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mcc encoder improperly handles cdp sequence numbers #1709

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#1721
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mcc encoder improperly handles cdp sequence numbers#1709
#1721
@programmerjake

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@programmerjake
programmerjake
opened on Jul 9, 2025

the mcc encoder currently tries to use 8 bits split across two bytes, which is incorrect. the correct way to handle it is to use a 16-bit counter:

ccextractor/src/lib_ccx/ccx_encoders_mcc.c

Lines 326 to 334 in 81fdecd

buff_ptr[8] = (uint8)((ctx->cdp_hdr_seq & 0xF0) >> 8);
buff_ptr[9] = (uint8)(ctx->cdp_hdr_seq & 0x0F);
buff_ptr[10] = CC_DATA_ID;
buff_ptr[11] = cc_count | 0xE0;
memcpy(&buff_ptr[12], cc_data, data_size);
uint8 *data_ptr = &buff_ptr[data_size + 12];
data_ptr[0] = CDP_FOOTER_ID;
data_ptr[1] = (uint8)((ctx->cdp_hdr_seq & 0xF0) >> 8);
data_ptr[2] = (uint8)(ctx->cdp_hdr_seq & 0x0F);

according to the specification: https://pub.smpte.org/latest/st334-2/st0334-2-2015.pdf

cdp_hdr_sequence_cntr – This is an unsigned 16-bit integer which shall be set to a value of 1 plus the value
of cdp_hdr_sequence_cntr in the previous CDP. The value of this counter shall wrap from 65535 to 0. For the
first CDP in a sequence of CDPs, cdp_hdr_sequence_cntr may be set to any 16-bit value.

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