fix: allow core-mt WASM memory to grow to avoid OOM on 4K frames (#946)

[ousamabenyounes]

The multi-threaded core build pinned INITIAL_MEMORY=1024MB with no growth, so decoding a single high-resolution (e.g. 4K) frame aborted with Aborted(OOM). Enable bounded -sALLOW_MEMORY_GROWTH -sMAXIMUM_MEMORY=2GB for the FFMPEG_MT build (growable SharedArrayBuffer is supported by modern browsers/Emscripten).

Test verification (RED → GREEN)

With the fix reverted, the new test fails (RED):

  [build] core-mt memory growth (#946)
core-mt build flags: ${FFMPEG_MT:+ -sINITIAL_MEMORY=1024MB}   # ALLOW_MEMORY_GROWTH is not recommended when using threads, thus we use a large initial memory
    1) allows memory growth up to a maximum for the multi-threaded build


  0 passing (7ms)
  1 failing

  1) [build] core-mt memory growth (#946)
       allows memory growth up to a maximum for the multi-threaded build:
     AssertionError [ERR_ASSERTION]: core-mt build must pass -sALLOW_MEMORY_GROWTH to avoid OOM on large frames
      at Context.<anonymous> (tests/build-mt-memory-growth.test.js:25:12)
      at process.processImmediate (node:internal/timers:484:21)

With the fix applied, the test passes (GREEN):

GREEN attempt 1/2 (exit 0)


  [build] core-mt memory growth (#946)
core-mt build flags: ${FFMPEG_MT:+ -sINITIAL_MEMORY=1024MB -sALLOW_MEMORY_GROWTH -sMAXIMUM_MEMORY=2GB} # start with a large initial memory, but still allow growth (up to 2GB) so decoding high-resolution input (e.g. 4K) does not abort with OOM (#946)
    ✔ allows memory growth up to a maximum for the multi-threaded build


  1 passing (6ms)

Full local suite

Command: npm run lint && npm run build && npm test

> lint
> npm-run-all lint:*

sh: 1: npm-run-all: not found

Fix #946

[netlify]

✅ Deploy Preview for ffmpegwasm canceled.

Name	Link
🔨 Latest commit	c8d67c5
🔍 Latest deploy log	https://app.netlify.com/projects/ffmpegwasm/deploys/6aa1e2c82fcd7b0008df1638