want NTSC or PAL
+   video), use the DV1394_INIT ioctl, passing in the parameters you
+   want in a struct dv1394_init.
+ 
+   Example 1:
+         To play a raw .DV file:   cat foo.DV > /dev/dv1394
+	 (cat will use write() internally)
+
+   Example 2:
+           static struct dv1394_init init = {
+	      0x63,        (broadcast channel)
+              4,           (four-frame ringbuffer)
+	      DV1394_NTSC, (send NTSC video)
+	      0, 0         (default empty packet rate)
+           }
+
+	   ioctl(fd, DV1394_INIT, &init);
+
+	   while(1) {
+	          read( <a raw DV file>, buf, DV1394_NTSC_FRAME_SIZE );
+		  write( <the dv1394 FD>, buf, DV1394_NTSC_FRAME_SIZE );
+           }
+
+   2)
+
+   For more control over buffering, and to avoid unnecessary copies
+   of the DV data, you can use the more sophisticated the mmap() interface. 
+   First, call the DV1394_INIT ioctl to specify your parameters, 
+   including the number of frames in the ringbuffer. Then, calling mmap() 
+   on the dv1394 device will give you direct access to the ringbuffer
+   from which the DV card reads your frame data.
+
+   The ringbuffer is simply one large, contiguous region of memory
+   containing two or more frames of packed DV data. Each frame of DV data
+   is 120000 bytes (NTSC) or 144000 bytes (PAL).
+
+   Fill one or more frames in the ringbuffer, then use the DV1394_SUBMIT_FRAMES
+   ioctl to begin I/O. You can use either the DV1394_WAIT_FRAMES ioctl
+   or select()/poll() to wait until the frames are transmitted. Next, you'll
+   need to call the DV1394_GET_STATUS ioctl to determine which ringbuffer
+   frames are clear (ready to be filled with new DV data). Finally, use
+   DV1394_SUBMIT_FRAMES again to send the new data to the DV output.
+
+
+   Example: here is what a four-frame ringbuffer might look like
+            during DV transmission:
+
+
+         frame 0   frame 1   frame 2   frame 3
+
+	*--------------------------------------*
+        | CLEAR   | DV data | DV data | CLEAR  |
+        *--------------------------------------*
+                   <ACTIVE> 
+
+	transmission goes in this direction --->>>
+
+
+   The DV hardware is currently transmitting the data in frame 1.
+   Once frame 1 is finished, it will automatically transmit frame 2.
+   (if frame 2 finishes before frame 3 is submitted, the device
+   will continue to transmit frame 2, and will increase the dropped_frames
+   counter each time it repeats the transmission).
+
+ 
+   If you called DV1394_GET_STATUS at this instant, you would
+   receive the following values:
+   
+                  n_frames          = 4
+		  active_frame      = 1
+		  first_clear_frame = 3
+		  n_clear_frames    = 2
+
+   At this point, you should write new DV data into frame 3 and optionally
+   frame 0. Then call DV1394_SUBMIT_FRAMES to inform the device that
+   it may transmit the new frames.
+
+   ERROR HANDLING
+
+   An error (buffer underflow/overflow or a break in the DV stream due
+   to a 1394 bus reset) can be detected by checking the dropped_frames
+   field of struct dv1394_status (obtained through the
+   DV1394_GET_STATUS ioctl).
+
+   The best way to recover from such an error is to re-initialize
+   dv1394, either by using the DV1394_INIT ioctl call, or closing the
+   file descriptor and opening it again. (note that you must unmap all
+   ringbuffer mappings when closing the file descriptor, or else
+   dv1394 will still be considered 'in use').
+
+   MAIN LOOP
+
+   For maximum efficiency and robustness against bus errors, you are
+   advised to model the main loop of your application after the
