[FFmpeg-devel] [PATCH v2] avutils/hwcontext: When deriving a hwdevice, search for existing device in both directions

[Chen, Wenbin]

Hi softworkz:

Any updates on this patch?
I want to submit pathes to qsv, but they depends on this patch

Thanks
Wenbin
> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Soft
> Works
> Sent: Thursday, August 19, 2021 3:52 PM
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH v2] avutils/hwcontext: When deriving a
> hwdevice, search for existing device in both directions
> 
> 
> 
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Xiang,
> > Haihao
> > Sent: Thursday, 19 August 2021 09:37
> > To: ffmpeg-devel at ffmpeg.org
> > Subject: Re: [FFmpeg-devel] [PATCH v2] avutils/hwcontext: When deriving a
> > hwdevice, search for existing device in both directions
> >
> > On Fri, 2021-08-13 at 06:29 +0000, Xiang, Haihao wrote:
> > > On Tue, 2021-08-10 at 09:52 +0000, Soft Works wrote:
> > > > The test /libavutil/tests/hwdevice checks that when deriving a device
> > > > from a source device and then deriving back to the type of the source
> > > > device, the result is matching the original source device, i.e. the
> > > > derivation mechanism doesn't create a new device in this case.
> > > >
> 
> [..]
> 
> > >
> > > video:143kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
> > muxing
> > > overhead: unknown
> > > corrupted size vs. prev_size in fastbins
> > > Aborted
> > >
> >
> > Hi Softworks,
> >
> > +        child_device->internal->derived_devices[ctx->type] =
> > av_buffer_create((uint8_t*)ctx, sizeof(*ctx), 0, ctx, 0);
> >
> > The above change introduces a new AVBufferRef for ctx. The first
> AVBufferRef
> > for
> > ctx is created when function av_hwdevice_ctx_alloc is called. So there are
> > two
> > different AVBufferRefs referring to the same ctx, then ctx will be double-
> > freed
> >
> > The change below is a bit ugly, but it may fix this double-free issue.
> >
> > +static void qsv_ctx_free(void *opaque, uint8_t *ctx)
> > +{
> > +    // Do nothing here
> > +    // ctx is freed in hwdevice_ctx_free
> > +}
> > +
> >  static int qsv_device_create(AVHWDeviceContext *ctx, const char *device,
> >                               AVDictionary *opts, int flags)
> >  {
> > @@ -1271,7 +1277,7 @@ static int qsv_device_create(AVHWDeviceContext
> *ctx,
> > const
> > char *device,
> >      ret = qsv_device_derive_from_child(ctx, impl, child_device, 0);
> >      if (ret >= 0) {
> >          ctx->internal->source_device = av_buffer_ref(priv-
> > >child_device_ctx);
> > -        child_device->internal->derived_devices[ctx->type] =
> > av_buffer_create((uint8_t*)ctx, sizeof(*ctx), 0, ctx, 0);
> > +        child_device->internal->derived_devices[ctx->type] =
> > av_buffer_create((uint8_t*)ctx, sizeof(*ctx), qsv_ctx_free, ctx, 0);
> >          if (!child_device->internal->derived_devices[ctx->type]) {
> >              return AVERROR(ENOMEM);
> >          }
> 
> Hi Haihao,
> 
> sorry for getting back late and thanks for your suggested fix.
> I'll apply it and submit a new patch version.
> 
> Best regards,
> softworkz
> 
> 
> 
> 
> 
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".