[FFmpeg-devel] GSoC

Dylan Fernando dylanf123 at gmail.com
Wed Mar 7 05:56:03 EET 2018


Thanks, it works now

Would trying to implement an OpenCL version of vf_fade be a good idea for a
qualification task, or would it be a better idea to try a different filter?

Regards,
Dylan

On Wed, Mar 7, 2018 at 1:20 AM, Mark Thompson <sw at jkqxz.net> wrote:

> On 06/03/18 12:37, Dylan Fernando wrote:
> > Hi,
> >
> > I am Dylan Fernando. I am a Computer Science student from Australia. I am
> > new to FFmpeg and I wish to apply for GSoC this year.
> > I would like to do the Video filtering with OpenCL project and I have a
> few
> > questions. Would trying to implement an opencl version of vf_fade be a
> good
> > idea for the qualification task, or would I be better off using a
> different
> > filter?
> >
> > Also, I’m having a bit of trouble with running unsharp_opencl. I tried
> > running:
> > ffmpeg -hide_banner -nostats -v verbose -init_hw_device opencl=ocl:0.1
> > -filter_hw_device ocl -i space.mpg -filter_complex unsharp_opencl
> output.mp4
> >
> > but I got the error:
> > [AVHWDeviceContext @ 0x7fdac050c700] 0.1: Apple / Intel(R) Iris(TM)
> > Graphics 6100
> > [mpeg @ 0x7fdac3132600] max_analyze_duration 5000000 reached at 5005000
> > microseconds st:0
> > Input #0, mpeg, from 'space.mpg':
> >   Duration: 00:00:21.99, start: 0.387500, bitrate: 6108 kb/s
> >     Stream #0:0[0x1e0]: Video: mpeg2video (Main), 1 reference frame,
> > yuv420p(tv, bt470bg, bottom first, left), 720x480 [SAR 8:9 DAR 4:3], 6000
> > kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
> > Stream mapping:
> >   Stream #0:0 (mpeg2video) -> unsharp_opencl
> >   unsharp_opencl -> Stream #0:0 (mpeg4)
> > Press [q] to stop, [?] for help
> > [graph 0 input from stream 0:0 @ 0x7fdac0418800] w:720 h:480
> pixfmt:yuv420p
> > tb:1/90000 fr:30000/1001 sar:8/9 sws_param:flags=2
> > [auto_scaler_0 @ 0x7fdac05232c0] w:iw h:ih flags:'bilinear' interl:0
> > [Parsed_unsharp_opencl_0 @ 0x7fdac0715a80] auto-inserting filter
> > 'auto_scaler_0' between the filter 'graph 0 input from stream 0:0' and
> the
> > filter 'Parsed_unsharp_opencl_0'
> > Impossible to convert between the formats supported by the filter 'graph
> 0
> > input from stream 0:0' and the filter 'auto_scaler_0'
> > Error reinitializing filters!
> > Failed to inject frame into filter network: Function not implemented
> > Error while processing the decoded data for stream #0:0
> > Conversion failed!
> >
> > How do I correctly run unsharp_opencl? Should I be running it on a
> > different video file?
>
> It's intended to be used in filter graphs where much of the activity is
> already happening on the GPU, so the input and output are in the
> AV_PIX_FMT_OPENCL format which contains GPU-side OpenCL images.
>
> If you want to use it standalone then you need hwupload and hwdownload
> filters to move the frames between the CPU and GPU.  For your example, it
> should work with:
>
> ffmpeg -init_hw_device opencl=ocl:0.1 -filter_hw_device ocl -i space.mpg
> -filter_complex hwupload,unsharp_opencl,hwdownload output.mp4
>
> (There are constraints on what formats can be used and therefore suitable
> files (or required format conversions), but I believe a normal yuv420p
> video like this should work in all cases.)
>
> - Mark
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