Camera board • V4L2 Camera HQ to H264 encoder efficiency (CM4)

Hello All,

I'm running HQ camera on Buster using V4L2 driver (direct V4L2 V4L2_MEMORY_MMAP buffer) on CM4.
In parallel I use /dev/video11 H264 encoder (also V4L2_MEMORY_MMAP buffers).

V4L2 camera output pixelformat is
[0]: 'pRCC' (12-bit Bayer RGRG/GBGB Packed)
Size: Discrete 4056x3040
Size: Discrete 2028x1520
Size: Discrete 2028x1080
[1]: 'RG12' (12-bit Bayer RGRG/GBGB)
Size: Discrete 4056x3040
Size: Discrete 2028x1520
Size: Discrete 2028x1080
[2]: 'pRAA' (10-bit Bayer RGRG/GBGB Packed)
Size: Discrete 1332x990
[3]: 'RG10' (10-bit Bayer RGRG/GBGB)
Size: Discrete 1332x990

H264 input is
ioctl: VIDIOC_ENUM_FMT
Type: Video Output Multiplanar

[0]: 'YU12' (Planar YUV 4:2:0)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[1]: 'YV12' (Planar YVU 4:2:0)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[2]: 'NV12' (Y/CbCr 4:2:0)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[3]: 'NV21' (Y/CrCb 4:2:0)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[4]: 'RGBP' (16-bit RGB 5-6-5)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[5]: 'RGB3' (24-bit RGB 8-8-8)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[6]: 'BGR3' (24-bit BGR 8-8-8)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[7]: 'BGR4' (32-bit BGRA/X 8-8-8-8)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[8]: 'YUYV' (YUYV 4:2:2)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[9]: 'YVYU' (YVYU 4:2:2)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[10]: 'UYVY' (UYVY 4:2:2)
Size: Stepwise 32x32 - 1920x1920 with step 1/1
[11]: 'VYUY' (VYUY 4:2:2)
Size: Stepwise 32x32 - 1920x1920 with step 1/1

1.It is impossible to directly stream camera output to H264, the data have to be converted....I'm i right?
2.What is the most efficient way to convert camera out data to H264 input data?
3.Does raspberry pi CM4 provides any hardware accelerations for converting formats?
4.What is the maximum possible resolution for video11?
5.What is the maximum possible framerate for 2028*1520 resolution using H264 encoder on video11? (if possible)
6.Should I look in to moving from V4L2_MEMORY_MMAP to V4L2_MEMORY_DMABUF?

Thanks in advance

Statistics: Posted by Alexey_Kh — Sat Jul 12, 2025 2:25 pm

---