Em 28-02-2012 08:06, Hans Verkuil escreveu:
> On Tuesday, February 28, 2012 11:54:54 Mauro Carvalho Chehab wrote:
>> Em 03-02-2012 08:06, Hans Verkuil escreveu:
>>> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>>>
>>> These new ioctls make it possible for the dv_timings API to replace
>>> the dv_preset API eventually.
>>>
>>> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>>> ---
>>> include/linux/videodev2.h | 110 ++++++++++++++++++++++++++++++++++++++++----
>>> 1 files changed, 100 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
>>> index 0db0503..e59cd02 100644
>>> --- a/include/linux/videodev2.h
>>> +++ b/include/linux/videodev2.h
>>> @@ -987,28 +987,42 @@ struct v4l2_dv_enum_preset {
>>> */
>>>
>>> /* BT.656/BT.1120 timing data */
>>> +
>>> +/*
>>> + * A note regarding vertical interlaced timings: height refers to the total
>>> + * height of the frame (= two fields). The blanking timings refer
>>> + * to the blanking of each field. So the height of the active frame is
>>> + * calculated as follows:
>>> + *
>>> + * act_height = height - vfrontporch - vsync - vbackporch -
>>> + * il_vfrontporch - il_vsync - il_vbackporch
>>> + *
>>> + * The active height of each field is act_height / 2.
>>> + */
>>> struct v4l2_bt_timings {
>>> - __u32 width; /* width in pixels */
>>> - __u32 height; /* height in lines */
>>> + __u32 width; /* total frame width in pixels */
>>> + __u32 height; /* total frame height in lines */
>>> __u32 interlaced; /* Interlaced or progressive */
>>> __u32 polarities; /* Positive or negative polarity */
>>> __u64 pixelclock; /* Pixel clock in HZ. Ex. 74.25MHz->74250000 */
>>> - __u32 hfrontporch; /* Horizpontal front porch in pixels */
>>> + __u32 hfrontporch; /* Horizontal front porch in pixels */
>>> __u32 hsync; /* Horizontal Sync length in pixels */
>>> __u32 hbackporch; /* Horizontal back porch in pixels */
>>> __u32 vfrontporch; /* Vertical front porch in pixels */
>>> __u32 vsync; /* Vertical Sync length in lines */
>>> __u32 vbackporch; /* Vertical back porch in lines */
>>> - __u32 il_vfrontporch; /* Vertical front porch for bottom field of
>>> - * interlaced field formats
>>> + __u32 il_vfrontporch; /* Vertical front porch for the even field
>>> + * (aka field 2) of interlaced field formats
>>> */
>>> - __u32 il_vsync; /* Vertical sync length for bottom field of
>>> - * interlaced field formats
>>> + __u32 il_vsync; /* Vertical sync length for the even field
>>> + * (aka field 2) of interlaced field formats
>>> */
>>> - __u32 il_vbackporch; /* Vertical back porch for bottom field of
>>> - * interlaced field formats
>>> + __u32 il_vbackporch; /* Vertical back porch for the even field
>>> + * (aka field 2) of interlaced field formats
>>> */
>>> - __u32 reserved[16];
>>> + __u32 standards; /* Standards the timing belongs to */
>>> + __u32 flags; /* Flags */
>>> + __u32 reserved[14];
>>> } __attribute__ ((packed));
>>>
>>> /* Interlaced or progressive format */
>>> @@ -1019,6 +1033,37 @@ struct v4l2_bt_timings {
>>> #define V4L2_DV_VSYNC_POS_POL 0x00000001
>>> #define V4L2_DV_HSYNC_POS_POL 0x00000002
>>>
>>> +/* Timings standards */
>>> +#define V4L2_DV_BT_STD_CEA861 (1 << 0) /* CEA-861 Digital TV Profile */
>>> +#define V4L2_DV_BT_STD_DMT (1 << 1) /* VESA Discrete Monitor Timings */
>>> +#define V4L2_DV_BT_STD_CVT (1 << 2) /* VESA Coordinated Video Timings */
>>> +#define V4L2_DV_BT_STD_GTF (1 << 3) /* VESA Generalized Timings Formula */
>>> +
>>> +/* Flags */
>>> +
>>> +/* CVT/GTF specific: timing uses reduced blanking (CVT) or the 'Secondary
>>> + GTF' curve (GTF). In both cases the horizontal and/or vertical blanking
>>> + intervals are reduced, allowing a higher resolution over the same
>>> + bandwidth. This is a read-only flag. */
>>> +#define V4L2_DV_FL_REDUCED_BLANKING (1 << 0)
>>
>>> +/* CEA-861 specific: set for CEA-861 formats with a framerate of a multiple
>>> + of six. These formats can be optionally played at 1 / 1.001 speed to
>>> + be compatible with the normal NTSC framerate of 29.97 frames per second.
>>> + This is a read-only flag. */
>>> +#define V4L2_DV_FL_NTSC_COMPATIBLE (1 << 1)
>>> +/* CEA-861 specific: only valid for video transmitters, the flag is cleared
>>> + by receivers.
>>> + If the framerate of the format is a multiple of six, then the pixelclock
>>> + used to set up the transmitter is divided by 1.001 to make it compatible
>>> + with NTSC framerates. Otherwise this flag is cleared. If the transmitter
>>> + can't generate such frequencies, then the flag will also be cleared. */
>>> +#define V4L2_DV_FL_DIVIDE_CLOCK_BY_1_001 (1 << 2)
>>
>> The two above have a conceptual problem: NTSC has nothing to do with the frequency.
