David Kibble

Thanks Jock - so it's just a modified ffmpeg you've created? Just trying to get my head around what I need to tackle here to make this work. Feels so close and getting h264 decode on the A13 with mainline would I'm sure be v-useful for lots of folks out there with the old hardware. Thanks again for a great forum!

Thanks robertoj - I'll have a look at Armbian and give it a shot. However - the slight problem here is the that our HMI apps are all built using a native DRM framework, (no X11) and they drive an RGB LCD, so the X11/HDMI solution isn't going to work for us. I think the modified MPV is very close, it looks to me like it's just the framebuffer output that failing rather than the h/w decode, which is a shame as the standard mpv outputs just fine to the DRM plane. Thanks for the advice, will give it a go, but maybe will also have a look at the modified ffmpeg. I'm still a bit confused about one thing though, maybe you can help? Does the modified ffmpeg (and mpv) drive the kernel v4l2-m2m driver directly or does it still rely on the userspace v4l2-request layer? Many thanks

Hi All - really hoping someone here can help me move forward in the right direction. I've been using Allwinner A13 hardware (Olimex SOM) for some years for small HMI applications without issue. Recently I've had the opportunity to explore a request to incorporate h264 video. I'm very aware of the A13's single core limits and therefore have been trying to get the VPU working. I don't use any sort of window manager (X11 / Wayland etc) so this DRM only. My current setup is: Olimex A13 SOM with 512MB RAM Fanscoo F43TAT007 touch LCD (RGB 666 interface) Kernel 6.2 with a few mods for the target LCD and all the necessary updates to the DT to get both the mali 400 GPU and the CEDRUS driver working Debian Bookworm Here are the relevant kernel modules loaded: lima 57344 0 sun4i_backend 20480 0 gpu_sched 32768 1 lima drm_shmem_helper 20480 1 lima sun4i_ss 32768 0 libdes 28672 1 sun4i_ss sunxi_cedrus 45056 0 v4l2_mem2mem 24576 1 sunxi_cedrus videobuf2_dma_contig 24576 1 sunxi_cedrus videobuf2_memops 20480 1 videobuf2_dma_contig videobuf2_v4l2 24576 2 sunxi_cedrus,v4l2_mem2mem videodev 200704 3 sunxi_cedrus,v4l2_mem2mem,videobuf2_v4l2 videobuf2_common 49152 5 sunxi_cedrus,videobuf2_dma_contig,videobuf2_memops,v4l2_mem2mem,videobuf2_v4l2 mc 49152 5 sunxi_cedrus,videobuf2_common,videodev,v4l2_mem2mem,videobuf2_v4l2 sun4i_drm 20480 0 sun4i_frontend 20480 2 sun4i_drm,sun4i_backend drm_dma_helper 16384 3 sun4i_drm,sun4i_backend,sun4i_frontend panel_simple 69632 0 sun4i_tcon 32768 1 sun4i_drm pwm_bl 24576 0 sun8i_tcon_top 16384 2 sun4i_drm,sun4i_tcon Initially I tried the cedrus v4l2-request VAAPI library route, but post kernel 5.9 that's pretty broken and looked like a lot of work. I then went through a process of getting up to kernel 6.2 so that I could try out gstreamer that claimed to have native v4l2 backend capability. That DOES play, but the video is very corrupt. Then I tried mpv which worked, but without h/w decoding so I began looking into compiling my own ffmpeg with v4l2 hardware decoding enabled. While digging into that I found this page! I can play a h264 RTSP video stream ok at 640x480 with s/w decoding which seems to prove the main parts of the video pipeline. I can see v4l2 drivers etc present in the kernel via lsmod along with the sunxi display frontend and backend etc. But - when I try to use your modified mpv with hwdec=drm the hardware decoder