On Sun, Jan 1, 2017 at 6:00 PM, <pkoshe...@gmail.com> wrote:
> From: Pavel Koshevoy <pkoshe...@gmail.com>
>
> NVDEC (CUVID) does not support unlimited video resolutions, so if the
> resolution of the source is known it can be used during avcodec_open2
> call to fail early, rather than failing later during
> avcodec_send_packet call.
>
> This problem surfaced when trying to decode 5120x2700 h246 video on
> Geforce GT 730 -- avcodec_open2 succeeded but decoding failed.
> ---
> libavcodec/cuvid.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/cuvid.c b/libavcodec/cuvid.c
> index 8fc713d..2e70b62 100644
> --- a/libavcodec/cuvid.c
> +++ b/libavcodec/cuvid.c
> @@ -625,8 +625,8 @@ static int cuvid_test_dummy_decoder(AVCodecContext
> *avctx, CUVIDPARSERPARAMS *cu
> cuinfo.ChromaFormat = cudaVideoChromaFormat_420;
> cuinfo.OutputFormat = cudaVideoSurfaceFormat_NV12;
>
> - cuinfo.ulWidth = 1280;
> - cuinfo.ulHeight = 720;
> + cuinfo.ulWidth = avctx->coded_width ? avctx->coded_width : 1280;
> + cuinfo.ulHeight = avctx->coded_height ? avctx->coded_height : 720;
> cuinfo.ulTargetWidth = cuinfo.ulWidth;
> cuinfo.ulTargetHeight = cuinfo.ulHeight;
>
> --
> 2.9.2
>
Perhaps a more comprehensive solution is needed. I've run into the
same problem again (avcodec_open2 succeeds, decoding spits errors)
when I tried to play back an mpeg2 stream with YUV422P pixel format.
I have a new patch but I'd like to test it on a Pascal GPU first. I
am still hoping that 422 decoding will work. It looks like it should
be supported, but I've observed on Geforce GT 730 that even though I
can instantiate a cuvid decoder with cudaVideoChromaFormat_422 without
error -- the decoded video is garbage everywhere except for 16-pixel
wide column along the left edge of the frame.
In ee88dcb2 cuvid_handle_video_sequence was hard-coded to error-out if
the chroma format is not 420. This looks like an NVIDIA driver/cuvid
bug... does anyone know how to bring it to their attention?
Pavel
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