Cool. Comments:
> /*
> * E N U M S
> */
> enum v4l2_field {
> V4L2_FIELD_ANY = 0, /* driver can choose from none,
> top, bottom, interlaced
> depending on whatever it thinks
> is approximate ... */
> V4L2_FIELD_NONE = 1, /* this device has no fields ... */
> V4L2_FIELD_TOP = 2, /* top field only */
> V4L2_FIELD_BOTTOM = 3, /* bottom field only */
> V4L2_FIELD_INTERLACED = 4, /* both fields interlaced */
> V4L2_FIELD_SEQUENTIAL = 5, /* both fields sequential into one
> buffer */
> V4L2_FIELD_ALTERNATE = 6, /* both fields alternating into
> separate buffers */
> };
1. Again I'll mention Ronald Bultje's comment that if a card provides
frames as V4L2_FIELD_INTERLACED, it should also be able to say
top-field-first or bottom-field first.
> struct v4l2_pix_format
> {
> __u32 width;
> __u32 height;
> __u32 pixelformat;
> enum v4l2_field field;
> __u32 bytesperline; /* for padding, zero if unused */
> __u32 sizeimage;
> #if 0
> /* FIXME: specify ITU-R 601, ... here ??? */
> __u32 colorspace;
> #endif
> __u32 priv; /* private data, depends on pixelformat */
> };
2. Doing a general colourspace definition is dangerous, IMHO, so I
like the idea of having a bunch of #defines, like with the video
standard. It will make things easier. Having a way to detect the
broken bt878 extents would kick! Comments on this as a start?
/* 601 transfer with oldschool chromaticities. */
#define V4L2_COLORSPACE_SMPTE170M 0x000001
/* I know this is used in some PAL areas I think. */
#define V4L2_COLORSPACE_SMPTE240M 0x000002
/* HD and modern captures. */
#define V4L2_COLORSPACE_REC709 0x000004
/* Be able to detect the broken BT878 extents. */
#define V4L2_COLORSPACE_BT878 0x000008
/* These should be useful. Assume 601 extents. */
#define V4L2_COLORSPACE_470_SYSTEM_M 0x000010
#define V4L2_COLORSPACE_470_SYSTEM_BG 0x000020
/* I know there will be cameras that send this. So, this is
* unspecified chromaticities and full 0-255 on each of the Y'CbCr
* components
*/
#define V4L2_COLORSPACE_JPEG 0x000040
/* For RGB colourspaces, this is probably a good start. */
#define V4L2_COLORSPACE_SRGB 0x000080
> struct v4l2_buffer
> {
> int index;
> enum v4l2_buf_type type;
> __u32 offset;
> __u32 length;
> __u32 bytesused;
> __u32 flags;
> enum v4l2_field field;
> struct timeval timestamp;
> struct v4l2_timecode timecode;
> __u32 sequence;
> __u32 reserved[3];
> };
3. You give one timestamp per buffer. It would be really awesome to
get, for an interlaced buffer, the timestamp of each field, rather than
being forced to use ALTERNATE.
> struct v4l2_captureparm
> {
> __u32 capability; /* Supported modes */
> __u32 capturemode; /* Current mode */
> unsigned long timeperframe; /* Time per frame in .1us units */
> __u32 extendedmode; /* Driver-specific extensions */
> __u32 readbuffers; /* # of buffers for read */
> __u32 reserved[4];
> };
> /* Flags for 'capability' and 'capturemode' fields */
> #define V4L2_MODE_HIGHQUALITY 0x0001 /* High quality imaging mode */
> #define V4L2_CAP_TIMEPERFRAME 0x1000 /* timeperframe field is supported */
4. I don't understand 'timeperframe'. We already have v4l2_standard,
shouldn't it just be retrieved from that? Also, it would be better to
do the numerator/denominator thing here too, no?
--
Billy Biggs
vektor@xxxxxxxxxxxx
