Tinybma

An optical flowmap generator from motion vectors using a Full Search Block Matching Algorithms (FSBMA) written in c++

Features:

• SAD based motion compensation on the luma chanel only (input images are converted from full sRGB to YUV BT.601)
• New: Bilinear subpixel motion compensation !
• Two visualization mode for computed motion vectors:
  • HSV mode where hue encodes orientation and value encodes normalized norm relative to the maximum displacement
  • UV mode where the red and green channels encode horizontal and vertical displacement
• Luma, residue and prediction visualization
• Reasonably fast: Block search and pixels transforms use all available cpu cores

Video demo

• Badapple but its a block matched motion compensation ! (before the 2026/03/09 update)

Build

cmake -DCMAKE_BUILD_TYPE=Release .
cmake --build .

Usage

Use tinybma -h to display program help.

Example

tinybma ./example/sintel_source.png ./example/sintel_target.png ./example/flowmap_b4_m16.png -v -b 4 -m 16 -l -r -p -s 1 -c hsv 

Which produces the following optical flowmap and residue based on two frames from The Blender open movie project Sintel:

Original reference frame (left) and original target frame (right)

1/4 optical flowmap with max search of 16px + 1 subpixel (left) and the residual image (right)

Predicted luma frame from computed motion vectors and residue

Available colormaps

	HSV map	UV map
Option	--colormap hsv or -c hsv	--colormap uv or -c uv
Result

Changelogs

• 2026/03/09
  • Added prediction frame visualisation
  • Fixed residue visualisation, now negative values were campled to 0
  • Added subpixel motion based on bilinear upsampling after whole pixel motion
  • Switched search metric from MSE to SAD