Re: [PATCH v2 0/7] media: rkvdec: Add HEVC backend

From: Alex Bee <knaerzche@gmail.com>
To: Nicolas Dufresne <nicolas.dufresne@collabora.com>,
	Diederik de Haas <didi.debian@cknow.org>,
	Jonas Karlman <jonas@kwiboo.se>,
	Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
	Detlev Casanova <detlev.casanova@collabora.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/7] media: rkvdec: Add HEVC backend
Date: Thu, 14 Aug 2025 23:25:57 +0200	[thread overview]
Message-ID: <09030afe-553d-46d7-bf85-d1c1fa73c352@gmail.com> (raw)
In-Reply-To: <816fa42715e8bc4bf538371975f97b6d102a74f5.camel@collabora.com>

Am 12.08.25 um 15:27 schrieb Nicolas Dufresne:
> Le mardi 12 août 2025 à 14:55 +0200, Diederik de Haas a écrit :
>> Hi again,
>>
>> On Tue Aug 12, 2025 at 2:11 PM CEST, Diederik de Haas wrote:
>>> On Sun Aug 10, 2025 at 11:24 PM CEST, Jonas Karlman wrote:
>>>> This series add a HEVC backend to the Rockchip Video Decoder driver.
>>>>
>>>> Patch 1 add the new HEVC backend.
>>>> Patch 2-3 add variants support to the driver.
>>>> Patch 4 add support for a rk3288 variant.
>>>> Patch 5 add a rk3328 variant to work around hw quirks.
>>>> Patch 6-7 add device tree node for rk3288.
>>>
>>> It looks like I had a previous version of linuxtv-rkvdec-hevc-v2 branch
>>> locally and that also had this commit:
>>> - media: rkvdec: Keep decoder clocks gated
>>>
>>> Is that one no longer needed/useful/etc ?
>>>
>>> And 'chewitt' also had a commit to fix 8/10-bit selection:
>>> https://github.com/chewitt/linux/commit/4b93b05d2ca608bc23f1d52bcc32df926d435c7c
>>> "WIP: media: rkvdec: fix 8-bit/10-bit format selection"
>>>
>>> I haven't tried that one (yet), but did  try an other variant with
>>> changing the ordering in rkvdec_hevc_decoded_fmts but that didn't work
>>> in my tests. (Can ofc be PEBKAC)
>>>
>>> Would that be useful? I do/did have consistent problems with playing
>>> 10-bit encoded video files.
>>
>> nvm about the 10-bit problem. It exists, but it's not restricted to HEVC
>> as it also exists with with H.264 files.
> 
> The referred patch is against some out-dated kernel. In mainline linux with
> have:
> 
> 	if (sps->bit_depth_luma_minus8 == 0) {
> 		if (sps->chroma_format_idc == 2)
> 			return RKVDEC_IMG_FMT_422_8BIT;
> 		else
> 			return RKVDEC_IMG_FMT_420_8BIT;
> 	} else if (sps->bit_depth_luma_minus8 == 2) {
> 		if (sps->chroma_format_idc == 2)
> 			return RKVDEC_IMG_FMT_422_10BIT;
> 		else
> 			return RKVDEC_IMG_FMT_420_10BIT;
> 	}
> 
> Which covers all cases supporte by the hardware. Chewitt seem to add a
> previously missing 10bit case, and forcing downconversion from 422 to 420. A
> downconversion is something to be chosen and applied by userspace, the kernel
> should pick a non-destructive format by default.

Please note that this patch is completely unrelated to this series, as it
is for Detlev's WIP rkvdec2 driver [0] and for H.265 codec only - rkvdec2
similar to rkvdec(1) only supports NV12 and NV15 for H.265 codec and
perfectly matches what is defined at [1].

[0] 
https://gitlab.collabora.com/detlev/linux/-/tree/add-vdpu381-and-383-to-rkvdec-v2
[1] 
https://gitlab.collabora.com/detlev/linux/-/blob/15352e295a0d38bd0450f608e7bbcbf16dfefd6b/drivers/media/platform/rockchip/rkvdec/rkvdec.c#L333

> Nicolas
> 
>>
>> Cheers,
>>    Diederik
>>
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