Re: YUV Overlay

Short on time at the moment, but I have the complete code on a github 
repo:

https://github.com/frezik/UAV-Pilot

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 01:00, 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
>>     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