[FFmpeg-user] Get Hardware Buffer from FFmpeg 4.0 + VideoToolBox

[Bo Zhou]

Thank you so much ! I'd like to have a try !

On Thu, Oct 4, 2018 at 2:10 AM <fumoboy007 at me.com> wrote:

> I recently did just this. frame->data[3] holds a CVPixelBufferRef. Here is
> some sample code in Swift:
>
> let pixelBuffer =
>    Unmanaged<CVPixelBuffer>.fromOpaque(frame!.pointee.data.3!)
>       .retain()
>       .takeRetainedValue()
>
> In C, you would do something like:
>
> CVPixelBufferRef pixelBuffer =
> CVPixelBufferRetain((CVPixelBufferRef)frame->data[3]);
>
> Cheers!
> fumoboy007
>
> On Sat Aug 18 05:50:45 EEST 2018, Bo Zhou <bo.schwarzstein at gmail.com>
> wrote:
>
> Hi !
>
> I'm using the FFmpeg 4.0.2 and successfully executed the example hw_decode
> on Mac. And I could see the trace log
>
>
> [h264 @ 0x7f97d9800000] Format videotoolbox_vld chosen by get_format().
> [h264 @ 0x7f97d9800000] Format videotoolbox_vld requires hwaccel
> initialisation.
> [h264 @ 0x7f97d9800000] Reinit context to 1280x720, pix_fmt:
> videotoolbox_vld
>
>
> Which should mean that it's using videotoolbox_vld .
>
> In the hw_decode.c file, we could find the following piece of code.
>
>         if (frame->format == hw_pix_fmt) {
>             /* retrieve data from GPU to CPU */
>             if ((ret = av_hwframe_transfer_data(sw_frame, frame, 0)) < 0) {
>                 fprintf(stderr, "Error transferring the data to system
> memory\n");
>                 goto fail;
>             }
>             tmp_frame = sw_frame;
>         } else
>             tmp_frame = frame;
>
> So I'd like to know is that possible to get the GPU buffer directly ? I
> could see the frame->data[3] and frame->buf[0] has a pointer, but how
> should I use them ? I just want to map the hardware buffer into OpenGL
> directly.
>
> Thank you very much.
>
>