mismatch with spec and Encoder bug related to JVET_Q0471_CHROMA_QT_SPLIT

[hanhuang]

Luma minimum QT size is mistakenly reduced by half in 4:2:2 format coding due to the integration of JVET_Q0471_CHROMA_QT_SPLIT. In the following quoted code, CHANNEL_TYPE_CHROMA should be replaced by chType.

#if JVET_Q0471_CHROMA_QT_SPLIT

minQtSize is in luma samples unit
const unsigned minQTThreshold = minQtSize >> ((area.chromaFormat == CHROMA_400) ? 0 : ((int) getChannelTypeScaleX(CHANNEL_TYPE_CHROMA, area.chromaFormat) - (int) getChannelTypeScaleY(CHANNEL_TYPE_CHROMA, area.chromaFormat)));
if( area.width <= minQTThreshold ) canQt = false;

#else

if( area.width <= minQtSize ) canQt = false;

#endif
#if JVET_Q0471_CHROMA_QT_SPLIT

minQtSize is in luma samples unit
const unsigned minQTThreshold = minQtSize >> ((area.chromaFormat == CHROMA_400) ? 0 : ((int) getChannelTypeScaleX(CHANNEL_TYPE_CHROMA, area.chromaFormat) - (int) getChannelTypeScaleY(CHANNEL_TYPE_CHROMA, area.chromaFormat)));
const bool isQtAllowed = area.width > minQTThreshold && currBtDepth == 0;

#else

const bool isQtAllowed = area.width > minQtSize && area.height > minQtSize && currBtDepth == 0;

#endif

Also, some encoder fast algorithm that determine the min and max QT split depth also depends on the minimum Qt size, which is not correctly changed accordingly.

A patch is attached to fix the issues.

[hanhuang]

fixed by JVET-R0131