Message-Id: <2B4BFCAC-57FF-429F-BD57-457E634A24E8@gmail.com>
Date: Tue, 4 Nov 2025 11:28:33 +0400
From: Christian Hewitt <christianshewitt@...il.com>
To: Zhentao Guo <zhentao.guo@...ogic.com>
Cc: Neil Armstrong <neil.armstrong@...aro.org>,
 Mauro Carvalho Chehab <mchehab@...nel.org>,
 Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Kevin Hilman <khilman@...libre.com>,
 Jerome Brunet <jbrunet@...libre.com>,
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
 linux-media@...r.kernel.org,
 devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org,
 linux-amlogic@...ts.infradead.org
Subject: Re: [PATCH 0/3] Add Amlogic stateless H.264 video decoder for S4

> On 28 Oct 2025, at 3:47 pm, Zhentao Guo <zhentao.guo@...ogic.com> wrote:
> 
> 在 2025/10/28 18:50, Neil Armstrong 写道:
>> [ EXTERNAL EMAIL ]
>> 
>> Hi,
>> 
>> On 10/27/25 06:42, Zhentao Guo via B4 Relay wrote:
>>> Introduce initial driver support for Amlogic's new video acceleration
>>> hardware architecture, designed for video stream decoding.
>>> 
>>> Compared to the current Amlogic video decoder hardware architecture,
>>> this new implementation eliminates the Esparser hardware component,
>>> enabling direct vb2 buffer input. The driver is designed to support
>>> the V4L2 M2M stateless decoder API. The initial phase includes support
>>> for H.264 decoding on Amlogic S805X2 platform.

S805X2 looks challenging to test (without hardware) and this will prevent
wider feedback. Can you extend the driver for G12B? - it has good upstream
support and lots of good boards. This would also demonstrate (in patches)
how further expansion is handled. The only minor complication is that
meson-g12-common.dtsi has vdec nodes for the staging driver that need to be
reworked. This probably leads into a discussion (with Neil mostly) about
how to drop/clean-up the staging driver. NB: There is also a canvas driver
long-merged upstream. Can this be reused or adapted instead of adding new
canvas code?

>>> The driver is capable of:
>>> - Supporting stateless H.264 decoding up to a resolution 1920x1088(on the S805X2 platform).
>>> - Supporting I/P/B frame handling.
>>> - Supporting vb2 mmap and dma-buf modes.
>>> - Supporting frame-based decode mode. (Note that some H.264 bitstreams require
>>>    DPB reordering to generate reference lists, the stateless decoder driver
>>>    cannot access reordered reference lists in this mode, requiring the driver
>>>    to perform reference list reordering itself)
>>> - Supporting NV12/NV21 output.
>>> - Supporting Annex B start codes.
>> 
>> Thanks for the initial drop, it's very nice !
>> 
>> First of all, this still requires some work so it would be better if you
>> used the RFC tag until all issues are sorted out.
>> 
> Thanks for the reminder, I will add the RFC tag from the next patch version.
>> You didn't tell anything about the firmware, did you build a specific version
>> of the firmware to handle the stateless and bypass ESPARSER ?
>> Will this technique work with the released firmwares of GXL/G12/SM1 ?
> For the firmware, we need to build a specific version for stateless decoder
> driver. The ESPARSER is fully dropped. As I mentioned, this technique needs
> specific firmware so it would not work with the released firmware of the older
> SOCs. We plan to submit the new firmware to the linux-firmware repo. I will
> share the commit once the upload is completed.

linux-firmware only accepts files for merged drivers so while things are
still in development you either need to share firmware blobs as an extra
patch with the series (tagged as DONOTMERGE) or you need to put files in
a repo and share a link in the cover-letter. You are welcome to abuse the
LibreELEC org on GitHub if you need somewhere friendly to push files (we
already host similar things for distro packaging).

>> Will you support the compressed format and 10bit with this ?
> No, the compressed format and 10bit are not supported.

Understood that AFBC and 10-bit are not part of this initial series, but
are they planned for a follow-up series? .. or never?