is detected, but then I get errors. Here's a bit of the mpv gpu trace log: vo/gpu/opengl] Initializing KMS [vo/gpu/opengl] Picked DRM card 0, primary node /dev/dri/card1 as the default. [vo/gpu/opengl] Driver: sun4i-drm 1.0.0 (20150629) [vo/gpu/opengl/kms] Connector 49 currently connected to encoder 48 [vo/gpu/opengl/kms] Selected Encoder 48 with CRTC 47 [vo/gpu/opengl/kms] Selected mode: 480x800 (480x800@60.01Hz) [vo/gpu/opengl] DRM Atomic support found [vo/gpu/opengl/kms] Using overlay plane 35 as draw plane [vo/gpu/opengl/kms] Using primary plane 31 as drmprime plane [vo/gpu] GBM_FORMAT_ARGB8888 supported by draw plane. [vo/gpu] Supported modifier: 0x0 [vo/gpu] Creating GBM device [vo/gpu] Initializing GBM surface (480 x 800) [vo/gpu/opengl] Initializing EGL [vo/gpu/opengl] EGL_VERSION=1.4 [vo/gpu/opengl] EGL_VENDOR=Mesa Project [vo/gpu/opengl] EGL_CLIENT_APIS=OpenGL OpenGL_ES [vo/gpu/opengl] Trying to create Desktop OpenGL context. .... [vo/gpu/opengl] Initializing EGL surface [vo/gpu] GL_VERSION='2.1 Mesa 22.3.6' [vo/gpu] Detected desktop OpenGL 2.1. [vo/gpu] GL_VENDOR='lima' [vo/gpu] GL_RENDERER='Mali400' [vo/gpu] GL_SHADING_LANGUAGE_VERSION='1.20' ... [vo/gpu] Loaded extension GL_ARB_map_buffer_range. [vo/gpu] Loaded extension GL_ARB_vertex_array_object. [vo/gpu] Loaded extension GL_ARB_texture_rg. [vo/gpu] Loaded extension GL_ARB_sync. [vo/gpu] Loaded extension GL_ARB_invalidate_subdata. [vo/gpu] Loaded extension GL_ARB_get_program_binary. [vo/gpu] Loaded extension GL_ARB_buffer_storage. [vo/gpu] Loaded extension GL_ARB_debug_output. [vo/gpu] Loaded extension GL_KHR_debug. [vo/gpu/opengl] Preparing framebuffer [vo/gpu/opengl] GBM surface using modifier 0x0 [vo/gpu] crtc is not VRR capable [vo/gpu/opengl] Could not find path to render node. VAAPI hwdec will be disabled [vo/gpu] Monitor pixel aspect: 1 ... [vo/gpu] No advanced processing required. Enabling dumb mode. [vo/gpu] Assuming 60.006001 FPS for display sync. [vo/gpu] Loading hwdec drivers for format: 'drm_prime' [vo/gpu] Loading hwdec driver 'drmprime-overlay' [vo/gpu/drmprime-overlay] Using overlay plane 35 as draw plane [vo/gpu/drmprime-overlay] Using primary plane 31 as drmprime plane [vo/gpu] Loading hwdec driver 'drmprime' [vo/gpu/drmprime] using EGL dmabuf interop [vo/gpu/drmprime] Using DRM device: /dev/dri/renderD128 Using hardware decoding (drm). VO: [gpu] 480x270 drm_prime[nv12] [vo/gpu] reconfig to 480x270 drm_prime[nv12] bt.601/bt.709/bt.1886/limited/display SP=1.000000 CL=mpeg2/4/h264 rot=270 [vo/gpu] Resize: 480x800 [vo/gpu] Window size: 480x800 (Borders: l=0 t=0 r=0 b=0) [vo/gpu] Video source: 480x270 (1:1) [vo/gpu] Video display: (0, 0) 270x480 -> (15, 0) 450x800 [vo/gpu] Video scale: 1.666667/1.666667 [vo/gpu] OSD borders: l=15 t=0 r=15 b=0 [vo/gpu] Video borders: l=15 t=0 r=15 b=0 [vo/gpu] Using HW-overlay mode. No GL filtering is performed on the video! [vo/gpu] No advanced processing required. Enabling dumb mode. [vo/gpu/drmprime-overlay] Failed to create framebuffer with drmModeAddFB2 on layer 0: Invalid argument I've highlighted the two obvious errors. The first one about the render node is odd as I do have a /dev/dri/renderD128 device I have enabled DRM debug via kernel cmd line, but nothing new showed up there, just a -22 for the drmModeAddFB2 call. I'm more than happy to go away and build / test / investigate, but this is now beyond my current limits of knowledge, so hoped someone here would be able to point me in the right direction? Many thanks