[FFmpeg-devel] [PATCH] vdpau: do not use buggy HEVC support by default

[Philip Langdale]

On Sat,  1 Jul 2017 11:40:38 +0200
wm4 <nfxjfg at googlemail.com> wrote:

> NVIDIA broke its own API when using VDPAU decoding. If you retrieve
> the decoded YUV data, or if you map the surfaces with GL interop, the
> result are interlacing artifacts. The only way to get non-broken data
> is by using the vdpau video mixer to convert it to RGB. There is no
> way to block the non-working operations in a reasonable way (a
> VdpVideoSurface has to support all operations).
> 
> NVIDIA refuses to fix this issue (it "fixed" it by making it work with
> the video mixer, but the rest is still broken). There is no sign of
> that changing.
> 
> Do not use HEVC by default with the generic hwaccle API. Detect
> whether it's the NVIDIA native implementation, and exit with an
> error. (The same thing work with the MESA implementation.)
> 
> As an escape hatch and to allow applications to use the decoder if
> they really want to (perhaps because they make sure to explicitly use
> the video mixer), reuse AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH to
> disable this check.
> 
> Once NVIDIA fixes the bug, working driver versions could be detected,
> and it could be allowed again.
> ---
>  libavcodec/vdpau.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/libavcodec/vdpau.c b/libavcodec/vdpau.c
> index 9c7804a287..42ebddbeee 100644
> --- a/libavcodec/vdpau.c
> +++ b/libavcodec/vdpau.c
> @@ -127,6 +127,8 @@ int ff_vdpau_common_init(AVCodecContext *avctx,
> VdpDecoderProfile profile, VdpVideoSurfaceQueryCapabilities
> *surface_query_caps; VdpDecoderQueryCapabilities *decoder_query_caps;
>      VdpDecoderCreate *create;
> +    VdpGetInformationString *info;
> +    const char *info_string;
>      void *func;
>      VdpStatus status;
>      VdpBool supported;
> @@ -209,6 +211,23 @@ int ff_vdpau_common_init(AVCodecContext *avctx,
> VdpDecoderProfile profile, return AVERROR(ENOTSUP);
>  
>      status = vdctx->get_proc_address(vdctx->device,
> +
> VDP_FUNC_ID_GET_INFORMATION_STRING,
> +                                     &func);
> +    if (status != VDP_STATUS_OK)
> +        return vdpau_error(status);
> +    else
> +        info = func;
> +
> +    status = info(&info_string);
> +    if (status != VDP_STATUS_OK)
> +        return vdpau_error(status);
> +    if (avctx->codec_id == AV_CODEC_ID_HEVC && strncmp(info_string,
> "NVIDIA ", 7) == 0 &&
> +        !(avctx->hwaccel_flags &
> AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH)) {
> +        av_log(avctx, AV_LOG_VERBOSE, "HEVC with NVIDIA VDPAU
> drivers is buggy, skipping.\n");
> +        return AVERROR(ENOTSUP);
> +    }
> +
> +    status = vdctx->get_proc_address(vdctx->device,
>                                       VDP_FUNC_ID_VIDEO_SURFACE_QUERY_CAPABILITIES,
>                                       &func);
>      if (status != VDP_STATUS_OK)

Go for it.

--phil