* mjpeg grabbing added, thanks to Paul Forgey <paulf at aphrodite dot com>

 that had done all the work.

Paul Forgey's notes:
--------------------

Unfortunatley, the v4l interface shows how much it sucks here.  I can't
wait for v4l2 to become more common.  Anyway, the mjpeg mechanism
captures completely differently than the uncompressed frame capture
mechanism.  This means the code has to split off a bunch to do similar
things depending on mjpeg being set or not.  For some reason, I can't
use non v4l2 calls to capture uncompressed frames from the lml33,
however I do have another bttv card on my system to test that I didn't
break the non-mjpeg stuff.

The Zoran encoders don't use square pixels.  So the 4:3 (or 16:9)
picture is going to show up as 720x480.  I don't know my way around the
code well enough to know how to specify a non-square pixel aspect
ratio.  If there isn't a way to do it, it would be nice to be able to
specify as an option the aspect ratio of the sourc.  Either 4:3 or 16:9
in the case of anamorphic S-Video, which does occur.

I stole the videodev_mjpeg.h header from the lavrec project.  Despite
the linux kernels having support for the Zoran cards, there doesn't seem
to be a reliable way to pick up this header, which is probably why
lavrec did it this way.  Since it only defines ioctl definitions, I
don't think using it is a legal problem.

I also modified the audio handling a bit.  If the card supports audio,
great, we'll set the card's parameters as we did before.  But if adev=
is specified, use it regardless.  The reason to do this is to capture
audio from the sound card with video coming from, say, a web cam or in
my case, an encoder card which doesn't have any audio capabilities at
all.

modules/access/v4l/Modules.am

-SOURCES_v4l = modules/access/v4l/v4l.c
+SOURCES_v4l = modules/access/v4l/v4l.c \
+	modules/access/v4l/videodev_mjpeg.h

