Hi,
I would appreciate someone could provide some hints on this.
Warm Regards,
Anil
On Wed, Sep 29, 2010 at 10:32 AM, Anil Sasidharan <anil...@gmail.com> wrote:
> Hi Deva,
>
> For one of our ongoing projects, I've been trying to get alpha
> blending work in Android on OMAP3EVM. For this we have implemented a simple
> Activity in Android that plays a video (on the video1 plane) and displays an
> image on the GFX plane. The image is rendered using drawable with some
> specific alpha value (to control transparency) . When this app is tested on
> the emulator as well as G1 phone (running Android Eclair), we were to see
> the expected output (video is viewable through transparent image).
>
> However while testing the same app on OMAP3EVM running Android
> (Eclair), the alpha blending never works. We are not able to see the
> underlying video plane at all (only the image gets displayed). Based on the
> discussion on this thread, I've looked at the liboverlay implementation in
> "hardware/ti/omap3/" folder. Apparently by default, LOCAL_ALPHA is disabled
> and the GLOBAL_ALPHA value is set to 255 (opaque ??). I've modified the code
> to enable LOCAL_ALPHA as well as GLOBAL_ALPHA with some lesser value (100)
> and executed the Android activity, but the result is the same.
>
> Since I was not able to do this programmatically, I've tried the
> omapdss sysfs entries to manipulate alpha values. The following commands are
> issued:
>
> echo "1" > /sys/devices/platform/omapdss/manager0/alpha_blending_enabled
> echo "100" > /sys/devices/platform/omapdss/overlay0/global_alpha
>
> Now the applications shows transparent image and video playback underneath.
>
> Some quetsions based on these observations:
> 1. Is the liboverlay implementation incomplete as far as "color-keying" and
> "alpha-blending" are concerned?
> 2. When I went through the v4l2 code for omap-vout, I do see a comment that
> the "global_alpha" is always 255 and cannot be changed. Is this
> understanding correct? If so "how did it work when I've set the global_alpha
> value using sysfs entry?
> 3. Do you any specific technical input on "how to get this working with
> Android"
> 4. Is local alpha tested on OMAP3530? Any clues?
>
> I know I'm firing a lot questions. It would be great if we could have some
> discussions on these points as well.
>
> Warm Regards,
> Anil
>
>
> On Mon, May 10, 2010 at 4:52 PM, Deva R <r.deva...@gmail.com> wrote:
>
>> hi,
>>
>> i havent tried per fb or video device level., but should be possible..
>>
>> can you check with local alpha flags, local to framebuffer and overlay
>> devices?
>> V4L2_FBUF_FLAG_LOCAL_ALPHA, V4L2_FBUF_FLAG_LOCAL_INV_ALPHA
>>
>>
>> On Mon, May 10, 2010 at 12:37 PM, Svetozar Miuchin
>> <svetozar.miuc...@gmail.com> wrote:
>> > Yes, but what I need to do is make all of the Android's surfaces
>> > beneath (and including) the video surface transparent, but leave the
>> > global alpha as is for the possible player's media controls. Any
>> > ideas?
>> >
>> > On May 6, 5:20 pm, Deva R <r.deva...@gmail.com> wrote:
>> >> you can chose the transparency level by tuning alpha blend..
>> >>
>> >> on enabling global alpha blending, the final ouptput pixel will be
>> arrived as,
>> >> output = (framebuffer pixel * alpha + video pixel * (255 - alpha))
>> / 255
>> >>
>> >> you need to set this alpha field with below ioctl commands..
>> >>
>> >> ret = v4l2_ioctl(fd, VIDIOC_G_FMT, &fmt);
>> >> fmt.fmt.win.global_alpha = alpha & 0xFF;
>> >> ret = v4l2_overlay_ioctl(fd, VIDIOC_S_FMT, &fmt);
>> >>
>> >> you can check complete source in our tree -
>> http://git.omapzoom.org/?p=platform/hardware/ti/omap3.git;a=blob;f=li...
>> >>
>> >> On Thu, May 6, 2010 at 7:55 PM, Svetozar Miuchin
>> >>
>> >>
>> >>
>> >> <svetozar.miuc...@gmail.com> wrote:
>> >> > You mean setting the global alpha to fully transparent? If so, I've
>> >> > thought about that, but that destroys the possibility of having on-
>> >> > screen media controls.. Right?
>> >>
>> >> > On May 6, 4:18 pm, Deva R <r.deva...@gmail.com> wrote:
>> >> >> You can enable alpha blending in your display driver, so both
>> graphics
>> >> >> and video overlay blend..
>> >>
>> >> >> my call sequence for this are like (get fb handle, toggle alpha
>> >> >> blending, set the fb options)
>> >>
>> >> >> v4l2_ioctl(fd, VIDIOC_G_FBUF, &fbuf);
>> >> >> fbuf.flags |= V4L2_FBUF_FLAG_GLOBAL_ALPHA;
>> >> >> v4l2_ioctl(fd, VIDIOC_S_FBUF, &fbuf);
>> >>
>> >> >> more info:http://v4l2spec.bytesex.org/spec/r10595.htm-> framebuffer
>> flags ->
>> >> >> V4L2_FBUF_FLAG_GLOBAL_ALPHA
>> >>
>> >> >> On Thu, May 6, 2010 at 7:20 PM, Svetozar Miuchin
>> >>
>> >> >> <svetozar.miuc...@gmail.com> wrote:
>> >> >> > Hi,
>> >> >> > I'm porting Android to a board with hardware video decoding
>> support.
>> >> >> > The board hardware draws the video into a video layer beneath the
>> >> >> > graphic layer. I've implemented a custom media player that passes
>> the
>> >> >> > calls to the hardware decoders, but I need to make Android's
>> surfaces
>> >> >> > transparent. Is there any way this is possible with the current
>> >> >> > Android architecture? I'm using the Eclair version for MIPS
>> >> >> > architectures.
>> >> >> > Thanks in advance,
>> >> >> > Svetozar
>> >>
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