>>
>> While, in practice, NTSC is only used on Countries with 60Hz power supply, and a
>> 1000/1001 shift is used there, to avoid flicker with the light bulbs, the
>> standard doesn't mean a 29.97 Hz frame rate.
>>
>> If you take a look at CEA-861, it doesn't mention there NTSC (well, except for a
>> reference for the existing standards), to avoid such conceptual issue.
>>
>> Besides that, PAL/M (and PAL/60) also uses a 29.97 Hz frame rate, in order to avoid
>> flicker.
>>
>> So, please don't call the flag as "NTSC_COMPATIBLE", and please fix the comments
>> to either not mention NTSC, or to use something more generic, like replacing:
>>
>> "...be compatible with the normal NTSC framerateof 29.97 frames per second."
>> with
>> "...be compatible with 60Hz based standards that use a framerate of 29.97
>> frames per second, like NTSC and PAL/M."
>
> I'll try and find a more neutral term. I'm not satisfied with the name either.
Ok, thanks!
>
>>
>>> +/* Specific to interlaced formats: if set, then field 1 is really one half-line
>>> + longer and field 2 is really one half-line shorter, so each field has
>>> + exactly the same number of half-lines. Whether half-lines can be detected
>>> + or used depends on the hardware. */
>>> +#define V4L2_DV_FL_HALF_LINE (1 << 0)
>>> +
>>>
>>> /* DV timings */
>>> struct v4l2_dv_timings {
>>> @@ -1032,6 +1077,47 @@ struct v4l2_dv_timings {
>>> /* Values for the type field */
>>> #define V4L2_DV_BT_656_1120 0 /* BT.656/1120 timing type */
>>>
>>> +
>>> +/* DV timings enumeration */
>>> +struct v4l2_enum_dv_timings {
>>> + __u32 index;
>>> + __u32 reserved[3];
>>> + struct v4l2_dv_timings timings;
>>> +};
>>> +
>>> +/* BT.656/BT.1120 timing capabilities */
>>> +struct v4l2_bt_timings_cap {
>>> + __u32 min_width; /* width in pixels */
>>> + __u32 max_width; /* width in pixels */
>>> + __u32 min_height; /* height in lines */
>>> + __u32 max_height; /* height in lines */
>>> + __u64 min_pixelclock; /* Pixel clock in HZ. Ex. 74.25MHz->74250000 */
>>> + __u64 max_pixelclock; /* Pixel clock in HZ. Ex. 74.25MHz->74250000 */
>>> + __u32 standards; /* Supported standards */
>>> + __u32 capabilities; /* See below */
>>> + __u32 reserved[16];
>>> +} __attribute__ ((packed));
>>
>> Hmm... why to define a new struct here, instead of just use struct v4l2_bt_timings ?
>
> Perhaps there is some misunderstanding here? Struct v4l2_bt_timings defines the
> timings of a particular format. Struct v4l2_bt_timings_cap defines the range of
> timings that the hardware is capable of. The fields are quite different between
> the two.
Ah, OK.
>
>>
>>> +
>>> +/* Supports interlaced formats */
>>> +#define V4L2_DV_BT_CAP_INTERLACED (1 << 0)
>>> +/* Supports progressive formats */
>>> +#define V4L2_DV_BT_CAP_PROGRESSIVE (1 << 1)
>>> +/* Supports CVT/GTF reduced blanking */
>>> +#define V4L2_DV_BT_CAP_REDUCED_BLANKING (1 << 2)
>>> +/* Supports custom formats */
>>> +#define V4L2_DV_BT_CAP_CUSTOM (1 << 3)
>>> +
>>> +/* DV timings capabilities */
>>> +struct v4l2_dv_timings_cap {
>>> + __u32 type;
>>
>> What are the posible values for type?
>
> Same as the type of v4l2_dv_timings. I'll clarify this.
>
>> Btw, it is a good idea to use kernel-doc-nano to describe the structures:
>>
>> /**
>> * struct v4l2_dv_timings_cap - DV timings capabilities
>> * @type: some description
>> ...
>> */
>>
>> As it documents better what is defined there.
>
> Certainly.
>
>>> + __u32 reserved[3];
>>> + union {
>>> + struct v4l2_bt_timings_cap bt;
>>> + __u32 raw_data[32];
>>> + };
>>> +};
>>> +
>>> +
>>> /*
>>> * V I D E O I N P U T S
>>> */
>>> @@ -2318,6 +2404,10 @@ struct v4l2_create_buffers {
>>> #define VIDIOC_G_SELECTION _IOWR('V', 94, struct v4l2_selection)
>>> #define VIDIOC_S_SELECTION _IOWR('V', 95, struct v4l2_selection)
>>>
>>> +#define VIDIOC_ENUM_DV_TIMINGS _IOWR('V', 96, struct v4l2_enum_dv_timings)
>>> +#define VIDIOC_QUERY_DV_TIMINGS _IOR('V', 97, struct v4l2_dv_timings)
>>> +#define VIDIOC_DV_TIMINGS_CAP _IOWR('V', 98, struct v4l2_dv_timings_cap)
>>> +
>>> /* Reminder: when adding new ioctls please add support for them to
>>> drivers/media/video/v4l2-compat-ioctl32.c as well! */
>>>
>>
>
> Thanks for reviewing this!
>
> Regards,
>
> Hans
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