modules/access/v4l/videodev_mjpeg.h

+/*****************************************************************************
+ * Copyright (C) lavrec (see http://mjpeg.sourceforge.net)
+ * ( XXX This file was get from the driver-zoran package and it is under GPL)
+ *
+ * $Id: videodev_mjpeg.h,v 1.1 2003/05/31 01:23:29 fenrir Exp $
+ *
+ * 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, USA.
+ *****************************************************************************/
+
+/* These are the MJPEG API extensions for the Video4Linux API,
+   first introduced by the Iomega Buz driver by Rainer Johanni
+   <rainer@johanni.de>
+*/
+
+/* This is identical with the mgavideo internal params struct,
+   please tell me if you change this struct here ! <gz@lysator.liu.se) */
+struct mjpeg_params
+{
+
+   /* The following parameters can only be queried */
+
+   int major_version;            /* Major version number of driver */
+   int minor_version;            /* Minor version number of driver */
+
+   /* Main control parameters */
+
+   int input;                    /* Input channel: 0 = Composite, 1 = S-VHS */
+   int norm;                     /* Norm: VIDEO_MODE_PAL or VIDEO_MODE_NTSC */
+   int decimation;               /* decimation of captured video,
+                                    enlargement of video played back.
+                                    Valid values are 1, 2, 4 or 0.
+                                    0 is a special value where the user
+                                    has full control over video scaling */
+
+   /* The following parameters only have to be set if decimation==0,
+      for other values of decimation they provide the data how the image is captured */
+
+   int HorDcm;                    /* Horizontal decimation: 1, 2 or 4 */
+   int VerDcm;                    /* Vertical decimation: 1 or 2 */
+   int TmpDcm;                    /* Temporal decimation: 1 or 2,
+                                     if TmpDcm==2 in capture every second frame is dropped,
+                                     in playback every frame is played twice */
+   int field_per_buff;            /* Number of fields per buffer: 1 or 2 */
+   int img_x;                     /* start of image in x direction */
+   int img_y;                     /* start of image in y direction */
+   int img_width;                 /* image width BEFORE decimation,
+                                     must be a multiple of HorDcm*16 */
+   int img_height;                /* image height BEFORE decimation,
+                                     must be a multiple of VerDcm*8 */
+
+   /* --- End of parameters for decimation==0 only --- */
+
+   /* JPEG control parameters */
+
+   int  quality;                  /* Measure for quality of compressed images.
+                                     Scales linearly with the size of the compressed images.
+                                     Must be beetween 0 and 100, 100 is a compression
+                                     ratio of 1:4 */
+
+   int  odd_even;                 /* Which field should come first ???
+                                     This is more aptly named "top_first",
+                                     i.e. (odd_even==1) --> top-field-first */
+
+   int  APPn;                     /* Number of APP segment to be written, must be 0..15 */
+   int  APP_len;                  /* Length of data in JPEG APPn segment */
+   char APP_data[60];             /* Data in the JPEG APPn segment. */
+
+   int  COM_len;                  /* Length of data in JPEG COM segment */
+   char COM_data[60];             /* Data in JPEG COM segment */
+
+   unsigned long jpeg_markers;    /* Which markers should go into the JPEG output.
+                                     Unless you exactly know what you do, leave them untouched.
+                                     Inluding less markers will make the resulting code
+                                     smaller, but there will be fewer aplications
+                                     which can read it.
+                                     The presence of the APP and COM marker is
+                                     influenced by APP0_len and COM_len ONLY! */
+#define JPEG_MARKER_DHT (1<<3)    /* Define Huffman Tables */
+#define JPEG_MARKER_DQT (1<<4)    /* Define Quantization Tables */
+#define JPEG_MARKER_DRI (1<<5)    /* Define Restart Interval */
+#define JPEG_MARKER_COM (1<<6)    /* Comment segment */
+#define JPEG_MARKER_APP (1<<7)    /* App segment, driver will allways use APP0 */
+
+   int  VFIFO_FB;                 /* Flag for enabling Video Fifo Feedback.
+                                     If this flag is turned on and JPEG decompressing
+                                     is going to the screen, the decompress process
+                                     is stopped every time the Video Fifo is full.
+                                     This enables a smooth decompress to the screen
+                                     but the video output signal will get scrambled */
+
+   /* Misc */
+
+	char reserved[312];  /* Makes 512 bytes for this structure */
+};
+
+struct mjpeg_requestbuffers
+{
+   unsigned long count;      /* Number of buffers for MJPEG grabbing */
+   unsigned long size;       /* Size PER BUFFER in bytes */
+};
+
+struct mjpeg_sync
+{
+   unsigned long frame;      /* Frame (0 - n) for double buffer */
+   unsigned long length;     /* number of code bytes in buffer (capture only) */
+   unsigned long seq;        /* frame sequence number */
+   struct timeval timestamp; /* timestamp */
+};
+
+struct mjpeg_status
+{
+   int input;                /* Input channel, has to be set prior to BUZIOC_G_STATUS */
+   int signal;               /* Returned: 1 if valid video signal detected */
+   int norm;                 /* Returned: VIDEO_MODE_PAL or VIDEO_MODE_NTSC */
+   int color;                /* Returned: 1 if color signal detected */
+};
+
+/*
+Private IOCTL to set up for displaying MJPEG
+*/
+#define MJPIOC_G_PARAMS       _IOR ('v', BASE_VIDIOCPRIVATE+0,  struct mjpeg_params)
+#define MJPIOC_S_PARAMS       _IOWR('v', BASE_VIDIOCPRIVATE+1,  struct mjpeg_params)
+#define MJPIOC_REQBUFS        _IOWR('v', BASE_VIDIOCPRIVATE+2,  struct mjpeg_requestbuffers)
+#define MJPIOC_QBUF_CAPT      _IOW ('v', BASE_VIDIOCPRIVATE+3,  int)
+#define MJPIOC_QBUF_PLAY      _IOW ('v', BASE_VIDIOCPRIVATE+4,  int)
+#define MJPIOC_SYNC           _IOR ('v', BASE_VIDIOCPRIVATE+5,  struct mjpeg_sync)
+#define MJPIOC_G_STATUS       _IOWR('v', BASE_VIDIOCPRIVATE+6,  struct mjpeg_status)