[FFmpeg-devel] [PATCH 2/2] libavutil/libavfilter: deshake opencl filter based on comments on 20130401

[Wei Gao]

2013/4/2 Stefano Sabatini <stefasab at gmail.com>

> On date Tuesday 2013-04-02 09:09:06 +0800, Wei Gao encoded:
> > Hi,
> >
> > Thanks for your reviewing, some questions and explanations are as follows
> >
> > Thanks
> > Best regards
> >
> >
> > 2013/4/1 Stefano Sabatini <stefasab at gmail.com>
> >
> > > On date Monday 2013-04-01 17:52:51 +0800, Wei Gao encoded:
> > > >
> > >
> > > > From 77b3811b748129c8018216989f5e9781d37d7ea0 Mon Sep 17 00:00:00
> 2001
> > > > From: highgod0401 <highgod0401 at gmail.com>
> > > > Date: Mon, 1 Apr 2013 17:48:34 +0800
> > > > Subject: [PATCH 2/2] deshake opencl filter based on comments on
> 20130401
> > > >
> > >
> > > > +        av_log(ctx, AV_LOG_ERROR, "error %s %d\n", "clSetKernelArg",
> > > status );                               \
> > >
> > > av_log(ctx, AV_LOG_ERROR, "cannot set kernel argument: %d\n", status );
> > >                             \
> > >
> > > or even better, export the error string API so you can put the OpenCL
> > > error (even if I noted it would be much better if the OpenCL lib
> > > supported such API).
> > >
>
> > should I add the api this patch or later? I think it just make static
> const
> > char *opencl_errstr(cl_int status) as a api
>
> As you prefer.
>
> You may have to simply do:
> opencl_errstr() -> av_opencl_errstr()
>
> and add a declaration to libavutil/opencl.h.
>
> or maybe -> av_opencl_strerror() for consistency with the standard
> strerror().
>
> >
> > >
> > > > +        return AVERROR_EXTERNAL;
> > >                                       \
> > > > +    }
> > > > +
> > >
>
> > > > +
> > > > +#if CONFIG_OPENCL
> > > > +
> > > > +typedef struct {
> > > > +    size_t buf_size;
> > > > +    cl_mem cl_buf;
> > > > +} OpenCLFrameBuf;
> > >
> > > For simplicity sake you should probably avoid this struct, and just
> > > put the field in the context below.
> > >
> > > cl_mem cl_inbuf;
> > > size_t cl_inbuf_size;
> > >
>
> > Can I add this  OpenCLFrameBuf to avfilter context? because all the
> opencl
> > filters will use  OpenCLFrameBuf cl_inbuf and
> > OpenCLFrameBuf cl_outbuf, and can I add a opencl flag to avfilter
> context?
>
> > because it is can make the opencl share buffer operation easily without
> add
> > api to opencl lib. share buffer means that if the current filter check
> that
> > the previous filter is opencl filter, then it will use the OpenCLFrameBuf
> > of pervious filter as a input( for image data), if the current filter
> check
> > that the next filter is opencl filter, then it can avoid copy the data to
> > CPU memory, it can save the time of copy data from CPU and GPU.
>
> I don't think we should mess with the AVFilterContext this way, there
> should be better ways to mark a buffer as an OpenCL buffer.
>
> Also keep in mind that when you request a frame, the frame request is
> passed to the next filter. If the next filter is an OpenCL filter, it
> should return an OpenCL buffer, which could be marked such that the
> receiving filter knows that it's an OpenCL buffer and can avoid
> GPU<->CPU memcpy operations.
>
do you mean use data[5] or data[6] as a opencl buffer? how can we pass the
request frame to the next filter? and now whether the filter is opencl is
decided by the "opencl" flag of each filter, so how the current filter konw
the next filter is opencl? should we add a opencl flag to avfilter context?

sorry, I am not very clear about the buffer system of ffmpeg.

> --
> FFmpeg = Fundamentalist and Free Muttering Prodigious Earthshaking Geisha
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