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DESCRIPTION
Decoder for ImageFX native IFF format: FORM INGF.
Expected pipeline:
ingf.demuxer (MMF_VIDEO_INGF) -> ingf.decoder (MMFC_VIDEO_ARGB32)
The demuxer provides a synthetic bytestream on its output port consisting
of concatenated IDAT payloads (one per layer). MMA_ExtraData points to an
INGF_EXTRADATA block (canvas size + layer descriptors + per-layer IDAT size).
This decoder:
- Pulls each layer's compressed IDAT block.
- Decompresses using ByteRun1 (PackBits style).
- Reconstructs per-scanline predictor/filter (observed: type 6 = delta16).
- Composites layers onto an ARGB32 canvas (flattened output).
Ports:
- port 0: input (MMF_VIDEO_INGF)
- port 1: output (MMFC_VIDEO_ARGB32)