List:       linux-video
Subject:    [video4linux] Draft API changes
From:       Alan Cox <alan () cymru ! net>
Date:       1998-08-09 23:19:00


I've updated ther API reference on

	http://roadrunner.swansea.linux.org.uk/v4lapi.shtml

The changes made based on the comments here are:

o	Added VID_TYPE_SUBCAPTURE 

	This is set by devices that support time and space capturing of
	only part of the image

o	Added a video_capture structure

	This sets the x,y, width, height decimation and flags to indicate
	what to capture. Right now the flags are "odd field only/even only"

o	Tuners have a norm field. 

	This lets you set the NORM by tuner if supported (VIDIO_TUNER_NORM set)

o	Audio changes

	Added a balance
	Added 'step' to give the step that is actually supported

o	VIDIOCGMBUF

	Get the mmap buffer description portably. The returned structure says
	how big the capture area is, how many frames it supports and their
	offsets. No more hardcoded BT848_FBUF's please ;)

o	VIDIOCGUNIT

	Lets you find the audio mixer, vbi etc for a given device. Thats needed
	so you get the right teletext with your tv and so on


The mmap description is pretty rough. I've kept the existing single block
and offsets behaviour as thats basically what we can get away with nicely
until 2.3 and DMA direct to user space without indirection. 

I've ignored the codec stuff. Obviously read/write have a meaning to codecs
but I think a codec API is very seperate to the capture API.


Ok start flaming ;)

Alan
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