How it works

Program structure

• process user input (width, height, framerate, depth units, time to capture)
• init file for raw HEVC output
• init Realsense D400 device
• init VAAPI encoder with HVE
• read depth data from the camera
• encode to HEVC Main10 profile
• write to raw HEVC file
• cleanup

The encoding

Realsense and VAAPI devices are configured to work together (no software depth processing on the host)

• VAAPI is configured for HEVC 10 bit per channel P010LE pixel format
• Realsense is configured to ouput P016LE (Y plane) compatible depth data
• P016LE data is binary compatible with P010LE data
• the data output by Realsense is directly fed to VAAPI hardware encoder
• the P010LE color data is filled with constant value

Pixel format	Side												Side
	MSB	15	14	...	7	6	5	4	3	2	1	0	LSB
P016LE		x	x	...	x	x	x	x	x	x	x	x
P010LE		x	x	...	x	x	0	0	0	0	0	0

The P010LE has data only in 10 MSB, zeroes in 6 LSB (ignored values).

We have 10 bits to encode 16 bit Realsense depth data which means range/precission trade-off:

• the trade-off is controlled with Realsense Depth Units (0.0001 - 0.01)
• the best precision/worst range is 6.4 mm/6.5472 m (for Depth Units 0.0001)
• the worst precission/best range is 64 cm/654.72 m (for Depth Units 0.01)
• all trade-offs in between are possible

For range: 65472 in binary is 10 ones followed by 6 zeroes.
For precision: we discard 6 bits of data (64 times worse precision than set in Depth Units).