[PATCH 04/10] staging: media: cedrus: mpeg2: use the field height for field pictures

[Nicolas Dufresne]

Le lundi 02 novembre 2026 à 18:02 +0100, Jernej Skrabec a écrit :
> A field picture covers only half of the macroblock rows of a frame, but
> the driver programs the coded and the boundary size of the whole frame
> for it, as for a frame picture.
> 
> Program the height of a field for field pictures, like the vendor
> library does.
> 
> Fixes: 50e761516f2b ("media: platform: Add Cedrus VPU decoder driver")
> Signed-off-by: Jernej Skrabec <jernej.skrabec at gmail.com>
> ---
>  drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c b/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
> index 10e98f08aafc..ca66a3c6b830 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
> @@ -58,6 +58,7 @@ static int cedrus_mpeg2_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
>  	struct vb2_queue *vq;
>  	const u8 *matrix;
>  	unsigned int i;
> +	bool field;
>  	u32 reg;
>  
>  	seq = run->mpeg2.sequence;
> @@ -108,13 +109,21 @@ static int cedrus_mpeg2_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
>  
>  	/* Set frame dimensions. */
>  
> +	/*
> +	 * Field pictures cover half of the frame's macroblock rows; the
> +	 * vendor library halves both the coded and the boundary height.
> +	 */
> +	field = pic->picture_structure != V4L2_MPEG2_PIC_FRAME;
> +
>  	reg = VE_DEC_MPEG_PICCODEDSIZE_WIDTH(seq->horizontal_size);
> -	reg |= VE_DEC_MPEG_PICCODEDSIZE_HEIGHT(seq->vertical_size);
> +	reg |= VE_DEC_MPEG_PICCODEDSIZE_HEIGHT(field ?
> +			ALIGN(seq->vertical_size, 32) / 2 : seq->vertical_size);
>  
>  	cedrus_write(dev, VE_DEC_MPEG_PICCODEDSIZE, reg);
>  
>  	reg = VE_DEC_MPEG_PICBOUNDSIZE_WIDTH(ctx->src_fmt.width);
> -	reg |= VE_DEC_MPEG_PICBOUNDSIZE_HEIGHT(ctx->src_fmt.height);
> +	reg |= VE_DEC_MPEG_PICBOUNDSIZE_HEIGHT(field ? ctx->src_fmt.height / 2 :
> +						   ctx->src_fmt.height);

I'm not entirely sure, but I see:

	fsize->stepwise.step_height = 1;

But I don't think interlaced video can have odd height in the first place. But
it also have an implication here as you are not rounding up to a multiple of 2.
Not sure what is the proper fix, but I have this impression something is
missing.

Nicolas

>  
>  	cedrus_write(dev, VE_DEC_MPEG_PICBOUNDSIZE, reg);
>  
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