[FFmpeg-devel] [PATCH] avcodec/nvdec: Round up odd width/height values

[Timo Rothenpieler]

Am 24.11.2017 um 19:24 schrieb Philip Langdale:
> nvdec will not produce odd width/height output, and while this is
> basically never an issue with most codecs, due to internal alignment
> requirements, you can get odd sized jpegs.
> 
> If an odd-sized jpb is encountered, nvdec will actually round down

jpg

> internally and produce output that is slightly smaller. This isn't
> the end of the world, as long as you know the output size doesn't
> match the original image resolution.
> 
> However, with an hwaccel, we don't know. The decoder controls
> the reported output size and the hwaccel cannot change it. I was
> able to trigger an error in mpv where it tries to copy the output
> surface as part of rendering and triggers a cuda error because
> cuda knows the output frame is smaller than expected.
> 
> To fix this, we can round up the configured width/height passed
> to nvdec so that the frames are always at least as large as the
> decoder's reported size, and data can be copied out safely.
> 
> In this particular jpeg case, you end up with a blank (green) line
> at the bottom due to nvdec refusing to decode the last line, but
> the behaviour matches cuviddec, so it's as good as you're going to
> get.
> 
> Signed-off-by: Philip Langdale <philipl at overt.org>
> ---
>   libavcodec/nvdec.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/nvdec.c b/libavcodec/nvdec.c
> index 206429c603..dc7badc4d9 100644
> --- a/libavcodec/nvdec.c
> +++ b/libavcodec/nvdec.c
> @@ -534,8 +534,8 @@ int ff_nvdec_frame_params(AVCodecContext *avctx,
>       }
>   
>       frames_ctx->format            = AV_PIX_FMT_CUDA;
> -    frames_ctx->width             = avctx->coded_width;
> -    frames_ctx->height            = avctx->coded_height;
> +    frames_ctx->width             = (avctx->coded_width + 1) & ~1;
> +    frames_ctx->height            = (avctx->coded_height + 1) & ~1;
>       frames_ctx->initial_pool_size = dpb_size;
>   
>       switch (sw_desc->comp[0].depth) {
> 

lgtm

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