how to use stateless-mpeg2-vp8-h264-v4 on imx8m with vpu?

[Martin Kepplinger <martin.kepplinger@puri.sm>]

Hi Ezequiel,

On the Librem 5 (imx8mq) I try to decode a (h264) full hd video file
using the VPU.

I'm running the following tree that doesn't change much, but adds the
VPU dts description:
https://source.puri.sm/martin.kepplinger/linux-next/-/commits/5.8-rc3/librem5___vpu
(output of "v4l-ctl --all" at the bottom).


I now run your version of ffmpeg:
https://gitlab.collabora.com/ezequiel/ffmpeg/-/commits/stateless-mpeg2-vp8-h264-v4
(with minor build fixes) but simply doing "ffplay <file>" seems like not
using /dev/video0

Is this supposed to work? If so, do I need to know anything about ffmpeg
to be able to test this? How do you verify that the v4l2 mem2mem device
(vpu) is being used?

thanks a lot,
                                martin



purism@pureos:~/ffmpeg_sources/ffmpeg$ v4l2-ctl --all
Driver Info:
	Driver name      : hantro-vpu
	Card type        : nxp,imx8mq-vpu-dec
	Bus info         : platform: hantro-vpu
	Driver version   : 5.8.0
	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
Media Driver Info:
	Driver name      : hantro-vpu
	Model            : hantro-vpu
	Serial           :
	Bus info         : platform: hantro-vpu
	Media version    : 5.8.0
	Hardware revision: 0x00000000 (0)
	Driver version   : 5.8.0
Interface Info:
	ID               : 0x0300000c
	Type             : V4L Video
Entity Info:
	ID               : 0x00000001 (1)
	Name             : nxp,imx8mq-vpu-dec-source
	Function         : V4L2 I/O
	Pad 0x01000002   : 0: Source
	  Link 0x02000008: to remote pad 0x1000004 of entity
'nxp,imx8mq-vpu-dec-proc': Data, Enabled, Immutable
Priority: 2
Format Video Capture Multiplanar:
	Width/Height      : 48/48
	Pixel Format      : 'NV12' (Y/CbCr 4:2:0)
	Field             : None
	Number of planes  : 1
	Flags             :
	Colorspace        : JPEG
	Transfer Function : Default
	YCbCr/HSV Encoding: Default
	Quantization      : Default
	Plane 0           :
	   Bytes per Line : 48
	   Size Image     : 3456
Format Video Output Multiplanar:
	Width/Height      : 48/48
	Pixel Format      : 'MG2S' (MPEG-2 Parsed Slice Data)
	Field             : None
	Number of planes  : 1
	Flags             :
	Colorspace        : JPEG
	Transfer Function : Default
	YCbCr/HSV Encoding: Default
	Quantization      : Default
	Plane 0           :
	   Bytes per Line : 0
	   Size Image     : 4608

Codec Controls

        mpeg_2_slice_parameters 0x009909fa (unknown): type=103
flags=has-payload
   mpeg_2_quantization_matrices 0x009909fb (unknown): type=104
flags=has-payload
                   h264_profile 0x00990a6b (menu)   : min=0 max=4
default=2 value=2
    h264_sequence_parameter_set 0x00990ce8 (unknown): type=110
flags=has-payload
     h264_picture_parameter_set 0x00990ce9 (unknown): type=111
flags=has-payload
            h264_scaling_matrix 0x00990cea (unknown): type=112
flags=has-payload
          h264_slice_parameters 0x00990ceb (unknown): type=113
flags=has-payload
         h264_decode_parameters 0x00990cec (unknown): type=114
flags=has-payload
               h264_decode_mode 0x00990ced (menu)   : min=1 max=1
default=1 value=1
                h264_start_code 0x00990cee (menu)   : min=1 max=1
default=1 value=1
               vp8_frame_header 0x009910d0 (unknown): type=301
flags=has-payload