Re: YUV Overlay

Well, that's a bug.  I'll have to update that script with the right 
module name.  Thanks for letting me know.

That script only dumps the video to a file without displaying it.  The 
script 'uav_video_display', released with version 0.5, is the important 
one here.

I ended up solving my overlay issue by doing most of it in C.  I 
probably needed to do this, anyway, as doing it with Perl datastructures 
would have meant creating an SV for each value in the three YUV channels 
and pushing them onto an AV.  720p is 0.9 megapixels, so that would have 
been a very expensive operation to do 30 times a second to handle 
realtime video.

The C technique is used in the recently released UAV::Pilot v0.5.

I have run across a new problem when trying to draw on top of the YUV 
overlay.  I can draw a line using the RGB colorspace, but it shows up 
black.  Maybe I need to convert RGB to YUV?  Or perhaps draw on a 
separate surface and blit that on top?

Thanks,
Timm

On 05.08.2013 08:41, Tobias Leich wrote:
> Hi, I installed UAV-Pilot right now, but it explodes like:
> $ bin/uav_video_dump
> Can't locate UAV/Pilot/Control/ARDrone/Video/FileDump.pm in @INC 
> (@INC
> contains: /etc/perl /usr/local/lib/perl/5.14.2
> /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5
> /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) 
> at
> bin/uav_video_dump line 9.
> BEGIN failed--compilation aborted at bin/uav_video_dump line 9.
>
> Is there something I can do in order to test your example script?
>
> Cheers, FROGGS
>
> Am 24.07.2013 22:53, schrieb [email protected]:
>> I've made a simplified, standalone example:
>>
>> http://pastebin.com/dPPNc8VL
>>
>> The big array at the top is a single YUV420P frame.  Expected 
>> behavior
>> is to display that frame in a window for 5 seconds, and then quit.  
>> If
>> I comment out the overlay handling, it displays a green background.
>>
>> I've verified that I'm running SDL 2.540.
>>
>> Thanks,
>> Timm
>>
>> On 24.07.2013 08:17, Kartik Thakore wrote:
>>> Can we run this with out needing ARDdrone?
>>>
>>> On Wed, Jul 24, 2013 at 8:22 AM, <[email protected]> wrote:
>>>
>>>> Short on time at the moment, but I have the complete code on a
>>>> github repo:
>>>>
>>>> https://github.com/frezik/UAV-Pilot [2]
>>>>
>>>> The relevant code is in UAV::Pilot::SDL::Video, and the decoding
>>>> happens in the xs file for UAV::Pilot::Video::H264Decoder.  The 
>>>> test
>>>> t/160_video_decode.t should run the decoding end of things. 
>>>> There's
>>>> a test video in t_data/ardrone_video_stream_dump.bin, though that
>>>> contains the PaVE headers from the UAV before each frame.  Those
>>>> headers can be stripped out by bin/uav_video_dump.
>>>>
>>>> I'll try to come up with a more concise example later this 
>>>> evening.
>>>>
>>>> Thanks,
>>>> Timm
>>>>
>>>> On 24.07.2013 01 [3]:00, Tobias Leich wrote:
>>>>
>>>>> Hi, can you paste a complete example please? Maybe with a link to 
>>>>> a
>>>>> test
>>>>> video file.
>>>>>
>>>>> What I would try first is SDL's latest release, which is 2.540 or 
>>>>> so.
>>>>>
>>>>> Cheers, FROGGS
>>>>>
>>>>> Am 23.07.2013 23:44, schrieb [email protected]:
>>>>>
>>>>>> I'm working on a project involving decoding h.264 video frames 
>>>>>> with
>>>>>> ffmpeg and then outputting them to an SDL surface. From what 
>>>>>> I've
>>>>>> read, the YUV overlay is meant for this kind of job, but I'm 
>>>>>> having
>>>>>> trouble getting it to work with the Perl bindings.
>>>>>>
>>>>>> One thing that seems odd to me in the Perl docs is:
>>>>>>
>>>>>>     As of release 2.3 direct right to overlay is disable.
>>>>>>
>>>>>> Besides the typos, this troubles me because it seems that 
>>>>>> disabling
>>>>>> the feature makes the YUV overlay completely useless.
>>>>>>
>>>>>> Not to be deterred, I wrote this code:
>>>>>>
>>>>>>     SDL::Video::lock_YUV_overlay( $overlay );
>>>>>>     # The order of array indexen is correct, according to:
>>>>>>     # http://dranger.com/ffmpeg/tutorial02.html [1]
>>>>>>     my $pitches = $overlay->pitches;
>>>>>>     $$pitches[0] = scalar @{ $last_vid_frame[0] };
>>>>>>     $$pitches[2] = scalar @{ $last_vid_frame[1] };
>>>>>>     $$pitches[1] = scalar @{ $last_vid_frame[2] };
>>>>>>     my $pixels = $overlay->pixels;
>>>>>>     $$pixels[0] = $last_vid_frame[0];
>>>>>>     $$pixels[2] = $last_vid_frame[1];
>>>>>>     $$pixels[1] = $last_vid_frame[2];
>>>>>>     SDL::Video::unlock_YUV_overlay( $overlay );
>>>>>>
>>>>>>     SDL::Video::update_rects( $sdl, $bg_rect );
>>>>>>     SDL::Video::display_YUV_overlay( $sdl, $bg_rect );
>>>>>>
>>>>>> When I run this, I get an error about not being able to find the
>>>>>> pitches() method against the class "SDL::Overlay".  Eh?  (Same 
>>>>>> thing
>>>>>> happens for the pixels() method if I put that call first.) I can 
>>>>>> call
>>>>>> width() and format() and such just fine on that object.
>>>>>>
>>>>>> If needed, I can handle the overlay entirely at the C level.  I 
>>>>>> may
>>>>>> end up doing that anyway; the C array that comes out of ffmpeg 
>>>>>> is
>>>>>> being transformed into a Perl array-of-arrays, which is going to
>>>>>> be an
>>>>>> expensive operation to do for 720p at 30 fps in realtime. But 
>>>>>> I'd
>>>>>> like
>>>>>> to try this at the Perl level for now.
>>>>>>
>>>>>> I might also have to convert the output from ffmpeg using
>>>>>> sws_scale().  It's coming out in YUV420P mode, and I'm using 
>>>>>> YV12 to
>>>>>> init the overlay. But I'd like to get the above working before
>>>>>> messing
>>>>>> with that.
>>>>>>
>>>>>> Thanks,
>>>>>> Timm Murray
>>>
>>>
>>>
>>> Links:
>>> ------
>>> [1] http://dranger.com/ffmpeg/tutorial02.html
>>> [2] https://github.com/frezik/UAV-Pilot
>>> [3] tel:24.07.2013%2001
>>