Description: I’m trying to achieve full GPU hardware acceleration for encoding video from a USB webcam (1920x1080@30fps) to H.264 RTSP stream using ffmpeg via MediaMTX Docker on a Raspberry Pi 4 Model B (4GB with PoE+ HAT and fan).
Current Setup: Raspberry Pi 4B 4GB with PoE+ HAT OS: Debian GNU/Linux 12 (bookworm) aarch64Kernel: 6.6.74-v8+ #1844 SMP PREEMPT Mon Jan 27 11:41:19 GMT 2025 Docker Compose: Code: Select all <https://forums.raspberrypi.com/viewtopic.php?t=383724#> services: mediamtx: image: bluenviron/mediamtx:latest-ffmpeg-rpi restart: always environment: - MTX_RTSPTRANSPORTS=tcp - MTX_WEBRTCADDITIONALHOSTS=192.168.1.1XX ports: - '8559:8559' devices: - "/dev/snd:/dev/snd" - "/dev/video11:/dev/video11" - "/dev/video0:/dev/video0" volumes: - /home/user/Documents/mediamtx/mediamtx_cam3.yml:/mediamtx.yml - /etc/localtime:/etc/localtime:ro MediaMTX Configuration (mediamtx.yml): Code: Select all <https://forums.raspberrypi.com/viewtopic.php?t=383724#> rtspAddress: :8559 writeQueueSize: 8192 protocols: [tcp] paths: swissten: runOnInit: > ffmpeg -hide_banner -hwaccel drm -thread_queue_size 64 -f v4l2 -input_format mjpeg -video_size 1920x1080 -framerate 30 -i /dev/video0 -f alsa -thread_queue_size 1024 -ac 2 -ar 48000 -i plughw:webcam -vsync 2 -b:v 4000k -maxrate 8000k -bufsize 7000k -acodec aac -b:a 226k -vf "format=yuv420p,vflip,hflip,drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf:text='%{localtime:%d.%m.%Y - %H\:%M\:%S}':fontcolor=white:fontsize=20:borderw=2:bordercolor=black:x=w-tw-10:y=h-th-10" -c:v h264_v4l2m2m -preset ultrafast -tune zerolatency -f rtsp rtsp://localhost:8559/swissten -rtsp_transport tcp runOnInitRestart: yes Problem: MediaMTX, ffmpeg streaming, and hardware-accelerated encoding to H.264 using h264_v4l2m2m are working. However, CPU usage spikes due to pixel format conversion from MJPEG to yuv420p, which is required by the h264_v4l2m2m encoder. This pixel format conversion is handled by the CPU, causing a bottleneck. What I’m Looking For: I’m seeking a method to achieve full GPU hardware acceleration: Either directly encode the MJPEG stream to H.264 using hardware acceleration. Or hardware encode the MJPEG to yuv420p, and then to H.264 using GPU, bypassing CPU for pixel format conversion. Additional Information: The /dev/video11 device is the hardware encoder (bcm2835-codec) on the Raspberry Pi: Code: Select all <https://forums.raspberrypi.com/viewtopic.php?t=383724#> [h264_v4l2m2m @ 0x5594dd9d20] Using device /dev/video11 [h264_v4l2m2m @ 0x5594dd9d20] driver 'bcm2835-codec' on card 'bcm2835-codec-encode' in mplane mode [h264_v4l2m2m @ 0x5594dd9d20] requesting formats: output=YU12 capture=H264 I had to add /dev/video11 in Docker to access the hardware encoder, and modified the MediaMTX configuration accordingly. Despite this, the pixel format conversion remains a CPU-bound process. Any suggestions or tools that could help pipe the 1080p@30fps stream from /dev/video0 to the HW encoder and output in yuv420p format without CPU bottleneck would be greatly appreciated. Thanks in advance! _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
