d263 may contain optional bitr box, and thus its size can be up to 23 bytes

        case FOURCC('d', '2', '6', '3'):

        {

            // d263 contains fixed 7 bytes:

            // vendor - 4 bytes

            // version - 1 byte

            // level - 1 byte

            // profile - 1 byte

            char buffer[7];

            if (chunk_data_size != (off64_t) sizeof(buffer)) {

            /*

             * d263 contains a fixed 7 bytes part:

             *   vendor - 4 bytes

             *   version - 1 byte

             *   level - 1 byte

             *   profile - 1 byte

             * optionally, "d263" box itself may contain a 16-byte

             * bit rate box (bitr)

             *   average bit rate - 4 bytes

             *   max bit rate - 4 bytes

             */

            char buffer[23];

            if (chunk_data_size != 7 &&

                chunk_data_size != 23) {

                LOGE("Incorrect D263 box size %lld", chunk_data_size);

                return ERROR_MALFORMED;

            }