Function readNv12Metadata

apps/desktop/src/utils/socket.ts:44–75

(buffer: ArrayBuffer)

};

function readNv12Metadata(buffer: ArrayBuffer): Nv12Metadata | null {
	if (buffer.byteLength < NV12_METADATA_SIZE) return null;

	const formatCheck = new DataView(buffer, buffer.byteLength - 4, 4);
	const magic = formatCheck.getUint32(0, true);
	if (magic !== NV12_VIDEO_MAGIC && magic !== NV12_FULL_MAGIC) return null;

	const metadataOffset = buffer.byteLength - NV12_METADATA_SIZE;
	const meta = new DataView(buffer, metadataOffset, NV12_METADATA_SIZE);
	const yStride = meta.getUint32(0, true);
	const height = meta.getUint32(4, true);
	const width = meta.getUint32(8, true);

	const ySize = yStride * height;
	const uvSize = yStride * Math.floor(height / 2);
	const totalSize = ySize + uvSize;
	if (
		yStride === 0 ||
		height === 0 ||
		width === 0 ||
		buffer.byteLength - NV12_METADATA_SIZE < totalSize
	) {
		return null;
	}

	return {
		yStride,
		height,
		width,
		fullRange: magic === NV12_FULL_MAGIC,
	};
}

export type FpsStats = {
	fps: number;