+   following pseudo-code example:
+
+   (checks of system call return values omitted for brevity; always
+   check return values in your code!)
+   
+   while( frames left ) {
+   
+    struct pollfd *pfd = ...;
+
+    pfd->fd = dv1394_fd;
+    pfd->revents = 0;
+    pfd->events = POLLOUT | POLLIN; (OUT for transmit, IN for receive)
+
+    (add other sources of I/O here)
+    
+    poll(pfd, 1, -1); (or select(); add a timeout if you want)
+
+    if(pfd->revents) {
+         struct dv1394_status status;
+	 
+         ioctl(dv1394_fd, DV1394_GET_STATUS, &status);
+
+	 if(status.dropped_frames > 0) {
+	      reset_dv1394();
+         } else {
+              for(int i = 0; i < status.n_clear_frames; i++) {
+	          copy_DV_frame();
+              }
+         }
+    }
+   }
+
+   where copy_DV_frame() reads or writes on the dv1394 file descriptor
+   (read/write mode) or copies data to/from the mmap ringbuffer and
+   then calls ioctl(DV1394_SUBMIT_FRAMES) to notify dv1394 that new
+   frames are availble (mmap mode).
+
+   reset_dv1394() is called in the event of a buffer
+   underflow/overflow or a halt in the DV stream (e.g. due to a 1394
+   bus reset). To guarantee recovery from the error, this function
+   should close the dv1394 file descriptor (and munmap() all
+   ringbuffer mappings, if you are using them), then re-open the
+   dv1394 device (and re-map the ringbuffer).
+   
+*/
+
+
+/* maximum number of frames in the ringbuffer */
+#define DV1394_MAX_FRAMES 32
+
+/* number of *full* isochronous packets per DV frame */
+#define DV1394_NTSC_PACKETS_PER_FRAME 250
+#define DV1394_PAL_PACKETS_PER_FRAME  300
+
+/* size of one frame's worth of DV data, in bytes */
+#define DV1394_NTSC_FRAME_SIZE (480 * DV1394_NTSC_PACKETS_PER_FRAME)
+#define DV1394_PAL_FRAME_SIZE  (480 * DV1394_PAL_PACKETS_PER_FRAME)
+
+
+/* ioctl() commands */
+
+enum {
+	/* I don't like using 0 as a valid ioctl() */
+	DV1394_INVALID = 0,
+
+
+	/* get the driver ready to transmit video.
+	   pass a struct dv1394_init* as the parameter (see below),
+	   or NULL to get default parameters */
+	DV1394_INIT,
+
+
+	/* stop transmitting video and free the ringbuffer */
+	DV1394_SHUTDOWN,
+
+
+	/* submit N new frames to be transmitted, where
+	   the index of the first new frame is first_clear_buffer,
+	   and the index of the last new frame is
+	   (first_clear_buffer + N) % n_frames */
+	DV1394_SUBMIT_FRAMES,
+
+
+	/* block until N buffers are clear (pass N as the parameter)
+	   Because we re-transmit the last frame on underrun, there
+	   will at most be n_frames - 1 clear frames at any time */
+	DV1394_WAIT_FRAMES,
+
+	/* capture new frames that have been received, where
+	   the index of the first new frame is first_clear_buffer,
+	   and the index of the last new frame is
+	   (first_clear_buffer + N) % n_frames */
+	DV1394_RECEIVE_FRAMES,
+
+
+	DV1394_START_RECEIVE,
+
+
+	/* pass a struct dv1394_status* as the parameter (see below) */
+	DV1394_GET_STATUS,
+};
+
+
+
+enum pal_or_ntsc {
+	DV1394_NTSC = 0,
+	DV1394_PAL
+};
+
+
+
+
+/* this is the argument to DV1394_INIT */
+struct dv1394_init {
+	/* DV1394_API_VERSION */
+	unsigned int api_version;
+	
+	/* isochronous transmission channel to use */
+	unsigned int channel;
+
+	/* number of frames in the ringbuffer. Must be at least 2
+	   and at most DV1394_MAX_FRAMES. */
+	unsigned int n_frames;
+
+	/* send/receive PAL or NTSC video format */
+	enum pal_or_ntsc format;
+
+	/* the following are used only for transmission */
+ 
+	/* set these to zero unless you want a
+	   non-default empty packet rate (see below) */
+	unsigned long cip_n;
+	unsigned long cip_d;