>>> This driver is tested with Gstreamer.
>>> Example:
>>> gst-launch-1.0 filesrc location=/tmp/video_640x360_mp4_hevc_450kbps_no_b.mp4 !
>>> parsebin ! v4l2slh264dec ! filesink location=/tmp/output.yuv
>>> 
>>> The driver passes v4l2 compliance test, test reports :
>>> v4l2-compliance 1.30.1, 64 bits, 64-bit time_t
>>> 
>>> Compliance test for aml-vdec-drv device /dev/video0:
>>> 
>>> Driver Info:
>>>          Driver name      : aml-vdec-drv
>>>          Card type        : platform:aml-vdec-drv
>>>          Bus info         : platform:fe320000.video-codec
>>>          Driver version   : 6.16.0
>>>          Capabilities     : 0x84204000
>>>                  Video Memory-to-Memory Multiplanar
>>>                  Streaming
>>>                  Extended Pix Format
>>>                  Device Capabilities
>>>          Device Caps      : 0x04204000
>>>                  Video Memory-to-Memory Multiplanar
>>>                  Streaming
>>>                  Extended Pix Format
>>>          Detected Stateless Decoder
>>> Media Driver Info:
>>>          Driver name      : aml-vdec-drv
>>>          Model            : aml-vdec-drv
>>>          Serial           :
>>>          Bus info         : platform:fe320000.video-codec
>>>          Media version    : 6.16.0
>>>          Hardware revision: 0x00000000 (0)
>>>          Driver version   : 6.16.0
>>> Interface Info:
>>>          ID               : 0x0300000c
>>>          Type             : V4L Video
>>> Entity Info:
>>>          ID               : 0x00000001 (1)
>>>          Name             : aml_dev_drv-source
>>>          Function         : V4L2 I/O
>>>          Pad 0x01000002   : 0: Source
>>>            Link 0x02000008: to remote pad 0x1000004 of entity 'aml_dev_drv-proc' (Video Decoder): Data, Enabled, Immutable
>>> 
>>> Required ioctls:
>>>          test MC information (see 'Media Driver Info' above): OK
>>>          test VIDIOC_QUERYCAP: OK
>>>          test invalid ioctls: OK
>>> 
>>> Allow for multiple opens:
>>>          test second /dev/video0 open: OK
>>>          test VIDIOC_QUERYCAP: OK
>>>          test VIDIOC_G/S_PRIORITY: OK
>>>          test for unlimited opens: OK
>>> 
>>> Debug ioctls:
>>>          test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
>>>          test VIDIOC_LOG_STATUS: OK (Not Supported)
>>> 
>>> Input ioctls:
>>>          test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
>>>          test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
>>>          test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
>>>          test VIDIOC_ENUMAUDIO: OK (Not Supported)
>>>          test VIDIOC_G/S/ENUMINPUT: OK (Not Supported)
>>>          test VIDIOC_G/S_AUDIO: OK (Not Supported)
>>>          Inputs: 0 Audio Inputs: 0 Tuners: 0
>>> 
>>> Output ioctls:
>>>          test VIDIOC_G/S_MODULATOR: OK (Not Supported)
>>>          test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
>>>          test VIDIOC_ENUMAUDOUT: OK (Not Supported)
>>>          test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
>>>          test VIDIOC_G/S_AUDOUT: OK (Not Supported)
>>>          Outputs: 0 Audio Outputs: 0 Modulators: 0
>>> 
>>> Input/Output configuration ioctls:
>>>          test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
>>>          test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
>>>          test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
>>>          test VIDIOC_G/S_EDID: OK (Not Supported)
>>> 
>>> Control ioctls:
>>>          test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
>>>          test VIDIOC_QUERYCTRL: OK
>>>          test VIDIOC_G/S_CTRL: OK
>>>          test VIDIOC_G/S/TRY_EXT_CTRLS: OK
>>>          test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK
>>>          test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
>>>          Standard Controls: 6 Private Controls: 0
>>>          Standard Compound Controls: 4 Private Compound Controls: 0
>>> 
>>> Format ioctls:
>>>          test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
>>>          test VIDIOC_G/S_PARM: OK (Not Supported)
>>>          test VIDIOC_G_FBUF: OK (Not Supported)
>>>          test VIDIOC_G_FMT: OK
>>>          test VIDIOC_TRY_FMT: OK
>>>          test VIDIOC_S_FMT: OK
>>>          test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
>>>          test Cropping: OK (Not Supported)
>>>          test Composing: OK (Not Supported)
>>>          test Scaling: OK (Not Supported)
>>> 
>>> Codec ioctls:
>>>          test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
>>>          test VIDIOC_G_ENC_INDEX: OK (Not Supported)
>>>          test VIDIOC_(TRY_)DECODER_CMD: OK
>>> 
>>> Buffer ioctls:
>>>          test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
>>>          test CREATE_BUFS maximum buffers: OK
>>>          test VIDIOC_REMOVE_BUFS: OK
>>>          test VIDIOC_EXPBUF: OK
>>>          test Requests: OK
>>>          test blocking wait: OK
>> 
>> Please also enable the streaming tests.
> Yes, we did some streaming tests with Gstreamer, fluster test and bug fix is also in progress.
>>> 
>>> Total for aml-vdec-drv device /dev/video0: 49, Succeeded: 49, Failed: 0, Warnings: 0
>>> 
>>> Some Fluster test cases are still failing. We will publish the final results
>>> once all these Fluster test failures have been resolved.
>> 
>> As Christian reported, please add the flutter results aswell.
> Thanks. We have now tested the JVT-AVC_V1.
> Result:
> Ran 54/135 tests successfully
> 
> - 52 test vectors failed due to interlaced or mbaff clips: The Amlogic stateless
>   decoder driver only support bitstreams with frame_mbs_only_flags == 1.
>   Test Vectors:
>         cabac_mot_fld0_full
>         cabac_mot_mbaff0_full
>         cabac_mot_picaff0_full
>         CABREF3_Sand_D
>         CAFI1_SVA_C
>         CAMA1_Sony_C
>         CAMA1_TOSHIBA_B
>         cama1_vtc_c
>         cama2_vtc_b
>         CAMA3_Sand_E
>         cama3_vtc_b
>         CAMACI3_Sony_C
>         CAMANL1_TOSHIBA_B
>         CAMANL2_TOSHIBA_B
>         CAMANL3_Sand_E
>         CAMASL3_Sony_B
>         CAMP_MOT_MBAFF_L30
>         CAMP_MOT_MBAFF_L31
>         CANLMA2_Sony_C
>         CANLMA3_Sony_C
>         CAPA1_TOSHIBA_B
>         CAPAMA3_Sand_F
>         cavlc_mot_fld0_full_B
>         cavlc_mot_mbaff0_full_B
>         cavlc_mot_picaff0_full_B
>         CVCANLMA2_Sony_C
>         CVFI1_Sony_D
>         CVFI1_SVA_C
>         CVFI2_Sony_H
>         CVFI2_SVA_C
>         CVMA1_Sony_D
>         CVMA1_TOSHIBA_B
>         CVMANL1_TOSHIBA_B
>         CVMANL2_TOSHIBA_B
>         CVMAPAQP3_Sony_E
>         CVMAQP2_Sony_G
>         CVMAQP3_Sony_D
>         CVMP_MOT_FLD_L30_B
>         CVNLFI1_Sony_C
>         CVNLFI2_Sony_H
>         CVPA1_TOSHIBA_B
>         FI1_Sony_E
>         MR6_BT_B
>         MR7_BT_B
>         MR8_BT_B
>         MR9_BT_B
>         Sharp_MP_Field_1_B
>         Sharp_MP_Field_2_B
>         Sharp_MP_Field_3_B
>         Sharp_MP_PAFF_1r2
>         Sharp_MP_PAFF_2r
>         CVMP_MOT_FRM_L31_B
> - 3 test vectors failed due to unsupported bitstream.
>   num_slice_group_minus1 greater than zero is not supported by the
>   hardware.
>   Test Vectors:
>         FM1_BT_B
>         FM1_FT_E
>         FM2_SVA_C
> - 2 test vectors failed because SP_SLICE type is not supported by the
>   hardware.
>   Test Vectors:
>         SP1_BT_A
>         sp2_bt_b
> 
> We are working with the remain failures, we think that these fail cases
> 
> must be resolved.
> 
> I'll add the fluster result to the cover-letter from the next patch version.

