Cross Compile with QT for raspberry pi

[ben80]

Hello, i just came across mdk-sdk and it might be what i am searching for a long time.
Currently i am displaying videos on a raspberry pi with hardware aceleration and would like to replace the "video tools" that i am using.
I cross compiled qt5 for raspberry pi and use POT (Link) to show the video. Unfortunately this is not very stable. Could someone answer my following questions :

• Can i cross-compile mdk-sdk with QT for raspberry pi?
• Can i use QTs qml code to play videos?
• Will it show videos hw accelerated (no sound needed)?
• does it work with qt5 and/or qt6?

Thanks a lot
Ben

[wang-bin]

download mdk-sdk-linux.tar.xz and extract it, include $MDK_SDK_DIR/mdk-sdk/lib/cmake/FindMDK.cmake or $MDK_SDK_DIR/mdk-sdk/mdk.pri in your cmake or qmake project, then you should be able to build your project, cross or native compile.

qml examples can be found here.

hw accelerated decoding and rendering are supported, delete libffmpeg.so.* in mdk-sdk to use system ffmpeg to support h264, hevc hardware decoder, use opengl es2/3 to support 0-copy rendering.

both qt5 and 6 are supportd.

[ben80]

What is the difference between qml, qmlrhi and qmlrhi0 examples?

When do you think the qtmuldimedia plugin will be ready for qt6?

Thanks

[wang-bin]

qml is based on opengl framebuffer, supports old qt versions. qmlrhi is based on rhi, qt >= 5.14 is required. qmlrhi0 is not maintaned. qmlrhi is recommended

[ben80]

Thanks, does "qml" (openly framebuffer) also work with qt6 or only qmlrhi? The qmlrhi example contains several "todos".

[wang-bin]

qml supports qt6. there are always some todos

[ben80]

I am making progress. I added some of your "qml-example" code to my app and it displays a video.
I added this line to the play() function:
internal_player->setDecoders(MediaType::Video, {"V4L2M2M", "FFmpeg:hwcontext=drm", "FFmpeg", "dav1d"});

I attached a log with your logging. Would you mind having a look at it?
Anything i should work on?

Thanks so far for your help.
mdk-sdk_log1.txt

[wang-bin]

[FFmpeg:h264_v4l2m2m] Using device /dev/video10
0x5582a61d60 buffering progress 56%
[FFmpeg:h264_v4l2m2m] driver 'bcm2835-codec' on card 'bcm2835-codec-decode' in mplane mode
[FFmpeg:h264_v4l2m2m] requesting formats: output=H264/none capture=YU12/yuv420p
0x5582a61d60 buffering progress 76%
02.09.2025 00:11:33.194 RX: SET_LOG_LEVEL 1
0x5582a61d60 buffering progress 96%
0x5582a61d60 buffering progress 100%
default 0x5582a61d60 FrameReader::update MediaStatus 0X14=>0X124
++++++++++++BUFFERING END++++++++++++
AVCodec.Video[h264_v4l2m2m.] decoder: 1 Single threads
unsupported avcodec options: hwaccel=v4l2m2m
h264 1280x720 yuv420p
ERROR! failed to setup video decoder

failed to use v4l2m2m decoder. can you try to delete libffmpeg.so* and try again?

[ben80]

I moved lib/arm64/libffmpeg.so.8 and got the following output.
mdk-sdk_log2.txt

[wang-bin]

this looks good, it's using hardware decoder