Method createCodecContext

src/video_decoder.ts:91–145

(config: VideoDecoderConfig)

	}

	private static createCodecContext(config: VideoDecoderConfig) {
		const inferred = inferCodecFromCodecString(config.codec);
		if (!inferred) {
			return null;
		}

		let codec: Codec | null;
		if (inferred === AV_CODEC_ID_AV1 || config.hardwareAcceleration !== 'prefer-hardware') {
			// https://github.com/opencv/opencv/issues/24430
			codec = Codec.findDecoder(inferred);
		} else {
			codec = getHardwareDecoderCodec(inferred) ?? Codec.findDecoder(inferred);
		}

		if (!codec) {
			return null;
		}

		const codecContext = new CodecContext();
		codecContext.allocContext3(codec);

		codecContext.width = config.codedWidth ?? 0; // Fucky that the dimensions can be optional, but oh well
		codecContext.height = config.codedHeight ?? 0;
		codecContext.codecType = AVMEDIA_TYPE_VIDEO;
		codecContext.codecId = inferred;
		codecContext.extraData = config.description
			? Buffer.from(toUint8Array(config.description))
			: null;

		if (config.colorSpace?.primaries) {
			const mapped = mapColorPrimaries(config.colorSpace.primaries);
			if (mapped !== null) {
				codecContext.colorPrimaries = mapped;
			}
		}
		if (config.colorSpace?.transfer) {
			const mapped = mapTransferCharacteristics(config.colorSpace.transfer);
			if (mapped !== null) {
				codecContext.colorTrc = mapped;
			}
		}
		if (config.colorSpace?.matrix) {
			const mapped = mapMatrixCoefficients(config.colorSpace.matrix);
			if (mapped !== null) {
				codecContext.colorSpace = mapped;
			}
		}
		if (config.colorSpace?.fullRange != null) {
			codecContext.colorRange = config.colorSpace.fullRange
				? AVCOL_RANGE_JPEG
				: AVCOL_RANGE_MPEG;
		}

		return codecContext;
	}

	/**
	 * Checks if the decoder can support the given configuration.