Thanks, it’s good to understand where things are. All good :)

Christian


>> 
>> Neil
>> 
>>> 
>>> Signed-off-by: Zhentao Guo <zhentao.guo@...ogic.com>
>>> ---
>>> Zhentao Guo (3):
>>>        dt-bindings: vdec: Add binding document of Amlogic decoder accelerator
>>>        dts: decoder: Support V4L2 stateless decoder dt node for S4
>>>        decoder: Add V4L2 stateless H.264 decoder driver
>>> 
>>>   .../bindings/media/amlogic,vcodec-dec.yaml         |   96 ++
>>>   MAINTAINERS                                        |    7 +
>>>   arch/arm64/boot/dts/amlogic/meson-s4.dtsi          |   24 +
>>>   drivers/media/platform/amlogic/Kconfig             |    2 +
>>>   drivers/media/platform/amlogic/Makefile            |    1 +
>>>   drivers/media/platform/amlogic/vdec/Kconfig        |   15 +
>>>   drivers/media/platform/amlogic/vdec/Makefile       |    4 +
>>>   drivers/media/platform/amlogic/vdec/aml_vdec.c     |  759 +++++++++
>>>   drivers/media/platform/amlogic/vdec/aml_vdec.h     |   31 +
>>>   .../platform/amlogic/vdec/aml_vdec_canvas_utils.c  |  154 ++
>>>   .../platform/amlogic/vdec/aml_vdec_canvas_utils.h  |   22 +
>>>   drivers/media/platform/amlogic/vdec/aml_vdec_drv.c |  263 +++
>>>   drivers/media/platform/amlogic/vdec/aml_vdec_drv.h |  194 +++
>>>   drivers/media/platform/amlogic/vdec/aml_vdec_hw.c  |  652 +++++++
>>>   drivers/media/platform/amlogic/vdec/aml_vdec_hw.h  |  182 ++
>>>   .../platform/amlogic/vdec/aml_vdec_platform.c      |   37 +
>>>   .../platform/amlogic/vdec/aml_vdec_platform.h      |   62 +
>>>   drivers/media/platform/amlogic/vdec/h264.c         | 1790 ++++++++++++++++++++
>>>   drivers/media/platform/amlogic/vdec/h264.h         |  300 ++++
>>>   drivers/media/platform/amlogic/vdec/reg_defines.h  |  175 ++
>>>   20 files changed, 4770 insertions(+)
>>> ---
>>> base-commit: 72fb0170ef1f45addf726319c52a0562b6913707
>>> change-id: 20251027-b4-s4-vdec-upstream-0603c1a4c84a
>>> 
>>> Best regards,
>> 
> Thank you
> 
> Zhentao
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic@...ts.infradead.org
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