Add single-image ASTC and KTX 1.0 muxers and demuxers for the
libastcenc codec. Validate the KTX layout, ASTC dimensions, color profile,
and compressed payload boundaries before exposing a packet to the decoder.
Map the KTX 1.0 2D linear and sRGB ASTC formats to the corresponding
libastcenc profiles, and reject unsupported HDR, 3D, array, cubemap, and
mipmap layouts instead of producing ambiguous image streams.
The KTX demuxer turns the KTXorientation key into display metadata, and the
KTX muxer writes the key back, so a stream copied from a flipped texture
keeps its row order. Its srgb option follows the encoder's color profile by
default, and an explicit value that contradicts a known profile is rejected
instead of silently relabelling the texture.
Signed-off-by: Jun Zhao <barryjzhao@tencent.com>
