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From: Hans Verkuil <>
To: Nicolas Dufresne <>,
	Chen-Yu Tsai <>
Cc: Ezequiel Garcia <>,
	Philipp Zabel <>,
	Mauro Carvalho Chehab <>,
	Greg Kroah-Hartman <>,,,,
Subject: Re: [PATCH] media: hantro: Hook up RK3399 JPEG encoder output
Date: Thu, 25 Nov 2021 09:44:45 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 23/11/2021 20:39, Nicolas Dufresne wrote:
> Le lundi 22 novembre 2021 à 11:57 +0800, Chen-Yu Tsai a écrit :
>> On Sat, Nov 20, 2021 at 12:00 AM Nicolas Dufresne <> wrote:
>>> Le vendredi 19 novembre 2021 à 15:46 +0800, Chen-Yu Tsai a écrit :
>>>> The JPEG encoder found in the Hantro H1 encoder block only produces a
>>>> raw entropy-encoded scan. The driver is responsible for building a JPEG
>>>> compliant bitstream and placing the entropy-encoded scan in it. Right
>>>> now the driver uses a bounce buffer for the hardware to output the raw
>>>> scan to.
>>>> In commit e765dba11ec2 ("hantro: Move hantro_enc_buf_finish to JPEG
>>>> codec_ops.done"), the code that copies the raw scan from the bounce
>>>> buffer to the capture buffer was moved, but was only hooked up for the
>>>> Hantro H1 (then RK3288) variant. The RK3399 variant was broken,
>>>> producing a JPEG bitstream without the scan, and the capture buffer's
>>>> .bytesused field unset.
>>>> Fix this by duplicating the code that is executed when the JPEG encoder
>>>> finishes encoding a frame. As the encoded length is read back from
>>>> hardware, and the variants having different register layouts, the
>>>> code is duplicated rather than shared.
>>>> Fixes: e765dba11ec2 ("hantro: Move hantro_enc_buf_finish to JPEG codec_ops.done")
>>>> Signed-off-by: Chen-Yu Tsai <>
>>>> ---
>>>> This was developed on the downstream ChromeOS 5.10 kernel (with a hack
>>>> for .data_offset) and tested with ChromeOS's jpeg_encode_accelerator_unittest
>>>> patched to accept non-JFIF JPEG streams (
>>>> This was then forward-ported to mainline (name and filename changes) and
>>>> compile tested only.
>>> Tested with GStreamer on top of 5.16-rc1 from media_stage.git. Not perfect but
>>> at least the the output it valid. Test command was:
>>>   gst-launch-1.0 videotestsrc num-buffers=2 ! v4l2jpegenc ! filesink
>>> location=test.jpg
>>> Notice that I encode two frames, it seems like the draining flow is broken in
>>> this driver. GStreamer will queue the frame and issue CMD_START immediately, the
>>> driver will skip the encode, leaving me with an empty file.
>> The hantro driver doesn't implement ENC_CMD, which IIRC is used for the
>> draining flow. I guess that's something to fix, since the mem2mem stateful
>> encoder spec seems to require it. Or does that spec not apply to the JPEG
>> encoders?
> I'm pretty sure its required. But this isn't a regression from this patch.

I don't think it is required for JPEG encoders today. Each frame is independent of
any other, so it behaves just like a m2m scaler for example.

It doesn't hurt to support it, but it shouldn't be necessary for jpeg codecs.

If there is a reason why this is needed, then it would likely also be needed for
m2m devices like scalers.



>>> Tested-by: Nicolas Dufresne <>
>> Thanks!
>> ChenYu

  reply	other threads:[~2021-11-25  8:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-19  7:46 [PATCH] media: hantro: Hook up RK3399 JPEG encoder output Chen-Yu Tsai
2021-11-19 16:00 ` Nicolas Dufresne
2021-11-22  3:57   ` Chen-Yu Tsai
2021-11-23 19:39     ` Nicolas Dufresne
2021-11-25  8:44       ` Hans Verkuil [this message]
2021-11-25 15:41         ` Nicolas Dufresne
2021-11-25 13:23 ` Ezequiel Garcia

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