# Four-source sports grid

Rendered and verified 2026-10-29. This is actual CoreMF output from four
independently recorded sports clips, replacing the generated-pattern grid on
the Technology page.

## Footage and reuse rights

Each linked source page identifies the footage as the creator's own work and
publishes it under [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/),
which permits commercial copying and adaptation. Credits are retained here
and beside the player. Original audio is removed; no music or voiceover is added.

| Grid position | Footage                                                                                                                                           | Creator                   | Source excerpt |
| ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------- | -------------- |
| Top left      | [Paris Volley–Resovia match](https://commons.wikimedia.org/wiki/File:Paris_Volley_Resovia%2C_24_October_2013_-_30.webm)                           | Shev123                   | 0–14 seconds   |
| Top right     | [Jakob Schubert bouldering](https://commons.wikimedia.org/wiki/File:Jakob_Schubert_JMM_2013_Annecy_2.webm)                                        | Shev123                   | 0–14 seconds   |
| Bottom left   | [Eliška Adamovská lead climbing](https://commons.wikimedia.org/wiki/File:2020-11-28_-_IFSC_Euros_-_Combined_W-L_-_Eli%C5%A1ka_Adamovsk%C3%A1.ogv) | Oleg Bkhambri (Voltmetro) | 30–44 seconds  |
| Bottom right  | [Body-surfing viewpoint at Stockton Beach](https://commons.wikimedia.org/wiki/File:Body_surfing_a_wave.webm)                                      | JaredMcKenzie             | 0–14 seconds   |

Source revisions, original download URLs and SHA-1/SHA-256 hashes are recorded
in [the media-rights record](sports-media-rights.json). Copies of the source
declarations and original downloads are retained with internal verification
evidence. No private or customer media is used.

CC0 addresses the creators' copyright; it does not grant trademark, privacy or
publicity rights. This technical processing demonstration does not imply
endorsement by the athletes, teams, events or creators. The footage dedication
does not license the CoreMF SDK.

## Data flow

Four silent H.264 files → four native decoder paths → CoreGL 2×2 GPU
composition → native H.264 encoder → MP4. The clips are separate recordings,
not synchronized camera angles of the same event. No RTC transport is involved.

Inputs are staged from the excerpts above to 640×360, square pixels and 25 fps.
Staging uses FFmpeg only for trimming, resizing, frame-rate conversion and audio
removal; the four-source composition and final encoding run through CoreMF.
For each original download, use this staging pattern (set `START` to 30 for
lead climbing and 0 for the other clips):

```sh
ffmpeg -ss START -i ORIGINAL -t 14 -an \
  -vf 'fps=25,scale=640:360:flags=lanczos,setsar=1' \
  -c:v libx264 -preset medium -crf 19 -pix_fmt yuv420p \
  -movflags +faststart INPUT.mp4
```

The existing development `runAPI` builds and executes the native graph using
[this compositor configuration](sports-grid.config.json):

```sh
runAPI -i volleyball.mp4 -i bouldering.mp4 -i lead-climbing.mp4 \
  -i body-surfing.mp4 -f glcomposite -n 4 \
  -filter-config '{"width":1280,"height":720,"layers":[{"input":0,"x":0,"y":0,"w":640,"h":360,"fit":"cover"},{"input":1,"x":640,"y":0,"w":640,"h":360,"fit":"cover"},{"input":2,"x":0,"y":360,"w":640,"h":360,"fit":"cover"},{"input":3,"x":640,"y":360,"w":640,"h":360,"fit":"cover"}]}' \
  -an -o sports-grid.mp4 -p tc -s 1280x720 -r 25
```

Shell quoting above is POSIX; Windows must pass the JSON as one argument.
The command uses the development runtime's available native encoder. No encoder
executable or library is included with the website media.

## Verified output

- [sports-grid.mp4](sports-grid.mp4): 14 seconds, 1280×720 H.264/YUV420P,
  25 fps, 350 decoded frames, no audio stream.
- [sports-grid.png](sports-grid.png): actual decoded output frame at two seconds.
- All four staged inputs and the final output passed complete error-checked
  decoding with FFmpeg. Frame counts were checked with `ffprobe -count_frames`.
- Existing Windows x86-64 MSVC Debug development runtime; Intel UHD Graphics
  770, ANGLE D3D11/OpenGL ES 3.0. The log reports GPU rendering (`software=0`)
  and native `libx264` encoding. GPU composition does not mean GPU encoding or
  an end-to-end GPU-resident pipeline.

This offline functional demonstration does not qualify dynamic MCU, independent
input synchronization, RTC capacity, performance or latency. The commercial
SDK uses its separately audited LGPL-compatible runtime and release qualification.

Runtime identities:

- CoreMF.dll SHA-256: `ca43814a2397d1434d2bf2879994a7c294eef0e76cd79a66eace6ce12e433531`
- runAPI.exe SHA-256: `b46d4c0a3d76f4e896e35c2a6051b0f8b99648e470fcea00cc85d5b8cfa1f881`