+
+	/* set this to zero unless you want a
+	   non-default SYT cycle offset (default = 3 cycles) */
+	unsigned int syt_offset;
+};
+
+/* NOTE: you may only allocate the DV frame ringbuffer once each time
+   you open the dv1394 device. DV1394_INIT will fail if you call it a
+   second time with different 'n_frames' or 'format' arguments (which
+   would imply a different size for the ringbuffer). If you need a
+   different buffer size, simply close and re-open the device, then
+   initialize it with your new settings. */
+   
+/* Q: What are cip_n and cip_d? */
+
+/*
+  A: DV video streams do not utilize 100% of the potential bandwidth offered
+  by IEEE 1394 (FireWire). To achieve the correct rate of data transmission,
+  DV devices must periodically insert empty packets into the 1394 data stream.
+  Typically there is one empty packet per 14-16 data-carrying packets.
+
+  Some DV devices will accept a wide range of empty packet rates, while others
+  require a precise rate. If the dv1394 driver produces empty packets at
+  a rate that your device does not accept, you may see ugly patterns on the
+  DV output, or even no output at all.
+
+  The default empty packet insertion rate seems to work for many people; if
+  your DV output is stable, you can simply ignore this discussion. However,
+  we have exposed the empty packet rate as a parameter to support devices that
+  do not work with the default rate. 
+
+  The decision to insert an empty packet is made with a numerator/denominator
+  algorithm. Empty packets are produced at an average rate of CIP_N / CIP_D.
+  You can alter the empty packet rate by passing non-zero values for cip_n
+  and cip_d to the INIT ioctl.
+  
+ */
+
+
+
+struct dv1394_status {
+	/* this embedded init struct returns the current dv1394
+	   parameters in use */
+	struct dv1394_init init;
+
+	/* the ringbuffer frame that is currently being
+	   displayed. (-1 if the device is not transmitting anything) */
+	int active_frame;
+
+	/* index of the first buffer (ahead of active_frame) that
+	   is ready to be filled with data */
+	unsigned int first_clear_frame;
+
+	/* how many buffers, including first_clear_buffer, are
+	   ready to be filled with data */
+	unsigned int n_clear_frames;
+
+	/* how many times the DV stream has underflowed, overflowed,
+	   or otherwise encountered an error, since the previous call
+	   to DV1394_GET_STATUS */
+	unsigned int dropped_frames;
+
+	/* N.B. The dropped_frames counter is only a lower bound on the actual
+	   number of dropped frames, with the special case that if dropped_frames
+	   is zero, then it is guaranteed that NO frames have been dropped
+	   since the last call to DV1394_GET_STATUS.
+	*/
+};
+
+
+#endif /* _DV_1394_H */

libavformat/grab.c

@@ -53,8 +53,6 @@ static int aiw_init(VideoData *s);
 static int aiw_read_picture(VideoData *s, uint8_t *data);
 static int aiw_close(VideoData *s);
 
-const char *v4l_device = "/dev/video";
-
 static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
 {
     VideoData *s = s1->priv_data;
@@ -80,9 +78,9 @@ static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
     s->height = height;
     s->frame_rate = frame_rate;
 
-    video_fd = open(v4l_device, O_RDWR);
+    video_fd = open(video_device, O_RDWR);
     if (video_fd < 0) {
-        perror(v4l_device);
+        perror(video_device);
         goto fail;
     }
     
@@ -339,7 +337,7 @@ static int grab_read_close(AVFormatContext *s1)
 }
 
 static AVInputFormat video_grab_device_format = {
-    "video_grab_device",
+    "video4linux",
     "video grab",
     sizeof(VideoData),
     NULL,