Add NVENC (h264_nvenc, hevc_nvenc) encoder support for Linux builds

[JonnyBurger]

This PR copies the changes from #16 so CircleCI runs on a branch owned by a maintainer account.\n\nOriginal PR: #16

[willy-scr]

Hi @JonnyBurger, I noticed the CircleCI Linux builds failed on this PR (build-linux-x64-gnu, build-linux-x64-musl, build-linux-arm-gnu, build-linux-arm-musl all failed).

I can't access the CircleCI logs directly — could you share what the error was?

My best guess is either:

1. nv-codec-headers git clone failed in the Docker container
2. make install PREFIX=remotion failed (maybe needs SUDO or different make flags)
3. FFmpeg configure couldn't find the ffnvcodec pkg-config file

Happy to fix once I know the error!

[willy-scr]

The CI build fails because compile-nvenc.mjs references a non-existent tag:

const NV_CODEC_HEADERS_TAG = "n12.2.16.0";

Tag n12.2.16.0 does not exist in FFmpeg/nv-codec-headers. Fix:

- const NV_CODEC_HEADERS_TAG = "n12.2.16.0";
+ const NV_CODEC_HEADERS_TAG = "n12.2.72.0";

n12.2.72.0 is the latest 12.x release, compatible with FFmpeg n7.1.

Already fixed on my fork's branch (willy-scr:feature/nvenc) — see commit 935216f.

[willy-scr]

@JonnyBurger This PR is ready to merge — all 6 CI checks are passing and mergeable_state is clean.

As noted in remotion-dev/remotion#7733, the rebuilt binary has --enable-encoder=h264_nvenc in the config string but the actual NVENC encoders are missing from libavcodec.so because the nv-codec-headers tag was still broken when the binary was built. Merging this PR first and then rebuilding the binaries should fix that.

[JonnyBurger]

Findings from the artifact size comparison:

Target	/zips	pr17-binaries	Delta
aarch64-unknown-linux-gnu.gz	6,826,509	7,043,212	+216,703
aarch64-unknown-linux-musl.gz	8,520,339	8,744,103	+223,764
x86_64-unknown-linux-gnu.gz	10,084,581	10,302,516	+217,935
x86_64-unknown-linux-musl.gz	10,418,370	10,633,345	+214,975
x86_64-pc-windows-gnu.gz	10,982,127	10,981,932	-195

Conclusion: Linux got bigger, Windows did not.

Implemented changes in build scripts:

1. Enable NVENC for Windows cross-builds too (so Windows should now reflect the same feature addition/size impact).
2. Exclude NVENC from Linux ARM64 builds (both GNU and musl), so arm64 targets do not carry this addition.

Technically this is now gated as: enable NVENC when running on Linux and either building Windows (windows target) or non-ARM64 Linux; skip on native Linux ARM64.

[willy-scr]

Looks good! The renderer code in remotion#7733 already handles both Linux and Windows NVENC selection (process.platform === 'linux' || process.platform === 'win32'), so enabling NVENC for Windows cross-builds here will work seamlessly.

The ARM64 exclusion makes sense — our probing logic (probe-encoder.ts) will simply not find NVENC encoders on ARM64 binaries and gracefully fall back to software encoding via the if-possible mode. No code changes needed on our side.

[JonnyBurger]

✅ Merged! Binary sizing verified:

• aarch64 Linux now correctly smaller (excluded NVENC)
• x86_64 Linux includes NVENC ✓
• x86_64 Windows includes NVENC ✓

This improvement is proceeding in the Remotion main repository. Thanks for the collaboration!