[linux-dvb] Recommendations for new V4 APIs

[Rob.McConnell@Zarlink.Com]

Hi Johannes,

I am finally moving back onto our new project (DTV-2) that has different
hardware to the last one (DTV-1).  I am now responsible for looking after
the Linux driver APIs and as such will be proposing that we use the Linux
DVB V4 ones.  Now, I have a few requirements that I wonder if you could
consider.

A) Our hardware has separate blocks for video decoding and video scaling.
The current V4 "video.h" header file does not contain any video scaling or
PIP support.  It only has the addition of my last change for setting the
presentation format.  In addition to this ioctl, we need the ability to set
the size and position of the decoded video (e.g. quarter screen).  As not
all STBs will be using DirectFB, I would like to propose a new video scaler
API that allows such features as:

1) Scaling the video to the desired size (width/height of picture).
2) Positioning the video (scaled or unscaled).
3) Setting the presentation format (move this from video.h to say
scaler.h).
4) Set the source to be from video decoder N.  This would work like the
current video decoder set source ioctl where you pass the video scaler
_device_ the fd of the required video decoder.
5) Means to set interlace/progressive output mode.
5) Get status of device (e.g. error reading the data from the video
decoder's frame store/buffer).
6) Get capabilities.

B) There is a need for a PIP device with such features as:

1) Setting source of PIP e.g. from output of video decoder (using fd as
handle).
2) Setting size of PIP output on screen (e.g. 1/2 or 1/4 scaling).
3) Setting position of PIP on display.
4) Setting size of border.
5) Setting colour of border.
6) Get status of device.
7) Get capabilities.

C) There is a requirement for setting up the DENC output characteristics.
The following functionality if required:

1) Setting the source of the DENC from the output of video scaler or video
decoder device and/or OSD (using fd as handle).
2) Setting the output format of the DENC to RGB, component YUV, S-video
(Y/C) and composite formats.
3) Setting colour standard (PAL/NTSC/SECAM).
4) Setting interlace or progressive scan output.
5) WSS (we can simply include vbi.h)
6) CGMS (copy generation management support).
7) Macrovision support.
8) Closed Captioning.
9) VPS (from vbi.h)
10) Teletext insertion into the vbi.
11) Get capabilities.


I would recommend that we either change "vbi.h" to "denc.h" and add the
extra functionality or create a new "denc.h" file that #include <vbi.h>.
What do you think?

Also, looking at the "vbi.h" file you have the DVB_VBI_SET_SOURCE ioctl
setting the source to be from the demux device.  This isn't always the
case, as you could have the Teletext or WSS data fed from memory.

Do you agree that we should create some new devices to handle these
requirements (especially for iDTVs/STBs)?  If so, then shall I generate
some initial header files that we can comment on and add extra
functionality?

Cheers,

Rob : )