linux-kernel - Re: [PATCH v2] media: mediatek: vcodec: Handle VP9 superframe bitstream with 8 sub-frames

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Date: Fri, 1 Mar 2024 16:13:44 +0100
From: Sebastian Fricke <sebastian.fricke@...labora.com>
To: Irui Wang <irui.wang@...iatek.com>
Cc: Hans Verkuil <hverkuil-cisco@...all.nl>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Tiffany Lin <tiffany.lin@...iatek.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	angelogioacchino.delregno@...labora.com,
	nicolas.dufresne@...labora.com,
	Yunfei Dong <yunfei.dong@...iatek.com>,
	Longfei Wang <longfei.wang@...iatek.com>,
	Maoguang Meng <maoguang.meng@...iatek.com>,
	Project_Global_Chrome_Upstream_Group@...iatek.com,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v2] media: mediatek: vcodec: Handle VP9 superframe
 bitstream with 8 sub-frames

Hey Irui,

On 29.02.2024 11:02, Irui Wang wrote:
>The VP9 bitstream has 8 sub-frames into one superframe, the superframe
>index validate failed when reach 8, modify the index checking so that the
>last sub-frame can be decoded normally with stateful vp9 decoder.

I find this commit message a bit confusing, you say that you couldn't
index the last superframe, but then you say that you modify the index
checking so that you can access the last sub-frame.

I would reword this section, here is my suggestion:

The VP9 bitstream uses superframes, which each contain 8 sub-frames,
enable accessing the last superframe by increasing the range of the
index validation as the maximum number of superframes is 8 and not 7.

The rest looks good as already mentioned by Nicolas.

Greetings,
Sebastian

>
>Signed-off-by: Irui Wang <irui.wang@...iatek.com>
>---
>changed with v1:
> - add a new define 'VP9_MAX_SUPER_FRAMES_NUM' for superframes.
>---
> .../mediatek/vcodec/decoder/vdec/vdec_vp9_if.c        | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_if.c b/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_if.c
>index 55355fa70090..039082f600c8 100644
>--- a/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_if.c
>+++ b/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_if.c
>@@ -16,6 +16,7 @@
> #include "../vdec_drv_base.h"
> #include "../vdec_vpu_if.h"
>
>+#define VP9_MAX_SUPER_FRAMES_NUM 8
> #define VP9_SUPER_FRAME_BS_SZ 64
> #define MAX_VP9_DPB_SIZE	9
>
>@@ -133,11 +134,11 @@ struct vp9_sf_ref_fb {
>  */
> struct vdec_vp9_vsi {
> 	unsigned char sf_bs_buf[VP9_SUPER_FRAME_BS_SZ];
>-	struct vp9_sf_ref_fb sf_ref_fb[VP9_MAX_FRM_BUF_NUM-1];
>+	struct vp9_sf_ref_fb sf_ref_fb[VP9_MAX_SUPER_FRAMES_NUM];
> 	int sf_next_ref_fb_idx;
> 	unsigned int sf_frm_cnt;
>-	unsigned int sf_frm_offset[VP9_MAX_FRM_BUF_NUM-1];
>-	unsigned int sf_frm_sz[VP9_MAX_FRM_BUF_NUM-1];
>+	unsigned int sf_frm_offset[VP9_MAX_SUPER_FRAMES_NUM];
>+	unsigned int sf_frm_sz[VP9_MAX_SUPER_FRAMES_NUM];
> 	unsigned int sf_frm_idx;
> 	unsigned int sf_init;
> 	struct vdec_fb fb;
>@@ -526,7 +527,7 @@ static void vp9_swap_frm_bufs(struct vdec_vp9_inst *inst)
> 	/* if this super frame and it is not last sub-frame, get next fb for
> 	 * sub-frame decode
> 	 */
>-	if (vsi->sf_frm_cnt > 0 && vsi->sf_frm_idx != vsi->sf_frm_cnt - 1)
>+	if (vsi->sf_frm_cnt > 0 && vsi->sf_frm_idx != vsi->sf_frm_cnt)
> 		vsi->sf_next_ref_fb_idx = vp9_get_sf_ref_fb(inst);
> }
>
>@@ -735,7 +736,7 @@ static void get_free_fb(struct vdec_vp9_inst *inst, struct vdec_fb **out_fb)
>
> static int validate_vsi_array_indexes(struct vdec_vp9_inst *inst,
> 		struct vdec_vp9_vsi *vsi) {
>-	if (vsi->sf_frm_idx >= VP9_MAX_FRM_BUF_NUM - 1) {
>+	if (vsi->sf_frm_idx > VP9_MAX_SUPER_FRAMES_NUM) {
> 		mtk_vdec_err(inst->ctx, "Invalid vsi->sf_frm_idx=%u.", vsi->sf_frm_idx);
> 		return -EIO;
> 	}
>-- 
>2.18.0
>
>